Dead battery puzzle.?

[RFC1]

Went to take the beast for a spin tonight but the battery was completely and utterly stone dead,
After "breaking" in i checked if anything had been left on, Nothing.

The car was used last tuesday so only a week since a good run. I dont have the alarm on when in the garage and it has always been fine for much longer than a week previously.

Its a real mystery as how the battery was so absolutely stone dead,
Any thoughts great Cerby experts ??

Cheers Sandy

[mart 63]

A crack in the big fuse?

[bobbins]

How old's the battery?

When they go, they go. If it's more than three years old and not regularly conditioned then it doesn't sound strange for it to die after a week sat around, IMHO.

[QBee]

Before you waste ages trying to check over the whole car, take the battery to your local auto spares indie and get them to test its quality using their fancy battery checker (recharge it first with your battery charger). Batteries typically last 4-6 years, maybe less in a TVR due to intermittent use. A new battery may be all you need.

Once past that, it may be worth getting a local auto-diagnostic guy to check if you have a major battery drain - I am presently searching for a 7 amp drain on my Audi A8. It's something major, like water ingress in the electrics, or a failed and earthing cabin heater (it has one to heat you before the engine warns up and takes over).

Good luck!

[RFC1]

Thanks for the input all. It is regularly on accumate if the car isnt used for over a week or so. Anyway its on accumate now so see what a day or 2 does to it,


Sandy

[fatjon]

The alarm takes the same current set or not. My quick test was to put an ammeter in series with the battery and then unplug the alarm box (behind helmet holder). Mine was taking 100ma so in round numbers a full charged battery dead in 2 weeks. If not it's fully charged it will be dead rather sooner. I dumped it and had a Viper fitted with door popping, proximity and all that nice stuff. It takes 1/10th of the current and never had the problem again. Maybe my alarm was faulty but it does seem to be a common Cerbera complaint though.

With hindsight, and I may be wrong, the siren has a backup battery so maybe that sucks excessive charging current when it's failing?

[sonnylad]

Worth checking the boot light is not staying on, had that once myself and it quicky drain the battery down.