I'm having some trouble with my 2007 L322 3.6TDV8.

I replaced the alternator just over a year ago, but with lockdown and working from home the car has not seen many miles since then, but has done trip away from home with long distances covered and with no issues over that time.

I replaced the battery shortly after the alternator, as the old battery was pretty much knackered at this point.

Since then I have killed the new battery with it being overly discharged, and to begin with I thought that I must be having an issue with parasitic battery drain. A few other odd things had happened since it had been 'laid up' for several months, including the motorised steering column having a mind of its own when you open the door (it would go to the end of its travel and then just keep going).

I thought it was parasitic drain as with the car doing nothing for 3 weeks it would always need charging up before it would start.

Today it wouldn't start without charging even though I drove it yesterday (about 30 miles in total, with 4 starts / stops). The day before yesterday I just about got it to start (I had to turn off lights, radio, heater etc).

Today checking the charging voltage this is pretty much fixed once the car is started, but the voltage is variable - i.e. for one journey it will be 13.2 , for the next 14.3 , for the next 13.9 etc. This doesnt seem to change regardless of the draw, so if it is sat at 13.9 it will stay there +/- 0.2v even if I put all of the seat heaters, the steering wheel heater, the front and rear screen defrost on, the lights on etc. It doesnt change with engine rpm (so you cant make it go from 13.2 to 13.9 etc.

I am at a loss to explain this. The alternator is a Denso OEM replacement. I didnt rigorously check charging from it post install, as it was reading 14v and the previous one had died completely, so it never crossed my mind that there may have been an issue with it.

Any ideas? Nothing coming up on my Autel Diagnostics that would be relevant as far as I can tell. I'm not certain there is a parasitic load - my charger reads pretty much 0 Amps once the battery is topped off.

I recall having similar concerns about a parasitic load and discounted that after using a clamp type ammeter like this

https://www.ebay.co.uk/itm/MT87-Digital-El...SwN4ZfnuRe

open the bonnet and clamp it over the earth lead then shut the door (but not the bonnet). from memory there was an initial load of about 15a dropping to 11 after the interior lights went out then down to a much lower value in milliamps after a few more minutes. 2010 VSE [Roger]

Yeah this sounds more like a drain problem to me too. Has the car been outside in the elements for all this time?

Might be worth checking the rear cubbies and spare wheel well for water ingress too.

The fact you've got electrical gremlins with the steering column too doesn't seem like a coincidence.

What is the battery voltage when the engine is off?