Battery Question

Bradymydog wrote:

pianotuna wrote:

adamis wrote:
I don't understand these arguments at all...

If you have a LiFePo4 battery and camp in extreme cold weather, move the battery to inside the camper. Problem solved...

Take it out of storage at -37 and let me know how that works for you.

It is fine if one were full time.

I'm still waiting for FWC to describe the power system he uses.

If I were to take mine out of storage at -37, assuming the batteries had some % of charge remaining, I would:

1. Shut off/disconnect any charging devices - solar, shore power, DC-DC charger, no genny running.

2. Start the furnace. My 2 BB batteries are inside the conditioned space and have a heat duct discharge adjacent to the batteries. Let the furnace run for 24 hrs. while monitoring the battery temp via my Victron BM712 and an external digital thermostat next to the batts. My external digital thermo switch, serves a double duty as my Victron DC/DC charger generates considerable heat, so I installed 2 small 4" fans which are set to come on at 30C. My BB batts do not have built in heaters which are available.

3. Once I'm confident the internal battery temp is above 32F/0C, I'd start charging them.

Note: If attempting to charge cold batteries, according Tony discussions with BB, the BB internal battery monitor will disconnect at 25F to prevent damage to the batteries. To reset the internal BM, just disconnect/reconnect the negative battery cable.

On a side note, the coldest I've ever experienced was during an extended business trip to Prince Albert, SK. I'm not sure I'd personally want to camp in that weather but with adequate preparation, it should be possible.

if you bought quality LFP you wouldn't need to disconect the sources of power as the BMS would have already done that internaly. most have a internal reset, dont know for sure why battle born went with one that needs a total reset of the BMS... maybe when they started it was all there was..

the one I have ordered disconects at what ever I set it at so I could put it at -3C and set the reconect at 0C so when it hits -3 it will automaticly shut off charging ability and when it warms up to 0 it alows charging again.

there are newer ones you can buy that have heaters built into the battery case and the BMS will automaticly shut off charging of the battery but reroute the power supply to the heaters untill they hit a spicifc temp then start charging the batteries. so if you have solar, in the morning when the sun starts coming out and you have 0.5amps of power, this could be warming the battery for an hour then when the real Amps start flowing you charging. for a truck camer who boondocks in the winter I like this setup if you dont want to move the batteries inside the conditiond space. just do some nice foam insulation around the batteries to mak the warming more efficient and I dont think it would ever be to cold to camp.

Steve