[bexlc]

My 93 325i just started this week to not crank. The battery is completely drained so I changed the battery and the issue is still occurring! My friend who's a mechanic has disconnected my trunk light, interior lights, and my alarm thinking that they are staying on and draining my battery. But it is still not cranking. It won't even turn on. It has to be jump started every single time I crank it if it has been more than a few hours. PLEASE HELP!!

 

[B_Rad_M3]

Faulty alternator?

 

[Eight Thirty]

somethings drawing power.

 

[dc_wright]

Or shorted cell in the battery..........

What's the battery voltage after it's been recharged? Should be about 12.5 volts. If not, bad battery.

What''s the battery voltage after recharge and install in the car? Should be at least 12 volts even if there's some load on it (except for cranking the engine). If not, bad battery unless you've got a ridiculous parasitic drain.

To check for a drain issue set up your meter for the highest current it can measure and connect it in series between the positive battery terminal and the battery cable. With the trunk lights and other items disconnected you should be measuring near zero amps. If near zero then go to alternator check.

Next, what's the voltage at the battery when the car is running? Should be about 14 volts, if not bad alternator. If current was near zero in drain test and voltage is about 14 with engine running then bad battery.

 

[bexlc]

I think we've fixed it. We found a short in one of the wires from the previous owner who put all these wires for an amp, and radio extras. My friend has taken out my radio and fitting a new one on and when he disconnected, the battery wasn't draining! If you saw this battery, you would laugh! It was put together with hot glue and telephone wires.
Thanks everyone for giving me suggestions to try.