Battery Light Staying On

[lankeela]

When I start my van sometimes the battery light stays on. If I turn it off and restart it, it usually goes off, sometimes taking a couple of restarts. It doesn't do it every time, and always starts ok if I've driven it a little way and stopped somewhere. I haven't done any long journeys lately, but assuming at some point it won't start at all. Is it likely to be the battery or alternator?

[TonyV]

My guess would be alternator, if you have access to a multimeter check voltage without car running, should be 12v and then check with motor running at 1200 rpm, would expect over 13v. If not you have a problem.

[davebro]

How old is the battery, does it start ok or sound like it's struggling to turn the engine over?
Any garage (Halfords) should be able to do a quick load test on the battery to determine it's condition,
Usually if the light stays on when the engine is running it means the battery isn't charging - so alternator or drive belt problem.

[TonyV]

However having reread your post if it starts intermittently could be battery connections or a bad earth.

[bhg481]

I'd go for the alternator - the electronics in the charging circuit might be playing up.

[lankeela]

Thanks was going to drop in at the garage and get them to check it, just handy to know what its likely to be.

[TonyV]

Good call bhg, I had to replace diodes in an alternator, when you could, and weren't a sealed unit.

[lankeela]

Booked it in, they are going to check it first and hope its just a loose connection.

[TonyV]

OK lankeela, hopefully a loose connection, don't be surprised if it isn't

[douglas9401]

"Any garage (Halfords)..."

Please, I'm not supposed to laugh heartily until my tablets have had a chance to start working.

[davebro]

Just a suggestion where can drive in and get some attention straight away. Not recommending them for serious work (I haven't used them).

I'm finding our local National Tyres quite good at the moment - on price & service.

[Espresso125]

i'd check your battery connections first, and the earth to bodywork lead
staring the engine repeatedly will knac*** the battery up quickly ,

[lankeela]

Van been in and checked, as I'd driven a little way before taking it in of course it didn't do it when they checked it. They left it a while and tried and again it was fine. Left it overnight and this morning it started straight away and the light went off the first time! They checked the battery and it had a full charge so they think it might just have been the brushes on the alternator. Went to pay and guess what they said? 'No Charge'! Which was a nice surprise.