SV-BAT-320

[mervg]

I understand that the SV backup battery is Li-ion and its cold charging spec is at 0C.  Is there a temp sense in the charging circuit so it does not charge below 0C or do I need to disconnect the battery in a cold soaked cockpit?
If Li-ion batteries are charged at low temps they plate metallic lithium and will eventually develop internal shorts.  I trying to be proactive and not have a 787 like issue behind the panel.

 

[dynonsupport]

There is not a temperature based limit inside SkyView for charging the battery. In 99% of flights, the last flight was a normal shutdown which means the battery is fully charged, and thus is not charging even if connected.

In the case that the battery is not fully charged when the plane is started and the battery is below freezing, then there is some chance of anode plating and loss of battery capacity, however this is mitigated by the fact that we don't charge the battery aggressively, in terms of charge rate as well as the ending voltage. There is an allowable charge rate below 0C; it's not a hard cutoff, and by not charging at max allowable rate we buy some overhead.

The battery does have an integrated safety circuit that monitors the battery voltage and current for any out of spec conditions. This means failures in the SkyView screen/controller are protected right inside the battery and the battery will disconnect if over charged, discharged too far, or if shorted out.

 

[mervg]

Thanks for the useful information.  I will keep it in mind.  BTW, it is -20C where I am at the moment and headed for -30 tonight.