Weird one - Advice needed please

[eyetac]

Hi, guys

I'm a little stumped on this one.

I have 2x 12v100ah LiFePO4 batteries in my mecer trolley inverter.
It's been running really well for years now.

I have an HA11 battery balancer that I installed to keep things, well.. balanced.

Recently I noticed that the voltage on battery B was dropping, but with my house move, I havn't checked it again until today.

I see now that it's at 0v on battery B 🙈 and has been on a steady decline.

What's weird is that, I also have a battery voltage meter built in which shows that with both batteries, I am getting a 27.6 combined voltage reading.

I connected the reader to each battery individually and saw they both had around 13.7v at full charge.

Even now, with everything reconnected, battery B still shows 0v on the HA11 balancer.

Any ideas?

Thanks, okes.

 

[Switch]

Might be a bad cell and you're reading surface voltage at full charge which is misleading. Try isolate the one battery, fully charge it and then put load on it while measuring with a multimeter, if there is significant voltage drop then you probably have a bad cell. Seeing it's a trolley battery, you might be able to take it to some place like battery centre who have testing equipment that could check for you.

 

[eyetac]

Esh, that doesn't sound good

Probably best to take it to Battery Center


Thanks for the advice, bud

 

[Killerwatt]

Swap battery A with battery B on the balancer and see if the lack of voltage moves with the battery. Sounds like the balancer is at fault to me.

 

[Divan85]

I think you are getting false readings from the balancer. The fact that you are getting combined reading of 27.6V means both 12V batteries are measuring 12V+ (although this could be charge voltage but then again if the battery was bad it wouldn't charge).

Do what @Killerwatt suggested and swap the batteries and see if the "fault" moves with the battery in which case it is a bad battery or if the "fault" stays then you know it is the balancer giving false readings.

 

[eyetac]

Thanks for the advice, guys

I'll try that out. But what's strange to me is that the reading on the app has a slow decline?

 

[Xtreme]

If it showing 0.00v is definitely not the battery that at fault.

 

[Confucius]

Lithium battery when dead, shouldn’t be at 0v. Doesn’t the inverter also have some battery level indicator. But I agree with @Killerwatt. Sounds more like the balancer is faulty

 

[eyetac]

It does, but the battery level works as one for both batteries and shows 4 bars.

The voltage meter I have installed on top shows a full 27v currently.

I have another balancer, but sadly it's not Bluetooth, so I won't be able to monitor the levels.

I think the first thing I will try is swap the batteries around.