battery question.on a 407

[trem1]

Well ive gone out to the car again and its got a flat battery again. It did this 2 weeks ago and the RAC said it was the battery, which is under warrenty so i took it back to the shop, who among other things said they couldnt check the battery asit was only showing 11.5volts and needed to be charged overnight or a run with ALL electric's switched off for at least 500 miles(bullshit i know)
So ive left the car all week, went to start it and clik..

Checked the voltage on the battery and its showing 12.35 Volts, would that be enough for just a clik,and no start??

[steve_earwig]

I'd expect it to have a go. What does it measure when you turn the key to "start"? When the battery died on my D8 it still measured something reasonable but had all the cranking power of a wet fart.

Check it right on the battery posts - one of the clamps might be loose or corroded.

[trem1]

I'd expect it to have a go. What does it measure when you turn the key to "start"? When the battery died on my D8 it still measured something reasonable but had all the cranking power of a wet fart.

Check it right on the battery posts - one of the clamps might be loose or corroded.

dunno steve im on my own and its dark, there speed clamps but are tight and i checked again on the bench before i connected the charger.
Any idea how to check the amps ??

[steve_earwig]

Oh, if it's in the car you could put the headlamps on (gah, too much else on my mind, sorry)

If they light up, try starting it.

[Doggy]

12.35 is fairly flat, (fully charged = 13.2 V. Fully discharged = 11.2 V.)

To hazard a guess, it looks like you have a charging problem / wiring issue. If you can re-charge it / get it going check the battery voltage, engine running, you should get about 14 V.

[trem1]

12.35 is fairly flat, (fully charged = 13.2 V. Fully discharged = 11.2 V.)

To hazard a guess, it looks like you have a charging problem / wiring issue. If you can re-charge it / get it going check the battery voltage, engine running, you should get about 14 V.

the RAC man did all the checks and it was/is charging fine. just need ammo now as the factors shop seem to want to wriggle out of changing it

[jasper5]

If you turn the key and the dash lights go dim or flicker when you get the click the battery is the problem.

If you get just a click and no flicker with the dash lights you may have a starter problem.

You can't test a battery unless it is fully charged.

[trem1]

If you turn the key and the dash lights go dim or flicker when you get the click the battery is the problem.

If you get just a click and no flicker with the dash lights you may have a starter problem.

You can't test a battery unless it is fully charged.

yea dashlights/interior lights etc dim when the keys turned

[trem1]

charged overnight and was 13.7v
took it back to carshop who tested it yet again and said its a good battery. He later rang me and asked me to go to ATS to use there meter to check which i did (and found out it was his mate ) And its a good battery, he did however give me a printout..see attachment, which says the start capacity is 65% i dont think that shows a good battery but hey what do i know.
So i came home and with my own meter on a warm engine IE: no glowplugs i got

12.79 whilst stood

9.77 whilst cranking

14.22 whilst engine running

your thoughts please

[jasper5]

Not sure that an overnight charge for a high capacity diesel battery is enough to fully charge it.

I usually charge diesel batteries at least 24 hours.

[trem1]

Not sure that an overnight charge for a high capacity diesel battery is enough to fully charge it.

I usually charge diesel batteries at least 24 hours.

the battery charger said it was fully charged ie: green light
If i put it on charge sunday evening till tuesday evening would that guarantee a full charge ??

[jasper5]

You would have thought so.

Something isn't right, can't tell without the car/battery to test.