MGB Register Forum

You wouldn't think I'm in work this morning! So 4 weeks of very happy motoring ... until someone spoils it! Went for a spin Sunday and absolutely fine. Cleaning up last night and noticed the interior light did not come on when I opened the door - tried to start and absolutely nothing. Wouldn't turn over and nothing electrical worked. Charged battery for 3 hours and boom - like concorde starting and everything was good. Having replaced lots of bits (see above) I'm thinking duff battery, I left something on (unlikely) or I have a drain somewhere (why has it worked fine for 4 weeks?) When it is used its always day light, only use indicators and sometimes the radio. I'm guessing that a fully charged duff battery, under those minimal loads, could last a while? I am suspect of the radio that was fitted recently in that, with the face panel off (the face panel is not an easy fit and needs some persuasion), a light on the unit is flashing. I'm tempted to disconnect the radio (is there a fuse somewhere?) and get my man to check battery which he did when changing the alternator - I think! I'll check for the hidden drain tonight after work having left the car for 24 hours with a charged battery - if it is draining I'll know.
Any pointers I've missed - thanks.

Hi Tony,
Make sure the radio is turned 'off' rather than the volume just turned right down to zero. If you only use the car in the daylight, you won't notice the light is on! It is amazing how quickly a radio can drain a fully charged battery when left on when the car is not being used.

Thanks Pete I shall. Funny how, since fitting, I've just had a funny feeling it wasn't right. Are they fused somewhere do you know? Thanks

Hi Tony,
It will most likely be fused, especially if a garage fitted the radio, and most likely it will be an in-line fuse near the back of the radio. You will probably need to pull the radio out to get there. Do you have the special extractors to do this - they normally come with the radio.

Afternoon Tony
My original reply appears not to have been posted.
If the radio is wired correctly it will operate when the ignition switch is turned one click. This is the auxiliary position which doesn't operate the ignition system. The radio will stay on until the ignition is turned completely off. The connection is part of the wiring harness and is behind the radio console. If wired correctly the radio will be off when the ignition is completely off irrespective of whether it has been left switched on.
. Vic Butler

Thanks all. Bought the radio off ebay (new) but very old with a cassette player. (Didn't want to spoil the interior with a new after market radio/CD) Don't have the keys to extract but my man will have. So got home and started the motor and ... boom .. 1st time with some gusto. The battery indicator on the battery is showing 'white' = charge battery. Back on charge now and shall use for work tomorrow as its just there and back. As its not my daily drive I'm tempted to just leave and see how we go for a few days. If the battery is losing charge I'll know when I start it. Daft question but with a fully charged duff battery how many starts would you think I'll get if its just run in daylight with only indicators being used? I think someone used the phrase ''batteries can fall off the cliff when duff''
Thanks all.

Hi Tony,
I'm a BGT owner (since 1978) and you may want to consider this solution to keeping the BGT battery in good shape. It's not very easy to get at as you will know, but I just check the electrolyte level once a year and haven't been let down by a flat battery yet.

# Fit a battery isolator switch - nothing too fancy - just a simple on/off with the key in the bulkhead behind the passenger seat. Prevents any leakage and is also a useful anti-theft device. Simply interrupts the earth strap which I think is fine.

# Use a CETEK (or similar) battery conditioner. I have a CETEK fitted and have wired the connector into the battery and have the connector end poking out under the battery lid/carpet so that I can connect the battery conditioner easily and every time I leave the B in the garage. I just leave it on all the time.

IanF.

Evening Tony.
Fit an AGM battery. Totally maintenance free and, unless there is an electrical leak, hold their charge for a very long time.
Take a look at my posting "MGB Batteries."
. Vic Butler.

Ian Fozzard wrote:
> Hi Tony,
> >
> # Fit a battery isolator switch - nothing too fancy - just a simple on/off
> with the key in the bulkhead behind the passenger seat. Prevents any
> leakage and is also a useful anti-theft device. Simply interrupts the
> earth strap which I think is fine.

> > IanF.

Thanks Ian - think I've got one!!! (Don't laugh) There is a switch in passenger well on right hand side which, when made with the engine running, stops the engine. I always thought it was a low level theft device ...... oopppss!!
Thanks

Thanks Vic for the AGM tip.

Evening Ian.
You have a low level anti theft switch. A battery isolator switch is mounted on the vertical part of the rear seat behind the driver and has a removable key.
. Vic Butler