For batteries use SLAs. Yes there are all manner of magic batteries out there that are supposed to do wonderful things, but they cost a fortune and to my mind involve too much worrying technology.
I've always used SLAs on my Hercules trike and my trike is a worker and often hauls large loads ranging from bags of coal to bags of compost and potting mix, large loads of scavenged bicycle parts, lengths of timber and even the weekly groceries
With a vehicle like a trike or a velocar the extra weight of the SLAs make little difference to general speed and performance and the big bonus is that the batteries can be charged with a very ordinary charger. It's a bit of an old husbands' tale that SLAs don't last, but I got four years out of my first set of batteries with no more maintenance than making sure they didn't sit around in a discharged state.
Money can't buy happiness, but it can buy chocolate which is almost the same thing
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