A lot of the battlebot type folks use NiCD batteries. There's nothing wrong with them except cost. Treated properly (they need more attention than your typical lead acid battery), they should last quite some time.
there is a huge difference between running a boat int eh water and a tank on the ground. the boat in the water has a prop that cuts through the water as it needs to, pushing the boat on the surface. the tank will be driving itselfalong ground that may have tall grass that will slow it down and draw more amps, it may even need to up hilll and draw even more amps, but it will run harder on the batteries than the boat ever will.
simply, the boat motors will have less resistance than the tank motors
will.
chris
-----Original Message-----
From: BrendanKotlanger-at-aol.com
To: tanks-at-rctankcombat.com
Sent: Wed, 16 Aug 2006 3:21 PM
Subject: Re: trying to figure out rpm's / track speed [TANKS]
My dad found the site in his search for batteries in his pt boat model. We have purchased 3 12 volt 10 ah batteries to power it. Each motor will run at 20 ah. If they work well in his boat without problems,
He is willing to buy them for his light tank. With the batteries, his tank is still cheaper then my panther. We will be running the tank at 24 volts with 2 of the 50 ah batteries which is more then what is in my tank.