Knackered battery or alternator or something else?
Discussion
Just wanted your advice before I go spend cash on the wrong thing!
I had my lights upgraded to halogen ones (that bit is good, I can now see in the dark, which is nice!)
However since then it seems as if I am pulling more juice from the battery than it is charging. I can go for about a week then it dies and I have to jump start, leave it running for half an hour and it is then fine.
This would seem to indicate that the battery is ok but that the electrics on the car are using more juice than is being recharged. So which bit do I replace?
The battery? Been on the car since I have had it. Should I go for more powerful one (circa £50)
The alternator? Been on the car since I have had it and apparently it is the upgraded version anyway because of the year it was built.
The brushes? I have heard these can wear unevenly, but would it cause this problem and how easy are they to replace?
A.N Other? Something that I haven't thought of?
Any advice gratefully received!
Cheers
Ace-T
I had my lights upgraded to halogen ones (that bit is good, I can now see in the dark, which is nice!)
However since then it seems as if I am pulling more juice from the battery than it is charging. I can go for about a week then it dies and I have to jump start, leave it running for half an hour and it is then fine.
This would seem to indicate that the battery is ok but that the electrics on the car are using more juice than is being recharged. So which bit do I replace?
The battery? Been on the car since I have had it. Should I go for more powerful one (circa £50)
The alternator? Been on the car since I have had it and apparently it is the upgraded version anyway because of the year it was built.
The brushes? I have heard these can wear unevenly, but would it cause this problem and how easy are they to replace?
A.N Other? Something that I haven't thought of?
Any advice gratefully received!
Cheers
Ace-T
This is difficult to answer without testing out the electrics.
Not necessarily, std Halogens are only 55w, so not much different power consumption from what you had before. The battery could be self discharging over time.
Alternatively, a std. alternator should easily cope with the headlights...so it may be duff.
You do really need to get it tested by an Auto electrical place.
Ace-T said:
had my lights upgraded to halogen ones ....I can go for about a week then it dies and I have to jump start, leave it running for half an hour and it is then fine...This would seem to indicate that the battery is ok
Not necessarily, std Halogens are only 55w, so not much different power consumption from what you had before. The battery could be self discharging over time.
Alternatively, a std. alternator should easily cope with the headlights...so it may be duff.
Ace-T said:
...So which bit do I replace?
The bit that's not working properly!! You do really need to get it tested by an Auto electrical place.
Plotless said:
To check the alternator, remove the positive from the battery whilst the engine is running.
Personally I woudn't do this.
If you can borrow a voltmeter it's not nessesary anyway.
Check voltage before starting engine, it should be higher when engine running, even at tickover, look for it to rise as the revs rise and then stabilise when you get to about 3000rpm 'ish and not rise any further as you rev the engine more.
If it doesn't rise at all (or only very slightly) the alternator's probably duff, if it keeps rising the regulator (inside the alt) is duff.
Edited by Dino42 on Sunday 10th December 19:53
Try this for "Something Else"....
Check the battery cable underneath the car where it comes out through the body and routes past the subframe. If it (the insulation) rubs through you get a live contact to earth (body) to the body which acts like a quiescent (sp) drain.
Car starts fine if you use it everyday etc. Leave it for a couple of days and it is as flat as a pancake...
Rub your fingers along the whole length of this part of the cable to check for chaffing through (especially by suframe) - I had a very similar problem and it was fixed with new unsulating material around the cable....
Good Luck.
Check the battery cable underneath the car where it comes out through the body and routes past the subframe. If it (the insulation) rubs through you get a live contact to earth (body) to the body which acts like a quiescent (sp) drain.
Car starts fine if you use it everyday etc. Leave it for a couple of days and it is as flat as a pancake...
Rub your fingers along the whole length of this part of the cable to check for chaffing through (especially by suframe) - I had a very similar problem and it was fixed with new unsulating material around the cable....
Good Luck.
Edited by fwdracer on Monday 11th December 11:12
Thanks for all the advice folks.
Chap in work with volt meter was kind enough to do the measuring thing (he used to be an engineer for a chap who raced minis and I never did get the volts and amps thing
). He checked the volts when off, idling, reving and idling again. He is pretty sure it was the battery that was shot so I got a new one this morning. So far so good.
Anyway I have had the car for nearly 3 years now with the same battery so seems reasonably likely it was on the way out.
Cheers
Ace-T
Chap in work with volt meter was kind enough to do the measuring thing (he used to be an engineer for a chap who raced minis and I never did get the volts and amps thing
). He checked the volts when off, idling, reving and idling again. He is pretty sure it was the battery that was shot so I got a new one this morning. So far so good. Anyway I have had the car for nearly 3 years now with the same battery so seems reasonably likely it was on the way out.
Cheers
Ace-T
Gassing Station | Classic Minis | Top of Page | What's New | My Stuff