Victron battery bank dead after just three seasons, any bright ideas?

[GEM43]

If you don't do something you're not going to get anywhere. How have you jumped to the "duff battery" ? What charger settings are you using ? How are you setting the Multi settings ?

Yes, I appreciate the need to delve deeper. Slightly put off by the Victron dire warnings if their configuration tool is used by a layman "trained professional only" it says. The duff battery conclusion is consequent of an engineer applying a battery tester this morning which identified one of the six as being well below the specification of the other five.

 

[Bobc]

I'd be grateful for any views on the below as I have a problem with our recently installed battery bank. The story is that in January 2022 I installed a new battery bank complete with new Victron Multi 3kw/120A and a Balmar 70A alternator etc. The battery bank comprises 6 x Victron Super Cycle AGM 125ah batteries.

Earlier this summer we had a couple of low voltage alarms, didn't worry too much about it initially as the fridge had been running for four hours overnight. However recently we were out sailing and had further low voltage alarms, something is up. I've extracted from VRM the graph below which covers a 26hr period during which we departed the marina berth (batteries fully charged, shorepower on), then anchored overnight then returned to the marina the next day. Here follows a description of what happened:

06.00 1st October - on marina berth, Multi in Storage mode 13.3v, 0.2A
08.54 - departing berth, engine running, shorepower off, 14.5v, 6.0A
09.15 - engine off, sailing, 13.34v, -4.5A Nav kit drawing power
12.00 - anchoring, engine on 14.4v, 23A Alternator charging
12.30 - anchored, engine off, 13.3v, -0.5A
20.45 - fridge on, 12.66v, -6.0A
21.30 - fridge off, 12.75v, -0.5A
02.00 2nd October - fridge on 12.65v, -6.3A
04.30 - fridge off, 12.66v, -0.5A
08.10 - departing anchorage, engine on, 14.4v, 27.7A
08.32 - Sailing, engine off - 12.88v, -5.5A
10.16 - Sailing, Voltage alarm 12.2v, -6A
11.05 - arrived close to marina, 11.12v, -5.5A
11.33 - arrived marina, engine on 14.3v, 31A
11.54 - on berth, engine off 12.9v, -5A
13.20 - on berth, fridge on 12.0v, -3A
13.30 - on berth, fridge off 12.5v, -0.5A
15.30 - fridge on, 12.3v, -6.6A
15.50 - shorepower reconnected

The above is a bit long-winded (!) but it explains the profile below.

View attachment 183901

Conclusion? Batteries are knackered. But how can that be? Here is the Victron shunt history which has not been reset since installation:

View attachment 183899

So the deepest discharge has been 131ah (17.5% of battery bank capacity). Min battery voltage at 10.71v - I don't know when this was, it could have been recently. The max voltage of 15.16v happened very soon after installation when the Balmar regulator was pushing very high voltages immediately after engine start then reducing to 14.8v after a few minutes. I subsequently changed the charge profile so that the max charge voltage was 14.9v.

Today I've had a look at the batteries. They look absolutely fine, no evidence of heating or case distortion. The batteries are temperature monitored to the Balmar and the Victron Multi. In the past 180 days the battery temperature has not exceeded 19deg C.

I have done further tests today. I won't bore you with all the details but in essence I turned the charger off, applied a 28A then a 50A load for a short period then left the batteries with a 5A load, you'll see below that the voltage began to plummet two hours later down to 11.5v.

View attachment 183900

I disconnected the batteries today to test the voltage of each individual battery, they all seemed pretty much the same, no variation between them.

So, I'd be grateful if anyone has any bright ideas. The future options seem to be new AGMs (Rolls or Lifeline not Victron) or maybe think about LifePo4.

I've just had exactly the same happen with 3 x Victron gel 110ah batteries, which are only 3 years old.

My conclusion is that they are over-priced rubbish.

 

[vas]

I've just had exactly the same happen with 3 x Victron gel 110ah batteries, which are only 3 years old.

My conclusion is that they are over-priced rubbish.

I'd generalise that into "something in the whole charge/discharge/configure path is rubbish"
Don't disagree with overpriced, but don't think their batteries are rubbish.

[\hides]

 

[PaulRainbow]

Yes, I appreciate the need to delve deeper. Slightly put off by the Victron dire warnings if their configuration tool is used by a layman "trained professional only" it says.

Victron Connect with a MK3 interfase is safe enough to use, unless you're careless. First thing to do is save current settings, then you can always revert to them if you do get in a muddle. You really do need to see what the Multi is doing.

The duff battery conclusion is consequent of an engineer applying a battery tester this morning which identified one of the six as being well below the specification of the other five.

Ah, didn't see mention of that.