It's a 12V 100Ah and it has discharged to 8.94V. It will not take a charge. I have tried the trailer onboard charger, connecting to another 12V and finally bought a dedicated Li charger with an "activation" feature. The last was suggested by the battery manufacturer. I don't know how it became so discharged. It was in the trailer and I'd pulled the fuse for the only known parasitic, the LP detector. It has a BT monitor feature that has also failed. Anyway, I'd appreciate any other suggestions for revival.

When my 48v battery discharged to 36v, none of my chargers would work. I finally found a source for 42v in my Segway scooter charger. That was just enough voltage to 'awaken' my shore charger.The point is, any known source of 12v, like another battery, should work for you.

shelbyfv wrote:It's a 12V 100Ah and it has discharged to 8.94V. It will not take a charge. I have tried the trailer onboard charger, connecting to another 12V and finally bought a dedicated Li charger with an "activation" feature. The last was suggested by the battery manufacturer. I don't know how it became so discharged. It was in the trailer and I'd pulled the fuse for the only known parasitic, the LP detector. It has a BT monitor feature that has also failed. Anyway, I'd appreciate any other suggestions for revival.If under warranty I would utilize that feature.If a fixed power supply such as an RV converter will not wake it up there may not be much that can be done externally. May have to open the case and charge the cells directly, bypassing the BMS. This is a tedious process and may need special equipment.

Thanks! The other 12V battery(13+V) didn't wake it up nor did the 14+V Li charger. I'm in contact with the mfg as it's still under warranty. Hopefully they'll offer an exchange. I'll update.

shelbyfv wrote:Thanks! The other 12V battery(13+V) didn't wake it up...That's odd. Good luck with it.. perhaps the BMS is shot. What brand battery are we talking about?

X2 on the warranty route.Most good quality companies will honor their warranties.Sounds like a BMS failure and generally when they fail, getting them to reconnect is a futile attempt at best.In the future, you will need to do more than removing the fuse for the LP detector, it isn't the only thing that draws power when things are turned off..Your RV fridge, 12V radio, furnace and even water heater if DSI all have control boards which are run off of 12V.. Those control boards even when the item is turned off all draw some power.. 12V radio uses 12V to keep your radio stations and memory settings even when powered off.Add in a battery disconnect switch right at the battery terminal, that will 100% isolate the battery from ever single phantom draw of the RV.

LFP/LiFePO battery asleep? | Good Sam Community

shelbyfv
Explorer
Aug 26, 2022
Thanks! The other 12V battery(13+V) didn't wake it up nor did the 14+V Li charger. I'm in contact with the mfg as it's still under warranty. Hopefully they'll offer an exchange. I'll update.
time2roll
Nomad
Aug 26, 2022
shelbyfv wrote:
It's a 12V 100Ah and it has discharged to 8.94V. It will not take a charge. I have tried the trailer onboard charger, connecting to another 12V and finally bought a dedicated Li charger with an "activation" feature. The last was suggested by the battery manufacturer. I don't know how it became so discharged. It was in the trailer and I'd pulled the fuse for the only known parasitic, the LP detector. It has a BT monitor feature that has also failed. Anyway, I'd appreciate any other suggestions for revival.
If under warranty I would utilize that feature.

If a fixed power supply such as an RV converter will not wake it up there may not be much that can be done externally. May have to open the case and charge the cells directly, bypassing the BMS. This is a tedious process and may need special equipment.
2oldman
Explorer II
Aug 26, 2022
When my 48v battery discharged to 36v, none of my chargers would work. I finally found a source for 42v in my Segway scooter charger. That was just enough voltage to 'awaken' my shore charger.

The point is, any known source of 12v, like another battery, should work for you.

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