Battery will not hold the charge.

[motrroc]

Hi lads.
I am having trouble getting my mini to start consistently. Initially the car would need to have being running every second day or else the battery would go flat. I had both a reconditioned alternator and then a new alternator put in as well as a new battery but the problem is still there. I started disconnecting the battery after every journey and that worked for a little while but now the only way to get it started is by jumping (it won't even start from a portable booster kit). My head lights dip slightly when the car is ticking over which suggests to me that there is a problem getting the charge back to the battery. I am wondering if someone could point me in the right direction to get this resolved.

Cheers

[woody]

You havn't said which model of mini you have but MPis seem to suffer most with this problem and its usually down to bad earths. The same could apply to any model of mini though.
1. Start with a known good fully charged battery fitted in the car.
2. Measure voltage at battery, should be 12v.
3. Start engine and measure voltage at battery, should be 13.8v.
4, Turn on lights and wipers and measure voltage at battery, should be about 13v.

This will tell you that the charging circuit is working ok.

[motrroc]

Thanks for the response. I have a 1994 mini cooper. As far as i know it is MPI.

I will definitely give that a go because i could have a faulty battery on my hands. Having carried out that test before however i was able to get the 12v from the new battery i had bought at the time. When i tested with the engine i was getting slightly higher than 13.5V. When all of the wipers, lights and heaters etc were on, the voltage was below 13v. I am wondering if i might have an exposed wire somewhere along the way that might be draining the power from the battery.

Cheers

[woody]

A '94 Cooper will be SPi.
What (if any) changes have been made to original wiring , Stereo ,spots, alarm, central locking,USB charger?

[motrroc]

The car was rebuilt around ten years ago. New spot lights, new stereo and speaker system placed in under the back seats. Last week i noticed that when i was putting my head lights on, the radio skipped in sync.

[woody]

Most stereos and amps have two power supplies, one permanent for memory and one switched with ignition.Incorrect wiring or faulty stereo could drain battery so I would disconnect altogether until problem is solved.