Batteries am I expecting too much?

[colyboy]

On our recent trip are two leisure batteries “went down” that’s after day of driving. That evening we had lights, TV and heating on high.

At home we had them fully charged . I then fitted one tested it and tested the second on its own. This evening I have been checking one of them , lights, TV and heating on high.

6.45 pm. 12.7
8.30 pm. 12.5
9.30 pm. 12.2
10.00 pm. 12.2


Are these figures about right (this is with one battery) or a, I worried about nothing!

Colyboy

 

[Boringfrog]

Do they recover when the load is taken off them?

 

[colyboy]

Just checked 10.25pm every thing off and still showing 12.2

I know in the morning (if it stops raining) the solar panels will charge them up. Of course they will charge up when I plug in the mains.

Colyboy

 

[two]

Probably time to change the batteries. They don't seem to have much capacity. How old are they?

 

[HandyAndy]

Its not really much good saying lights, tv and heating. You need to know the amp draw to make any sort of educated guess.

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[PhilandMena]

Its your heater Chum, it will e taking a huge draw from the batteries.

 

[jezport]

If your telly is an old one it will take up to 4A, the heating will use 4A on full fan but shouldnt stay at full for long, lights if LED should use barely anything.

2 leisure batteries should handle that for a few nights before being down to 12.2v

 

[Lenny HB]

Its your heater Chum, it will e taking a huge draw from the batteries.

Old wives tales, if it's a Combi, draws 5-6 amps running at full chat, the van is up to temp drops to just over an amp with older Combi's with a CP Plus controller less than an amp.

 

[PhilandMena]

If your telly is an old one it will take up to 4A, the heating will use 4A on full fan but shouldnt stay at full for long, lights if LED should use barely anything.

2 leisure batteries should handle that for a few nights before being down to 12.2v

The OP does not say what kind of heater he is using and that leaves us all guessing. @jezport has given the correct answer and it is now for the O.P to either provide more information so he can be given the correct advice or do the math and resolve it for himself.

 

[GPW]

Buy something like this:



install it carefully as per instructions (Shunt on -ve wire to hab battery, you'll need a short wire from the shunt to the battery too of appropriate thickness and terminals).

This will not only give you the power usage but also the Wh = Watt hours. From a 100 Ah AGM battery you'd expect 75 Ah at 12V = 900 Wh, for a wet cell about 50 Ah at 12V = 600 Wh.

It's also possible the battery is never fully charged, AGM batteries require stints at 14.7V which may be more than the alternator is prepared to give in a simple split charge system.

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[colyboy]

Thanks for all your replies. Sorry not au fait with amps? List below some of my answers to your questions.

2017 Hymer

Combi 6 heater

TV two years old

Batteries two years old “Platinum “ 100w. But for these tests only using one



All LED lights

2.45 pm. Just checked and it reads 13.5 charged by solar panels

Local garage charged them up fully but could not do a “drop test”. As Leisure. Batteries are made up differently than car batteries !

Colyboy

 

[Steve N Tracy]

13.5 volts is more then likely the Solar input voltage you will need to wait until its dark to test the battery without disconnecting it.

 

[pappajohn]

2.45 pm. Just checked and it reads 13.5 charged by solar panels

That will be the panel voltage, not the batteries stored voltage.
Turn off/Disconnect solar, leave an hour or so without any use then check again

 

[two]

If the batteries discharge quickly they have lost capacity. Maybe they've been left discharged for a time? They are unlikely to recover and will need to be replaced.

I've killed many a battery by not looking after/storing them properly. I've used fancy conditioning equipment that was claimed to recover dead and sulphated batteries to no effect. Put it down to experience and get rid.
I used to consider the batteries to be an expendable but am having better luck these days.

 

[GPW]

13.5 volts is more then likely the Solar input voltage you will need to wait until its dark to test the battery without disconnecting it.

Indeed, the happy float voltage for any lead-acid is 13.8 and the peak voltage for proper charging is 14.4 for wet and 14.7V for AGM/GEL.
Unless you get to 14.4 / 14.7 on a moderately regular basis the battery life won't be very long, perhaps you need a better quality MPPT solar charger and/or B2B system.

To some extent shonky charging systems can be hidden by installing a £900+ Lithium battery but it's actually cheaper to just buy a decent charger and a new AGM or Gel battery IMO.

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