I have a weird problem, solar is functional but batteries are dead

Hey all,

My van has been sitting unused for a while as I’ve been traveling. Unfortunately, on my most recent check after a couple of weeks away, I found the two 170aH Li-ion batteries were reading at 0% charge on the solar charge controller.

The only things running in the van were two Maxxair fans, the draw was under an amp, and the batteries maintained more or less full charge right up until now.

I have 7 200W solar panels on the roof connected to a Renogy Rover Li 60 Amp MPPT Solar Charge Controller, currently the controller is reading ~130 volts coming in from the solar panels (it’s a sunny day here, but I’m in England so that doesn’t mean much), but only 1v going into the battery and 0 amps.

The controller is also reading a BAT-LDV fault, which is an over-discharge fault code.

I disconnected the loads and left it for two days but there has been no improvement in the batteries.

I’m freaking out a bit because we’re in the dead of winter here in the UK, and mold is starting to accumulate for the first time on a bunch of stuff. Also concerned the Li batteries will be ruined. I don’t have a ton of time to devote to the van anymore and it’s stressing me out. I have a Renogy Inverter/Charger but I don’t think it’ll work without any load in the batteries.

I built the system myself, and it worked great for 8 months, the breaker between the charge controller and batteries is running a current according to the multimeter, and there’s obviously current coming in from the panels.

Does anyone have any ideas? I’ve also been looking for a forum that specialises in van electricals and/or solar with no luck.

Greetings & Welcome!

With the batteries shut down, the solar more than likely fried the controller. A fairly common occurrence with lithium batteries.

Disconnect the batteries (Disconnect the solar first though!!!) and try to charge them via shore power and an appropriate charger. They might be salvageable but are very likely damaged.

When reconnecting, battery first, controller 2nd, and solar last.

Lithium batteries are far too picky to be a good choice to begin with. (too hot, too cold, over/under charge specs, etc.) Good old deep cycle lead acid is far more reliable, and the lithiums aren’t lasting any longer and many of the warranties are worthless, even from the major sellers. Basically they blame it on you and don’t honor the warranty.

If you can’t salvage them, I’d switch away from lithium.

Trusting solar is questionable to begin with, and trusting it during the winter is even more questionable. With a week of rain, just those 2 fans could drain the batteries dead. You’re better off turning off all loads when away for more than a day. Leave the roof vents open, but not running, and crack your front windows to create natural but unpowered air flow.


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