Ok, what are some of the things that can kill my battery overnight? This has happened twice in the last two weeks. The battery is only a month old, the alt. is new. I do not have the factory changer installed (have read they can kill a battery). Since this is intermittent it is a tough one to diagnose. I jump it, it starts runs great battery charges and runs holds a charge. Tested fine at auto parts store. MFU? Keyless entry module? A sticking realy? Anyone delt with this before?

Dodger

 

My first guess (based on ZERO electrical prowess) is that you've got a draw going on you don't know about. Closest thing to your three guesses is a sticking relay right? I
Not sure how to find it short of test lighting everything or popping thefuses one at a time and waiting for it to NOT die.

 

Wild guess; maybe a sticking door switch, dome light stays on, draining the battery.

 

A test for the battery - take off the negative lead and leave it overnight as you normally do, attach and see if it crank up. That would remove the battery from the list of possibles.

You'll need a lot of time or a sensitive amp meter to find the drain, then remove fuses one at a time to isolate it. One of the problems with this is various loads on the battery can be very high current, and mess up a meter on a sensitive scale. So don't turn on head lights, etc. You remove a battery lead and put the amp meter in series with it. You should get some sort of drain reading. Some will be normal, because there are things like the keyless remote that have a small drain. Once you see the drain you can start unplugging fuses to narrow it down. But before you get started take out both dome light bulbs and the cargo area bulb, they will show a lot of drain when you open a door to get at the fuse panels.

 

Im dealing with this right now as well, I read on other forums that the alarm system is the likely culprit followed by a bad relay. Im gonna tackle this over the weekend. The way Ive always tested for this is to pull the negative terminal, place the black wire on your multimeter to the neg post on the battery, the read wire to the neg battery terminal, plug the red wire into the 10A or 20A port on the multimeter and switch it to amps. If there is a large amp pull start pulling fuses and relays till one of them drops the amount of amps drastically...then you know what is pulling power.

 

That's way better than my idea

 

Have you checked your belt routing?

 

Start with Spike's suggestion very belt is properly routed.

Secondly, I keep my overhead light turned to the off position.

If it is a drain, you can get in the habit of disconnecting the negative terminal until you resolve it.

An ammeter in series with the negative terminal will show you how much current you are draining, and go from those results.

You make have corrosion bridging a path somewhere.

 

Here's reading from my 97 D1, engine off, doors closed. I have an aftermarket radio, and the OEM CD stacker under passenger seat is unplugged. When I measured on the negative lead, I got the following:

Initial connection 225 milliamps (mA), drops to 155, the after 10 seconds drops to about 20 mA. Hood alarm switch seems to make perhaps 1 mA change.

Took out fuse box fuse MF 3, dropped to 2.9 mA. The clock has to run on something...

Used RAVE to see where MF 3 went, and then unplugged:

Sattelite fuse panel 1, fuse 1, 15 amp unit - dropped from 20 to 13 mA (central locking)

Sattelite fuse panel 2, F6 - increased to 62 mA! Not sure why.

The central locking monitors door signals, so it will always draw power.

Now I don't know if my numbers are the norm. 20 milliamps is not a lot to a big fully charged battery, so it would take extended parking for many days. The idea that an unplugged fuse can cause one module to signal another, and increase power drain, is possible. All those extra luxury features have power demands, and some are always on.

I think the average Rover would need a much higher draw to knock down a battery overnight.

At my work we have boats with solar panels to keep batteries charged, disconnect switches to keep batteries from being drawn down to zero during periods of inactivity, etc. We have some vehicles that don't get much use, and Harbor Freight has some cheap solar panels that plug into the lighter socket to keep the battery up. I've also had corrosion in places that drained power and killed batteries.

 

Well I must thank everyone for the info. I tried most of these multimeter last night. The problem is intermittent. Got in this morning and it cranked right up. It has sat for two weeks when I was at National Guard training and start right up, and that was last month. I kept checking on it last night to see if the dome lights came on, and they didn't. It has only killed tha battery twice in two weeks. I have intermittent problems!