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Old 03-18-2009, 01:11 AM   #45 (permalink)
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Originally Posted by MazdaMatt View Post
Could we select what is the most likely battery choice for a DIY EV and design the charger accordingly? I like the idea of 240/120 and selectable amperage draw.
I agree that these would be the easiest things to implement. A lot of this would all be software related, i believe. A knob for peak voltage and for max current would be pretty easy to do.

Determining when to end charge could be tricky. Typically, you'd wait until the final current drops to a constant level. But depending on the final voltage, that current can range from 2 amps to 5 amps (if you're gassing a flooded LA pack). I think it'd be easy to have a knob for the amount of time (0 to 3 hours) to hold that final constant amperage. The controller could have a software algorithm to determine when the amps drop to a constant value and then hold that for the specified time.

Oh, maybe another knob for float voltage, unless you want to have a thermal probe to adjust the float voltage automatically.

So we're at 4 knobs, and maybe a switch for 120/240.

But, as I'm thinking, this is all software stuff. I've made some progress with the hardware - see below!
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