Electrician's approval

The Finnish Transport Safety Agency, or Trafi for short, requires that all M-class vehicles be inspected by a qualified electrician when converting to electric drive. Yesterday, I had a visit from two such individuals and we filled a form suggested by the chairman of Sähköajoneuvoyhdistys (Electric Vehicle Association of Finland). Most of the time was spent pondering on what we should exactly be measuring, but we figured it all out in the end. All tests passed with flying colours. Next up, the registration inspection.

As a bit of bad news, two of my old 40 Ah cells shot up to well over 4 volts while charging both packs in parallel. I had bottom balanced everything pretty well this time, so either they've lost some capacity before or charging two packs of different Ah does not work as I thought.  I'm sort of leaning towards lost capacity, since I wasn't quite as thorough with my balancing when I did it a couple of years back and I pushed these cells down to 2 volts a couple times, so I may have hurt these two or they were bad to begin with. I had marked these two cells as A and B when I drained them earlier, because they were at a lower voltage than the rest of the cells, which would also suggest that they in fact are lower in capacity than the rest. I'll need to get a couple new cells or figure out another solution. As a stopgap I can always drop the front pack offline by using the service switch, which both front and rear packs now have.