Time for Lithium House

[Delta Riverat]

The wiring looks fine. The batts are seven years old. When mine were 7 years old they were shot.

Not like dhays, the voltage (no load) was fine but no capacity or current left.

 

[twistedtree]

Could be a dead cell in each battery, or it could just be that the batteries have not been throughly enough charged over the years. This is one reason why lead batteries need a long absorb cycle, and some more than others. Are they by chance Rolls batteries? If they are flooded, an SG reading would tell you most everything.

 

[dhays]

What you are saying is that one of the 6V in each 12V battery pair was low? The wiring is as correct as can be done. In each pair, the same current has to go through each member of the series pair. So I'd say just a classic cell imbalance issue. Were these flooded, and did you ever equalize? The ones at 6.4V are normal, the ones at 4.3V are dead.

AGM. I did equalize but likely not as often as I should have.

Anyone want a couple decent L16 AGMs?

 

[dhays]

Could be a dead cell in each battery, or it could just be that the batteries have not been throughly enough charged over the years. This is one reason why lead batteries need a long absorb cycle, and some more than others. Are they by chance Rolls batteries? If they are flooded, an SG reading would tell you most everything.

They are USBatteries AGMs. They were charged according to USBatteries charging recomendations. Other than not being equalized as often as maybe they should be, they were charged well.

 

[Delta Riverat]

I still suspect dead cells. The voltage difference is the same and just about 2/3 cells working. Tall batts make it easier to happen, more vertical plate material to slough off and pile up at the bottom.

Yup, just another reason to do the LiFePO4 - My smile is because I'll never have to do the house bank again!

Those lead-acid starters on the other hand...

 

[SteveK]

@luna are you thinking a poor ground, as in not 100% clean connection?

 

[luna]

Stevek..

Thinking with whats left between my ears is being overly optimistic.

I have seen similar failures of AGM batteries.
One of my dockmates experienced the same kind of failure (the batteries where the load was connected on their positive terminal got killed) about 18 months ago.

Just thought someone in the TF world might have better insights.

Not to worry, LiFePO4 is in the throes of fixing this now.

 

[dhays]

@luna are you thinking a poor ground, as in not 100% clean connection?

I was wondering about the connections as well. However, when I disconnected the cables, they all looked great. I had connected them with No-Ox like I do all those connections. I didn't make the cables but had them made professionally, so I assume they were done well.

But, you never know. A bad cell in two of them would be the cleanest explanation. It makes me sad to recycle two of those L16s that appear to be in great shape. Even if I had a good use for them, to be honest after having just removed all four of them, I'm not sure I'm up for picking them up again. Each of them is 121lbs and I feel every one of those pounds now.

 

[SteveK]

Dave, On my house batteries I have a shunt inline and negative grounds to engine and excetera. Multiple places away from battery on the way to bond with the alternator to complete a circuit. The positive from battery may have connection points between too, but this thought is about negative since two batts are charged.
I like a mystery, then again, it just may be a coincidence and really two dead cells.