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diy solar

Dead SOK LiFePo4 Battery

bajajoaquin

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Joined
Sep 1, 2021
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46
I was just wrapping up my solar install and my brother got careless with a wire and it sparked short and killed my new SOK 206ah LiFePO4 battery. It was installed and powering a CD player through a fuse block and inverter (thanks Will, for the wiring diagram!). When the wire hit the aluminum frame of the RV door, it sparked and the CD player went dead. No fuses were blown. We installed the old FLA battery, and everything works normally.

Is it possible that the BMS in the battery has prevented damage, and there's something I can do to save the battery? I'm headed out on a trip to Baja California on Wednesday, so I'm limited on time to get parts or send things to service. I have an email in to SOK, but it's Sunday night, so I figured I'd check here as well.
 
Most likely the BMS either went into a protect mode, or may have failed, but the cells are most likely fine. Will has a few videos on the SOK batteries, they do not look too hard to open up, but the first thing to try is just connect a charger as that seems to wake up the BMS out of a protect shut down. If a charger does not wake it up, pop the top off and check the cells and see if they are all still in a safe range. Look for any failed connections, and there may also be an internal fuse.

How full was the battery? I ask this because my JK-BMS will only power up from a charger, if the charger voltage is at least 5 volts higher than the battery voltage. When my battery bank was near full, the 58.8 volt absorb voltage was not enough to trigger it. I found that I could add a 9 volt battery in series to get the needed voltage boost.
 
Yeah, it was his video on the SOK that convinced me to get it.

What charger would wake the BMS out of a protect shut down? I'm happy to buy one if it's available locally. The ones I have on hand are:

old-school transformer 12v chargers
some Battery Tender brand trickle chargers
The Progressive Dynamics AC-DC charger in the motorhome (single-stage 13.6v)
The Rich Solar MPPT 40a controller

I think the battery was pretty low. The MPPT controller said it was 12.8v resting before I hooked up the solar.
 
As long as you only put it on for a few minutes, none of those should hurt anything. Monitor the voltage and don't let it stay over 16 volts for any length of time. If it was fully charged when it shut down, the cells could be as high as 3.5 each x 4 = 14 volts, so a spike to 19 volts might be needed to make it go on. The old school transformer might do it. The rest are too "smart" to let the leads go that high.
 
The trickle charger got confused so I put the transformer on it while I went and got my multimeter. Looks like it did the trick. Thanks.

And by the way, I opened it up and saw no obvious fuses. Just FYI

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