I have recently had a spilt charge system installed in the van and being a bit geeky...here are the results for the past 2 weeks....
Week1 (Monday started with fully charged battery)
Mon Runtime 5 hours 5 minutes, distance travelled 13Km
Tue Runtime 4 hours 2 minutes, distance travelled 32Km
Wed Runtime 5 hours 15 minutes distance travalled 42Km
Thur Runtime 2 hours 44 minutes, distance travelled 23Km
Week2 (Monday started with fully charged battery)
Mon Runtime 3 hours 43minutes, distance travelled 47Km
Tue Runtime 6 hours 18 minutes, distance travelled 45Km
Wed Runtime 6 hours 18 minutes, distance travelled 54Km
Thur Runtime 4 hours 18minutes, distance travelled 31Km
Fri Runtime 3hours 38 minutes, distanced travelled 5Km...Hooked battery upto my indoors charger and it showed the battery to be half full.
On fridays I take the battery out of the van and charge fully...so far so good, I cannot help with amp/hour stats and the like but am pleased so far...have had a 6 1st cleans this week and I generally push the flow rate up high for these...so am pleased.
I use a pump controller so I suppose this helps with pump (100psi) usages against battery drain...Battery is a 80amp/hour leisure.
Hope this helps anyone thinking about this type of system....saves lugging the battery in and out every night....this is not very scientific but it is just my observations.

Cheers
Dave.