Knowledge Base

Now let's do it logically

I returned from a 2 week holiday to find the battery on my MR2 MK2 as dead as a dodo, oh fishhooks!

A new battery was fitted , '30, don't beleive all this guff about special batteries. If a bog standard battery doesn't do the job you've other problems.

I connected the positive lead to the battery, then joined the negative lead in series through a multimeter on the DC Amps range. Oh dear 0.25amps and no lights etc on. This will soon make a battery useless. ie 1 amperehour every 4 hours. 60AH battery from full charge to zero in 4*60=240hours, or 10days!

On reading IMOC Electrical I was supprised that I was unable to find what the base current should be, and many articles suggesting fancy batteries. Lets be serious, if the base current is such that it will run down a battery in a month or so, then there is something adrift and needs sorted.

Pull the fuses, one at a time, and check the current draw, replace the fuse and move on to the next one.

I was stuck without a circuit diagram, this is where I found links from IMOC really useful.

The problem was a duff Alarm ( It is under the passenger side headlamp. Jack up car,remove wheel, little plastic cover, and some of the plastic wheel arch). Ok it is a bit of a pain but a mans got to do....

Without the alarm the base current dropped to 0.02 amps (20 ma)ie roughly 100 days before dead battery,that seems right enough.

Fit new Alarm, job done , no problems since.

I trust this will be of some use to any MR2 owners with a dead battery syndrome and no obvious reason, ie lights left on or boot switch stuck etc.

: Sun Aug 20, 2006 8:09 am

This has come up at the perfect time, My battery has been going dead after around 1-2 days of the car being left.. no lights or electrics on.

How do you check for the draw on the battery..... was a bit confused about that bit.

: Wed Apr 11, 2007 7:52 pm

Excellent article. It is very true that if the battery is being run down over a short period of time continually then something is wrong somewhere.

However a cheap as chips battery with the very bare minimum CCA and Ah rating is a false economy. There's no such thing as too much power in a battery.

Think about it. �30 for an under-powered battery that will struggle in the winter for 2-years then die. Or �50 for something with extra cold starting power that will cruise through at least 4 winters.

Just my tuppence worth [Smile]