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Flat Battery


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hi all this sounds strange !


while on site hooked up to mains the reading for the battery was dropping each day from 13+ down to 11. 5 when we went out and left the awning light on to come back to

that night the lights were very dim ( maybe like me ! )

i thought that if we were on mains

1 it would keep battery fully charged

2 the lights should be on full brightness all the time they were on


we know we were on mains because the fridge was on mains supply and water heater was on

are we missing a trick ?


please advise asap son is using this weekend and don't want him to have problems


thanks all

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Fist - disconnect your clamps on your battery and connect a meter and read off the voltage. If you are getting at least 12v, then the battery charger is okay. Anything below then it is'nt.


Check your fuses and circuit generally.


Come back if you still have no result,




Pete of the BO

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When on EHU the 12 volt supply in the power centre is connected to the battery to recharge it and also to power the 12 volt devices in the van. The fact that your battery meter has dropped despite being on EHU and now the 12 volt lamps are dim would indicate that the power centre has no 12 volt output so the van has been running down the battery. This can be proved by temporarily disconnecting the battery and any 12 volt light will go out.


How the charger gets it own supply varies from van to van but the obvious things to look for is a switch to turn it on, mcb trips to drop and remove the 240 volts mains from the charger or a output fuse blown on the 12 volt side. As a quick fix you could reconnect the car and run the engine for a while to top up the battery a little. While doing it again all the 12 volt circuits will go off as the engine is running. Given the time of day there is little else you can do at the moment.


If every thing is OK but still with no output from the charger/supply then there is a strong possibility it has failed. Until you can get that repaired then the only option is to connect a separate charger to the battery powered from the van mains As you are asking it to recharge the battery and power the van 12 volts you will need a full charger in the region of 8 Amps at least if not more. In the meantime you should avoid drawing any more power from the battery as when the lights are noticably dim the battery is to all intents flat and to try and draw more from it may cause permanent damage.

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Hi toanda.


For your lights to become very dim, it is obvious that the battery is not being charged by the caravan charger unit. Assuming that you have a multi-meter (and know how to use one), I suggest that you do the following: -


There is usually a fuse in the lead from the charger to the battery. Have you located it and checked that this is intact?

Have you checked that there is 230v. being applied to the battery charger unit from the mains distribution board in the caravan?

If there is not, check all MCB's and any separate RCD that may be installed in the mains distribution board.


Incidentally, in order to charge your battery, you should be getting a 13. 8v. output from your battery charger. If the voltage is less than this value, then there is a fault with the charging unit (See table below showing battery voltages and state of charge)


Open Circuit Voltage (12 V) Approximate charge

12. 65 V = 100%

12. 45 V = 75%

12. 24 V = 50%

12. 06 V = 25%

11. 89 V = 0%


Running the above suggested checks should indicate which area the fault is located, but if you 'draw a blank', the come back and we will dig a little deeper.


Hope that this helps,




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