# Leisure battery not charging off alternator...



## 125675 (Jul 12, 2009)

Hi all - thank you in advance for any help you can provide.

I am currently on an extended trip and am running a separate fridge off my leisure battery (a new 110ah wet cell battery). The battery appears to charge up okay on mains (presumably via the built-in zig x-7 charger) although it would ideally be quicker, however it does not appear to charge when running off the engine. This limits the time I can be off a hook-up more than I would like. 

The charging voltage when running the engine is only 12.6v on the leisure battery and around 13.8v on the vehicle battery (which charges fine). Is this voltage drop normal on such a setup? 

Any ideas on the best approach to circumvent this problem? I'm thinking a battery to battery split charging system of some kind, removing the existing alternator to leisure battery wiring. Or is there an easier solution (I would want it setup so as to separate the two batteries when not charging).

Your wisdom would be greatly received!

Thanks,

Alex.


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## geraldandannie (Jun 4, 2006)

Hi Alex

Firstly, welcome to MotorhomeFacts  

I had this problem on my first van. It turns out the fuse had blown in the feed to the leisure batteries. On our Peugeot-based Autosleeper, the fuse dangled down inside the engine compartment 8O 

Normally, there is a split charge relay on most motorhomes. Have you checked?

Gerald


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## DABurleigh (May 9, 2005)

If the voltage on your leisure battery goes NOT increase as the engine is started then certainly check fuses and relay in the alternator - vehicle battery - leisure battery cabling.

If it DOES increase then the cabling is too thin, so thicken it after checking for poor contacts 

Dave


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## CliveMott (Mar 10, 2008)

Basic wiring scheme here :-

http://www.motts.org/SPLIT CHARGING SYSTEM.htm

c.


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## 125675 (Jul 12, 2009)

Thakns - I think the fuse is okay as the voltage is higher when running the alternator - but I'll check just in case.

Is anyone familiar with the wiring on these vans, is there a straight run from the alternator to the control panel?

Thanks.

Alex.


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## 125675 (Jul 12, 2009)

*Still struggling to sort the problem!!*

Hi - still trying to sort this problem but with no luck as yet!

There voltage when running the engine is higher therefore I don't believe there is a dud fuse (which I have also visually checked for).

I've been trying to find any point of voltage drop and having checked the connections and cabling have had no luck as yet. The wiring from the relays up front to the leisure battery do not seem to route via the x-7 charger and control panel as I had assumed (thinking there might be a voltage drop there).

I have noticed that the voltage from the alternator at the leisure battery does occasionally rise to 13.8v but only on random occasions - could the relays in the split charging system be at fault? The wiring and contacts appear to be in good shape and certainly thicker than 2.5mm, more like 5mm, so not sure the wiring is necessarily at fault here.

Any thoughts gratefully received!


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## DABurleigh (May 9, 2005)

Run a test cable (not wire) from alternator to leisure battery, making contact after starting the engine. At least that will tell you what you should be getting and confirm the alternator is doing its job OK. Then you can attack the existing wiring/ relay to isolate the problem.

Dave


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## pieterv (Feb 3, 2009)

Since the voltage does occasionally rise to 13.8V it looks like a wobbly connection or the split charge relay is making intermitant contact.

I would have someone check the voltage at the leisure battery whilst you go around and wobble the cable that goes from leisure battery to split charge relay to alternator until you find the poor connection.

Pieter


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## skiboycey (May 21, 2009)

You might have a duff earth connection somewhere. Make sure the engine earth strap is nicely connected - they often suffer from electrochemical corrosion where they meet the steel of the body. You should find a fair sized length of braided cable running from the engine to the chassis which you can unbolt and clean up the ends of with a file or emery cloth. Re-mount it using copper or graphite grease. You can buy it at Halfords or other motor shop or at Maplins.

It would be worth doing this for the earth connection to the split charge relay (if there is one) or for the charging box and also for the leisure battery. I'd also take off all the connections and make sure they're nice and shiny and grease them with conductive grease as well. IF there's a relay sometimes they're not up to the job of charging a fully flattened leisure battery and the connections inside get pitted or sometimes they can even partially melt the plastic surrounding them meaning they don't touch properly. Sometimes you can see this as a slight resistance across them or if you take it apart you can visually see the damage. I wired two 40 amp relays in parallel on my self-build after repeated problems using only one. This solved it.

Some electronic chargers have quite complex charging regimes where they 'rest' the vehicle battery from time to time and this might explain why the voltage occasionally rises and falls. It it's a relay this obviously isn't the case...

Finally the leisure battery might be knackered. This is actually probably the most likely problem. Sometimes they'll accept some charge and look fairly normal but then go flat as soon as you use them. You could swap your starting and leisure batteries over and try it all out that way or better pop a spare starter battery in place of the leisure one and see if that makes it work better. You won't hurt a leisure battery starting a warm engine a few times nor will you hurt a starter battery discharging it to 12.2 volts or so a couple of times if you use it temporarily as a leisure battery. In fact in my self-build van I use two 120 amp hour starter batteries for the leisure circuit and they've been fine for 3 years of nearly full-time use...

Hope some of this is useful to you.

Regards, Mark


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