Help.. Voltage drop on a battery. Problem???

It does not seem that your battery was properly charged in the first place. If it was your display should have been reading 12.8 volts. ( after resting from recharging) Our far from new 110 ah battery would drop from 12.8 to 12.6 after power moving out of storage but then normally recover to 12.7. The gauge in our Bailey wasn't the most accurate though, often giving some very strange readings, so perhaps best to check with a multi meter. You are correct in that LED lights pull very little and should not have that effect. Could be you have been sold  a duff battery. Happened to us once. I bought a battery from the shop at our caravan dealer. 8 months later the van was in for service and their tests showed it was in need of replacement. They replaced it under the battery warranty.

You are also correct that totally flattening a battery will damage it 12.2 volts is any empty / recharge me reading. Going below this is not good for battery longevity. Of course, unless you are intending to use the caravan off grid, when on EHU your vans inbuilt chatter will be running the 12 volt lights, fans pumps etc, as well as charging your battery. Even so you do need to sort out if the battery is OK, particularly if you are going to use a mover, as some will not work once the voltage falls below a certain level.

+1  i agree with Stevels post

Agree with the above, the voltage should not drop this low. After charging, the battery will be over 13 volts but will drop back to about 12.7 volts after the “surface charge” has dissipated - a few hours or short application of a load. Batteries differ slightly and the meter in the van will not be very accurate.

I am assuming that the battery is “sealed” in other words there are no removable plugs for topping up with distilled water. Sealed batteries require a different setting on the charger and, of course, you should use a decent charger with multiple stages.

There is no simple way to test a leisure battery other than to see how long it lasts when being discharged. You can test this on the bench by connecting something like an old car headlamp bulb and calculating the current from the wattage. Not much use if you don’t have a good multimeter though so most people just try it in the van and see what happens.

I bought a new battery early last year, did not charge it at all before installing, after install checked it would power the mover ok, which it did, and then left it to do its own thing. my onboard volt meter in the control panel never shows above 12.5v, my hand held shows 12.8v.

Hi

Thanks for all the replies.

Following your advice I've bought a CTEK smart charger and a multi meter. The battery is now being recharged and I'll check it's voltage once the charger has done it's thing.

Thanks

John

Good choice in my view. I have a CTEK & have followed the advice to do a full Recondition every year or so. However, as a newbie Campervanner I need to find out if one should take a different approach to charging Leisure batteries than is recommended for car batteries. 

The CTEK chargers seem to be very good.  (Mine is a MSX 10).  It does get quite warm in the Bulk stage.  I'm trying to 'recover' a battery at the moment, but I suspect it's too far gone and it could well be time for a new one...

David 

I would check that the battery terminals are clean and tight. From the description, I would be looking for bad connections, causing high resistance and volt drop.

John, did you ever get a resolution to your problem.  I am experiencing the exact same in my Coachman 575.  Makes no sense to me.  Voltage drops from 100% to 65% just by putting a LED light on and then back up after.  Connections are tight and battery is new.