That's weird, probably points to something up with the BECM then... maybe....?? Pete
__________________________________________________
2014 L405 Autobiography SDV8 4.4 Loire Blue Ebony interior
2011 L322 Vogue SE 4.4 TDV8 Baltic Blue. Parchment over Navy Interior. Sold
2012 L322 Autobiography 5.0 Supercharged Ipanema Sand, Jet Interior. Sold
2002 L322 Vogue 4.4 V8 Epson Green, Ivory over Aspen Interior (Fatty Offroader) Sold
-Click for Project Fatty off roader-

For my tupenny worth if we tried to get to the bottom of every fault on these early L322s we would never be on the road!
The piggy back basically does what RR should of done in the first place isolate some power hungry ecu or other totally unnecessary piece of electronics when the key is removed!

I would also suggest RR stop fiddling with Alternator loading software and let the battery take what it wants it worked well enough on cars before the industry went mad. Has anyone tried defeating that piece of pointless wizardry by supplying the field coil from elsewhere. I believe a flat charge piece of firmware exist but at the main dealer and how much?

The massive quantity of interior lights draw over 7A and need a battery of their own, if you were lucky enough to have a properly charged battery it would be ok to accidently leave them on overnight but most batteries never reach full charge.

If it was up to me cars would have dual power rails aux and priority and aux would have a big fat isolator

FWIW I would also keep an eye on the cargo hatch lights,
fold the cover up so you can see the lights go out when the top hatch is closed ,

Its not uncommon for the latch to wear out, this means the latch may not fully lock electrically. thus shutting off the lights, and BECM.

Or it may not fully unlock mechanically. Thus requiring another push on the unlocking button
In either case a new latch mechanism should be fitted.

Thanks all for the suggestions! I've currently not found The Fault. I don't think it is the hatch door lights, these seems to be off when closing the hatch.

The project today has been to try to fix the buzzing/vibration noise from the windscreen when driving over 100kmh. Before I bought the FFRR three weeks ago, the windscreen was replaced. I've found suggestions in the forums regarding the buzzing noise, and I've now used sealant between the bottom seal and the windscreen - hope that cures that problem .

I'm not sure that the ampere readings on the Unit-T 203 Clamp Multimeter are 100% correct, it seems to be very sensitive to EM fields around the car, and in particular around the battery compartment. I've therefore installed a quite long and thick earth cable between the neg pole on the battery and the earth connection in the car - to be able to pull out the earth cable and use the clamp multimeter around the cable a bit outside of the car. The clamp multimeter reads between 10A and 0,2A depending on the time since locking/ignition off, and which fuse I've been pulled out. Therefore I today tried to use another multimeter connected between the battery (neg) and earth, but that didn't work - seems that the amere-reading on that other multimeter does not work.

Anyone that have installed an amperemeter with a shunt in the FFRR? I've installed a DCC4000 in our sailing boat, and I'm now considering installing a similar kind of instrument in the RR.

Based on the reading from other posts about similar battery drain issues, I thought that fuse #49 could be the problem. I used the piggy-back fuse solution to disconnect fuse #49 (nav, radio,...), but that could not be a permanent soliution: I had to use Autostore to search for radio stations each time I turned the ignition on... My thinking now on what to do if/when I find The source of the problem: Use the piggy-back solution to disconnect that circuit when the ignition is not ON.

I also have had this issue on and off. I am beginning to think my problem is the RF receiver for the key waking the BECM

The best and easy method of checking current flow is to put a multimeter set to dc millivolts across the battery earth lead as all leads have a resistance and the voltage drop across the short earth lead is proportional to current flow. Connection wise I have a lead from negative clamp into the car and the other to the cigarette lighter earth. To get current you will need to do comparisons but basically should be 0mV anything over 50 mV is bad news. I would not advise an ammeter in circuit as it will need very thick wire and can introduce other faults due to extra connections and voltage drop.

RR are not the only vehicles to have this problem but it just seems that way!

I've now «settled down» with the following temporary solution:

Fuse piggy back from a spare ignition fuse to the fuse #12, thus shutting off the AC (and the interior air temperature fan in the console) when the ignition is not on. With this set up, the clamp meter shows -0.16A and +0.01A (i.e. 0.07A) over the ground cable from the battery after 40-50 minutes since I remotely locked the doors. I use the clamp to measure the current in both directions (turning the cable 180 degrees) at the same physical spot. Doing the measure this way, I think that I can rule out the present EM fields, and hence I can use the average of the two readings: 0.07A as a correct reading. I can try to take some pictures of this the next time, and try to upload them.

I can only say that it is easy to ignore the issue. Fundamentally a lot of RR go around with half charged batteries the voltage of a fully charged battery should be 12.75v mine is regularly below this after a long run. My advice would be to fully charge your battery with at least a 4A charger overnight , trickle chargers do not work on these cars, and then have it tested for capacity.
The 920A capacity should go a long way with only 70 mA discharge, but often we do not have that capacity because the power management software is playing with the alternator output. Lead acid batteries need regular exercise to prevent plates from oxidizing and making the battery lazy.
IMHO software is the root of all evil why is it our problem to put bugs right by paying dealer £££s for the latest firmware upgrade it should be right at the start