flat battery

loz

Free Member
Joined
Feb 2, 2009
Messages
7
I went to collect my motorhome out of storage to give it a wash and brushup. I last used it in november . I had a flat battery.being new to motorhoming i didnt realise that an unused battery runs down . Ive read about small solar panels that you can fit on the dashboard when the van is in storage .can they plug into the cigerette lighter socket and are they any good .some advice would be very helpfull . also do i need to charge the leisure battery during storage .::bigsmile:
 

Diabalo

Funster
Joined
Oct 14, 2007
Messages
2,275
Location
Rochester
MH
Coachbuilt
Exp
12
Hi Loz

I have the small jobbie and it does not keep up with the drain this tme of year and I am looking into getting a bigger panel.

The other thing is your socket on the dash may be only be live with the ignition on if so you would not be able to charge through it.
 

pappajohn

LIFE MEMBER
Joined
Aug 26, 2007
Messages
35,861
Location
YO11 2BD
MH
Homeless
Exp
Since 2005
hi, not only will the battery self discharge but things like the alarm, clock, radio memory and such will drain it.

yes, the leisure battery will need charging as well.

if its accessable you'd be better removing it and keeping it at home, charging it occasionaly.

small solar panels, the type that sit on the dash might keep a FULLY CHARGED battery topped up, but only a fully charged one, it wont charge a flat battery.
the panel should, ideally, be facing the sun as much as possible.
 

Gonewiththewind

Free Member
Joined
Sep 13, 2007
Messages
852
Location
Lancashire
Exp
July 2007
I am a solar believer. I have a 130 Watt panel on the roof that keeps my habitat batteries fully charged. I have a small one on the dash that keeps my starter battery charged. As already said, will only maintain a fully charged battery, will NOT charge a flat battery. They come with 2 connecting systems, Cig lighter and croc clips. For convenience I rewired my cig lighter directly to Battery, as most come connected through ignition switch. Maplin sell them for about £12.
Good luck which ever route you take

Don
 

Tony Lee

Free Member
Joined
Sep 28, 2008
Messages
274
A standard lead acid battery can lose up to 30% of its charge every month just sitting there - and if it is supplying security system, radio settings and the like, a couple of months would see your engine battery dead flat. Same with the leisure battery - battery management system, gas alarms, frost protection valve all take a small draw and will flatten the battery over two or three months.
A flat battery can freeze and that is also bad news.
AGM and Gel batteries fare better as far as self-discharge goes and normally are freeze-resistant, but the phantom loads will still flatten them and once they are dead flat, it is only another month before they are not dead flat, but dead.

If you have no use for the van for say four months, I would suggest taking them both home and even if you have a crappy taper charger rather than a good three-stage one, putting them on charge for one day each fortnight should keep them in top condition. Batteries don't need exercising, they last far longer if they are kept properly fully charged. Ideally, a quality charger with a correct float setting can be left connected permanently and if they are of the same type, could be connected to both batteries in parallel.
Some say an AGM - with typical self-discharge rates of around 5% per month - are better fully charged and then left disconnected for 6 months before running it through another three-stage cycle.



Solar - yes real good when the sun shines - but I was told that in Stuttgart it NEVER snows before christmas. We got there mid-December to find the MH topped off with 6" of snow. Not much solar output through that lot.
 
Last edited:

Kon tiki

Free Member
Joined
Oct 11, 2007
Messages
490
Location
North Wales
MH
Low Line
Exp
20+
Is it posible to charge both the leisure battery & the engine battery from one solar panel? My 85amp gel leisure battery usually gets charged qite quickly & I was wondering how I could also keep the engine battery charged as well. I was having problems with my engine battery failing (it has since been repaced under the van warranty) I managed to get started after getting it charged from a friendly French motohomer using his generator to boost it. It would be handy to have the option to be able to send the charge to either battery.
The solar panel was fitted to my van through a Steca charge controller connected straight to the battery. On the Schaudt electroblock there is a connector for a solar panel input, should this be used or is it better the way the dealer has connected it straight to the battery?
 

Tony Lee

Free Member
Joined
Sep 28, 2008
Messages
274
Some battery management systems - that allow the alternator to charge the leisure battery when driving - also have a trickle charge in the reverse direction via a diode and a limiting resistor. Works when the EHU is live - and maybe if solar is hooked up. Crude, but the engine battery doesn't need much topping up usually
 
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