# I'm confused....



## ronin56 (May 25, 2007)

Having stayed for a couple of nights on an aire without hook-up my leisure battery was flattened. A two hour drive home and a solar panel would, I thought, give it some charge but I decided to take it out to charge it fully. Before doing so I put my multimeter on it and it recorded 13.04 volts!

My first reaction was 'Great' but then I thought I'd look online to see if my instinct was correct and I find that half the world thinks "What's the problem" and the other half thinks I've got a dead battery! Can anybody give me a definitive answer?


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## rayc (Jun 3, 2008)

ronin56 said:


> Having stayed for a couple of nights on an aire without hook-up my leisure battery was flattened. A two hour drive home and a solar panel would, I thought, give it some charge but I decided to take it out to charge it fully. Before doing so I put my multimeter on it and it recorded 13.04 volts!
> 
> My first reaction was 'Great' but then I thought I'd look online to see if my instinct was correct and I find that half the world thinks "What's the problem" and the other half thinks I've got a dead battery! Can anybody give me a definitive answer?


Measuring the off load voltage of a battery, especially when it has been recently 'charged' by the alternator is no indication of its condition. What happens if you start to load it with equipment, does the voltage drop off rapidly?


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## ronin56 (May 25, 2007)

*Battery*

Not got to that stage yet Ray, I was so surprised that it appeared to have (more than) a full charge that I've just left it in my barn and posted this to see if anybody knows what's going on. I'll put it back on the van tomorrow and see what happens. If the worst comes to the worst I know somebody locally with a battery tester but I was interested to hear what people who are used to dealing with leisure batteries, as opposed to engine batteries had to say about this.


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## DABurleigh (May 9, 2005)

I can definitely say there is insufficient information to conclude whether you have any problem.

Dave


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## DTPCHEMICALS (Jul 24, 2006)

I definatley have a problem. :? 
Permanently :? :lol: 


It started 5 years ago when I joined MHF
Dave p


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## Morphology (Jul 23, 2010)

You need to leave it at least 24 hrs after charging it for the voltage to stabilise before you can trust the open-circuit (ie no load) voltage.

What did it measure the next day?


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## ronin56 (May 25, 2007)

OK, I've measured it 24 hours after being on charge i.e. when I took it out of the van, and the reading was 12.91 volts.


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## DABurleigh (May 9, 2005)

Back to square 1 I think. Why, precisely, do you think you have a problem?

Dave


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## ronin56 (May 25, 2007)

Partially because I wasn't expecting it to charge fully from flat with just a two hour journey, partially because I wasn't expecting to get more than 13 volts from a 12 volt battery and partially because of comments elsewhere that such a reading meant my battery had a fault. Not to worry, I'll put it back on and see how it goes!


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## UncleNorm (May 1, 2005)

Hi ronin!

As Dave has suggested...



> I can definitely say there is insufficient information to conclude whether you have any problem.


... a little more info would be helpful.

Do you have just the one leisure battery?
Do you have lots of halogen light fitments?
Do you have a Truma Combi-boiler where the fan runs most of the time?

Anecdote: To avoid the problems of a flat leisure battery, I fitted a second, and off we went on a Thursday for the weekend. By Saturday teatime, the batteries were screaming "Charge me!" After just two days!! Out come the meters, in the hands of very helpful MHF friends who declared, "There's nothing wrong with your batteries!" I ran the engine for 45 minutes to put some charge back into the batteries.

Next move then was to change all the halogen to LEDs. That gave me 3 days, instead of 2. I also added a 120w solar panel. That sorted the problem, unless we're in a deep mid-winter scenario!!

After caravanning and having just ONE battery last a fortnight, I guess it comes as shock when action needs taking so soon with a MH. Que sera! :roll:


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## DABurleigh (May 9, 2005)

Ron,


ronin56 said:


> Partially because I wasn't expecting it to charge fully from flat with just a two hour journey


It won't.



ronin56 said:


> partially because I wasn't expecting to get more than 13 volts from a 12 volt battery


You will.



ronin56 said:


> partially because of comments elsewhere that such a reading meant my battery had a fault.


I don't know who said what about what.

Dave


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## Morphology (Jul 23, 2010)

If we're talking about a wet (ie Lead-Acid rather than Gel) battery, then I believe the following open-circuit voltages apply:

12.6 to 12.80V - Fully Charged 

12.40V - 50% Discharged 

10.70V- Fully Discharged 

So. Sounds like it's fully charged to me.

If it doesn't power the 12v appliances in the van for as long as you think it ought to, then you are going to have to put an ampmeter in series with it, and see how much current is being drawn.

As @UncleNorm says, you'd be surprised how much current things like halogen bulbs, heating fans and TV can consume.

Morph


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## ronin56 (May 25, 2007)

Thanks for the helpful replies guys. To answer some of the questions: 

Yes, I do have only one leisure battery and it's lead acid.

Yes, I do have some halogen lights but didn't use them much on this occasion, the main lighting is by one of those 'eco' bulbs.

Yes, I do have a Combi boiler and it was in action for most of the first night. It's my suspicion that this was the main culprit. I also used an inverter to charge my laptop which I think maybe finished it off. The television was also in use.

I have a solar panel. 

As for the comment about not charging fully in a two hour journey, the evidence is that the night before I left the aire the battery wouldn't power the lights but when I tested it today it appears fully charged! The engine battery is new and recently fully charged so the only thing I can think is that most of the journey's generation was dedicated to the leisure battery.

Anyway, from what you've told me it appears that my battery is probably in good order but I need to be more judicious in its usage. I will change the halogens and be more aware when using the heater. Normally we go to campsites with hookup so I didn't really know what to expect when the leisure battery was put to the test. At least it has been a learning experience!

Thanks again.


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## UncleNorm (May 1, 2005)

Thanks for coming back to us Ronin. It's good when we get feedback.

One thing I did not mention which you did was the television... If AuntieSandra and I watch DVDs for 2 - 3 hours in an evening, and have the heating on, I would not be surprised to see our batteries - we have 2 - down to 60 - 70%. Without the solar panel, we'd struggle to get another evening out of the batteries. With the solar panel, the batteries can be back up to 100% by the time we're up for breakfast. In the summer, that could be 8.00am!! In the autumn, when the heating might be on through the day too, the batteries can take a big hit. 

Fortunately, we seldom stay for more than a couple of nights without electrics. The engine restores the batteries whilst we're driving. 

To maintain the engine starter battery when parked-up, we have a Battery Master. This takes excess charging from the leisure batteries and sends it to the engine battery. Three and a half years, not had a flat battery. :roll:


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