Charge the batteries fully. The battery indicator won't reset until the batteries have a full charge.

DairyBill,
did you disconnect the low batteries out of the system? I'm pretty sure this unit has a battery connector where you can disconnect the battery pack from the machine.
One other thing is even though the better battery pack you have connected to it is showing 25v it might still not be enough to force the bdi to reset.
You could try putting a short charge on them and then connecting them to the machine while the surface charge is still high, this may force the bdi to reset back to full.

Thanks for all your input here. I was able to get a 24v source from a pallet jack with 4 brand new batteries. Now the strange part, I have 25 volts going into the unit but the display is saying "Low Voltage" on a 24v system. Anyone have any ideas before I'm forced to call out an overpriced tech?

In similar situation with different piece of equipment, I jumped across the appropriate terminals on the relay that was on the charger for a few minutes and made the charger output. After a while charger stayed on with jumper removed. Charger has to be accessible. Eventually put a momentary switch in it as this was a chronic problem with operators killing the battery so charger would not auto start.

now brewski's idea will work too but doing it that way there are things you need to keep in mind and watch for.
when you start lifting the basket you'll have to remove the top mast cover and grab the chains and make sure they are pulled up with the basket, if not they can bunch up and jam inside the channel and cause problems when you try to lower it back down.
This method is more risky also when dealing with the chains, if the basket slips your fingers can get caught up in the chains.

Thanks, good idea. I have a couple 24v pallet jacks I can play with. Pretty sure these batteries will be dry when I get to them, I didn't know this piece of equipment even existed until someone asked if I could help, no PM's being done of course....

well that is unfortunate but you only have a couple of choices
1 - remove the basket
2 - find another 24v source, then locate the battery pack connector, unplug the battery pack, then temporarily jumper it onto the truck side battery connector where the batteries connect to the machine.

If your charger is not starting because of low or no voltage then jumper the power source across the battery connector on the battery side to boost their voltage so the charger sensor can see enough voltage to allow the charger to start up.
I have done this before when batteries get too low to allow the charger to start, it fools the charger enough to allow it to turn on and start charging the batteries. Once they get enough charge in them then the external jumpered power source can be removed.

No option other than lifting the platform with a hoist or forklift if I remember correctly.