It may or it may not. The interior lights are switched on and off by the BRM electronically, basically by a power transistor inside the BPM. The transistor also provides the gradual fade-out of the lights and is supposed to shut down to zero current flow when the fade-out is completed. But, if something goes wrong with this fade circuit, a small current flow may remain through the transistor or the circuitry driving it. In such a case, a similar parasitic current draw may be present even with the LED bulbs and they may even not completely fade-out but remain glowing since the 50 mA current flow (that I found on my car) may be sufficient to still keep the LED-s partially "alive" as they operate at much smaller currents than the conventional bulbs.

I may do another test by removing all the bulbs of the interior lights to see if the parasitic current draw then disappears but this would only reconfirm that there is a partial fault in the BPM's lights control circuitry.

 

I was going to suggest removing all interior bulbs as well. Excellent info though, I'm sure it will help someone in the future.

 

I tested with all interior light bulbs (those that are controlled by the BPM via fuse #7) removed and the extra parasitic current draw remained the same (total 0.08 A meaning 0.05 A extra). This means that the extra current is not flowing through the bulbs but through some other part of the BPM's circuitry related to the interior lights and the shifter lock (line "17" from fuse #7). I opened up a spare (used) BPM that I have to have a look inside. It is extremely complex and it has 24 power transistors controlling (switching on and off) various things, a number of micro chips and hundreds of other miniature components. So, I just closed it back.

The extra 0.05 A current draw, although rather small in terms of electrical currents, means a lot for the discharge of the battery. With my present parasitic draw of 0.08 A, I estimated that the battery would last for some 20 days. If I remove the extra 0.05 A, the battery will last almost 2 months so I am going to install the timer relay I mentioned earlier to cut-off the fuse #7 line 1-2 minutes after the engine switch off (so that I can still have the interior lights while I am getting out of the car).

 

Be careful not to cut off your fob reception relay MS.

 

There is no relay for the fob reception module (the SLCM). It is powered by a permanent 12 V supply from fuse #10 of the Trunk Fuse Box, i.e. completely independent of the BPM (and its fuse #7 in the LH Heelboard that I am going to isolate).

I have already tested the car's functions with the LH Heelboard fuse #7 out; everything works (including starting the engine) except only the interior lights and the shifter lock solenoid (puddle lights work). I checked these functions immediately after removal of the fuse #7 and also after more that 1 hour (and the next day) when all systems had gone into the sleep mode.

 

My car still has the .04-.03 draw. Yet it still draines a lot just sitting overnight. If I don't drive for longer than a day, I disconnect it and the battery holds charge perfectly.

 

I do the same with my car, as I am never sure it will be again driven in a day or several weeks.
If I had a power outlet in my garage, I should hook her up to a tender, but I haven't, so just take the negative pole off the battery.
Velcro-ed a M10 wrench on the steel battery holder for that.
But there are some fancy battery dis-connectors out there, even remote controlled ones ...

 

I have completed my installation of the timer relay isolating the Fuse #7 in the LH Heelboard, about 1 min. after I switch the ignition "off". The relay will engage again and hold, also for about 1 min., when I unlock the car (the timer relay is energised by the flashes of the turn signals). The relay will stay permanently "on" the moment I turn the ignition key to ACC and, of course, while the ignition is "on". I have determined that the Fuse #7 (and my timer relay) control the following:

1. Interior Lights
2. Boot Lights
3. Shifter Lock

My installation:









With this installation, I have 0.03 amps battery drain (0.08 before) after one hour from car lock. This should go further down after 2 days by another 8 mA, i.e the drain will be 0.022 amps.

With the battery drain of 0.03 amps, I have monitored my current battery voltage drop over 10 days. This battery is not very good actually as it was once (soon after I bought it) subject to a serious over-discharge while I was away for a week. When I came back I found that (due to a fault in my alarm siren), even though the car was off and locked, the SC electric pump was running and the throttle body was humming. I disconnected the battery and found that it had just about 11 volts meaning that, while under load by the SC pump and the TB, this voltage was even lower which caused the sulfation process in the battery to take place (it starts at 10.8 volts). The battery drain monitor results:

Day 0 12.52
Day 1 12.44
Day 2 12.40
Day 3 12.37
Day 4 12.33
Day 5 12.31
Day 6 12.28
Day 7 12.27
Day 8 12.26
Day 9 12.24
Day 10 12.22

I am going to install a new battery soon and repeat the test (will inform on the results for comparison)

 

I completed the battery drain test using a new AGM battery. The results are as follows (not much difference between the two).

.....................Delkor ~ 2.5 years old ........ Varta AGM New
Day 0 ...................12.52 ................................12.49
Day 1 ...................12.44 ................................12.46
Day 2 ...................12.40 ................................12.43
Day 3 ...................12.37 ................................12.40
Day 4 ...................12.33 ................................12.37
Day 5 ...................12.31 ................................12.35
Day 6 ...................12.28 ................................12.32
Day 7 ...................12.27 ................................12.30
Day 8 ...................12.26 ................................12.28
Day 9 ...................12.24 ................................12.26
Day 10 .................12.22 ................................12.24

This shows that my 2.5 years old battery, having similar results as a new battery, is actually good (I suspected earlier that it was not very good). So it seems that, with 0.03 Amps current draw, even though it can be considered rather small, it is inevitable that the battery voltage will drop over time approximately at the rate as shown. It appears that initially the voltage drop is somewhat higher but, when it reaches ~12.30 volts, it slows down to just 0.02 volts a day. The drop possibly reduces even further after the initial 10 days (when it gets 12.20 volts and below) but I haven't performed my test longer. In any case, I was able to easily start the engine when my battery was reading 12.00 after longer sitting.

I am now thinking, since X308 is so sensitive to the battery voltage, to install a Lithium battery, Braille i34C, which I have in another car. Maybe X308 was designed for the future - the Lithium car batteries that maintain ~13 volts over most of their state of charge.

 

Funny. Those voltage drops are prety much a copy to mine.

 

I'm puzzled - why has a new AGM battery such a low max voltage?

Did you fully charge it? Batteries are commonly NOT fully charged despite sellers often saying they are

Are you measuring at the battery terminals?

 

Both batteries were not fully charged but they were at similar voltages at the starts of my tests. I took the readings, for both batteries, in exactly the same fashion every day: I would only unlock the boot/trunk with the remote and open it; the boot lights would be off due to my "power saving" relay installation which disables the line from Fuse #7. Of course, I measured the voltages directly on the battery terminals and with an expensive Fluke multimeter.

 

So, you don't have to be concerned anymore; situation normal! Cheers.

 

If not fully charged and left like that you can shorten battery life a lot.