batt flatery...3 times

[dvsfin]

ok here it is guys...my battery keeps going dead flat in one day...i have been through 3 batteries and all the same...i suspect something in my car is draining it...but i have no clue what it is and how to check...i suspect my alarm system because it randomly goes off with nothing disturbing it...but also the voltage drop could be setting it off...i dont know...does anyone know how i can find out what it is..?

[75wagon]

OK, here's what you need to do.
1.Take your positive off your battery and fit a test light between the clamp and the battery post. The light should come on.

2. Then remove all of your fuses, the light should go out.

3. Replace them one by one, when the light comes on there is the drain on your circuit.

4. Trace the affected circuit back using the test light to work out where your short is.

Does this help?

Dave...

[camB]

Yeah, coz it literally could be anything. I'd hooked the alternator wires up wrongly and the battery last about two days each time. Resorted to an auto elec. Dave's idea sounds eminently sensible.

[dvsfin]

thanks dave i will have to do that...but what if its my alarm...i dont think it has a fuse...and if it does i dont know where it is

[colta51]

ya alarm will hav a few fuses thay will be under the dash sumwere (depends on the person who fitted it!)
but i dont think it wood be the alarm? is it draining it completly flat or just to flat to start?
if its just to flat to start you mite need to put a relay in to take extra volts from the battery straight to the starter motor!
i had to do this to my mums old gk sigma because it was loosing power sum were between the key and the starter! hope this helps

[dvsfin]

well before it was just going too flat to start...but the last 2 times it went dead...not even reds

[75wagon]

Check the voltage of your battery as it is, then charge it and see what it is after.
If it's under 12 volts after being charged it's stuffed (or your charger doesn't work)

but i dont think it wood be the alarm? is it draining it completely flat or just to flat to start?

One of the blokes I work with, had a problem with the alarm in his Commodore. It had a small power drain on the battery, so if the car sat for 8 hours it wouldn't be able to start. He used the method mentioned in my above post and couldn't find the power drain(it was too small). It ended up being the power wire for the alarm, it was being pinched by the battery and was just earthing against the battery box.

but what if its my alarm...i dont think it has a fuse...and if it does i dont know where it is

There will be an inline fuse somewhere or one fitted to the alarm itself. They would never fit a power wire without a fuse, it's a fire hazard. (unless it was fitted by someone who didn't know what they were doing?)

If you can't find the fuse just disable it by disconnecting the power wire. On that point, does it have an immobiliser as a feature on it? You might not be able to start the car at all if that is the case

Dave...

[JJPotter]

If you have a mutimeter (or know someone who does) you can check the voltage at the battery terminals while the engine is running. If it's less than 13-14V there may (more than likely) be an issue with the alternator. If you dont have a multimeter you can get an el cheapo one from Dick Smiths (or similar) for 20 bucks. The light suggestion is also a good idea .

[oldn64]

when you say the battery keeps going flat is this even after you drive it... ie you charge it off the mains power and then drive for a period and then park and then it will not start the next day? if so you definately need to check the alternator as a starting point to see if it is topping the battery up.

As a side note are you purchasing a small battery or a larger v8/6 cylinder size battery?

Cheers

[trainzkid88]

if you have a faulty alternator this may confirm it start car remove positive lead from battery if car stop straight away alternator is not providing enough power to run car which is what it's designed to do the battery is only to start the car be quickly recharged by the alternator and the smooth out power supply from the alternator only supplying power when the alternator output is insufficient. short stop start driving also shortens battery life to help with that take car for fifteen minute drive at highway speeds and back once a week to give it a good charge. if your alternator is the factory standard unit and you are running accessories such CD player extra speakers and an amp , driving lights, uhf radio etc. your alternator may not be big enough current out put to supply the power the car needs if your car draws 50 amps with every thing turned on you need more than a fifty amp alternator to run the car and charge the battery 60amps would be suitable.

also if your battery is to big or to small you will have the same problem a century 57 or 57 vt would probably fit but check with your auto electrician or century agent for the correct battery. for a car that sit for a week or more without running a 57mf would be better as they handle sitting for long periods better also put battery on charge before you put it in the car new automotive batteries are not fully charged when you buy them or at the factory they are just filled. I know this as I used to work in battery shop

[dvsfin]

my car is fine now, I found it was the alarm draining the battery and the battery wasn't the best.

I replaced the battery and the car is regulrly driven now so it's not a problem.

cheers though,

Aaron