philip_m,
the one thing you guys that want to put these smaller batteries into trucks that normally take these large industrial batteries are not considering is that you're not taking into consideration that the battery is also a counterweight. If you try and put these smaller batteries in you deminish the trucks ability to pick up a rated load. The stability of the machine is severely compromised when you do this.
Also in todays control systems they are designed to run on a specific amp rating versus the voltage and these systems are very sensitive to the fluctuations caused by using such a small array of batteries. Even though you may get the truck to run voltage wise, the battery array's amp load is not sustainable using these small cells and the control system sees this and will fault out in most cases because of the wrong type of battery.
But as i said at first, the MOST important fact the truck stability, you NEED the weight from the battery to keep the truck stable when lifting loads.
If you're just building a battery pack to move the machine around then it MIGHT work for that, but don't use it for your normal power source fulltime.

Your best bet is to get the old battery (if you still have it) reconditioned.
And a note about reconditioned batteries is that they are not going to be like a NEW battery and you will still be prone to dealing with any weak cells that were deemed good at the time of reconditioning that would be prone to fail at a later time. Any cell in a battery no matter how big or small are only designed to be charged and discharged a certain number of times, anything you get after that fact will be based on how well it has been maintained over time. They ALL will fail eventually once they reach and or go past their cycle time.
In short, a reconditioned battery is just buying a bit more 'uncertain' time is all.