PG DRIVES TECHNOLOGY
43
CHAPTER 2 - INSTALLATION
SK77898/2
13 Battery Gauge
For optimum accuracy of the battery gauge and low battery indicator, the control
system should  be programmed  with the  approximate nominal capacity  of the
wheelchair battery. However, accuracy is not greatly affected if the programmed
type and capacity do not closely match the battery.
The  most  important  factor  affecting  the  accuracy  of  the  battery  gauge  is  the
resistance of the cable and connections between the battery and the control system.
The control system must be matched approximately to the cable resistance of your
wheelchair to make the battery gauge accurate. The parameter for adjustment is
Cable Resistance, refer to Chapter 3 for details on programming
As a guide, 2.5 mm
2
 cable has a resistance of about 8 milliohms per meter; 4 mm
2
cable  has about 5  milliohms per meter. Circuit breakers  and  connectors usually
account for about 15 milliohms.
These values will be chosen at the time the control system is being specified by the
wheelchair manufacturer. Like the preset acceleration rates, once the values for the
battery are decided, they are programmed into control systems during manufacture
and should never need changing.
 Control systems are set for a nominal 40amp hour battery and a 40 milliohm
cable resistance.
If you need advice, contact PGDT