the early generation cards are all preset and cannot be set, the later generation cards do have a setting that can be set using the handset. all cards are designed at the voltage ranges indicated on the card id sticker and cannot be adjusted outside of those ranges without damaging the card.

If your having issues with the bdi there are settings for the bdi usually on the guage itself on the older systems that have the self contained guages, newer systems that have a dash display interfaced with the card will show the BDI state of the battery.
Early generation cards have a built in battery low voltage cutback. The EV100T, F , S and P cards automatically open the fwd/rev contactors if battery volts drop below 50% of the rated voltage on the battery on the 36/84v trucks and the 24v trucks do the same when more than 75% drop is sensed.
BDI interrupt is not applicable in the T, F, and S cards but is in the P series card.
Most of these early generation cards only have trimpot adjustments in the front of the card also so there is no battery setting.
The onboard BDI setting did not come into play until the LX and ZX and after and incorporated a BDI state of charge function and on the pump controllers they had a pump cutout feature that would kill the hydraulic pump when the battery dropped to 10% of its normal full charge.

BATTERY DISCHARGE INDICATION - This feature uses the latest in microprocessor technology to provide accurate battery state of charge information and supplies passive and active
warning signals to the vehicle operator.
Features and functions:
Displays 100 to 0 percent charge
Display blinks with 20% charge
Disables pump circuit with 10% charge
Auto ranging for 36/48 volt operation
Adjustable for use on 24 to 80 volts

This can be adjusted with the EV100 handset
Function 15 you can use to set the voltage of the truck with, there is a chart in the EV manual that shows you in detail how to do this.
Also function 14 for the internal resistance values can be tweaked as well to fine-tune the system to get a more accurate BDI reading, there is a chart and instructions on how to do this in the manual also.

Word to the wise though, if you never have done this before you may want to get someone that has to help you with it. Setting these settings incorrectly can damage the system.

fsip dot biz is where you can find the GE manuals, go there and find your manual and read it, you will be suprised at what you can find out just by reading them. :)