Batteries

[Baden87]

Hi
On my new 2019 Autotrail it came with 2 90 amp batteries fitted in parallel mode ,on the batterie monitor It’s showing 12.4 volts in the mornings before sun comes up to echarge with solar panel , I only use an led reading light nothing else , is this normal ehaviour ?

 

[Lenny HB]

Nope, if they were fully charged before an evenings use they should have been over 12.7v. Just one LED on for a few hours I wouldn't expect to see any drop in off load voltage or at the outside down to 12.6.
12.4 is 75% charged.
First thing to do is check the voltage at the battery with a multimeter to make sure it is not the control panel reading low.
Also are you sure nothing else is on e.g. boiler for hot water if so you would be reading an on load voltage which is lower than off load.

 

[PeteH]

With "modern" appliances, using "tech", there will always be "ghost" drains, even a digital clock permanently consumes a few milliamps and even your solar charger will have a standing drain, the refrigerator?, other drains could be a T-V/Radio, left on standby for example?. I can see a noticeable drop in my car overnight. 0.5v would not be out of order IMV, especially if you are using even one LED. A check on the accuracy of the panel as Lenny said, will not hurt. Also you don`t say what type of batteries you have?.

 

[Pausim]

The control panel and 12v distribution unit have quiescent loads and I suspect you leave them on overnight.

 

[Lenny HB]

Even with the standby loads often up to half an amp I wouldn't expect a drop of that much. 1/2 amp for 12 hours is less than 3.5% of the battery capacity.

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[Blue Knight]

Even with the standby loads often up to half an amp I wouldn't expect a drop of that much. 1/2 amp for 12 hours is less than 3.5% of the battery capacity.

His batteries must be c.30-months old Lenny so with it standing around for the first year (through the build process and on the forecourt etc) then perhaps they are heavily sulphated and ready for 'battery heaven'.

Also, what voltage does the standard AT charger push out - I thought it was 13.8v but I could be wrong.

 

[Lenny HB]

Also, what voltage does the standard AT charger push out - I thought it was 13.8v but I could be wrong.

The Sargent units have been multi stage chargers for many years now.

Probably worth running a slow discharge test on the batteries it would give a good idea of their condition.