If I didn't have a large solar system I'd consider a HEV. But with having pre-paid electricity from solar, charging a BEV is more practical than using that electricity to run an electrolyzer to generate hydrogen and store it to pump into a HEV. The last I read the round trip to run an electrolyzer to generate hydrogen, store it, then retrieve the electricity from the fuel cell when I need it loses 40% to 60% of the power. But when my home solar batteries I get about 95% of what I put into them (round trip). Once I put that into a BEV, which would involved converting DC to AC to run my normal charger, then AC to DC within the car to charge the car's battery, I believe I'd have an overall efficiency of 85% to 90%.
That may not be good for a cross country trip like a HEV can do with just a couple of fill ups (assuming you can find a couple of hydrogen stations along the way). But it's great for running a BEV ~200 miles per week on average, the BEV getting 300 miles on a max charge, let's say it's more like 270 miles because nothing is as good as advertised, and that's assuming charging the BEV to 100% instead of 80% like they suggest, so now let's say it's 205 miles per charge. Then if you don't like letting the BEV get below 100 miles left on charge let's say I need it charged at least every 3 days. That means I can go 2 days in a row with rain (no solar power) before I give up and charge it from a charger that is constantly powered (read: increase my power bill if no solar is making it free).
Anytime I come home with over 100 miles left on the charge I'll plug my BEV into a charger outlet that's powered only when my solar system has about 80% charge in the home batteries (meaning way more than I need to power my house through the night without pulling power from the utility). Thus my BEV will be charged for a while with pre-paid power from the solar system (it's free, but it cost money up front), then quit being charged when the home solar batteries' charge drops below 80%. Then if I stay home the next day, around noon or 1 PM on a sunny day my home solar batteries will be charged 80% and my EV will go back to automatically being charged by my solar system's automatic trigger.
I'm expecting the end result to be that about 90% of all power I consume to be free from solar, including powering the house and charging the EV. This past year 57% of all power I consumed was free with my current system in my two-story all-electric house. My current system would pay for itself on about the 10th year. My upgrade with EV cost (as opposed to buying and gassing up a used car every now and then) will pay for itself on about the 12th or 13th year.
And by "pay for itself" I'm including paying the interest on the HELOC I took out to fund all of that. Think of the HELOC and interest as a fixed payment part of my budget, replacing the unpredictable costs I used to have to provide energy to my house and gas up a car to drive it ~200 miles per week.
One of the biggest draw back of solar systems is the replacement costs even the best system on the market can’t last for 20 years and the cost never lowers.
The hydrogen combustion engine if far more cheaper than having to pay out for $20.000 battery they has a short life span.
Not much plus of the solar systems even during world war II the Brits had hydrogen stoves the government handed out lasted for years.