I can share my experience with an "all-electric" van. We built up an E-350 van with a CCV top. I didn't want to mess with the installation and space of a propane tank, nor with another fuel to worry about. So I went with lithium batteries and use the alternator and solar to keep them charged.
Here is a summary of the electrical system:
> 4 - 100 watt solar panels
> 2 - 100 amp-hour LiFePO4 batteries
> 2000 watt inverter
> 12V 130L fridge
> Webasto Petro Heater
> 2.6 gal HW heater with 12 volt heating element
- The hot water is automatically energized when the battery capacity hits 100%, so most of the time it is heated with "excessive solar" power.
Our experience has been great. We have over 150 nights using the van. Our normal travel experience is getting to camp in the afternoon with the batteries at 100% and the HW tank full of hot water. We cook our dinner, run the fridge, use the lights, etc in the evening. Quite often we are in the mountains so we run the heater for a few hours in the morning, before we get out of bed. Usually by morning the battery is at 60-70%. If it's a sunny morning, the battery is back to 100% by 9 am. We usually drive each day, so even if the sun is not out, the batteries are fully charged after an hour of driving.
Here is a recent real life experience:
Just last week we were camping in southern Utah and ran our batteries down to around 30% by morning. That is the lowest state-of-charge we have ever been.
We used a lot of electricity that night and morning. Dinner was cooked on the induction cooktop and the InstaPot. We heated enough water for both of us to take showers. My wife blow-dried and straightened her hair (I know??). It was got dark and cold early that evening, so we ran lights for most of the evening. The Webasto heater ran 6-8 hours that night and morning. Breakfast was pancakes, cooked on the induction cooktop. However, it was cold, so the fridge didn't have to run too hard.
Plus, we were camped in a narrow canyon, so the morning sun never did hit our solar panels before we left camp, so no recharging from the sun.
This was the most electricity we had used in one night of camping, and we still had 30% left (however, I don't think I would ever run it to zero).
So, in summary, the system has worked great. Solar panels and Li batteries are expensive, but prices are coming down. I don't know if I would do this type of system with lead-acid, or gel batteries. My research determined it would take 4 times the weight and space to deliver the same amp-hours of battery capacity.
You can review my build in my build thread:
Let me know if you have any questions.