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:

Thursday, August 23, 2012

Battery Pack Balancing Update

The pack balancing is going well, albeit slowly. I have two 180mA current source chargers running all the time balancing the cells in packs that didn't show alerts during the drive. I move them to the next pack when the pack under charge gets to 59 VDC (3.69 * 16). As well as that, I am pulling each of the 5 alerting packs (minus one that was too difficult to remove and responded to 3.5 days of 180mA charging) out of the car, lifting the lid, and charging the low cells with an Individual Cell Charger (ICC).

The ICC is a small PC power supply that has an adjustable 5V, 5A output. It doesn't adjust all the way down to 3.7V so I have two 3A diodes in series and have it set to 5.2VDC. The diodes drop 1.6V at 3A and 1.5V at 180mA so it's reasonably safe to leave unattended. When I pull a pack from the car, I start by measuring all cell pairs then use the ICC on the low cells. I generally find that there are about 12 cell pairs over 3.6V and 4 at 3.3 to 3.4. The 3.3V seem to need about 4 AH put into them. Cells that have been 3.2V have needed up to 17AH. Considering the cell pairs are 20AH, that's pretty discharged.

So far all but one of the packs (the one that had a cell that took 17AH) I have pulled out have had the 180mA treatment before I decided to remove them, but pack #9 which get removed from the car tonight has only had the post-drive charge to 58.4V, (the 3A charger cut back after only an hour) so it will be interesting to see the SOC of the cells.
I only have one of the alerting packs left to pull out of the car, pack #9.

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