Battery drain - Mercedes Burford Duo

The power control system on current A/S Motor-Homes (at least on my 2014 model) comprise of;-  EC500 Power Supply Unit PSU, EC480 Control Panel CP, PX-300 Battery Charger/Power Supply and an EM40 Interface Unit which is where the tow bar harness should be connected. 

This EM40 unit also houses fuses for the fridge, vehicle battery, radio and other systems.

The EC500 can be left switched on continuous charge (see my statement previously) whilst in storage (confirmed by Sargent at the time and clearly stated in the owners manual).
 
- Peter#1 and I discussed this last year when I was putting my Malvern  to bed for the winter and I can confirm it emerged in perfect health, battery wise, at the start of the season this year - so it seems to work!

Can't speak for the PC system fitted in your van Groundhog but it might be worth a phone call to Sargent technical support to check on the acceptability of permanent ECU whilst in storage.

Liam

I've had a few attempts to find the 'switch' which on a rhd model should be on the right of the passenger footwell. I've just been and ripped everything out and it is NOT there!

I have however had a look at the starter battery for the first time (pics above). The -ve terminal is to the front and the +ve to the back with most of the +ve connections disappearing into a tray adjacent to the passenger seat plinth. There is a dark grey +ve connection that may go out of the bottom of the battery box but I couldn't trace it easily.

Obviously the battery shouldn't drain but if you do want to disconnect it in storage it is an easy job to disconnect the -ve terminal. Of course central locking and alarms won't work and you probably have to follow a 'disconnection procedure' to avoid setting the alarm off at the time of disconnection.

Re disconnection mentioned by Peter#1 above - reading the MB manual it is not encouraged! 
According to the manual there is a strict process that must be followed - i.e. engagement of the ignition key before and after and the mention of some effect on data within the vehicle's black box.
 
I agree with Peter#1's comments regarding the cons of disconnection - your insurance company might not be too pleased if the alarm is not operating.

Any battery drain should be minimal these days - modern vehicle black boxes and the latest alarms go into sleep mode to reduce power consumption so any major drain must therefore be attributable to other after market products that are not power conserves or a wiring fault in the system. 

So at least two weeks should not be an unreasonable expectation to leave a vehicle without any power input and still operate successfully at the end of it - after all how long do you leave your car when you go on holiday?

Liam

Peter#1, is the -ve disconnect not on the driver's side lower door post? In your pic 2, were does the large black cable go to?

My van is away at the storage, so can't check if mine has the -ve disconnect terminal, not really a switch.

The large black cable seems to be a plastic sleeve over a copper braid.  It disappears under the plastic trim on the right hand side of the passenger footwell (where I would have expect to find the 'switch') and I presume goes to a chassis bonding point.




The grey cable connected to the +ve comes out of the back of the battery box into a corrugated conduit that then runs forwards under the battery box to the engine bay.

Thanks everyone for your comments and suggestions.  Particularly Mark from Derby who indicates that there may be an inherent problem being looked at by AS.  Yesterday we took the van for a 2 hour drive and when we got back the battery was showing Amber to just barely Green, so suspect that this battery may be shot.  Pressed the isolation switch when we left and and took out a couple of fuses.  Am going up this morning to see if there is any change.  It needs a new battery for sure but am probably going to take it to an auto electrician to see if they can find anything.

Hi everyone,

Thanks for all of your comments.  Have taken the van into a reputable diagnostic auto technician and they have confirmed that it is not the tow bar.  However they have found that there is quite a high drain on the battery into the autosleeper bit.  They could try to track it down but it is really a warranty job.  We are off on holiday in it shortly for a month so are going to put up with it and when we get back get it in to AS to be checked.