Hi everyone, so my 'rada is draining its battery while sitting overnight.

I know its not the battery because it did the same thing with two batteries on different nights. It's not the alternator as when the car is running it charges at 14.4V observed with a multimeter 30 seconds after the car has been started.

I see no lights on, but when it happened again this morning the battery felt warm next to the stone cold engine, so there is something electrical draining it while sitting.

Installed my charged spare battery but am now reduced to disconnecting the neg terminal every time I arrive at work or home. Annoying.

So this weekend I want to try to isolate the problem... but where to start?

What systems are running, in the background, while the car sitting? I'd like to disable the security system, but what else can be taken offline?

Any advice is greatly appreciated.

Ian.

Some circuits stay live, but not enough current is drawn to flatten a battery overnight. Over 3 months, yes. Use a multimeter to confirm current draw with everything turned off.

Possibilities:

Boot light staying on.
Alternator diode defective. Feel the alternator after standing all night (battery connected). If it feels warmer than the engine block, you found the culprit.
Dud battery. I've just replaced a 2 year old battery, fine during the day but no start in ther morning. (Put it on charger, look for one cell bubbling away furiously.)

Hi everyone, so my 'rada is draining its battery while sitting overnight.

I know its not the battery because it did the same thing with two batteries on different nights. It's not the alternator as when the car is running it charges at 14.4V observed with a multimeter 30 seconds after the car has been started.

I see no lights on, but when it happened again this morning the battery felt warm next to the stone cold engine, so there is something electrical draining it while sitting.

Installed my charged spare battery but am now reduced to disconnecting the neg terminal every time I arrive at work or home. Annoying.

So this weekend I want to try to isolate the problem... but where to start?

What systems are running, in the background, while the car sitting? I'd like to disable the security system, but what else can be taken offline?

Any advice is greatly appreciated.

Ian.


https://www.youtube.com/watch?v=KF1gijj03_0

Eric the Car guy. One of my favourite sources for "how to" info

Go to the fuse box, pull the fuses one at a time and use the ammeter function of your multimeter to check how much current will flow from one side of the fuse holder to the other. It may spike within the first 10 seconds as the system is renergised then it should settle back down for you to take a reading.