Implement charging error detection and handling

[ljungqvistaxel]

When charging batteries, safety it important. The BMS should detect abnormalities like overheating, overcharging and stop charging if sudden changes in monitored data occurs.

Requirements/thoughts:

• Handle temperature that is too high or too low.
• Handle sudden drop or rise in current or voltage.
• Something more?

[ljungqvistaxel]

Effort: 5