PR #73 breaks temperature dependance

[chetan201]

What's expected - (reverting back to pr #68

What's observed in pr #73 -

[chetan201]

@mikofski
off the top of your head, do you know why this might be happening?
Shall I revert the master to PR #68 meanwhile?

[mikofski]

Yes, it's because we fixed vmax at stc condition. But at -40C, -25C, and zero degrees Celsius, the cell voltage will be greater than it would at stc. So therefore vmax is not high enough.

The fix should be to use the larger of vmax at stc versus vmax at the desired cell temperature.

Reverting to #68 fixes this problem for now, but then recreates the problem where we get weird behavior when there is heavy voltage mismatch or bypass diode activation.

I'm sorry I hadn't considered temperatures lower than stc. It's uncommon to see temps this low but not impossible, eg snowy conditions.

Thanks for bringing this to my attention. Nice catch. Really useful information for me!

[mikofski]

Another fix idea, would be to just pick a 4th quadrant current, like -10A, and just go up to that value always. I'll try to implement one of these two approaches and put in a new PR asap. Until then, yes, I think you would be better reverting to 4943742

sorry!