Hi Guys,

My local dealers cant find a battery leak amounting to 1 A per hour ( drops from 100% or 12.6V down to 50% or 12.2V in 36 hours. They could only detect a 100mA drop overall. The battery shows no drop over three days when disconnected.
I'm planning to use the Millivolt test method and was wondering if anyone can see a flaw in my method - have I missed anything...

1) Fully charge battery
2) Jam down the bonnet switch by the passenger side front suspension turret (so I can get at fuses)
3) Jam down the switch by the passenger front door (so I can get at inside fuses)
4) Fully lock car (obviously leaving bonnet and passenger door open) and leave for half an hour to switch into sleep mode (Is there an internal movement alarm? If so how do I kill it?)
5) Put millivoltmeter across ends of fuses noting any > 0.1 mV

To get a 1A drain I need 2mV on a 30A fuse up to over 10mV on a 10A fuse

Thanks for any advice

 

Has anyone tried removing individual fuses one at a time to locate the circuit? Once the circuit is identified, individual components in the circuit can be checked.

 

May assist:-
Possible battery drain?

 

I would personally use a 1 ohm resistor and install it between the battery post and the battery terminal using a spare battery terminal to attach it to the battery post (you can then trap the other lead of the resistor in the battery terminal). You can then use alligator clips to attach to the resistor. From there, it is a straight 1 to 1 relationship (ie, 1 amp is 1 volt, 1 milliamp is 1 millivolt). Makes it much easier to see any change too since you are dealing with a larger voltage.

You can also "trick" the car into thinking that the door is shut by simply using a screw driver to roll the C clip in the door latch to the closed position. Then, all you have to do is make sure to unlock and "open" the door (ie, pull on the door handle) to get the C clip back to the proper position to properly close the door. This will allow you to crawl in and out of the car to replace fuses and relays as needed.

 

What NBcat says is the way to go, put your current meter between the battery negative post and the disconnected negative terminal, start pulling fuses till you see the current drop(pull then replace if no current drop). Once found you can ID what is on the circuit and find the cause.

Do you happen to have a stuck CD in the CD player?

 

Look for the thread about
quiescent
(current / power draw / etc) as it also covers the kinds of things for this car as well as the expected drain over time.

 

When you trip the latches in the XK8, are the switches (doors, hood, truck, etc) the only way to open them?

 

@XK8 = wrong forum, this is X Type (X400)

 

Sorry

 

Recently went thru searching for a parasitic drain for a friend. Before starting I had found this You tube video. Gotta admit was super simple and it worked.

 

Great video, Avern