Truma Solar Dual Battery Charger Overcharging

Aug 25, 2006
My latest Coachman VIP 2019 has a Truma Solar Dual Battery Charger 100w system fitted.
The Coachman display panel only indicates the leisure battery overall voltage not charge, or so I believe?
It's feeding a 120w sealed wet battery and it is in store. My concern is safety and fire risk?
One the first month of ownership I have noticed the leisure battery voltage grow from 13.4 volt to as of today (Overcast) 15 volts, which I have never seen before on any of my caravans or campers?
The the tempriture probe has not been fitted but the battery dose not feel warm.
The Coachman gauge is showing 15 volt with the warning of overcharge and contact your dealer it it continues? Which i am trying to do with little success to date. The voltage range is in the manual shown as 8 - 15 V but the charging for a wet battery is shown as Absorbtion range 14.6 V Float 13.8 and Equalisation 14.8 V with a Maximum charging voltage of 16.6 V
Should I be concerned this will either damage the battery and or cause a fire risk from overcharging?
Thanks Peter
Nov 16, 2015
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Welcome to the Forum Peter, If you have the operators manual for the Truma system, is there a phone number in that to contact Truma direct, rather than your caravan dealer.
Mar 14, 2005
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Yes you should be concerned about overcharging any type of accumulator, But I do wonder if your information panel is actually showing the correct voltages. Historically analogue caravan voltmeters have been hopelessly inadequate and digital displays are often several tenths of a volt out when compared to a calibrated DMM.

Also if the charge controller is a multistage device, it might not have reached the maintenance charge regime. Whilst you contract is with your seller, I would be surprised if a caravan dealer were fully up to speed on such devises, So as Hutch suggests contacting Truma may be your best bet.
Oct 3, 2013
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As the Prof says the voltmeters caravan manufacturers fit are not accurate.I've found the difference between the voltmeter fitted and a digital multimeter to be as much as 0.5volts.
Haven't checked the charging current yet,hope to do so soon.
If a battery is being charged it can get slightly warm (also happens during discharge)
Jun 17, 2011
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Whilst sorting this out you might remove the fuse. This is near the controller for the solar panel. I’ve got the same caravan so would be pleased to hear the outcome.


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