Mini E drivers charging without an EVSE

Todd and Kari with Mini E #140 just posted a link to a You Tube video with Josh from AC Propulsion.  If you look at 4 minutes and 50 seconds, you can clearly see that AC Propulsion has connected a 30 amp, 120 volt "Travel Trailer" plug directly to the charging cord for the Mini E.  This allows them to charge at 3600 watts at a Recreational Vehicle park in the US.  This is more than twice as fast as the usual 110 volt 12 amp yellow charging EVSE (Electric Vehicle Service Equipment) that Mini supplies in the US.  But I find it a bit odd that they are showing this, because the electrical code requires that drawing current at 100% of a connector capacity (30 amps in this case) should be limited to 3 hours, which is not long enough to fully charge the Mini E.  The code says to limit current to 80% of rated capacity when the load duration exceeds 3 hours.  But then again, AC Propulsion can probably set the current draw to 24 amps in their car, which the rest of us cannot do.  We have to live with 12, 32 and 50 amp settings.  (All of which actually draw slightly less than what the setting shows.)

Then I see that MINI-E Driver Stefan Reitmeier from Germany posted a picture of his car plugged into a wall outlet without an EVSE.  Maybe the regulations are more rational in Germany than in the US?

In any case, AC Propulsion has state of the art safety features built into the charging system in the car.  But only an external EVSE can provide the "dead front" connector to the car.  In other words, the connector face stays unpowered until it is actually engaged in the car receptacle.  So although I admit I have charged without an EVSE myself, we should all avoid it whenever possible and stick to the US rules and Mini guidelines.

It is interesting though.  Someday the US rules may change and charging will be more flexible.

Multiple power sources

An isolation transformer from a surplus dealer in Brooklyn

It has been a week since I posted a blog about the need for multiple power inlets on early electric cars.  I have not heard a single product announcement yet.  What is taking so long?  Clearly I am going to have to explain how to do it.

Let's skip over the most obvious case, where you are charging outside in the winter, you have access to two outlets on different circuits at 110 volts 15 amps, and you have a small cabin heater that you bought from J.C. Whitney or the like.  Mount the heater safely, plug it in the second circuit, then your car is warm when you leave and you don't need to run the built in heater as much, extending your range.  If you have air cooled batteries like the Mini E where the air comes from the cabin, then you have even warmed up your batteries and significantly increased your range.  This is as trivial as it is important.

But now we turn to summer.  You have found two outlets that you know are on different circuit breakers, and you want to charge faster than you can from one 110 volt outlet?  First of all, Mini does not want you fooling around with their research car, so forget it.  But if you have a Tesla, a DIY electric car you built yourself, or an electric car you own, maybe you have some options.  The first and most obvious is the Quick 220 safety box.  This device is simple, safe and reliable.  It can detect two circuits that are on different phases and which therefore must be on separate circuits.  It is available in 15 or 20 amp versions and provides a 220 volt outlet, either the type you find on a 220 volt air conditioner, or a twist lock.  Tesla provides adapters for air conditioner receptacles, DIY types will have to make something.  I don't know what the options are for Leaf or Volt owners yet.  Maybe they will be like Mini and stick to the letter of the electrical code, maybe they will be advocates for changing the code to facilitate electric cars in a safe way.  We'll see.

Quick 220 safety box, Model: A220-20D Version 2

The limitation of this approach is that it does not work with Ground Fault Interrupters.  And just about every outdoor or garage outlet in the US has a GFI.  If you find one that does not have a GFI, it should be upgraded.  So what do you do now?  Or let's say you have found two outlets on separate circuits, but they are on the same phase?  The power is there, but cannot be stacked up to 220 volts.  What to do?

The low tech solution for combining power from two GFI outlets into one receptacle involves an isolation transformer in addition to the Quick 220 box above.  (It can also be used for two circuits on the same phase.)  If one of the GFI supplies is isolated and the neutral side of the transformer output is tied to the neutral of other GFI, then the Quick 220 box can safely combine the two 110 volt sources into 220 volts.  There are lots of things you have to get right:  the transformer has to be big enough, the phasing has to be correct, the neutral wiring is tricky.  It can be done, but don't try it at home as they say.  Get a professional to help.  And watch out for cheap Asian or Indian made transformers advertised on the Internet.  Many are not transformers, they are Autoformers.  The difference is that a transformer has electrical isolation between the primary and secondary windings.  An Autoformer does not.  An autoformer will not work here.  Period.

Topaz 91002-11 transformer 2.5 kVA, Dual Standard Electric F246 Powerstat 7.2 kVA combined variable autoformers with T5587 Choke

Once you do get a transformer setup like this working, your car still may not want to charge.  The Mini E is very fussy about the stability of the voltage source for charging, and this is a good thing.  It prevents charging from undersized extension cords, corroded outlets, and other fire hazards.  Nor would it like the voltage drop across a small transformer.  I do not know, but I would assume all electric cars from reputable manufacturers have similar discriminating tastes in electricity supplies.  So what to do?

There are several options if your car charger refuses to continue charging once it realizes the hokey setup you are trying to feed it with.  I have a large Variac that I used to adjust my 108 volt supply at my work place up to 125 volts to charge a little faster.  I expect that could be used, but it is expensive unless you have access to a surplus dealer like I did.  It might be possible to load the transformer with a electric space heater and turn the heater down as the car ramps up its current draw.  But this could cause you to trip a circuit breaker if you don't get the timing right.

All this is way too complicated for the average driver.  The only reason I bring it up is that it can be done.  And the people who should be doing it are the people bringing us the first generation of electric cars.  Modern electronics can do the combining efficiently and safely.  UL might have an aneurysm, and OPEC will probably bribe UL not to approve it.  But it can be done.  And someone should get working on it.

The one thing electric cars need most but no one is offering

Every electric car, no matter the manufacturer (or start up), is offering one and only one power inlet.

Is this the only way it could be?  Gas cars have only one filler pipe for the gas tank.  So electric cars should have only one power receptacle, correct?

Wrong!  At least in the USA.  Much of the world has 220 volts as their standard supply voltage, which makes for a faster charging process.  But in the USA we stayed with 110 volts even after light bulbs switched from carbon filaments to tungsten one hundred years ago.  Since wires are more or less the same diameter in European homes as in US homes, this means there is less power available from US outlets, even if they are nominally safer.

There are many places in the US where it is easy to find multiple electrical outlets near each other that are on separate circuits. I always used two circuits in my garage in winter, one for charging the Mini E and one for keeping the cabin warm, which helps improve the battery performance greatly.  (Of course the charging circuit was usually the 220 volt wall box and the heater was on 110 volts, but bear with me.)

At my work place in the winter, I used two separate, dedicated 110 volt circuits.  One for charging, one for heating the car.  I have done the same thing when stopping to charge at the homes of several other Mini E drivers.  Plug the car into the charging box and run the cabin heater to a regular outdoor receptacle.

I have seen three separate 110 volt outlets at multiple shopping centers that have reserved parking spots for electric cars.  Truck stops with the "Idle Aire" system provide three 20 amp outlets right next to each other, all on separate circuits.  All sorts of camp grounds have multiple circuits side by side.

There is no reason not to provide a second connector, designed into electric cars, so that you can either run the cabin heating or cooling WHILE charging from a separate circuit, or simply double the charging rate if both circuits are 110 volts.

How to protect against someone plugging two cords into the SAME circuit?  This is a very easy engineering task.  If two circuits are out of phase with each other, they are guaranteed to be on different circuits.  This was the case I had at work, this is the case with "Idle Aire", and the shopping center parking lots.

So, why not provide even more than two power inlets on an electric car?  Actually the limit would be three.  In industrial or commercial locations where power is generally supplied in three phases, three would be the maximum that could be definitively distinguished from each other, and thus verified to be on separate circuits.  Idle Aire provides three outlets right next to each other, all on separate phases. Same in the shopping center parking lots.  The two outlets I had access to at work were on different phases of a three phase supply, although I did not get around to finding a third circuit.

In the long run, two (or three) power inlets in an electric car might not be necessary, but in the short run it strikes me as essential for flexibility.  And I don't hear any one talking about providing it.  This is an engineering crime of omission.  I cannot think of another thing that would improve the flexibility and even viability of early electric cars more than multiple power inlets.

And best of all, I don't see anything in the National Electrical Code or recommended practices of the Society of Automotive Engineers that forbids it.

So here is how it would work.

1) Plug in the first cord, the car starts charging.
2) Plug in cord number 2, and if the car can verify that the circuit is separate from the first, you either double your charging rate or use the added power to heat or cool the cabin, as you choose.
3) Plug in cord number 3, and if the car can verify that the circuit is separate from the first, you again increase your charging rate.

I understand that the coming BMW electric car will heat or cool the cabin from "shore power" but only after the battery is fully charged.  With a single 110 volt supply, that is about all you can do.  But with two circuits, it could be extremely useful at times to condition the cabin temperature BEFORE charging is complete.  I speak from experience.  25,000 miles of electric car experience in the Mini E, to be precise.  Much of it in cold weather.

There is a commercially available safety device that can combine two 110 volt outlets into a single 220 volt outlet.  But for practical purposes, it would be of limited use for an electric car although I have heard of a Tesla driver using one effectively.  These devices are popular for, say, contractors that need to operate a 220 volt floor sander in an older house, or operation of European instrumentation in a US facility.  But for outdoor use with an electric car, the omnipresence of Ground Fault Interrupters (GFIs) makes this "Quick 220" box unusable for the average electric car driver.  It only works without a GFI.

However, a properly engineered electronic interface in an electric car could easily take advantage of multiple separate 110 volt circuits to get faster charge times without special infrastructure installations in the early days of electric cars.  And I don't hear anyone talking about it!  Why?  Has no one noticed?  Are you guys asleep or something?  Hello?  Is anybody out there?  Don't make me do it myself!

Why is it difficult to charge from a generator?

A dual section "Variac", 7 kVA maximum.  For use at 110 volt 12 amps, the minimum safe power capacity required is about 2 kVA.

I heard from other Mini E drivers that charging the car from a generator was usually unsuccessful. I never had occasion to try it, but it seems like a valuable backup plan if you could count on using a generator. So I wondered why it doesn't work. The story goes that large diesel generators sometimes work, but the Mini E always refuses to charge from a small gasoline generator.

I believe the reason is actually a safety feature built into the circuitry from AC Propulsion. The car measures the supply voltage before it starts charging, and then if the voltage drops too much as the car starts to draw power, it will stop charging. It figures you are using an extension cord that is too long, too thin, or has corroded connections or is somehow otherwise a fire hazard.  This is why Mini explicitly says not to use an extension cord.

I noticed this safety mechanism once when I was trying to charge from a 110 volt outlet at a considerable distance. I had some very heavy cable (10 gauge, rated at 30 amps) but even though I was only drawing 12 amps, the car would refuse to charge through this very long extension.  So after a long dry spell, I drove on the grass to get closer to the outlet and found that I could charge if I plugged in directly, or even if I used 100 feet of my heavy cord. But at 180 feet, it would refuse. If I recall correctly, the limit was about 8 volts of drop from no load to full load. More than 8 volts drop and the car refused to charge.

I had a large variable transformer for other reasons, so eventually I tried using it to correct for the voltage drop.  It worked, and I was able to charge the car even using 180 feet of heavy cord.  I would set the "Variac" (as it is called) so that the output voltage was equal to the input, which was about 110 volts. Then as the Mini E started drawing current, I would turn up the knob so that the output voltage stayed at 110 volts, more or less. And the car kept charging.

A Variac usually can adjust the output voltage over a range from +20% to -100% of the input

So my theory is that a small generator would have a significant voltage drop under load. A Variac could compensate for this drop. If someone who is still driving the Mini E has a small generator and would like to test this theory, leave a comment and I will get back to you.  Maybe we can try it sometime.

It might not work, since a small generator would also change its frequency with load. I don't know if the Mini E cares about power line frequency, but it might. And frequency is harder to compensate for than voltage is. The large diesel generators that have been reported to sometimes work for charging the Mini E would likely have less variation in both frequency and voltage than a small generator.

If you are curious about the theory behind this voltage drop measurement, see the technical discussion on Wikipedia about Thévenin's theorem.

J1772 standard plug appears for sale on the internet

Those of us who could not renew our lease on the Mini E had the option of keeping the wall mounted EVSE, which is the safety and convenience interface box for charging.  But since it has a connector that is specific to the Mini E, it is of limited use.

Clipper Creek, the manufacturer of the EVSE (electric vehicle service equipment) supplied with the Mini E has not yet been able to supply an upgrade cord and connector to convert to the new standard connector, called the SAE J1772 connector.  This will be used by the Nissan Leaf, Chevy Volt, and other upcoming electric cars for sale in the US market.

Before giving the links to the connectors for sale on the Internet, allow me to speculate as to why UL is giving Clipper Creek a hard time about upgrading existing 240 volt EVSE boxes to J1772.

One of the UL requirements met by the Clipper Creek wall box appears to be that it is explosion proof, like all electrical equipment that might be installed at a gasoline filling station is required to be.  This means that the enclosure is sealed and air tight.  If the cable were changed and the new cable were not exactly the same diameter, it might not meet these requirements.

Even in your garage, this might be important.  Building and electrical codes usually require that all possible sources of ignition in a garage such as electrical outlets (which can cause sparks), switches, water heaters with an open flame, etc., must all be installed at least 18 inches above the floor, where gasoline fumes collect.  Your car does not emit gas fumes, you say?  Not today.  Maybe tomorrow.  Stuff breaks.  It is better if your house does not explode just because a hose clamp splits in your car.

The kind of spark that can be created from a 240 volt 50 amp breaker in an EVSE it much more intense than what you get from a light switch.  Better to keep it sealed in an air tight box, don't you think?  Not to mention that UL requires these EVSE to be safe around cars powered by lead acid batteries that can emit lots of hydrogen gas.  (If you have one of those, code requires that the EVSE starts a ventilation fan before charging in an enclosed space.  The Clipper Creek EVSE can provide for that too.)

So anyone who is considering converting the connector on your Clipper Creek box, please keep the safety points above in mind.  If you think it cannot happen to you, try typing "house explosion" into Google news.

And of course, the current rating on the new cable must equal or exceed the rating of your EVSE.  Don't go putting a 32 amp cable on a 50 amp Clipper Creek box.

Now, here is what I found for sale today:

70 amp connector and socket, 40 foot cable, $475 from Current EV Tech
The picture at the top of this post came from the above link.  The blog where I originally found this catalog said that Current EV Tech once offered a UL certified J1772 plug from ITT Cannon for over $800.  I don't know if this link is also from ITT cannon, which is a very reputable name in connectors.

32 amp plug only, $450
Not much info on this page, it lists a part number that appears to be of Chinese origin. It might be the same as the one above for all I can tell, but no mention is made of a cable that I can find today.

Like all things electronic, I expect the prices to drop and UL certification to be more common.  Just watch out for the seal going into the EVSE box, try to keep it air tight.

Charging safety

I recently posted some photos of the last long trip we took in the Mini E before we had to return the electric car. This 1000 mile round trip involved charging the car at RV campgrounds. This is technically not allowed by the National Electrical Code, which allows an RV to connect to a 50 amp 240 outlet but does not allow electric cars to charge from them. I generally agree with this regulation, as I am an electrical engineer who is quite concerned with safety.  The old connector design is not particularly safe for frequent use, especially outdoors. RVs are "grandfathered" in, but newer safer connection technology should be required for electric car charging.

Shortly after I posted these photos, Mini emailed a reminder all the lessees that this sort of connection is actually forbidden by the terms of the lease. They said in part "...It is crucial to the safe operation of the vehicle that any equipment not supplied by MINI, never be used to charge or operate your MINI E. This includes any electrical connection adapter for the vehicle, OUC, or wallbox, and also prohibits the use of the OUC or the wallbox in any location not specifically intended for its designed or installed use."

I would not recommend that anyone else do what I did. And I should mention that with one exception, either myself or my wife (who is also an engineer) was constantly monitoring the charging connection and process on this trip. Part of the motivation for trying this was to see if cross country travel could be at all practical in a production electric car. The idea was not to repeatedly take long trips with a research vehicle like the Mini E. My conclusion is that cross country travel is just barely practical if the electric car has AT LEAST a 50 amp BUILT IN charging ability. Note that NONE of the several electric cars soon to come to market offers this. The only exception is the Tesla, which offers up to 80 amps as I understand it. But 80 amps can only be supplied from dedicated EV connections, since the largest commonly available general purpose outlet in the US is 50 amps.

I understand that Tesla has figured out a way to allow their customers to safely charge from the connections available at RV campgrounds, the so called NEMA 14-50 outlets which are also commonly used for electric stoves in the US. But Telsa sells their cars, so they can afford to develop a small travel version of the safety and convenience interface, the so called EVSE box (Electric Vehicle Service Equipment) like our larger Clipper Creek box. BMW is only leasing the Mini E as part of a research project, and we should all respect the constraints this places on what is offered.

But an even larger motivation of posting what we did on our long trip was aimed at the Mini E drivers out there that are doing even riskier things. I wanted to show that you CAN use the Clipper Creek safety interface.  NO ONE should be charging their car without taking advantage of the numerous safety features offered by the Electric Vehicle Service Equipment box, even if you are traveling. Yes, it is big but there is that roof rack available from Mini that I showed in all the photos, without saying one word about it until now. Hint hint!

From the way the news is coming in, this will all be moot soon enough when fast chargers are available in more places. But that will take time. Meanwhile, there will always be people pushing the envelope. The real point of my posting was this: If you are going to break the rules, DON'T CHARGE WITHOUT THE EVSE! ALWAYS USE A SAFETY BOX! Really, Mini is right, please don't break any of the rules. But for those out there who are going to break some anyway, be aware of what is a "mortal sin" and what is a "venial sin", so to say.

And especially, do not ever run 30 amps through the small yellow "occasional use cord". I know there are some who have tried this, but there is a large risk of fire. 12 amps max for the little yellow EVSE!

Four light bulbs = 15,000 miles in the Mini E

There has been an interesting analogy mentioned on a few blogs lately, and I have confirmed the calculation.

The claim is that driving 15,000 miles per year in a Mini E or a similar electric car uses about as much electricity as four 100 watt light bulbs burning all year. You can read Tom's explanation here, near the end of the fifth paragraph. So much for those who say large numbers of electric cars cannot be supported by the present electric grid. Nonsense!

To go further, I am curious how many of those 4 light bulbs I can offset by efficiency measures. So I just counted up all the light bulbs in my house, found out how much electricity this house used last year and got average percentages of residential electricity usage consumed by lighting from a Wikipedia article.

Here is how it works out: I have over one hundred light bulbs in my home, but according to the statistics they are probably only on for an average of 2.3% of the time. My math says this is equivalent to two light bulbs being on all year, one of them at 60 watts and the other at 75 watts. That's roughly 1.2 megawatt hours per year for lighting, or 12% of the total 10 mWh this house used last year.

Even so, since about 93 of my lights are now high efficiency fluorescent bulbs, I am saving about the equivalent of one of those 100 watt incandescent bulbs burning all year. One down, three to go to offset the electricity used by an electric car.

We have only been in our new house for several months, but our electricity usage is trending 10% below last year, even though this summer was much hotter. This is because we keep the thermostat at 78 degrees F in summer and open windows at night if is cool outside. So I figure that saves the equivalent of about another two light bulbs burning all year at 100 watts each. Now I am three down, one to go.

Many other electric car drivers have mentioned that they have installed solar power on their homes, which easily offsets more than all the energy used by their electric car. We have looked into solar power, but here in North Carolina we see a better return from installing a ground source heat pump to replace the upstairs zone of our air conditioning and furnace. So we are doing that now.
I have not run the numbers yet, but I feel confident that we have already offset more than enough electricity to power an electric car. We don't have the Mini E anymore, since they would not let us bring it to North Carolina. But we will probably get another electric car in the near future.

Plus, we will probably add solar power in the coming years. We are holding off for several reasons: While the federal and state tax incentives in North Carolina cover two thirds of solar power installation cost, the market for the production credits has dried up here. I understand that in New Jersey, the Solar Renewable Energy Credits (SRECs) can be worth about 60 cents per kilowatt hour generated. But at the moment there is almost no market for SRECs in NC. Plus, electricity in NC costs about half of what it costs in NJ. So payback times for solar power are longer in NC. In addition we are in an urban setting and have a lot of trees, not to mention a hip roof, all of which is less than ideal for solar power. Still, we believe we can design a good system to generate 3 kilowatts of solar power in the coming years. Maybe more over time if micro inverters that support battery backup systems become available. And of course prices of solar panels should continue to drop.

So in summary the argument that electric cars just move pollution from the tail pipe to the smoke stack is ridiculous. It is easy to offset the electricity used by an electric car.

Pictures from our 1000 mile trip

It has been a couple months since we moved out of the support area around New York city, and had to give back the electric Mini E. But before we left, we took a drive to North Carolina from New Jersey in the electric. That post is here. Now that we are settled in after the move, here are some pictures for the big trip in the Mini E:

This was our first charging stop at Ken's house, charging at 50 amps with Ken's Mini E in the background. (Ken has since returned his Mini E as well, but he still has home made electric Metro I bet.)

The next stop is one of our favorites, Bar Harbor Marina and RV park in Abingdon, Maryland. They are friendly, the fee was $10 (shows as a dump station visit on the receipt), the place is pleasant and shady, and best of all their electric service is well maintained. We had charged at 50 amps at this particular parking spot last winter for three hours with no trouble. This time it was summer and perhaps because it was warmer, the breaker did trip after an hour of charging. No problem, we pulled into an adjacent spot where we completed charging without further interruption. And, the maintenance guy came over to work on the outlet and breaker box as soon as he heard we had trouble. His question about the Mini E was unique, he wanted to know if it could be towed behind an RV and charge the Mini E battery by Regenerative braking while it was being towed. (I wonder what Mini would say to that...)

Our next stop was just as friendly, same $10 fee, at much larger RV park near Washington DC. But we had much more trouble with keeping the breakers on at 50 amps. Ken told me he had charged here also, but perhaps it was in cooler weather. In any case, after plugging in and starting to charge at 50 amps, we heard a sound you might describe as "Snap, crackle and pop" coming from the breaker box for 10 seconds or so. Something was heating up and perhaps boiling off moisture. We noticed this at many campgrounds. It was early in the season, perhaps there was a lot of condensation in the boxes from winter. But the car did not charge for more than twenty minutes before the breaker tripped, and the breaker felt quite warm. This is caused either by wires that are not tight, corrosion on contacts, very old breakers that have tripped many times, or under sized wire. In the picture above, you can see that we tried an adjacent outlet without moving the car, an unexpected benefit of the very long six gauge cable that I added to the Clipper Creek box. In the end we moved to an adjacent camp site that was more in the shade, where we found an outlet that did not trip. This was a frustrating stop, but I did not complain. We did not know at this point that we would have this problem at many more campgrounds.

There were many good stops, some where they asked us what we thought we should pay, and we never had a single breaker trip. We even stopped at one place where they did not want to take more than $2 to charge the car. The stop in Amelia's Court House, Virginia, was just plain delightful. At other stops they insisted on full price like an overnight RV stay (usually around $35) even though we expected to leave in 3 hours, but there was no breaker that would stay on for more than 15 minutes. So much for high price meaning high quality.

One very friendly KOA where we stayed overnight was an interesting situation. They had mostly the older hookups, which are only 120 volts. Usually there are two of the common household outlets (NEMA 5-20) and one Travel Trailer connection, a 30 amp 120 volt outlet. We had called ahead and asked if we could use one of their few 50 amp 240 volt sites for a couple hours and then rent a cabin to stay over night. With the charging problems at our previous stops that day, we arrived later than expected and the 50 amp sites were all taken. (I could have put down a deposit but I would have had to pay the full over night rate for an RV.) We rented a cabin and I did what I had hoped not to do, I plugged into the TT-30 outlet and charged the car at 30 amps, 120 volts overnight. That is fast enough to reach 100% by morning, but the Clipper Creek equipment (shown above) is not set up for 120 volts at 30 amp, so I had to use a direct connection. I have since figured out how to adapt the large Clipper Creek box to 120 volt input, by using an international 240 to 120 volt travel transformer to keep the brains happy but wiring the relay for 120 volt operation. Too late now, I don't have the car to test it anymore! But that night I charged without the safety equipment, shame on me. I have heard of someone charging through the small yellow Clipper Creek box (shown below) at 30 amps, which is literally risking a fire especially in warmer weather.

Instead, I wired the heavy orange cable from the large Clipper Creek box directly to a TT-30 plug and connected to the Mini E without the safety box that keeps the car plug de-energized when it is disconnected. Fortunately no children were up and about by the time we plugged in. It turned out fine, but I won't do that again.

By the way, a county park just west of Washington DC had the newest electrical connections we saw. In the photo above, the NEMA 14-50 is on the left and the TT-30 is on the right. We had very good luck charging here. The fee was more than the usual $10 but less an over night RV stay. At this point we were happy to pay, since we were on the return trip and our previous stop had such bad wiring that we gave up with less than 50% charge after paying $35 for a so called 50 amp outlet that would not even deliver 30 amps without tripping the breaker.

While talking to many campground owners, several of them clearly were thinking this might be the Next Big Thing, and talked about adding charging spots specifically for electric cars. Others, as I have noted above, were completely clueless. I hope someone creates an internet site for rating campgrounds in terms of being friendly to electric cars, having good power that can sustain 50 amps without interruptions, etc.

We miss the Mini E, and none of the soon-to-be-available electric car options get close to that built-in 50 amp charging ability which makes cross country travel possible, if leisurely. It is fun to see that Li-ion Motors, near us here in North Carolina, won part of the X prize. They offer a converted Mini on their web site. I have no idea what the charge time is, they have not answered my email yet. But my daily commute is down from 120 + miles to about 20, so I can bicycle a couple times a week. Maybe I will survive without an electric car for now. Sniff.

This is a little off topic, but in Southern New Jersey the power company PSE & G has been putting up solar power panels on telephone poles. There are hundreds of them it seems. Above you can see one of them right in front of Ken's house, where we charged up many times. These panels use a micro inverter. We have looked into adding solar panels on our house, but we have lots of trees around and traditional solar panels do not like any shade on any panel in an array. A small amount of shade can cause a huge drop in power output because of the way the cells are wired in series. Now that micro inverters are competitive, the partial shade problem is significantly reduced. The only remaining problem is that micro inverters are not yet compatible with battery backup systems. And I for one do not like the idea of spending tens of thousands of dollars on a solar power array that stops producing if the grid goes down. Which is what they do without battery backup. It is a safety requirement, technically called Island Protection mode.

Higher efficiency means more variation in range

It became very clear over the course of over 27 thousand miles in the Mini E that the range is very elastic. If I knew I had to go farther than usual, I was confident I could always do it just by driving slower and more gently than usual. As long as the whole trip was less than 150 miles.

The big point here is that the more efficient a drive train is, the more variation in range there will be between driving aggressively and driving gently.

Here is an easy way to think about it without much math:

Let's say you have a very inefficient drive train that wastes 90% of your fuel no matter how you drive. The greatest effect you could have on your range by driving either very aggressively or very gently might be about 10%.

Now let's say you have a very efficient drive train that only wastes 10% of your fuel, worst case. Then you might expect that you could change your range by 90% depending on how you drive.

The average gas car is not as bad as the first example, but not far off.

The Mini E is not quite as good as the second example, but not far off.

Which is why an electric car can have a large variation in range depending on how smart or dumb the driver is about driving on any given day.

And this is also another reason why smart people with a little experience never ever have range anxiety in an electric car. We always start off in the morning with 100% charge, we know what our cars can do and how to get them to do it. And we plan accordingly.

And if we know we have the range, the Mini E has the performance to make dumb driving (that is, fast driving) a really fun time. But only when we know we can afford it. And then there are drivers who just cannot slow down, no matter what. Well, they are another story.

Maybe I'll cook up a first order mathematical treatment of this assertion about range variation if I can get one or two of my engineering buddies to check my work, and I'll post it in the near future.

By the way, show me a car that always has a full tank in the morning, where the driver never has to go out of the way to get fuel, and the driver never has to waste any time while the car is fueling, and I will show you an electric car.

Why is it that carcinogenic car drivers don't get this?

Even though the Mini E was returned a month ago, I plan a few more posts. One will be the experiences of a friend who drove my Mini E for the last few weeks after I moved out of New Jersey. (He liked it, even though he mostly charged it at 12 amps.) Another will be about the amazing "Variac" and why it became my best friend while charging the car at work. Perhaps the last post will be about the problems some people have reported when trying to charge from a generator and how to work around these problems.

500 miles from home

Our first really long trip taken by charging the electric car at "RV parks" was not always fun. But it can be done. We drove from New Jersey to North Carolina. We did not quite make it in two days as planned, but almost.

The short story is that many campgrounds or Recreational Vehicle (RV) Parks that have 50 amp receptacles do not maintain them well. The screws on the connectors, circuit breakers, and buss bars should be tightened periodically. Breakers that have tripped many times tend to get weak, and trip at lower than rated current. These circuit breakers should be replaced.

Without this maintenance, the circuits can run hot and will not sustain the 100% current rating for 3 hours, which the specifications require. (For more than 3 hours, load must be reduced to 80% of rating. Fortunately, the Mini E draws 48 amps for about 2.5 hours and then current draw decreases for the last 30 minutes of charging.)

We had varying trouble with circuit breakers tripping at almost half of the campgrounds we visited. At one campground, we tried over 6 camp sites before finding a power outlet that would charge the car for more than 10 minutes or so. On the return trip, we gave up completely at one campground and left with only 50% charge because no circuits would stay on for long.

For this and other reasons, our travels took a bit longer than planned. Of course the best course of action when a 50 amp circuit will not support 50 amps is to reduce charging current to 32 amps, and get where you are going later than planned.

Disclaimer: The US National Electrical Code does not approve of operating Electric Vehicle Service Equipment rated over 1500 watts (which is the size of the Mini E slow charger) unless it is permanently connected to a circuit that is rated at 20% higher amperage than what the car draws. The fact that RVs are allowed to connected through a NEMA 14-50 connector at 240 volts 50 amps, while an electric car is not allowed to do so, might be thought of as a Grandfather clause. The NEMA 14-50 connector is old and not particularly safe for the general public to use on a daily basis. It is not so problematic when hidden behind your kitchen stove for 10 years at a time.

Anyone employing such unapproved uses should be well trained and carefully monitor the connections while charging a car. Really, it should not be done at all. Hopefully we will have purpose designed charging infrastructure more widely installed soon.

I have heard that Tesla supports charging through a NEMA 14-50 plug. If that is true, I am curious how they do that with the electrical code as it stands today. And Tesla has quite a few more options for setting the charging current. It would be nice to be able to reduce current to 40 amps in the Mini E for instance.

The bottom line on our trip is that traveling long distances by electric car is possible now. It takes a lot of planning, and the first trip might be troublesome but once you learn which campgrounds to avoid, it can be very pleasant albeit slower than piston powered travel. We enjoyed driving a couple hours and then stopping for a couple hours to hike, eat, nap, or whatever before heading out again. That is, when we were at well maintained camp grounds.

Oh, and bring bottled water. Don't trust the well water at campgrounds.

Yeah, and as other bloggers have mentioned, the only 240 volt receptacles at campgrounds in the US are those that are nominally rated 50 amps. The 30 amp receptacles are 120 volt "NEMA TT-30" and cannot be used with the Clipper Creek safety box. 20 amp receptacles are always the standard home style (NEMA 5-20) plugs. We did use 20 amp outlets at motels with the slow charger. More and more motels seem to know where their outdoor outlets are and are OK with them being used.

Three quarters through

 After eight months and almost 20,000 miles, I am three quarters of the way through the one year lease of the electric Mini. And I am happier than I expected. The driving experience makes even "luxury" cars seem primitive by comparison, not to mention stinky. There have been issues with the Mini E but most are in the past and issues are to be expected with a prototype.   Due to the issues I have experienced, Mini has waived several of the lease payments so I cannot complain at all about the expense.

I continue to easily get 120 mile range with just a little caution even in the cold weather.  Although, to get this range in the cold I should not have to use an auxiliary space heater to warm up the battery while it is parked and charging.  But the car is a prototype and this is a small concession that will not be needed in production models.  And being from Minnesota, plugging in a heater in the car is only natural when the weather is such I am putting on wool underwear anyway.

They are still working on the built in cabin heater. I use it on short trips when I don't need 100+ mile range. The built in heater was very strong at first but quickly went weak. They replaced a control module and some wiring a month ago and it was wicked hot for 6 days. Not very long.  Then it got really hot only half of the time, so it went back in for service. They sent it to northern New Jersey for a complete tear down of the heater. This time they replaced the heater core and some more wiring.  They claimed it measured between 130 and 150 degrees F at the vents when they were done, but when I picked it up it was lukewarm again.  I have tried it a few times since and every time it has been quite hot, but they understand there is work to be done to get the heater right.  I think they said they now have my old heater core in one of the engineering mules and are evaluating what is wrong.

But the big problem for a small number of us with high voltage from the power company is fixed. Charging problems are a thing of the past.

Compared to the other options out there, I don't see anything close to the Mini E. The Leaf has a shorter range and does not have complete thermal management for the battery, so I might as well stay with the Mini E which I know how to manage manually. The Volt has absurdly short electric range, especially after I have been spoiled by the Mini E.  Plus the Volt still  carries around a big can of cancer causing poison called gasoline.  That's is what I'm trying to get away from!  And the upcoming BMW electric does not present the air of humility that I look for in a car, if you can forgive me for getting subjective.  So if they offer to let me extend the lease on the Mini E, I will try to hang on to it for as long as possible.

No more charging problems, heater still an issue

The electricians came by today and  installed a buck transformer which lowers my charging voltage to 240 volts from the unusually  high 252 volts that I normally have.  This should be end of my charging problems.

The transformer (really an autoformer in this configuration) is branded Acme.  If you can believe it.  It hums quietly.  My wife hates things that hum.  But I can turn off the breaker when I'm not charging the car.

 Acme?  Not Sola?  Not Square D?  I wonder if Grainger carries Acme?  Or Graybar?  Well.  Interesting.  Anyway.  I'm trying not to look at the country of origin sticker.

I had the car in for 18,000 mile service last week.  They fixed the heater.  It was wicked hot for about 6 days.  Now it has gone lukewarm again.  I guess those folks at Behr have a ways to go up the learning curve on high voltage electric heaters. 

They also put in my fourth PEU.  This one does not hum.  The old one hummed loudly.

All in all I am happy.  Big snow here in Jersey.  Lots of fun.  And the E is moving again.  Yea!

UPDATE:  OK, my electrician assures me that Acme is well known and respected brand in transformers, and it is labeled as made in NAFTA, if you catch my meaning if you get my drift.  But I couldn't resist the chance to invoke Wile E. Coyote again.  He became my alter ego for a while there.

All the cabin heat you could want and no range decrease

There is a report that a new Electric Vehicle planned by Volvo incorporates a liquid fuel cabin heater:

Volvo EV uses E85 for Cabin Heat

What I find interesting here is the comments after the article which make it clear this is far from a new idea.  I was aware of the old air cooled VW Beetles in the 1960s that had accessory cabin heaters which burned gasoline.  (I heard descriptions of these heaters failing which gave new meaning to the phrase Flame Out.  As in flames coming out of the dash vents.)  But several 1990 vintage EVs also used some variety of liquid fuel cabin heaters as do many (most?) contemporary EVs in Norway, where there are a lot of EVs.  Hmm, does that oil producing country know something we don't?

I'll stick with the long underwear and wool socks, thank you very much.  But great idea.  Even the Corvair used a liquid fuel cabin heater.  (I didn't know the Corvair had an air cooled engine.)

Does anyone know if E85 burning at atmospheric pressure in a simple furnace type of heat exchanger burns more cleanly than under the crazy cycles of a piston engine?  I assume so.  Now where does the heater exhaust go in an automotive package?  I presume a tail pipe, not a chimney or (God forbid) the cabin?

Still, liquid fuels are efficient at providing heat and electricity is efficient and smooth at providing motive force.  Use the best tool for the job.

The elctricians are coming!

Got the call from Franklin Electric today, the buck transformers arrived.  They will be by next week to knock my line voltage down to 240 volts from the 252 volts that PSE&G supplies.  This will be the end of my cold weather charging problems.

I have heard that voltage tolerance is actually a regulatory function, meaning a political decision in the local area.  A friend up in upstate NY who works for the power company says they can deliver plus or minus 10% of nominal, which surprises me.  (Nominal being 120 or 240.)  If I recall correctly, the good folks at quick220.com were telling me that the Arizona utility they talked to aims at plus or minus 5% for class A service, meaning not at peak load in the summer.  Class B service is plus 5% minus 10% tolerance.  This makes sense.  I have seen minus 10% at work in the summer, which works out to 108 volts.

Another PEU bites the dust

I was getting close to 18,000 miles. My third Power Electronics Unit has hummed while charging since they installed it. At my last regular service I mentioned the humming but they did not change the PEU.

When Mini engineering visited my home to diagnose the cold weather problem with fast charging, they agreed the humming was not good and directed the dealer to replace my PEU as soon as I could bring it in.

Well, a busy month at work meant I put off going in for service until the regular interval. Friday night when I got home with an ambient temperature of 18 degrees F, I had more than the usual trouble getting the car to start charging at 50 amps because of the cold. After about a dozen attempts to get it to start charging, the humming got extremely loud, the lights in the house dimmed (my wife noticed that upstairs) and the car cut off charging after 5 seconds as usual. I stopped trying to get the car to charge.

I dropped it off at the dealer on the weekend with red tape over the charging port and warned them not to try to charge it until the PEU is repaired. The contacts on the plug and the charging port are dark now, as if it got hot.

Maybe too much attention was paid to over voltage cutoff for safety, since an overly aggressive threshold is what has caused a cold weather problem with the fast charger for a few of us. And the AC Propulsion box has its own over voltage safety cutoff also. Maybe a fast electronic cutoff for over current conditions would be in order. The circuit breaker in the electric panel is enough for human safety but may be too slow to protect the connectors on the car. Over current cutoff might be a good feature for Clipper Creek to add to the wall box.

Hey, I'm glad it happened to me. A civilian might have been upset. I do similar stuff at my job so this does not bother me at all. I actually find it to be gratifying when I find a new problem of this magnitude. I bet Mini and AC Propulsion both learn a lot from this. And I bet nobody else ever has this happen to them. Seems like a one in a million failure mode. Good thing to find and fix before they make a million electric cars.

Some car heaters are dangerous, but this one looks safe

I bought a space heater for the car and posted a link awhile back. The thing was made in China and it is dangerous. The fan stopped, the coils started glowing red and smoke came from the plastic cover. It does not appear to have an overheat shutoff like every hair dryer.

The older heater I got from Napa years ago seems very safe but appears to be discontinued. I hear it cycling off and on as the car gets very warm, so I know the safety sensor is working.  I suspect it was from ZeroStart, which is a Canadian arm of Phillips Tempro.  They still offer a better model with a metal case:

900 watt 120 volt car heater from JC Whitney 

Looks to be around $110 but if it does not set my car on fire, it might be worth it since keeping the batteries warm is giving me Great Range!  Every one else is complaining but I am getting the best range I ever have even in this cold.

The northern Europeans seem to have more choices for car interior preheaters.  They cannot afford to warm their cars up by idling since the fuel prices are higher there.  But the DEFA brand of heaters does not seem to be available in the US.

Let me count the ways...

In our neighborhood in the winter, many people idle their cars in the morning to warm them up before leaving.  And since most cars run a rich fuel mixture when cold, the neighborhood smells like an oil refinery in Louisiana in the summer.  It Stinks.

This is not the only reason I love the Mini E, which does not contribute to this problem.

We heard today from someone who has an autistic child in the family that living within 3 miles of a major highway is a significant risk factor for having an autistic child.

This is not the only reason I love the Mini E, which does not contribute to this problem.

There was a report recently about the health problems caused by dust from automobile brake linings, which are still severe even though asbestos is no longer used.  I for one usually walk 3 miles a day but I cannot walk near busy roads or my eyes get irritated.

This is not the only reason I love the Mini E, which hardly contributes to this problem because of regenerative brakes which create no dust.

And don't even get me started about OPEC, geopolitical stability, global warming, and on and on and on.

These are not the only reasons I love the Mini E, which does not contribute to these problems.

Back when I did my long commute to work in a gasoline car, I was often exhausted by it.  Now with the vibration free and noise free and fume free Mini E, I am rarely fatigued by the drive.

Should I go on?  I think the point is clear.

There has been a lot of discussion on this blog about the issues with the Mini E.  They are minor minor minor compared to the advantages.

What really bugs the Boss

Now that the charging problem is (soon to be) behind us, I got my wife to drive the Mini E again.  She had been a big fan and always wanted to drive it.  If it is the gas car, she never wants to drive.  But awhile ago she soured on the Mini E and I assumed it was the charging problem, which is now over.

But that was only a small part of it.

So she drove the the store the other evening while I was the passenger.  Short trip, lots of charge, cold night, so what do I do that I never do on my long commute to work?

Turn on the heater!

And what does the heater do that is very reminiscent of a Microsoft product or device?

It crashes!  It was very warm for several minutes and then ice cold.  And nothing I did with the knobs made any difference once it went cold.

And my wife's tone made it very clear that this is why she has soured on the car.  I recall once several weeks ago she eagerly took the Mini E to choir practice, about 25 miles away.  The heater crashed on her, and she froze.  Never since has she wanted to take the Mini E.

I suspect the PTC design (positive temperature coefficient) is simply unstable and if the fan is too low for the heat setting, it cuts off.  But I will have to take some data.  I think Robert pointed this out first, and I recall Tom agreeing the heater was not dependable.

I don't know if this problem is in just a few cars or all of them.  Or something wacky like the charging problem that arguably had to do with outside variables.  (Any Mini E would have had that charging problem at my house probably.)  I suppose I have to head over to the Facebook discussion group and see who else has observed this issue.

I do know that if there is any hope of extending the lease on my Mini E, it will only be possible if Mini can make that heater dependable.  Because my boss likes to be toasty warm and does not like to have to think about a fussy heater when she is driving.  And that is the way it should be.

Diagnosis - high voltage

So the team from BMW came by last week to verify their plan of adding a buck transformer to lower my line voltage.  Yes, of course it worked to fix the problem with the fast charger not starting.  The electrician will be coming back in a week or so to install the smallish transformer permanently.

I assume the six of us with this problem all had positive results from this test.  This is really a work-around and not a root cause solution, but it is good enough for a prototype program.  The bigger question in my mind is whether the analysis they have done explains what Mike and myself and others have observed:

1) Waiting will allow the car to start charging even if the line voltage is still higher than nominal.

2) The problem is worse in the cold regardless of line voltage.

3) When the voltage is really high and the temperature really low, there are three stages of symptoms:  No response at all, then after waiting awhile the car will blink once and wall box will shut off with the red light, then wait longer and the car will blink several times before stopping while the wall box stays on.  Eventually if you wait long enough the car will charge normally.

Of course this might only be if the garage is warm enough and the only real variables are voltage and temperature.

But hey, the problem solution is complete.  All I care about is soon I won't have to turn on the 8000 watt sauna heater in the basement to pull down the line voltage far enough to get my car to start charging.

But the good folks at BMW might want to dig a little deeper.  Cold weather performance is what separates the Men from the Boys, as they say.

Happiness is a warm battery

Everything is fine now, the batteries thawed out nicely and stayed warm enough with the portable heater on the floor to charge all night.  I left for home with 85% charge today.

And now I have an analysis target for that annoying monster of data that I have in my trip logs.

I am going to troll through that data and see if the temperature of the batteries on departure is related to the range.  Most people are complaining about a big drop in range in the cold, but not me.  And as far as I can tell no one but me is preheating the car from shore power and thereby keeping the batteries really warm.

Of course, I just had the one glaring exception of last Saturday when the batteries got so cold that they stopped charging from the slow charger.  (I suspect the fast charger would cause enough self heating of the batteries that they would not have stopped charging at 10 degrees F ambient temperature.)

I expect that the data will show the range hardly affected by the cold weather as long as the batteries are warm.

Dogged the cold "bullet"

Drove to work last Saturday, the first time I have driven very aggressively in the Mini E. On arrival I had 15% charge left, batteries up at 90 degrees F, and the forecast saying ten degrees expected that night.

Plugged in the car on the slow charger, but with only a few hours at work and much lower charge than usual, it was clear I was leaving the Mini E over night and driving my gas car home for the 65+ mile drive.

I left my 900 watt 120 volt accessory cabin heater on the timer to run 30 minutes on and 30 minutes off all night. But I did not have a good feeling with the low temperature forecast. So I went back on Sunday and sure enough, it had stopped charging at 40% and did not want to start charging again.

Driving around the parking lot, I had the symbol with the thermometer in a gear on the dash. The book says that means the battery is too hot (there was no regenerative braking) but I think it also comes on when the battery is too cold. The dash display said 56 degrees F but someone says that is the warmest battery pack, I suspect some packs were too cold to charge.

When trying to restart the charging, the car would blink several times and then the safety box would cut off with a slow blinking red light. I think it was labeled "charging fault" but I did not pay much attention.

I turned on the built in heater AND plugged in the 120 volt accessory heater full time, and for a while I aimed the accessory heater straight down the vents to the battery packs, switching back and forth between the two vents.

After this heating, the charging would start and kept going for over an hour. The battery temperature on the dash display came up to 59 degrees. So I went home, leaving the accessory heater running full time all night in the Mini E. I'll see if the car is still charging in the morning.

I knew when Mini said you have to have a garage for this car, they meant it. A prototype with an air cooled battery is not up for New York Metro area winters outside. I was afraid I was headed down the path that some others have reported with a hard failure and weeks with no word from service. Maybe I still am, tomorrow will tell. But next time I leave it outside on a cold winter night, the accessory heater is staying on full time. Part time is good enough for in the garage only.

But I am completely confident that the production electric cars with liquid based temperature regulation for the battery will not have this problem even parked outside.

Heated seats and blankets

When we visited Ken last week to charge at his place on our trip, he mentioned that a heated seat would be nice in the Mini E and probably use less power, thereby not reducing the driving range as much as the cabin heater.

Now, I like to brag that I don't use the heat on my 120 mile commute but I admit it is getting a little old.  And it turns out there are many 12 volt electric blankets and heated seat cushions on the Internet for sale.  The hard part is finding one that specifies the amount of power it draws.  The Mini E has only one 12 volt outlet that I can find, which is limited to 200 watts.

Here are some that do specify power drain:

60 watt heated blanket

45 watt heated seat cushion

80 watt 12 volt blanket

I think I am going shopping.  I might have to retire my hot water bottle if one of these work.  But then I won't be able to call myself a Manly Man anymore, using a sissy heater...

Does wearing wool underwear qualify one as a Manly Man?

Buck Boost transformers

A few posts ago, I speculated about a way to lower the AC power line voltage for those half dozen of us that are having trouble with the fast charging in cold weather. It is clear that the problem is related to a supply voltage that is slightly above nominal. The car should accept this voltage and indeed it does but only in warm weather. So OK, great, we found a small problem that AC Propulsion and Mini can fix before the production car comes out. But the problem remains for six of us in the frozen north.

The cost of a transformer that can sustain 12,000 watts for my 50 amp charger is prohibitive, as is the size. It occurred to me that all that is needed is a small transformer with a 12 volt 60 amp output, wired to oppose the 240 volts from the power company feed. This is only a 720 watt transformer, much cheaper and smaller than 12,000 watts.

Well, none of my engineering colleagues had heard of this but everyone thought it should work, at least theoretically. (None of us specialize in power transmission, so what do we know? Nada.) When drawing up my idea shown above, I looked around the net and behold, there is an entire class of such devices called Buck Boost transformers. Technically they should be called "autoformers" since the primary and secondary windings are connected.

Whatever.

I got the call today, Mini is coming by next week to either fix my charging problem or at least test a fix. I suspect they already figured out the Buck Boost Autoformer option. We'll see.

And yes, the National Electrical Code has a whole section on how to wire the things. So it is all kosher. Well, maybe not the switch I show in my fantasy schematic. That would let you easily go back to the higher voltage in summer and charge a few minutes faster. But I have not read the code in detail to see if it is allowed. I bet not. But theoretically it should work without burning down the house.

Public power for electric car charging

I have heard there is public access to power for slow chargers (so called "level one" charging) in Washington DC but we did not look them up on our trip. However I have seen them at the Lehigh Valley mall in Allentown PA and I hear the Saucon Valley mall and King of Prussia mall also has them. The security people have the electric Gem cars for patrolling, and a few spots are reserved next to their parking spots with 20 amp 120 volt GFI outlets by each one.

The photo was taken on Christmas Eve at Lehigh Valley mall, so it is not too surprising that someone parked in the spots reserved for charging electric cars. I will contact security at the mall to make sure a charging spot is available before driving the Mini E there and charging. These spots are just to the left of the Apple computer store, which is to the right of the photo frame.

It would be fun to get two or three Mini Es to go together and all charge at once.

The first LONG trip

We got the roof rack and cargo carrier on Mini E #458 and headed off for the New Year's holiday. We stopped and used other fast charger's along the way and then the slow charger when we were far from New Jersey. Thanks to Ken and Amy, Joyce and Tom, Stephen and Phyllis and others for letting us charge on the way. I guess 200 miles in one day is not that much but without public infrastructure for fast charging, it was an adventure.

Not much impact on range from the roof top cargo carrier when driving reasonably slowly. Still getting 100+ plus mile range by also taking it easy on the heater. A lap blanket does wonders in addition to tricks mentioned in earlier posts.