Honestly speaking, battery operated machines doesnt give u the length of time required to polish an entire car no matter how good it is. Even when u see furniture ppl come fix up furniture at your place, everywhere they go they will try to borrow a power socket to charge their batteries while they have other spare batteries to work. If u really talk about mobile detailing, then a generator set is the more practical solution, and that is definitely not a DIY home detailer's ideal situation.
So what would be my best recommendation? I have 2:
1) Send your car to a good detailer u trust and have seen their work, go for a good 2-3 step compound polish. After that try your best to wash yourself and wax regularly to keep the paint always looking good.
2) If u do get a battery operated device, then complete 1 panel a day. Clay, compound, polish, wax 1 panel a day. Your batteries only last that long, so u should at least target to complete 1 panel before the batteries finish so that u dont have to worry about it being naked before moving to next panel. Finish 1 panel, go home and charge the batteries and repeat next day.
Hope this helps.
Btw what are the differences using hand polish and machines other than suffering from muscle pain and effectiveness? Can hand polish achieve the same result like machines?