LFP/LiFePO battery asleep?

Shelbyfv,

I hope this works out for you.

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!

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.

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.

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.

shelbyfv wrote:
It's a Renogy battery and they have been good responding to emails and offering suggestions..

Good brand then they should be responsible.

Just one more idea... a few times when I've been remiss in allowing my 48v pack to deplete to unusable, I simply disconnected the negative cable and let it sit for a while. That 'rebooted' the system (I guess) and allowed some life to return. I do not recall the actual voltage when it woke up, but it must have been over 36 volts to allow the charger to function. It may have been around 42 volts, but that's a guess.

Why it dropped to 36v this time is not understood.

Lead acid batteries also do not have a "BMS" built in that can go wrong and GC batteries tend to tolerate things like running it flat very well with perhaps a bit of loss of capacity and life.

Fair chance the actual individual cells inside your Lithium battery are OK but the BMS has either detected a fault in one or more cells or just plain failed to reconnect for charging after being run down.. Either way, requires replacing the entire battery as the final solution if your charger fails to wake the BMS for charging.

It's a Renogy battery and they have been good responding to emails and offering suggestions. We'll see how it goes from now on. I actually have a convenient battery disconnect but I forgot to use it. I pulled the fuse for so many years it became habit. :o Anyway, pretty sure something went wrong with this one. None of my lead acid batteries ever died under these circumstances. Fingers crossed.

X2 on the warranty route.

Most good quality companies will honor their warranties.

Sounds like a BMS failure and generally when they fail, getting them to reconnect is a futile attempt at best.

In the future, you will need to do more than removing the fuse for the LP detector, it isn't the only thing that draws power when things are turned off..

Your RV fridge, 12V radio, furnace and even water heater if DSI all have control boards which are run off of 12V.. Those control boards even when the item is turned off all draw some power.. 12V radio uses 12V to keep your radio stations and memory settings even when powered off.

Add in a battery disconnect switch right at the battery terminal, that will 100% isolate the battery from ever single phantom draw of the RV.

shelbyfv wrote:
Thanks! The other 12V battery(13+V) didn't wake it up...

That's odd. Good luck with it.. perhaps the BMS is shot. What brand battery are we talking about?