Hi all,

I have an intermittent problem with my battery draining. I can leave it for weeks with no problem, but then overnight the battery will drain sometimes.

I have a newer style alternator which has good diodes, a CD player which I have disconnected, and an immobiliser which I initially thought was the problem. If you hold the enable button, down, the lights keep flashing so I thought it must have been stuck down overnight or something. But since I've been keeping the remotes on my desk, I can't see how that would be happening now.

This is a 60ah battery (20h rate), and it's draining enough that it won't turn over, so we're looking at a few amps here. The battery is only a new months old, and works great unless it's decided to discharge overnight.

Ideas?

Nobody?

When you say:
"I can leave it for weeks with no problem, but then overnight the battery will drain sometimes."
Does that mean the battery goes flat after 8 days, or its random?
If its random, I'd check battery terminals and wiring condition for bad / corroded wires or similar. Thats sometimes an easy difference between easy and difficult starting.

It's random. The battery terminals are good, and the battery is definitely very flat when it decides to have an episode (the indicator shows it needs a charge.) I've checked the current drain and it's very low (about 6mA), so it's an intermittent problem, I just can't see where it would be coming from.

Give the battery a proper charge.
I've been having problems with my car lately, I'd have to jump start the car every time I wanted to drive it, but a good day on the battery charger and I can now leave it for a week or more and its fine. Probably just needs a good charge.
If the indicator shows it needs a change theres always a chance its had it. Still under warranty?

There are many things that could be contributing to this. When car is driven how long has it been driven for ? Enough to replenish the battery ?
Don't say it CAN'T be the battery as it is new. We do come across faulty new batteries occasionally. One good way of checking if you have a drain in the system is by disconnecting the battery when you park the car. If it still goes flat it has an internal short or drain (Faulty). If you car has an intermittent drain you can not look for it while it does not exist it has to be there to look for it. Guessing might cause other problems. On the other hand if Drain is there you can trace where it is going by disconnection the wires on fuse box one at a time and see which one clears it. When there is a drain you can tell by connecting a test lamp in series between a battery post and the cable terminal (positive or negative) If there is a drain the current will make the lamp illuminate. if the wire causing the drain is disconnected the lamp will go out . Don't let any smoke out of the wires as it is getting quite hard to find now a days and expensive.

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DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

I fully charged the battery when it went flat. It's either perfectly fine or completely flat.

I've been disconnecting the battery and it hasn't been going flat. The problem is that there is is no drain when I have measured it. As you said Convertible Mini, I can't look for it if it when it doesn't exist. Since I've been disconnecting it, I've been using the multimeter to check the drain as I'm disconnecting it (putting one lead on the battery terminal, and one on the clamp, then disconnecting the lamp). It's usually around the 6mA mark.

Yes it is always annoying and frustrating when there is a drain that is not there when you want to look for it. If it is there you can somehow isolate by trial and error to find out which circuit is draining. Otherwise you have to wait till it comes back. Alarm or radio ? Do your stop lights work with Ignition on or off? Maybe they are coming on on their own but only if they are not controlled by Ignition this can happen.

_________________
DID I MENTION THAT I AM THE BEST SUPPLIER FOR MINI ELECTRICAL PARTS AND REPAIRS?
"Let us remove your "SHORTS"

It really does sound like a alternator diode problem. If it is happeneing quite regularly, try popping the alternator plug at nights. If your problem goes away, you will have nailed it down.

Al