The recommended battery for my ENTZ is a standard 4.8VNiMH
. The problem with that is that;
1) they don't hold peak charge for long if charged in advance
I've been running a similar sized yacht since the late'80s using 4 AA rechargeables. Back then, a 650mAH set gave over an hour. Nowadays, play all evening using 2000mAH cells.
Don't hold peak charge? NiCads had the reputation of leaking energy, never heard of that as a problem with NiMH. When you look at ESC threads, you get the impression that oriental amps are smaller than western ones, probably something to do with consumer protection legislation. The same could apply to oriental ampere-hours. Be careful who you buy from.
I usually just connect my battery to my trusty trickle charger when I get home from the pond, and forget about it until I want to use it. Sometimes I forget, but the second session works just as well.
You get a heck of a lot of good quality sets of NiMH cells for the cost of one lithium charger, and much less chance of burning the house down.