25 October 2009

Brown out protection

We had a visit yesterday during the rain from Don (#364) who stopped by for a recharge. While we were eating diner, I noticed the lights dim for a second. This is not unusual during a lightning storm, but I went to peek at #364 and sure enough, the Clipper Creek box was doing its job and stopped charging for a minute. A few mintes later it restarted automatically. I had not witnessed this before.

This is a built in feature of the Clipper Creek box that goes beyond what the Society of Automotive Engineers require in specification J1772, which governs Electric Vehicle Service Equipment. The interface box (EVSE) detects brown out conditions (probably due to a lightning strike or someone hitting a power pole in the rain) and suspends charging for a random time, making it easier for the utilities to get power back up to specified voltages.

This is not a big deal yet, but when there are millions of electric cars on the road, this will be one of several Big Deals for power grid stability.

And you guys that are complaining about the empty space in the box (many on the Tesla forums) - the Clipper Creek box was designed back in the 1990s in the era of the EV1 from GM. Back then, the electronics to do all the safety functions took up all the room in that box. They redesigned the electronics onto a smaller board when this second wave of EV's started, but with the low volumes at present, it does not make sense to tool up a new casting for the enclosure when the old one works.

And I wonder if maybe the extra room in there might come in handy for the Vehicle to Grid functions that are coming, and other smart metering that can save us money as drivers? We'll see.

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