after going through all the posts here am i correct in karait's posts as instructing you on how to assemble a forklift battery (basically build one yourself?)
i would not advise that, you can buy them already assembled and save yourself alot of trouble.

all you need is the battery compartment size and truck specs which are usually stamped on the dataplate of the truck. Or you can supply the full model and serial number of the truck and someone with a manual on that truck can then give you the battery specifications for that truck so you can get the correct battery.

Once you get the truck information and determine what battery size and voltage goes in the machine call the battery company and order it.
Assembling industrial batteries should ONLY be done by the manufacturer of the battery or a qualified industrial battery vendor service center. Paying them to assemble one may cost you more than just buying one (preassembled) straight away. Plus trying to find a battery center to assemble one from components you buy might be harder to do than you think. Unless they sell the components you're providing they probably wont touch it with a 10 meter pole ;o)

just some thoughts on this that came to mind