Hi, I have been testing a small device which will keep your van mounted system battery charged and is cheap as chips and so easy to fit.
I have been using a standard 12v van battery (not the expensive deep cycle leisure battery~) to run my system for the last 4 months with one of these fitted and have never had to charge the system battery up manually. (i.e removing it from the van)
The total cost for the kit with the correct wire and fuses works out at around £25
Anyone interested?

I used to have an auto electrical business and still have a few contacts so was thinking of buying a bulk order if there is enough interest??
Let me know and i will keep you all posted.
Thanks
Dave