P38A Electrickery drain,where am I going wrong?

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Another update, :( son in law had a Fiat in his garage with a similar problem which was traced to the radio??? Problem with the constant live, so before I went away I pulled the radio out. Two weeks later and....... the bastard was as flat as a witch's tit.:mad: sorry for the outrage and for any offence caused to any well endowed female member's of the occult, if it got past the mods.:D
 
You know it isn't that then so you're further ahead.

I took off one of the terminals to my battery (earth?) and used jump leads to go via my digital multimeter. You can disable the bonnet switches and then wait for it to "sleep" and if it doesn't then start pulling fuses.

Does it have the headlamp wipers? Got a feeling someone may have had an issue in the past from those causing a drain.

IIRC, mine was stuffed diodes in the alternator in the end.
 
Grrrrrr said:
You know it isn't that then so you're further ahead.

I took off one of the terminals to my battery (earth?) and used jump leads to go via my digital multimeter. You can disable the bonnet switches and then wait for it to "sleep" and if it doesn't then start pulling fuses.

Does it have the headlamp wipers? Got a feeling someone may have had an issue in the past from those causing a drain.

IIRC, mine was stuffed diodes in the alternator in the end.
Click to expand...
Hi Grrrrrr, good point, radio going back in today. Battery on charge overnight so I may get back to it today but the lawns look as if they need cutting. I have disconnected the alternator lead to battery and there wasn't a spark when I reconnected it. I have a spare bonnet catch which I put in the o/s lock .;). I'll carry on rewardless.:D
 
I was having a similar drainage problem on a Classic Audi 100S Coupe and I solved it by fitting an isolator switch which stopped all power being drained from the battery. It is fitted into the mains lead and when switched off makes the electrics think there is no battery also a very good any theft deterent. I think the switch cost me about £4 from Halford rather than keep on replacing batteries that have been drained and won't recharge.
 
icy said:
I was having a similar drainage problem on a Classic Audi 100S Coupe and I solved it by fitting an isolator switch which stopped all power being drained from the battery. It is fitted into the mains lead and when switched off makes the electrics think there is no battery also a very good any theft deterent. I think the switch cost me about £4 from Halford rather than keep on replacing batteries that have been drained and won't recharge.
Click to expand...
Thought of that but I couldn't live with resetting the windows, sunroof and radio every time I powered it up. ;)
 
Well...put the multimeter on today and this is the result.from locked it showed 1.01, after 2 minutes dropped to. 24 ,I guess the becm has gone to sleep. When I pulled fuse 33 the drain went to .49 This fuse is for the diagnostics. Replacing the fuse the reading drops to .16 after 30 seconds ??? Help!!! Photos attached.
 

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I haven't got RAVE on this machine but some back of the envelope calcs indicate to me that @ 0.24A draw a 60Ahr battery (that's the standard fitted to a RR?) should last over 240 hours (10 days).

What does RAVE say the BECM should draw when asleep? I'd have thought 0.125A would be about right but guess these are old electronics.

So the draw only changed after you removed fuse 33? And it stayed at 0.49A even if you waited 10 minutes?
 
NVB said:
I had a 250ma drain on my L322 and it flattened the battery in 3-4 days. A clamp meter and a multimeter found about half the drain, which was the mobile phone module. I have yet to find the rest cos it is much better now and I gave up looking. Might start again in the spring, but it's not too difficult to find once you get going.
Click to expand...

0.25A is a lot for the L322 so wonder if the P38 is the same?! If so you have an issue somewhere.

Were those measurements with the alternator positive removed?
 
Grrrrrr said:
I haven't got RAVE on this machine but some back of the envelope calcs indicate to me that @ 0.24A draw a 60Ahr battery (that's the standard fitted to a RR?) should last over 240 hours (10 days).

What does RAVE say the BECM should draw when asleep? I'd have thought 0.125A would be about right but guess these are old electronics.

So the draw only changed after you removed fuse 33? And it stayed at 0.49A even if you waited 10 minutes?
Click to expand...
No it dropped to .16 after 30 secs.
 
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