Luis,
I have to say I believe your way over thinking this. A refridgerator runs the same when the motor kicks on and draws a consistant amount of voltage, With forklifts there are too many variable's, application, battery size, wet cell, gel cell, cable condition, charger type, the state of charge the battery is in when put on charge, forklifts motors condition, Ac motors or dc motors. The list goes on.

I have never seen any data plate on a forklift that indicates power consumption or power savings and thats because of all the variables. I am sure there is a way of figuring out what you need but unless your running a 30 truck fleet for a company that budgets down to the penny, I feel your pulling your hair out for no reason.

I'm not trying to be rude but look at your application and your budget and start narrowing down what type of forklift will work best for your company. A forklift that is inexpensive to run is great but if it cant fully perform all the functions that you need it to does not sound like a good purchase.

I'm no expert but I do know that cost can not be the driving factor when purchasing a forklift. In the U.S we have a saying, " You get what you pay for".

Alabama