lifepo4 battery wont charge now

[fakdaddy]

Hi all
Reads 12.5v right now.

I've hooked a NOCO 5A with lifep04 support on it --- it just turns on and off like it cant detect.
Bought a lifepo4 charger from amazon - heagstat - same thing.

Wpnt charge just makes both kind of "not detect it".

thoughts ? Less than 9 months old.

 

[Kornbread]

Reset the battery?

 

[fakdaddy]

Is that safe ? And how do you do that

 

[Substrate]

You didn't state how big the battery is. If the battery is small, like 5 to 7Ah or so, when the Noco tries to push 5a into it, the BMS triggers with overcurrent.

Your battery specs should tell you how much charge current you can apply. Could this be the problem?

 

[fakdaddy]

Sorry 50ah

The vendor is replacing it. Weird though I've only bought two lifepo4 batteries and both have died in under 12months Just using for a trolling motor.

 

[Substrate]

Ah, be sure to see this thread. Perhaps you are running near the hairy edge with motor surges. MinnKota has an interesting statement to never exceed 65-85% with LFP:

Lifepo4 trolling motor help

Someone please help- I purchased 2 Power Sonic PSL-12450 Lifepo4 They are rated 45Ah 25a draw each I have them ran in parallel to get 90ah and 50a draw My trolling motor is Minn Kota 55 lb thrust 50a draw It will run all day up to speed 3 On speed 4 and 5 the batteries cut off and then reset...

diysolarforum.com

Maybe a 100ah would help solve your problem....

 

[Supervstech]

Do you have any low voltage disconnect on the battery?
If the trolling motor depletes the bank below bms cutoff, it won't register as a battery until it is recharged.
Get a power supply, not a battery charger, so you can charge above the cutoff and let the charger see it.

 

[fakdaddy]

Yeah weird part is it shows 11v which per my mind means its not disconnected/shutoff.
The trick of adding a 12v supply diret from another battery until it detects and turns on doesnt work either

company is sending a new one
just weird I have had 3 lifepo4 batteries and all failed within a year with 1 issue or another
common problem ?

 

[Supervstech]

Sounds like a bms failure.
11V is VERY low, so it may be simply damaged, but there may be a way to recover it, since it is above 10V...

 

[Substrate]

Let's find the commonality:

What are the brand(s) / model of the battery you are killing?
Where they purchased new or used?
Where they purchased from an authorized dealer?

What is your trolling motor and setup?
Are these being killed under normal load, or are they being tested free-running with props in the air and no load?

More info might help others avoid something similar.

 

[fakdaddy]

Chins/Ampere Time on good old Amazon.
50ah
Trolling motors are different - one has max draw of 24A and other of 50A.

Anyway just curious - alls good as long as they replace Which they have.

 

[Supervstech]

Chins/Ampere Time on good old Amazon.
50ah
Trolling motors are different - one has max draw of 24A and other of 50A.

Anyway just curious - alls good as long as they replace Which they have.

Yes, getting replacement is good, but preventing failure is better.
Get a good low voltage disconnect so the bank doesn't deplete below bms triggers.

 

[Substrate]

Cool - I still have the feeling that instead of the kill-n-replace routine of 50ah types, try a single 100ah instead.

 

[RCinFLA]

You likely have a low cell shutdown on BMS with charging path enabled. Charger likely puts a minor load on battery to make sure it is a valid battery before starting charging. Slight load on battery that has BMS with discharge disabled will collapse in voltage, so charger thinks there is no valid battery connected.

Just because you have 12.5v overall reading on a high impedance DVM doesn't mean one of the cells is not below low cell voltage cutout.

If you have a power supply, prime the charge a little until BMS reactivates. Just watch you don't pump in too much current for battery AH size.