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Battery draining problem
Posted: Thu Oct 02, 2014 7:03 pm
by Tim M
Hi
On my Moggie the battery seems to drain suddenly intermittently. It is running a dynamo and I think the Voltage Regulator is faulty so have purchased a new one. The battery is new. Might this do the trick? Thanks

Re: Battery draining problem
Posted: Thu Oct 02, 2014 9:21 pm
by bmcecosse
It may - if the old Reg was faulty and 'sticking in' at times - but the Ign warning light would then be ON when you switched off... Was it ??
Re: Battery draining problem
Posted: Thu Oct 02, 2014 10:20 pm
by Tim M
No, the light was off.
Re: Battery draining problem
Posted: Fri Oct 03, 2014 7:55 am
by bmcecosse
Well I doubt it is the Regulator... Look elsewhere..
Re: Battery draining problem
Posted: Fri Oct 03, 2014 8:30 am
by Trickydicky
It is possible that your "new" battery may be faulty, was it happening before you replaced it?
Is the dynamo charging the battery, it should read 13.5-14v across the terminals when revving the engine.
Re: Battery draining problem
Posted: Fri Oct 03, 2014 11:47 am
by simmitc
Does it go flat whilst running or only when switched off? Have you checked that it is the battery (voltmeter on terminals, or hydrometer)? If it is just the electrics on the car fail, but the battery is OK, then it could be a loose connection - was the new battery fitted correctly? When it goes flat, does everything stop working, or only some things? Is a courtesy light switch sticking on? All sorts of possibilities, need a bit more information.
Re: Battery draining problem
Posted: Fri Oct 03, 2014 12:35 pm
by Tim M
Thanks for the replies. I have now tested the voltage across the terminals as the car was being revved and all seemed to be working well. When the battery dies the whole car gets knocked out but the culprit could have been my five year old who has been into the car and put the lights on!
I have the new voltage regulator anyway so I'll save it for a rainy day as all sorted for now. Thanks everyone again.
