flat battery - Help please !!!!!!!
flat battery - Help please !!!!!!!
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Discussion

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
Have not been out much recently. About three weeks. But have been letting the car run for 15/20 minutes every third day or so.
went to move the car out of the garage tonight and youve guessed it .. a dead battery.
Question oh car guru`s .. Would you expect the battery to go dead with me only running the car as I have been ? Usually fires staright away..and.. If not, what would you be checking for ?

Many thanks
Adrian

pies

13,116 posts

285 months

Monday 3rd December 2007
quotequote all
When you started the engine up did you take the revs up to above 2k,if not the alternator doesn't charge the battery IIRC smile

jimed

1,508 posts

235 months

Monday 3rd December 2007
quotequote all
I would have expected your battery to have quite a bit of charge in it after the running its had, I assume with the charging light out and it doesn't need to be drastically topped up with distilled water. How old is it though as they can just go - even newish ones can as well but then its a warranty job. I have a 3 year warranty one on the S and it was replaced after only 8 months as it just failed on one cell but that's all it takes.
Jim

Hoover.

5,993 posts

271 months

Monday 3rd December 2007
quotequote all
I've 2 duff batteries this year..... totally drained, not able to charge.... all replaced under warranty......

griffo52

18 posts

274 months

Monday 3rd December 2007
quotequote all
For checking the battery correctly you will need a digital voltmeter.

It would also help is you have a trickle charger.

In the first instance it would be worth charging the battery with a trickle charger for a day or so.( always turn off the charger before connecting or disconnecting the leads because of the risk of explosion )
When you have charged her for a day or so, turn the charger off & leave her for a few hours, then using your digital multimeter check the voltage accurately.

It should be 12.50 or above, any less that this indicates the battery is on the way out. If it is above 12.50 it just means that you need to trickle charge her once a week to keep her in good condition.

The Motor trade sells battery conditioners which are very low chargers which you leave connected, I prefer not to leave them permanently connected but to put them on for a dy or two every 2 weeks.

This should keep your battery in OK condition during the winter, but remember Batteries all have a shelf life and maybe it's time to replace yours.

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
pies said:
When you started the engine up did you take the revs up to above 2k,if not the alternator doesn't charge the battery IIRC smile
In a word Colin `No` ! I usually drive the car every week without fail but the last 2/3 weeks I havnt had time. I will recharde my newish battery (6 months old) and re-try ! Lest hope thats all it is. Cheers !

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
Hoover. said:
I've 2 duff batteries this year..... totally drained, not able to charge.... all replaced under warranty......
Steve, hi matey. If you remember last year I had this battery replaced under warrantee. Was perfectly fine until today. Also this is the longest I havnt driven the car. Cheers.

GreenV8S

31,017 posts

313 months

Monday 3rd December 2007
quotequote all
Twenty minutes of daytime driving should be ample to replace the battery charge used to start the car.

If you have any heavy electric loads on, it can take much longer.

If the engine is just sitting at tickover it has relatively little charging capability and will not put much charge into the battery. (If it's at night with the lights on, fans on etc and left idling it can actually flatten the battery with the engine running.)

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
GreenV8S said:
Twenty minutes of daytime driving should be ample to replace the battery charge used to start the car.

If you have any heavy electric loads on, it can take much longer.

If the engine is just sitting at tickover it has relatively little charging capability and will not put much charge into the battery. (If it's at night with the lights on, fans on etc and left idling it can actually flatten the battery with the engine running.)
Cheers. pretty certain you are right and it hasnt had a chance to recgarge properly. It has been left running at tickover so i guess no suprise really.
Ah well, time to find that charger !

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
sorry, someone please remind me,,, is it positive lead off first then positive on last when refitted ? sorry to ask a dum question !

tvrgit

8,489 posts

281 months

Monday 3rd December 2007
quotequote all
Mr Clifford said:
sorry, someone please remind me,,, is it positive lead off first then positive on last when refitted ? sorry to ask a dum question !
Earth off first and on last.

Mr Clifford

Original Poster:

816 posts

256 months

Monday 3rd December 2007
quotequote all
tvrgit said:
Mr Clifford said:
sorry, someone please remind me,,, is it positive lead off first then positive on last when refitted ? sorry to ask a dum question !
Earth off first and on last.
Cheers beer