LFP/LiFePO battery asleep?

[shelbyfv]

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.

[time2roll]

shelbyfv wrote:
Renogy determined the battery was defective though they didn't say what specifically was wrong. They offered me a replacement or a full refund, even though the time frame for a refund had expired. I chose the refund because my plans for the trailer have become uncertain. Anyway, I think that's good customer service. All done via email, I never tried to call them.

I doubt they know what is wrong. Just no worky.

[pianotuna]

Shelbyfv,

That's an excellent result. Well Done!

[shelbyfv]

Renogy determined the battery was defective though they didn't say what specifically was wrong. They offered me a replacement or a full refund, even though the time frame for a refund had expired. I chose the refund because my plans for the trailer have become uncertain. Anyway, I think that's good customer service. All done via email, I never tried to call them.

[jaycocreek]

Let us know what the problem was....

I accidentally shorted my stand alone 100ah lfp battery..It was dead with no power at all..I thought this was an expensive mistake...lol..But I hooked my Noco genius 10 amp charger to it and it popped right back on like nothing had happened..The BMS must have saved me and the Noco charger woke it up..

[shelbyfv]

FedEx picked it up today, will be returned to Renogy for postmortem.

[shelbyfv]

Today they say they will arrange to pick up the battery and test it. Replace it if found to be defective. Hopefully they will let me know what the issue is, we'll see. I'll update, though I figure it may take awhile.

[3_tons]

Thanks for the kindly update 🙂 It would be great to know what the issue here is!

3 tons

[shelbyfv]

Update- Email today from Renogy asking me to try something I've already tried, connecting to a Li specific charger with activation feature. Hopefully just a miscommunication and not foot dragging. Guess we'll see what tomorrow's email brings. Reinforces my opinion that it's better to buy through Amazon if that's an option. No hassle returns....

[3_tons]

time2roll wrote:
Yes. Load disconnect does work on some. After disconnect period go direct to charging.

May charge at very low current until the voltage comes up. The BT app should work if the BMS wakes up.

X2, disconnect, wait 15 seconds, then re-connect and try a charge..

3 tons

[Flapper]

I'm with the "failed BMS" suggestions. Such a low level of discharge permanently damages the battery, with no recovery possible. BUT, a reputable company (such as Renogy) should have a low voltage safety built in to the BMS - preventing over discharge. So no matter which issue - failed BMS or over drawn cells, it should be a warranty item for them to replace....

[pianotuna]

Shelbyfv,

I hope this works out for you.

[2oldman]

shelbyfv wrote:
I really liked the battery. Twice the capacity of the old one and so much lighter.

And no water or corrosion. They are nice.. but can be finicky!

[shelbyfv]

The person at Renogy who has been responding to my emails seems to work night shift. Maybe I'll know more tomorrow, unless they are already off for the weekend. I really liked the battery. Twice the capacity of the old one and so much lighter. Easy to maneuver in and out of the battery cave.

[wa8yxm]

In addition to the external charger LI batteries have some kind of electronics inside the case that is supposed to protect and balance the cells. (Like equalization but it's done differently) You may have lost a cell and the BMS (Battery Monitoring System) is refusing a charge to protect from "FLAME ON"

Just a guess..

I recently read a post by an expert who takes these batteries. opens them up and often as not finds the BMS has failed (or one cell) he has a source of replacement electronics so he gets basically Free Batteries.

Alas I did not save a link.