http://www.sterling-power.com/products-altreg.htm
Everyone should be running one of these. IMO
We have one fitted to a berlingo. NEVER had to take the system battery out too re-charge.
Hope this helps someone!!
http://www.sterling-power.com/products-altbatt.htm
Hi Dave
These (and upgraded alternators and a lot of other stuff) were what the NHS Ambulances were eventually fitted with to overcome their ongoing flat auxillary battery issues that 'was putting patients lives at risk' about 10 years ago.
£120.00 for an updated smart box is rather a big ask cost wise for our business. (I think I would rather put that to a new brush and pole.

)
I keep looking at these and keep discounting them due to the cost. Is your auxillary battery a leisure batt on the Berlingo, and if so, what size is it and have you any idea at what amperage it accepts a charge from the Sterling 'box'.
I don't know what batteries the ambulances use, but I always was taught that you can't hurry charging a leisure battery. I had also thought that a solar charger on the roof of the van was also a good idea as RC does.
Connecting up a battery charger isn't a big deal when done at the same time as filling up the tank with water TBH.
I was looking at the battery to battery unit at £250.00 that overcomes the issue with Ford using their ECU to regulate battery charging.