# leisure battery issues!!



## seanoo (Mar 31, 2007)

hi everyone, now for my next problem!
i have two 110ah leisure batts. i also have 200 watts of solar panels on the roof and mppt charge controller. the problem is that the panels charge the batteries all day up to 13.8 v. then 4 hours after dark with no use the voltage reads 13.2 volts (at the terminals with a voltmeter) this seems a little high to me but i'm sure someone will put me right. anyway i hope your not too bored yet! here comes the second half-- i put the tv and sat box on 45watt telly and a pace minibox , voltage drops to 12.6 and stays there for about 1 hour then then drops to about 12.2 after another hour. after that it drops very rapidly to below 11 volts. switch off everything and voltage comes back up to 12.9 volts. i know this is a bit of a curly one but would like to hear a technical explanation if possible. are my batteries nackered? they hold a charge nicely but dont seem to have any capacity to run the tv for more than 3 hours tops! also the voltage seems to come up to 13.8 volts very quickly the next morning when the panel start to do their job. all the best sean


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## Drew (May 30, 2005)

Hi,

One of your batteries might be faulty or even both of them. Have them checked out at your local Battery Dealers, only they can give you an accurate answer to your question.

Regards

Drew


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## DABurleigh (May 9, 2005)

"hear a technical explanation if possible. are my batteries nackered?"

Using a technical term, yes.

If you had a significant unknown load the solar wouldn't be managing to get the voltage up so well.

Dave


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## sallytrafic (Jan 17, 2006)

All I can add to Dave's post is that I think (k)nackered is spelt with a k


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## TDG (May 26, 2009)

sallytrafic said:


> All I can add to Dave's post is that I think (k)nackered is spelt with a k


Now we're getting highly technical :lol:


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## weldted (May 1, 2005)

*battery capacity*

Have you tried separating the batteries? First a simple one, check the engine batteries voltage with your meter with the engine running, then the leisure batteries the voltage should be the same within .5 of a volt. You say you have a mppt regulator, on mine the maximum charge point is adjustable, as in an ideal world your leisure batteries need 14.4 to 14.8 to fully charge them, do you have an indicator light that show when the controller thinks the batteries are fully charged again this is adjustable.If charging from the mains your standard onboard charger probably is regulated to 13.8 volts to prevent gassing. try charging on hook up if possible overnight, then switch off charger disconnect both leisure batteries after approx one hour if they are fully charger they should read 12.8. The reason for waiting one hour is to allow the free surface charge to clear. It is probably the one or both of your batteries may be faulty and ideally both should be renewed at the same time or the old one will pull the new one down to its level. But the checks i have suggested only cost time and you will kick yourself if it is not your batteries??


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## C7KEN (May 27, 2005)

Hi Sean
I get the same sort of readings on the control panel over the door. I dont go as low as 11v but putting on the TV and Sat etc the voltage shows an immediate drop from over 13v to just over 12v. Are you saying that all your figures are taken direct from batt terminals with a meter? and not by reading the control panel meter. My 3 batteries were all changed at the same time last year so i'm fairly sure they are OK. Infact since then I have disconnected 2 at a time and the readings on each individual one when left connected is the same I think its the original equipment control panel meter that is not accurate. With the engine running it never shows over 14v and I also have a Sterling B2B charger connected so I would expect a higher reading some of the time I always have enough power so I stopped being concerned about it. Maybe I will get the multimeter out and check the voltage at the terminals and see if it is different.


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## DABurleigh (May 9, 2005)

Yes. Good point. All subsequent advice presumes OP facts are true; life is difficult enough 

Dave


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## seanoo (Mar 31, 2007)

All subsequent advice presumes OP facts are true.

why wouldnt they be dave? 

thanks weldted , thats the sort of advice i was looking for. will have a go and see what happens. all the best sean


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## DABurleigh (May 9, 2005)

If the meter readings are not a true reflection of voltage at the battery terminals, as Ken questions.

Dave


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## seanoo (Mar 31, 2007)

hi dave , i thought the "at the terminals with a voltmeter" bit in my op sort of tells you that my readings were not off the panel. regards sean


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## DABurleigh (May 9, 2005)

Ha ha indeed, sorry about that! 

I should have had the courage of my convictions which led to my original post rather than be led astray by that Ken! :-D

Dave


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## C7KEN (May 27, 2005)

I know the 13.2 volts was at the terminals with a meter but was questioning whether the later readings were taken in the same way. It could have been by just glancing at the panel. Now that we know they are maybe new batteries are necessary


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## seanoo (Mar 31, 2007)

hi ken, hows things? i did all the measuring with the said voltmeter so it was as accurate as possible. my panel is the same as yours in the way it just makes up numbers it wants!! not reliable at all. all the best mate , sean


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## peedee (May 10, 2005)

I would forget all about voltages and loads. Whilst voltages might give you an idea as to the state of a battery the best way to check how they are doing is with a hydrometer which you can buy from any good motorist centre for about £3. Measure the SG (specific gravity) of each cell. ( there are 6 cells in a 12volt battery)Most hydrometers have three markings on them, green orange and red, all your cells after fully charging should be up in the green area. If even one cell is down, say in the orange area or even the red, you have a problem and the battery will need replacing.

peedee


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## sallytrafic (Jan 17, 2006)

I think at least one cell and probably most of them are exhibiting high internal resistance. I don't know if this is factual but I remember reading something to the effect that batteries that exhibit prolonged surface effect may have high internal resistance ie the plates may be sulphated.

(Surface effect shows up when a battery retains a higher than normal voltage when it comes off charge. All batteries exhibit this to some extent and it is caused by the fact that the chemical reaction initially takes place at the surface of the plates and then the chemical reactions take time to permeate throughout the plates. The OP stated when the battery came off charge it stayed at 13.2V.)

Impedance testing by a modern battery tester is the only way to be sure, failing that a discharge test monitoring the SGs.


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