Battery looses charge

[RNRMF]

Yo.

My battery seems to loose charge slowly, if I don't use her for a couple of days it struggles to turn over and is dead after 3/4 days of not using it. The battery is new-ish and good as I replaced it shortly after I got the car because of this problem.

It's getting on my tits now, any ideas what it could be?

[t boy]

bad eath

[RNRMF]

How do I find it or will it only be either the neg connection on the batt or the earth strap on the engine/bulkhead?

[t boy]

it is more then likely the one on your engine but i would change both there only about £4 or could be your alternater (think i spelt that right )

[Tommy Cooper]

my guess would be alternator can you check the alternator output with an volt / amp meter ???

[RNRMF]

Cool, will replace them sometime then.

Colm: I have a multimeter but zero knowledge of how to use it - I bought one ages ago because it was cheap and looked cool :LOL:

[Iceman]

Get a multimeter and set it to 20 on the volts part connect it to your battery and see if you have a good 12volts. Then start your car and connect it to your alternator the big brown wire and earth. Then see if you have about 13.5 volts from there if both are good you have a drain. This could be a short somewhere or as steve said a bad earth. Or if you have an accessory on like a clock it could be that draining it.
FAZ

[RNRMF]

Cool, cheers for the info guys. I'll give that a go.

[McDuck]

mine did the same thing.. turned out to be the alternator not working properly

[STEALTH GT]

I HAD A PROB LIKE THIS A WHILE AGO ON MINI JINX :rolleyes:. IT TURNED OUT THAT THE STARTER MOTOR WAS BEGINING TO SEIZE UP AN WAS GETTING OLD AND LAZY AND WAS JUST EATING THE BATTERY EVERY TIME I TRIED TO START THE CAR.

[chrisls]

A good way of testing a drain is....

Disconnect the battery, and stick the multimeter on 'amps', should have a higher rated one, maybe 10 amps, which will need the wires changing over a bit probably. Then connect it to the battery and the battery lead to complete the circuit again.

This will tell you the current flowing in/out (the same thing) the battery when it is switched off doing nothing. It should be less than 0.5amps, little bit of power to things like the radio. If it's a couple of amps, more than 2 there's a problem.

The regulator in the alternator can brake. It is designed to give a steady voltage on it's output but the diode inside can instead drain the battery when the alternator isn't charging.

WARNING! This method might brake your multimeter! Or, at least blow a fuse inside it if the current draw is more than the multimeter can handle. If you want I can test it with mine because mine will just blow a fuse, which I've got shed loads of. Quick and easy for me to have a look sometime.

[Tommy Cooper]

hmmm sounds like you could be our battery check and wiring man at future fix it days... I have a klaxon horn that needs looking at ! ;o)

[chrisls]

Definitely have a look at wiring, can't promise anything but with a bit of time i can work most stuff out.

This electrical and electronic engineering degree I'm doing will come in useful for something!

Also completely rewired my car, full custom loom, so I can't be that bad, everything works perfectly on it!

[RNRMF]

Oooh, if you could bring your multimeter to the next Tues meet that would be awesome - my one cost about five quid so would probably melt/explode :LOL:

[chrisls]

I wouldn't worry, mines gone bang, pop and sparked numerous times before and every time I open it up a new piece of something falls out! Still works wonderfully though!

Yeah, no worries. I keep it in me car all the time, just remind me when we're there to have a look.