Try using seperate battery's for pumps and heater. Small 22ah battery's on eBay for £27 charge them daily this puts less strain on the big battery that fires you heater.
You are on the right track but a 22 amp battery wouldn't be big enough to drive 2 Shurflo pumps pulling 4 amps an hour each for a full days work.
If my memory serves me V8edd has a diesel heater. If he does then that draws 'mega' current when starting (up to 12 amps) which is getting out of the Leisure battery league and into the starter battery league. However, the heater draws about 2.5 amps under full heat and around 2 amps on half burn which a leisure battery would be happy with. However running 2 pumps and a diesel heater off the same battery is pushing the leisure battery too far, and would be the reason why it isn't lasting.
I don't know how many times the heater cycles on and off a day, but if it was me and my round, I would be tempted to try the diesel heater off the van battery and the pumps off the leisure battery.
We had a 17ah battery powering one shurflo 100psi pumps and that lasted a couple of days.
Its all down to pump running time in the end and how much current the pump is drawing. During an 8 hour day my pump may actually only pump water for 3 hours at a guess although I have always tried to play safe with 5 hours in any calculations. If that is so then a 22 amp battery should just make it for 2 days.
I've always had a big battery (110 amp) so your experience has got me thinking. How much time do we actually spend cleaning and rinsing and how much time do we spend doing other things?
Two of us used to do a couple of blocks of flats (27 flats) together off my van. Incorporated into this day were other big residential jobs including a couple of large conservatories. Full day from 8.30 to 5, just one stop for a coffee/milk shake at McDonalds. During that day we used around 550 litres of water on a reduced flow rate of about 1.5 lpm. I had all the juliet balconies to do (18 in all) and I did waste water while feeding the brush inbetween the bars. During the course of the day the 2 of us only spent 6 hours at most actually pumping water as we came home with about 100 litres still in the tank. To me this is quite an eye opener as my gut feel was that we spent a lot longer than this actually 'on the glass'.
If our pumps were drawing 3.5 amps at that slightly reduced flow rate, then we would have used 21 amps. A bit close for comfort to be honest for me, although the split charge relay would have put a little back into the battery during that day that may have covered the use of the remaining 100 litres had we needed to use it.
