Electrics help needed

[PJGWiltshire]

Having a few issues with the van around electrics.
Since coming out of lock down have given the van a couple of run outs to check on everything. 1st run out back on 30th March found the the motherboard on the Dometic fridge failed and new one ordered and due to be replaced. At the same time the 1 year Sterling B2B sent out an overheat alarm. The b2B was removed and sent back to Sterling who fixed the charger (It was a faulty fan).
The B2B was returned to me and on Thursday this last week it was reinstalled and found to be working correctly.
Now here things start acting strange.

On that Thursday having installed the B2B took the van for drive for an hour also the van was left in a sunny location with solar panel doing its bit. I noticed by late in the afternoon the battery level on the control panel was showing 13v. (I do not have a Victron battery monitor)
So the van was left unattended around 6pm now in shade, we were due to be in the road the following day so around 10.ppm I had reason to go in the van and after opening up and turning on the lights a bleep alarm was activated from the control pane. I noticed that is was the alarm for low voltage in the leisure batteries.. It was showing 10.6v and very soon after the control panel shut down and light failed. Clearly the safety power cut off had kicked in.

Took the van for a drive and the B2B kicked in. An hour later battery level above 11v. Following morning reading down to 10.6 or something but no shut down.
Then Friday on the road for two hours and then sat around in full sunshine for 4 hours, again battery level 13+ v. Followed by another 2 hour drive. Parking up at 7.30pm with a good 13+v on the indicator. Following morning battery level 10.6v frost all around use needing heating on so start engine, B2B giving charge and showing 14v charge. Sun soon up and without B2B again volt level slowly climbs uptown over 13v on solar.
Again overnight volt level drops down to 10+volts. The van had not been used whilst left unattended until we returned to it to sleep at 11.00pm when the low volt level seen. This morning fro m10 v with a drive and solar by 12pm volt showing over 13 v.
So decided to check if the battery is simply failing to hold any charge. I decided to remover the main mega fuse from the B2B so any possible draw from that could not occur and then turned the leisure battery isolator switch off thus no draw from the habitation side.

Five hours later wanting to check if the batteries were holding a charge. I turned on the isolating switch, now 12v power has got to the control panel but all that is happing is the screen is flashing on and off thus seeing all the symbols that could be illuminated in the screen but the screen is not lite up by the back light. Pressing the on/off button is not activating the control panel thus no supply is getting through to the ,light and pump. 12v is supplied to the heating controller but again it will not start heating or hot water boiler. The fridge has 12v supply and will work on gas(even with the faulty fridge control panel as it would do this but will bot switch off and switch automatically thus a nw panel to be fitted)

I have disconnected the positive feed to the isolation switch and then plugged in EHU and the control panel does exactly the same as on 12v

So are there any thoughts out there what could be the problem

 

[two]

Sounds like your habitation battery has failed.
Have you checked the voltage with a meter?

 

[autorouter]

One way a battery fails is that one of the six cells short-circuits. If you do the maths you'll see that if 6 cells give 12.6V then 5 cells give 10.5V.

The chargers (B2B, solar etc) will temporarily lift the voltage, but with no charging it settles back to 10.5V again. Sorry, but it looks like a new battery is needed.

 

[Googlebot]

I would go for hab battery being knackered as well.

Mine did the same when it failed.

 

[PJGWiltshire]

I half expected that and I was looking to change them to Lithium so them crashing is not a real issue. I know I gave a lot of history leading upto today, its around the control panel that is concerning me. The failure of that is strange. Is it the case that as the batteries have now crashed very low say 3 or 4 volts, as I had totally isolated them from solar, when I turned them on something within the controller has kicked in as they are very low voltage thus the controller will not start up. Even 240v supply will not work. Is it a case the they controller needs to see batteries up in the 13 v range before it will allow itself to now restart as its shut down into a safe mode?

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[PJGWiltshire]

I would go for hab battery being knackered as well.

Mine did the same when it failed.

To just confirm, when your batteries failed your controller just shut down and would not restart until new batteries?

 

[Googlebot]

Not quite, it was a dumb system so wasn’t that clever. I know in the Hymer it won’t switch back on till a certain voltage though.

 

[Richard n Ann]

To just confirm, when your batteries failed your controller just shut down and would not restart until new batteries?

Our battery failed with a shorted cell in 2019, was reading 10 odd volts after the solar controller shut down. It shut down due to high battery temperature. It had been throwing 7+ amps at it all day

 

[PJGWiltshire]

Our battery failed with a shorted cell in 2019, was reading 10 odd volts after the solar controller shut down. It shut down due to high battery temperature. It had been throwing 7+ amps at it all day

Yes found one if the batteries very warm and smell coming from the area of batteries. Was going to buy Lithium but just went ahead and ordered replacement Gells. Will be here in next two hours. Just hope the controller resets its self

 

[Mr Librium]

Yes found one if the batteries very warm and smell coming from the area of batteries. Was going to buy Lithium but just went ahead and ordered replacement Gells. Will be here in next two hours. Just hope the controller resets its self

If you have two batteries, it could just be one of them that is knackered, meaning that the charger will only see the voltage of the good battery and will stop charging when it reaches the correct voltage, leaving the faulty battery under charged.
I had this issue a few weeks back... the batteries need to be charged individually around once a year to maintain a good voltage balance as they eventually drift apart in voltage.
A proper battery check by a good auto electrician will confirm this usually with a printout as per the image.

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[autorouter]

A proper battery check by a good auto electrician will confirm this usually with a printout as per the image.

That's a proper battery check for a starter battery. Notice the CCA (Cold Cranking Amps) which is the amps the battery is capable of supplying to the starter motor - a massive current for a very short time. The failed battery could 'only' supply 446A, but the good battery could supply 742A.

However that's not a good test for a leisure battery, which typically will rarely supply more than about 20A, but over a period of hours or days, not seconds. Unfortunately a leisure battery test is a bit more, er, leisurely. For example, for a 100Ah leisure battery, loading with 5A for 10 hours (= 50 amp-hours) will take it down to 50%. Checking the voltage after 10 hours will tell you if the battery is at 50%, or has lost capacity and is down to well below that.

 

[Lenny HB]

As autorouter says that type of test is meaningless on a leisure battery you will often get a result of 80% plus but the battery is hopeless on in a slow drain situation.
I had a couple fail test result was 80%, in leisure use one was good for 10ah the other 11ah.

 

[Mr Librium]

That's a proper battery check for a starter battery. Notice the CCA (Cold Cranking Amps) which is the amps the battery is capable of supplying to the starter motor - a massive current for a very short time. The failed battery could 'only' supply 446A, but the good battery could supply 742A.

However that's not a good test for a leisure battery, which typically will rarely supply more than about 20A, but over a period of hours or days, not seconds. Unfortunately a leisure battery test is a bit more, er, leisurely. For example, for a 100Ah leisure battery, loading with 5A for 10 hours (= 50 amp-hours) will take it down to 50%. Checking the voltage after 10 hours will tell you if the battery is at 50%, or has lost capacity and is down to well below that.

I agree, but it was enough to determine if the battery was up the shoot and got me a replacement battery.
The response from the seller of the battery was:
"Hello, the other battery seems to be in very good health for its age, your battery is rated in MCA (marine crank amps) and the battery has been tested in CCA (cold crank amps ). 1 MCA is equal to about 0.77 CCA that means when the battery is new it would produce 770CCA and yours is reading 742CCA."