Wayne,

I would offer this input on your situation. Once you've selected a lift that you think will do the work, considering aisle width, capacity etc. the decision becomes power. Electric lifts are getting more efficient in terms of their consumption rates and they can definitely handle your work. Todays lifts use more power by running the hydraulic functions than traveling (with a load). So, lead acid will work but as mentioned in other replies the maintenance will become an issue sooner than later. If you haven't already discussed the improvements a lithium ion battery offers, you should look there next. In many cases using lithium ion can double and sometimes triple the capacity of lead acid in the same size battery case. Voltage is important too and is directly related to overall efficiency of the combination of lift truck and power source. You should be looking at the highest voltage you can find in a lift truck combined with a high ah capacity lithium battery. The work will get done. Oh and you might even be able to find a lift that offers a smaller battery compartment (read smaller wheelbase, smaller aisle width). You'll spend some money to acquire the equipment but your cost of ownership will most likely be really low in terms of daily maintenance, repairs, electricity/charging costs, etc. over the next 5-7 years compared to whatever you're doing now. And it's safer & better for the lift than lead acid overall. The ramp is definitely an issue but the good news is you can get a demo to run in your operation for a few weeks, where you'll able to see what actually works and collect consumption data along the way. That way you can buy the power you need for the operation. It's totally doable and easier than you think. Good luck!