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Charge controller won’t awaken dead LFP battery

troymanz

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Dec 24, 2021
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I currently live in my van which is outfitted with 400W of solar, a Renogy Rover 40A charge controller, and a SOK 206aH battery. Had a few days of cloudy weather and the battery died this morning (reading 0.7V on the charge controller). The sun has since came out and now the charge controller says the battery is at 1.4V but gives no indication that the battery is being recharged.

The battery has overdischarge protection and the Renogy charge controller says it has a function to awaken dead batteries, but I’m uncertain if the battery is permanently damaged or if there is something I need to do to get my solar system to charge the battery. Any help would be appreciated
 
The BMS has tripped. Use the Renogy function, or you likely need to connect it to a consistent 12V source.

The BMS is there to protect the battery. Unlikely any measurable damage has occurred. The cells are designed to go down to that level thousands of times.
 
On another note, your solar is probably woefully inadequate even when it's sunny. Flat panels on a roof do well in Winter to harvest about 40% of what they do during Summer. You should have an alternate means of charging the house battery from the Van's 12V system.
 
Thank you! I connected a battery charger and that’s all it took to reset the BMS trip. The charge controller took over from there. Odd that Renogy claims the Rover 40A can awaken a sleeping LFP battery on its own… maybe that’s under different conditions? I’ll write to Renogy to find out more.

Good point about winter vs summer and having a backup like alternator charging. We at least made it through the solstice without any issues. I failed to mention that running an electric heater for a few hours is what initially depleted most of the battery. Won’t be doing that ever again!
 
Oof. Electric heat is devastating. The only tolerable way we've found is an electric blanket UNDER a big thick comforter to keep the heat in. It's the only way I can get my wife to tolerate me leaving the RV furnace on 50°F at night. :)
 
Usually the rover will not fire up unless the battery is putting out sufficient voltage.

I might be wrong, but I believe that the rover is "powered" by the battery pack, not from incoming solar.

Long term, it is worth looking at an alternative solar charge controller because the settings built in to the one that we set up for a customer"s van weren't really correct and we could not change them.

The only reason that we used it was that the customer already owned it and insisted. If I knew then what I know now, I would have just purchased a different controller and thrown that thing away. Would have cost me less money than it did trying to get that thing to work right.
 
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