Flat Motorhome Battery (1 Viewer)

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nannas-boy

Free Member
May 6, 2008
58
4
Funster No
2,540
Hiya, wonder if anybody can help , we have had our motorhome parked up for the past 6 weeks not been able to go out in it, everything was turned off when we left it, but on getting in it today totally flat wouldnt start, the 12 volt leisure battery is fine its showing almost full, why would the van battery go flat like this?What would be draining it ?
 

Brisey

Deceased RIP
Sep 4, 2007
8,087
17,512
Sutton on Sea
Funster No
223
MH
Coachbuilt
Exp
Since 2003
Is it fitted with an alarm??? next possible cause could be the radio especially if it is connected directly to the battery circuit and not through the ignition switch.
 

GJH

LIFE MEMBER
Aug 20, 2007
29,450
38,828
Acklam, Teesside, originally Glossop
Funster No
127
MH
None, now sold
Exp
2006 to 2022
Is it fitted with an alarm??? next possible cause could be the radio especially if it is connected directly to the battery circuit and not through the ignition switch.

Yes, we suffered a flat battery during our first winter with the van, when it was unused for a while. Turned out to be the radio - it needs to be positively turned off using the on/off switch rather than just switching off with the ignition.

Graham
 
J

jkm

Deleted User
Hiya, wonder if anybody can help , we have had our motorhome parked up for the past 6 weeks not been able to go out in it, everything was turned off when we left it, but on getting in it today totally flat wouldnt start, the 12 volt leisure battery is fine its showing almost full, why would the van battery go flat like this?What would be draining it ?

Had a similar problem with the batteries on our Arto a couple of years ago, on doing some testing it was apparent that some of the electrical equipment could give quite a discharge but not all time, in particular the CB appeared to be causing quite a drain on the leisure battery when switched off. We had to call out the RAC a couple of times when both the van battery and the leisure batteries virtually discharged over a weekend we finished up installing a new main battery (it was 6years old) we also added a 200A socket permanently wired to make it easier to jump start as the terminals are almost impossible to access. We also make sure that the leisure battery is regularly checked for acid level (its normally on charge when we are at home). No trouble since and the van was unused for over 2 months earlier this year while we were in the states, it started first time when we got back - just for the record our main battery is not linked into the leisure system charger.

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American Dream

Free Member
Aug 20, 2007
0
156
Lincoln
Funster No
125
MH
?
Exp
?
Radio and alarm/immobiliser come to mind.:thumb:

I always put the charger on the day before....if it's been stood without a run...just in case.:thumb:

Steve.
 

pappajohn

LIFE MEMBER
Aug 26, 2007
43,500
50,905
Dark side of the moon
Funster No
172
Exp
Since 2005
the radio in my car caused the same problem.
as there is no accessory position on the ignition on the old corsa's i wired it direct to the fuse box, both power wire and memory wire which , when radio turned off was still pulling 200milli-amps effectively on standby.
200mah = 4.5 amps per day x 7 days = 31.5amp drain....no wonder it wouldnt start after a week.
 

Brenintot

Free Member
Jul 24, 2008
24
0
Cwmbran, South Wales, UK
Funster No
3,434
MH
C Class
Exp
Since 1980
As everything is switched off, you will need to establish if there is a fault with the battery. You could charge it up & take it to your local motor factors/garage & ask them to load test the it for you.

If the battery is OK then measure the battery drain between the removed Red + terminal lead & the + battery terminal post. With a suitable digital multimeter and a setting of DC Amps the should be a reading of 0.001 - 0.003 ma. If you get a reading of around 0.25a this would indicate battery drain via a radio or alarm system. leave the meter connected for 30 sec to 2 mins to obtain a accurate reading.

Safety Note - you are connecting a meter in series & it is important that you establish that if you suspect there is any current drain that it is it is 'low' before you connect any multimeter.

If you don't have acces to both of the above, fully charge the battery & disconect the suspect equipment by removing the supply fuses & leave it stand for 3-4 days. if the van starts OK the problem is within that circuit.
Regards
Brenintot
Chris Tottle - Photography: Welcome
 
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nannas-boy

Free Member
May 6, 2008
58
4
Funster No
2,540
Thank you for all your suggestions, we are thinking the radio could be the problem, because we do just turn it off with the ignition, so we are going to turn it off with the on /off button from now on. Just another queery you very helpful people might help me out with, just lately the alarm seems to be playing up , when we lock the doors the alarm does 3 beeps and the the alarm triggers itself off within 10 minutes, it never used to do these 3 beeps, so now we just have to lock it with the key. Could this be something as well thats connected to why the battery went flat? Really do appreciate your help .
 

American Dream

Free Member
Aug 20, 2007
0
156
Lincoln
Funster No
125
MH
?
Exp
?
Has it got door/bonnet sensors fitted.Maybe it's thinking a door isnt shut properly.Just a thought.

Or is it that the battery volts are falling to a point where it is not able to sustain it working?Does this happen with a fully charged battery?

Can you give more info on the Alarm make and model please?

Is it aftermarket or Factory fitted?

Interesting...Just found this.May or may not be relevant Link Removed

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wanderer

Free Member
Apr 14, 2008
643
769
huntingdon
Funster No
2,152
MH
a class Arto
Exp
since 2008
hi
We went to go away last week and found our battery flat. Called out the AA for a start which worked straight away but the battery would not hold a charge going below 8 on the meter when trying to start via the ignition. Ended up buying a new battery ,Now all working fine
wanderer
 
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nannas-boy

Free Member
May 6, 2008
58
4
Funster No
2,540
Thank you American Dream, ok the alarm is an auto watch 161RLi/T remote controlled alarm , I have just got the booklet here now and it doesnt give any fault finding information. But what you found with the chap with the Honda car doing the same sounds familiar.
Yes its still doing it with the fully charged battery, it does have the sensors on the doors but they seem to be all closed properly. The alarm was already fitted when we bought it but it worked fine up till a acouple of months ago, its a baffler? What can you suggest please?
 

American Dream

Free Member
Aug 20, 2007
0
156
Lincoln
Funster No
125
MH
?
Exp
?
In past experience, door sensors are very vulnerable to moisture/corrosion.Where are they mounted on the door post?

Have you had them off and managed to clean them?

If you can get to the connectors can you check the resistance when operated and released?

I still suspect a faulty sensor/wiring somewhere.

I'd personally start by re-plugging all connectors after inspecting them and cleaning if necessary.

Any Pictures please?
 
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