[Coulomb]

Incidentally, what gave rise to the problem is that I added two cells to a 40 cell pack. Even with 42 cells, the old programming should cover the charging… It’s a 520V algorithm 133-142V in 1V steps. I have drained the battery down below 134V, and I’m trying to charge it to 142, Which is about 3.38V per cell.

3.38 VPC is quite low. You'd really want to go to around 3.55 VPC, which was 142 V for your 40-cell configuration.

If you're stuck at setting 7 (139 V), then even a battery drained to 134 V (it might have sprung back a bit in voltage) might look too high to start charging. And 139 V / 42 cells = 3.31 VPC, not even at the resting voltage of a 50% charged cell.

I think you will need reprogramming for about 42 x 3.55 = 149 V. Elcon in California could do it (if they are still interested in these older models), and Paul could probably do it. Though he may have a slightly different lithium algorithm than the "520V" (nothing to do with voltage) "curve" or "algorithm". Or you could do it yourself; the instructions and software are on this forum, but it's a bit daunting for most.

It's also possible that your charger's voltage measurements have drifted over the years, so it could do with a calibration. I believe that Paul can do this too, but it wipes out your existing charge program. No problem if it is going to be overwritten anyway for higher voltage.

I believe that your 120 V hardware can go up to 154 V (at full power; 161 V at half power).