car battery voltage

[burts]

I have another post about my van not turning over. It struggled to start a few times this week and now will not crank or turn over. Lights and dash work. Windscreen wipers seem a little slower but I can't be certain.

I have read a battery reading 12v is fine however m Haynes manual says a battery under 12.2 is discharged.

So with the van off my battery reads 12.1 and with the lights on or windscreen wipers going it reads about 11.7. So is the battery my problem?

 

[Burnerman]

There's certainly a problem somewhere.....with the engine running, look for 14.4v at the battery with the lights on.
With the engine off and rested for an hour, look for 12.5v approx.
When cranking to start, the battery voltage shouldn't drop below 11v.
A motor factor will happily do a current drop test on your battery, and be even happier to sell you a new one if you need it!
John

 

[burts]

John I have another topic. The van will not turn over.
It had trouble starting a few times this week and today is just finished.

12. 1 with engine off and about 11.7 with lights on. I am not doubled handed to see what it drops too when the ignition is turnt.

By the sounds of it my battery is too low anyway at 12.1?

I know with it running it should read higher to prove the alternator is working. So are we thinking just a new battery?

 

[Burnerman]

It does sound to me that the battery is goosed......even totally dud battery will show around 12v when standing, but when its under load (lights or cranking) the true voltage will be shown on your meter.
The 14.4v test shows that the alternator has a healthy output, which of course needs to be tested.
Can you get a mate to crank the engine while you look at the meter? I usually balance the meter on the screen if I'm working alone.
John

 

[burts]

Not a chance on a sunday night! Day of rest for everyone. Then everyone will be at work tomo morn. If the meter reads 11.7 with the lights on then hopefully it is just a dead battery. It never just all of a sudden stopped. It has got worse this week so that indicates a battery. I will pick one upp from eurocarparts tomo and hopefully be good as I have a central heating system to finish tomo!

No customer believes you when you say your van has broke down!

 

[Burnerman]

Do make sure the battery terminals are tight.....if there's a resistance for some reason, they'll get warm when trying to crank.
Typically a battery will give you 6 years or slightly more, depending on use.
John

 

[burts]

The van is a 53 plate and I think it is the original battery. I will check all nuts tomo. No tools out on a sunday

 

[Burnerman]

If its the original battery, its on borrowed time......be lucky mate!
John

 

[JulianP]

If the meter reads 11.7 with the lights on then hopefully it is just a dead battery. It never just all of a sudden stopped. It has got worse this week so that indicates a battery. I will pick one upp from eurocarparts tomo and hopefully be good as I have a central heating system to finish tomo!

!

Don't do that, you must test the voltage with the engine running to ascertain if the charging system is OK or not. Chances are the alternator is fubarred or the belt is slack/missing.

The battery is likely dead because it's not receiving any charge - changing it will not cure your problem - well it will for a few days probably!

I'd not use Eurocarparts for a battery if you do find it needs one - they're OK but personally speaking I'd sooner give my hard earned to another motor factor.

 

[burts]

Right Julian, I know I have to test the charging system but the van does not start so I can not do that. Obviously if I buy a new battery and it is not up at 13- 14 v or what it should be when charging then I shall take the van straight to my mechanic.

I had a full service and my timing belt changed 2 months ago. Nothing during that could have affected anything?

 

[Mursal]

If its the battery, why did it not start when you jumped it from your sisters car?

 

[AlanE]

If its the battery, why did it not start when you jumped it from your sisters car?

If he was using cheap quality jump leads, and his own battery was that low, there could have been too higher voltage drop accross them so he still didn't have enough power to start vehicle.

 

[JulianP]

Right Julian, I know I have to test the charging system but the van does not start so I can not do that. ?

Well you've got to get it started so either get some good jump leads, run it off down a hill, snatch it with a tow rope or get a few mates to give you a push!

Chucking a new battery in it without any attempt to verify the charging system is working is taking about a 50% risk of wasting your cash....