Taming Lester 2

Today's Lester adventure is that I got brave and powered the charger up at full line voltage while connected to the car's battery pack. Not all at once, of course, I eased into it while watching the gate voltage and current while powering a 300 watt, 130 volt lamp. Now I am really seeing spots. When it looked like there wouldn't be any flying pieces, I installed a 100 ampere DC rated circuit breaker and 12 gauge pigtail that mated with the EV's Anderson connector. The K&W has a mating Anderson connector, so making the switch between chargers was simple. I used to use this connector when I charged the car direct from photovoltaic power (130 VDC @ 8 amps)

I put the whole mess on an old typing table frame, and powered it up at 120 volts first (the Lester has a 120 volt tap on the transformer primary). I was able to push 18 amps into the already fully-charged battery pack for a brief period. I didn't want to fry anything, especially since the Variac I'm using is rated at 10 amps, and it was passing 20.

Next I tried 240 volts, but I had to keep a lid on the current, as the name plate on the charger indicates that it draws 29 amps at this voltage. I did increase the current until I saw 20 amps of battery charge current.

That's about the end of the line until I have the phase control IC's so I can vary the charge current continuously from 0 - 100%, whatever that turns out to be. The Variac won't stand too much abuse, and it makes a lot of ominous humming sounds under heavy load, I don't think it was designed for this much current at such an awful power factor.

Part 3