Low bat voltage conundrum

I have a situation that I am unsure how to resolve. I have 2 mpp solar lv2424 all in one charge controller, inverters, and a victron 75/10 charge controller, all connected through buss bars to 3 24v 100ah lifepo4 batteries.

This setup has been up and running for almost a year. Now, none of the charge controllers will turn on. What I think happened is the battery voltage got low enough that the bms has disconnected the batteries. I have read that you can wake the bms up by bypassing the bms and charging the batteries a bit, but I don't have any other 24v battery charger.

Right now, I have all the solar panels disconnected because I don't want pv voltage going to the charge controller without a functioning battery connected.

Is there another way I can wake my batteries up?

I have no problem buying a 24v charger, and running it off my generator, but not sure which to get. I tried the aims one that was supposed to change 12 and 24v and got burned. I found out that aims was having trouble with that model working with 24v and I had to send it back. If you have a recommendation for a good 24v charger, that would be appreciated.

SeanWatts said:

Is there another way I can wake my batteries up?

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What is the voltage of your panels?

If i were desperate, i would connect a panel (or array) that was close to 28-40V directly to the battery bus bar to wake them up and put enough charge on so that the battery(s) are recognized. Slow and gentle, especially if voltage on the high side above battery voltage.

I would monitor this closely. And of course i would never recommend that anybody else try this...

MisterSandals said:

What is the voltage of your panels?

If i were desperate, i would connect a panel (or array) that was close to 28-40V directly to the battery bus bar to wake them up and put enough charge on so that the battery(s) are recognized. Slow and gentle, especially if voltage on the high side above battery voltage.

I would monitor this closely. And of course i would never recommend that anybody else try this...

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I have some extra panels that I could rig something like that up with.

I have some 100 watt panels that have 22.6 open circuit voltage, and I have some 230 watt panels that are 37 open circuit voltage.

Or, I just remembered I have a couple rc car/truck chargers. Maybe I could set one up to charge 8s for just long enough to wake up the bms. Is that feasible?

SeanWatts said:

and I have some 230 watt panels that are 37 open circuit voltage.

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One of these to the bus bar sounds pretty reasonable.

SeanWatts said:

Or, I just remembered I have a couple rc car/truck chargers. Maybe I could set one up to charge 8s for just long enough to wake up the bms. Is that feasible?

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Absolutely! It may complain because it expects balance wires. But it should work just fine.

MisterSandals said:

One of these to the bus bar sounds pretty reasonable.

Absolutely! It may complain because it expects balance wires. But it should work just fine.

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Awesome! Thanks for your help, crisis avoided.

I just remembered I have another option of a 10 amp variable dc power supply, that I used when I built the batteries. I might set it to 25-26 volts and 9 or so amps, and see if that wakes up the bms. I think it should. If not, I can move to the rc charger, and I am going to keep direct pv to last resort.