Service manual

Course # 1 Manual
Rev. 1/02 page # 14
Service & Parts Education
Old batteries lose their ability to store and release
power, due to increased internal resistance. This
means that as you try to take power from the battery,
some of that power is used up in the process of pass-
ing through the battery, resulting in less voltage at the
posts. The more power drawn, the lower the voltage
available. When this lost voltage drops (as a pair) the
output 0-2 volts their GOOD, 2-2.5 their POOR, 2.5
or higher replace the batteries.
Testing under load is the only way to spot this prob-
lem. While special battery load testing equipment is
available, it is costly and difficult to transport.
Use a digital voltmeter to check battery charge level
at the charger connector. It is located on the side of
the wheelchair frame.
TECH NOTE: READ the instructions CAREFULLY
before using the digital voltmeter.
1. Ensure that power is OFF.
2. Make sure batteries are fully charged.
3. Remove the footrests from the wheelchair and
place the front of the wheelchair against a wall,
workbench or other stationary object.
4. Place the voltmeter leads into the charger plug
on the wheelchair (see Figure 1). Most digital volt-
meters are not affected by polarity, however, ana-
log meters (meters with swinging needles) can
be and should be used carefully. A good meter
reading should be 25.6 or higher VDC.
5. Have two (2) individuals (one [1] on each arm)
apply as much downward pressure as possible
on the arms of the wheelchair.
*6. Turn the power ON and push the joystick for-
ward, trying to drive the wheelchair through the
stationary object. This puts a heavy load on the
batteries as they try to push through the station-
ary object. Read the meter while the motors are
straining to determine the voltage under load.
TECH NOTE: If the voltage drops to less than 23.1
volts from a pair of fully charged batteries while un-
der load, they should be replaced regardless of the
unloaded voltages.
Front View of
Joystick
RII/RII-LP
Charger Port
FIELD LOAD TEST POINT WITH MULTIMETER
Battery Charger
Connector
13
**CAUTION**
Be sure not to stall motors for a long
period of time. Stalling the motors for
extended periods of time, may cause hot
spots on the commutator plates.
Charger Plug
Port
Static Battery
Voltage
Test Point
3
1
2
+
-
Female Charger
Plug
Figure 1.
FIELD LOAD TEST