Avoid giving free energy at the end of a grid outage

[brtietz]

The check_SOC() function in capacity_t was written before the grid outage code, and didn't expect the SOC limits to change dynamically during the simulation. Therefore at the end of the grid outage, the check_SOC() function granted the battery some free energy.

Changing the function means that the charge value is only adjusted when the current is adjusted, and the battery doesn't spontaneously gain energy without charging.

Test file here: ssc_1270_test_case (2).zip
Expectation is that the grid outage will end a few hours before the battery recharges above 10% (even though the minimum SOC is 30%.

Fixes #1270

[sjanzou]

Maybe one more test to update - seems consistent on all platforms

[brtietz]

Thanks for flagging! I also realized the max SOC code required the same change, so have updated the test file and the manual tests to deal with that case.

[sjanzou]

Thanks for updating the tests. The max SOC seems to work without the "free energy" results now!

[dguittet]

It makes sense that the charge in the battery doesn't change unless there's some charging or discharging