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p38swansea

Member

• Dec 10, 2017

• #1

I know this has been talked about before, but I think my problem is more extreme.
My 99 4.6 has drained 2 large batteries in the space of 4 hours each.
The RF receiver is disconnected, and the ignition key flap closes.
What could be causing such a large drain? The batteries were both 95Ah 800CCA
Thanks

 

gstuart

D3 Grandad

Full Member

• Dec 10, 2017

• #2

hi

is this any use to u

http://www.rangerovers.net/repairdetails/electrical/batdrain.html

 

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p38swansea

Member

• Dec 10, 2017

• #3

Thanks for your reply, I've had a read through of that site before, and it seems to only detail the issues with the RF receiver, which is disconnected in my car

 

brianp38dse

Well-Known Member

• Dec 10, 2017

• #4

Connect up a multi meter on amps and see how big the drain is, then pull and replace fuses till the drain stops then see what that fuse powers and that will tell you what to check.

 

Wazzajnr

Well-Known Member

• Dec 11, 2017

• #5

brianp38dse said:

Connect up a multi meter on amps and see how big the drain is, then pull and replace fuses till the drain stops then see what that fuse powers and that will tell you what to check.

Click to expand...

If it's flattening a 95ah battery in 4 hours, most multimeters will not work. You're looking at a clampmeter to measure that kind of current.
Sounds like it's pulling 20 amps or more and most multimeter will only do 10 amps (some of the better ones will do 20 but if you are in that level of discharge I wouldn't risk popping the multimeter)

 

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Colthebrummie

Well-Known Member

• Dec 11, 2017

• #6

For that kind of drain to be happening, I would think something must be getting warm. I'd use my laser temperature thing to go around all the electrical circuits looking for a hot spot. Is your fuse box dry?

Col

 

brianp38dse

Well-Known Member

• Dec 11, 2017

• #7

Might be worth checking out the alternator disconnect the feed wire that goes to the battery and see if it still drains, the regulator packs can go.

 

dubbleRR

Well-Known Member

• Dec 11, 2017

• #8

+ 1 on the alternator ,If the positive lead sparks on re connection to the back of the alternator ,chances are its the diode pack ...The only other thing that pulls power is cd player amp demisters. heated seats.With every thing off try pulling relays in the fuse box and put it back in if it clicks that circuit is live ,after 10 minutes or so if any relay is warm its not switching off the relay its self might be duff....

 

discool

Well-Known Member

• Dec 11, 2017

• #9

CD player, amps, demisters,heated seats etc etc are all ignition switch supply controlled, so if the switch is off then those items won't be an issue.




Sent from my iPad Air on a train.

 

martyuk

Well-Known Member

• Dec 20, 2017

• #10

If you're still having issues with it in January and fancy a jaunt down the M4, then I don't mind having a look for you.

I've got a clamp meter which if there's a drain that big, it should pick it up. As others have suggested - try disconnecting the feed wire from the alternator first and see if that sorts it... if not, it's a case of trying to measure the drain and pulling fuse to see when it disappears to help narrow down the circuit that's causing it.

 

Grrrrrr

Technician, Bodgit & Scarper Ltd

• Dec 21, 2017

• #11

+1 on alternator.
Aftermarket stereo might be causing issues, especially if the permanent 12V and switched live are, well, switched.