Leisure battery question (1 Viewer)

Jun 6, 2022
296
610
Bottesford, Scunthorpe, UK
Funster No
89,122
MH
Autotrail Cheyenne
Exp
Newbie
I have 2 100ah lead leisure batteries, I added 1 shortly after getting MH, I fitted then in parallel and I also wired the inverter direct (switched) but not used in anger yet, we went out for a night on a campsite with grandson without EHU, we lost 12v about 10pm with leisure battery voltage down to 10v, I have a solar panel (unknown wattage) and I know it wont charge at night but I thought 200ah would have lasted a bit longer than that.
In the battery compartment there is a second harness connection for the second battery to the Sargent EC325, my question is would it benefit me to use said connection and undo the parallel set up and from what I have read I can choose which battery to use/charge or do I leave as parallel?
 
Mar 30, 2019
2,701
4,963
Cardiff, UK
Funster No
59,476
MH
Coachbuilt
Exp
Since 2016
If you have recently added a second battery it seems likely that the original one is suspect and is dragging the new one down. Unless of course you are running multiple items with your inverter and draining both. I would disconnect both and charge them individually and see if one loses charge with nothing connected.
 
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OP
OP
NigelNovice
Jun 6, 2022
296
610
Bottesford, Scunthorpe, UK
Funster No
89,122
MH
Autotrail Cheyenne
Exp
Newbie
If you have recently added a second battery it seems likely that the original one is suspect and is dragging the new one down. Unless of course you are running multiple items with your inverter and draining both. I would disconnect both and charge them individually and see if one loses charge with nothing connected.
I did suspect the older one draining but I did disconnect when I got home and measure voltage on both and they were both reading within a couple of points of each other 12.5 and 12.3, I also checked the Solar panel on a not to sunny Saturday was putting in 2.4 amps and about 16v
 
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Mar 30, 2019
2,701
4,963
Cardiff, UK
Funster No
59,476
MH
Coachbuilt
Exp
Since 2016
I did suspect the older one draining but I did disconnect when I got home and measure voltage on both and they were both reading within a couple of points of each other 12.5 and 12.3, I also checked the Solar panel on a not to sunny Saturday was putting in 2.4 amps and about 16v
Check them both again after being disconnected for a couple of days. If one is faulty it should lose charge.
Do you know what condition the batteries were in when you arrived on site?

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Mar 30, 2019
2,701
4,963
Cardiff, UK
Funster No
59,476
MH
Coachbuilt
Exp
Since 2016
Grandson had telly on 12v not used Inverter yet, I dont know the age of first Leisure battery either, only bought second one in April
Must be a faulty battery. I have two 110amp batteries and I can watch TV, charge phones, use the microwave and run an electric blanket through an inverter all night and still only use about half of the 110 available amps.
 
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funflair

LIFE MEMBER
Dec 11, 2013
18,936
29,102
Guisborough
Funster No
29,351
MH
MORELO palace
Exp
since 2012
12.8 is fully charged so it's highly doubtful you can have used enough power to drain both batteries. Separate and check đź‘Ť
The battery/batteries could hold a charge but have very little actual capacity I believe.
 
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Apr 27, 2016
6,567
7,437
Manchester
Funster No
42,762
MH
A class Hymer
Exp
Since the 80s
There are several ways a battery can fail, and one way is that is loses capacity. It charges up and goes into float charging as normal, but when you apply a load to it, it behaves like a battery with capacity of 50Ah or less.

You can test this by charging it to 100% full, then applying a known load and see how long it lasts. For a 100Ah battery, a 5A load should last 100/5 = 20 hours. So in 10 hours it should only be down to 50%. If you have a method of measuring the amps, just switch on several devices until you get about 5A drain.

It's best to test both batteries separately, because very likely only one has failed.
 
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Nov 4, 2011
5,699
39,046
Uk
Funster No
18,763
MH
A class
Exp
2001
You have 2x 100amp batteries but you only really have 100amps and if down to 10volts they’re probably toast
 
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