# Is my leisure battery dead and what do I do next???



## marco_b (Jul 18, 2008)

Hiya,

Due to brain malfunction I inadvertantly left the water heater in my 1993 Hymer B544 on all week. Oddly enough, the gas didn't run out, but the leisure battery was down to 10 and a bit volts at the end of it all.

Now it doesn't seem to hold charge at all well.

So there's a bunch of questions:

Is it true that if you let your leisure battery get below about 11.5v it kills it permanently?

If not, can you rescue it with a fancy multi-stage charger?

Why did this happen anyway? I thought vans were meant to trip out the 12v supply once it got too low so you couldn't wreck the battery.

And if it's really dead, do I just buy the cheapest replacement I can find? or spend twice the amount on a posh Elecsol or something?

How do I check if it's really turned its toes up?

Finally, is there merit in replacing the 240v charger built into the van with one of these Sterling multi-stage jobs - or equivalent? I guess half the charging the second battery gets in our case is from the alternator as we're driving. I just keep reading that you should give your battery a good blast every so often with 14.4v which the internal 240v charger (1993 vintage) probably doesn't.

Sorry for the huge numbers of questions - I've been all over the site, and still can't really find the answers! 

btw just back from a great long weekend - first night at Kielder, then in a field next to friends' cottage in the borders - so remote they haven't even got mains water or power, then Edinburgh for a gig, St Abbs Head today - this is why we got the van. What a life changer, just brilliant.

Mark and Sue


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## CliveMott (Mar 10, 2008)

Firstly I would leave your van on hookup for 24 hours then measure the battery terminal voltage with a digital multimeter. Check it gets to 14.0 volts or very close. 
Then do a discharge test. Its not complicated, just turn on some known wattage downlighters (like 10 watts each) say 3 off them which is 30 watts and should take 2.5 amps. If these bulbs stay illuminated for 24 hours then you have taken out at least 60 ampere hours and your battery is well and truly serviceable. If you manage this then put it back on charge for another 24 hours directly. If the bulbs only last for a short time then its time for a new battery. 

Providing you buy a LEISURE or DEEP CYCLE battery then the most economical way to progress is to by a wet electrolyte battery, they are the least costly and provide the best value for your cash. 

If you intend to regularly nearly flatten your leisure battery then those with carbon fibre technology like Eleksol are supposed to tolerate this abuse better. But if you normally look after your battery then Paying for Eleksol is unnecessary. 

Make sure your van charger is set to WET if you use a WET cell battery or GEL if you use a GEL or AGM battery. 

C.


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## marco_b (Jul 18, 2008)

This is really good, thanks Clive



CliveMott said:


> Firstly I would leave your van on hookup for 24 hours then measure the battery terminal voltage with a digital multimeter. Check it gets to 14.0 volts or very close.


It's been on hookup for 22 hours, then a three hour drive. Now its off the van and in the kitchen, and it's 12.8v. Doesn't look good to me. I'll see if I can find a 12v lamp and get it hooked up and do that discharge test.



 CliveMott said:


> Make sure your van charger is set to WET if you use a WET cell battery or GEL if you use a GEL or AGM battery.


Pretty low-tech van this old Hymer, there's no setting for different battery types. Which is why I was wondering about a new internal charger, but they all seem a lot of money...

M


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## H1-GBV (Feb 28, 2006)

I think your battery probably is dead, but someone with more knowledge will give you more info, I expect.

My battery charger "blew up" when I was attempting a repair, so I bought a "fancy" multi-stage charger (CTEK XS 7000) for about £100 - from Motaman. It seems to work well, and is smaller and more convenient than the supplied one - I have fitted it underneath the floor of the wardrobe, giving me a little more locker space.

When I had battery problems, I replaced my original 85Ah one with a 110Ah. The problem (losing voltage fairly quickly when the heater and lights are on) was not much better, so I have connected the old (5-6 years) one in parallel with the "new" (2 years) one (NOT recommended). We have just had a long weekend and the voltage never dipped below 12.6V (no heater on!!).

I am working on the principle that if I do the correct thing, I will have to buy 2 new, matched batteries; by doing it wrongly, I will get a few months (years?) extra use out of my previous expenditure. So, if you can rescue your old battery, you might consider using it alongside a new one to give you extra capacity (assuming you have room). Certainly, I would buy 2 cheap batteries in preference to 1 expensive one. I'm sure others will recommend the opposite - only you can choose!

Good luck

Gordon


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## blondy (Aug 23, 2007)

HI, Don't assume that the batts are us as it dropped to 10v.
recently one of my motors with 2 batts dropped to 4.5 volts( long story why). I connected my commercial charger to them and feared the worst
but lo and behold they came back perfect, they were nearly new batts.
.
As for charging on the move, I and many others have a Sterling batt to batt charger fitted which does appear to put more in the battery as claimed
I wouldn't be without mine after having 2 M/Hs without one.
cheers


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## advancedroadcraft (Jun 24, 2009)

*Reviving old (dying?) batteries.*

And if you haven't junked it yet and want to give it your best shot then, in addition to a "smart" charger, some of us oldies who grew up with clunkers that just HAD to be made to last still swear by "Batt Aid" tablets!


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## marco_b (Jul 18, 2008)

Thanks, looks like I need a proper multi-stage charger - probably not a bad idea to take the battery out of the van every so often and charge it properly anyway. Off to see if I can borrow one before giving up on the battery.

Not sure about aspirin for batteries mind, but I'll look into it...

M


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