Design work
I’m working on firming up my requirements for the Ghia’s performance, and how to best achieve them. Bob Brant’s book “Build Your Own Electric Vehicle” is chock full of formulae for calculating this stuff, but I’m missing some critical numbers for the Ghia (the shop manual hasn’t shown up yet).
At the moment, I’m guessing that I’ll have 10 or 12 Optima Yellow Top batteries in the car, preferably under the back seat (or what passes for one in the Ghia).
The Optimas are sealed batteries and are fairly expensive. Since they’re sealed, you don’t want to overcharge them - there’s no way to put water back into them if you boil it off. This means you need some way of making sure the battery charging procedure is regulated on a per-battery basis.
It turns out that there doesn’t appear to be a well-accepted retail product that you can just buy and install. The closest is something called the Rudman Regulator, but you need a certain amount of electronics smarts to install and troubleshoot them. I don’t have these particular smarts yet.
There’s a product called the PowerCheq, but it’s got a bad reputation on the EV Discussion List. It tends to catch fire, and it can destroy batteries under certain circumstances. It’s also too expensive.
So I’m putting a lot of skull sweat into Internet research and plain old thinking about my alternatives. The EV list has been quite helpful in eliminating some products that aren’t made any more, and the various problems with the ones that do exist today. There was also an amazing message from Lee Hart which described some really simple regulators that even I could probably build and install safely.
I’ve just this evening turned up a reference to an option for a “regulator shutoff” option for the Russco brand of charger, which is apparently a very nice lower cost charger. Strangely, Russco doesn’t appear to have a web presence of any sort - I spent quite a while looking for one. I finally asked for info from Electro Automotive - we’ll see what they say.
I’ve also asked them (and EV America) for some recommendations and calculations on my Karmann Ghia. They both offer to run some numbers for you free of charge. Let’s see if I’ve guessed right so far.
Thu, 04 Sep 2003
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