Battery light staying on

[Walter Sobchak]

The battery light on the dash doesn't go out after the car has been started, the car was sitting for a while and the battery went flat, I then charged it up and this is the first time its been driven and the light stays on, does this happen quite alot?, faulty warning light showing up?(I'm hoping) or is this an alternator problem?, or a general TVR electrical niggle?.
It displayed 8.8 volts while cranking over and went back up to 11.5 while being driven, car was fine until left sitting and the battery becoming flat, any ideas what it could be?.

[SP6 Animal]

Battery should be showing 14V whilst running could well be alternator.

[Arapo]

Correct - when the car is running the indication should be around 14V.. It should be above 12v when you switch the car on, before you start it up.

Not sure how old your battery is, but sounds like you need a good charge or a new one...

[Walter Sobchak]

What would be the cause most likely, the battery or the alternator?
The car has cut out again and the battery light has stayed on, it was absolutely fine before it was left sitting a while and allowed to go flat, which makes me think that it's less likely to be the alternator

Edited by Walter Sobchak on Thursday 8th April 15:23

[NCE 61]

Walter Sobchak said:

What would be the cause most likely, the battery or the alternator?

Or the 100 amp fuse which is located underneath the airbox.

[Konrod]

Hi Walter. The only real way to be sure is to access the battery, and then measure the voltage across the battery with engine off, and repeat with engine running. Should be more than 12V (and preferably around 13V) with engine off and between 14V and 14.4V with the engine running (be careful with the probes when you're doing this). Actually, you may be able to check this at the Anderson connector - anyone else know???

If you don't have 12V -13V with engine off but do have 14V+ with engine on, battery is stuffed. If you don't have 14V+ with engine on then alternator isn't charging or the fuse between alternator and battery has blown ("mythical" 100A fuse - not sure where this is on the Tuscan).

HTH

[Walter Sobchak]

NCE 61 said:

Walter Sobchak said:

What would be the cause most likely, the battery or the alternator?

Or the 100 amp fuse which is located underneath the airbox.

does this sound like the fuse could have gone?, I'm not sure what this fuse actually does but if it's between the alternator and the battery this sounds most likely as the car was fine before the battery went flat.