Main needs -
- Charge the van battery from the previous night.[/*]
- Heat water for showering and dish washing[/*]
- Cook Dinner[/*]
So, if I use the genny, I can charge the battery from it through the Projecta, which ensures full charge.
I can cook tea wherever possible with the microwave in <10 minutes. Which saves LPG.
My hot water system is duel gas/240VAC, so I can also heat water for the dishes and then for a shower using 240V, which also saves LPG.
In this way, my 3 way fridge, which is running on gas pretty well gets all of what I have on board. Stove tops and gas hot water chew gas much quicker than the fridge and I only have 2 x 4.5kg bottles.
I usually run the genny for 3 hours, but with the BM, I switch off when the battery is at 100%.
Water is another precious resource and I have found I can shower in 3-4 litres. Again process, I turn water on, get wet and wet down a scrunchy sponge, the tap is on only enough to get a weak constant spray. I then turn the water off, put shower gel on the scrunchy and wash all over (face last). Then turn water on and quickly rinse. I also have plastic bowl at the kitchen sink, that has a small amount of water in it at breakfast, in which I leave the dishes to discourage ants. So I only do the dishes after dinner once a day, again to save water. My van only has a 60 litre tank, I can make last 5-7 days. I carry 2 x 20 l jerry cans to get water and refill the tank when needed.
It's all about extending the time between re supply. When I'm away from the van during the day, the only thing using any resource is the LPG for the fridge. Without the diesel heater my 12 VDC use is about 10 AH, with it, it will be 20-25 amps, I won't know till I test it. (and about 1.5l of diesel for 12 hours comfort overnight.)
Food for thought, hope this helps...