[mannyo]

My D3 does not get much use for weeks on end, and then I'll do a 400 mile return journey.

For example in the last 5 weeks my D3 has been used almost daily, yet it has covered just 55 miles.

As a result I think that the car is consuming more power than I am putting back in, that coupled with the slight battery drain issue is leading to less power.

After 5 weeks I am getting up in the morning to find that the BCM has turned a lot of stuff off, so keyless entry is disabled and the light in the door is not flashing so I need to use the unlock button on the key to open the car. Once inside I can start the car with the start button, and the battery monitor is down at 15% or so. After driving to work, its up at about 80%, but I switch off at that point. Same at the end of the day, except I usually leave the engine running for a bit to get the battery meter to 100%

We all know the battery meter is just measuring voltage, and I confirmed that with the meter on 100% the battery is still receiving current from the alternator, which once charged the BCM stops.

So looking for a charger really, not to expensive but something I could use say weekly to topup the battery. I've tried a big solar one directly on the battery but I don't think it was doing much as they tend to be to help maintain a well charged battery.

Battery is fine, its 20 months old and never been run fully flat and always starts the car without issue. The car will be fine for several weeks after the long run, before getting back to where I am now.