This blog documents the restoration, and conversion, of a 1965 Humber (Singer) Vogue to a fully electric vehicle. The Vogue will be powered by an 11kW(modified), 3 phase industrial AC motor, controlled by an industry standard Variable Speed Drive (VSD) or Inverter. To be able to produce the 400 volts phase to phase the VSD will need about 600 VDC of batteries. A big thanks to the contributors on the AEVA forum:

Saturday, December 8, 2012

Pack Balancing and Charger Modifications

With all the manual(ish) pack balancing I do, I had already designed a small circuit that would automatically deliver 3A until the pack's BMS cut out, then dial back to 180mA - the balancing current for my packs. I wasn't looking forward to making these, nor fitting them.
With that in mind I thought I would try again to find a schematic of the Kingpan chargers that I am using. I found a thread on Endless-sphere that (somewhat indirectly - I can't figure out now how I found it) pointed to a site in Europe where a guy (thanks Albert) had reversed engineered some other brand of charger based on a TL494 chip (my favourite PWM controller).

I grabbed the circuit, pulled the lid off one of my spare chargers and - guess what - yes they are practically identical. There are a few resistor values that are different but just about everything is the same. It was relatively easy to devise a small daughter board that used the Op-amp that was driving the transition of a bi-colour LED on the charger to trigger the changer to cut it's current from 3A down to 180mA. The challenge was to be able to do the modifications without having to remove the main PCB from the case - with all the complications of re-seating power devices on heatsinks. I found that the best was was to remove one resistor and solder on four wires to a daughter board. The daughter board is circled in red. The heatshrink gets cut down, shrunk, then glued to the nearest strong component. I'll improve that toroid's mounting too - while I have the Sikaflex out.
Now this charger has built-in balancing tailored to my pack's BMSs.
I don't have to do all the chargers at once, just as I get around to them.

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