Methods of finding battery drain

[Majik 0]

What method do people use to test battery drain?

My battery keeps going flat enough to just not crank it over, i've had the battery tested under load and its fine.

So somewhere in the car, something is draining my battery previously i used a light probe which acts like a bulb when connected in a circuit to show current.

If the probe (both sides) is connected to the positive side of the battery only, a glow on the bulb indicated a current draw.....how does this work?

What amount of amperage is acceptable for alarm etc and how much would drain the battery quickly?

Thanks in Advance

Majik

[h100vw 0]

Majik, you need to get a digital voltmeter. Disconnect the earth lead at the battery and stick the meter inline and set it to read current(Amps).

 

Look at the current drawn. assuming you have a 60Ah battery. This will produce 60A for one hour or 30A for 2 hours etc. You can work out how quick the battery will drain.

 

If you are looking at anything more than 1/2 an Amp, ign off, something is soaking up loads of current.

 

I'd go along the fusebox, pull the fuses one at a time and monitor the current on the meter. Make a note of what results you get with what fuse pulled. If it's not obvious which is high, post your list for us to look at.

 

Also, are you sure the battery contacts and earths are clean? Was your battery checked out in situ or was it removed from the car. It is possible that the battery would check ok but with the load of the starter and some shitty connections it wouldn't turn the motor over. I had this a couple of weeks back on my Golf.

 

Gavin

[Riki 0]

If you have trouble cranking over check the heavy red cable that goes from the battery onto the starter. These are really bad for corrosion . Take it off the starter and give both the terminals a clean up with emery paper until they are shiny. If there is excessive resistance there your starter will be lazy and your alternator will not charge properly.

 

Hope this helps.