Field Load Test - Invacare Pronto M50 Service Manual

SECTION 3—SAFETY INSPECTION/TROUBLESHOOTING

Field Load Test

NOTE: For this procedure, refer to FIGURE 3.1 on page 31.
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 passing through the battery, resulting in less voltage at the
posts. The more power drawn, the lower the voltage available. When this lost voltage
drops the output 1.0 volts under load (2.0 for a pair), replace the batteries.
To spot this problem, test batteries under load.
Use a digital voltmeter to check battery charge level at the charger connector. The charger
connector is located on the joystick.
NOTE: Read these instructions carefully and the manufacturer's instructions on the digital
voltmeter before using the digital voltmeter.
1. Ensure that power is Off.
2. Make sure battery is fully charged. An extremely discharged battery will exhibit the
same symptoms as a bad one.
3. Remove the footrests from the wheelchair. Refer to Front Riggings/FootBoard on
page 73.
4. Connect the voltmeter leads to the charger port on the wheelchair as shown in
FIGURE 3.1. Most digital voltmeters are not affected by polarity, however, analog
meters (meters with swinging needles) can be and should be used carefully. A good
meter reading should be 25.5 to 26 VDC.
When performing STEPS 5 and 6, ensure feet are clear from casters and wall,
otherwise injury may result.
5. Sit in wheelchair and place feet against a wall, workbench or other stationary object.
6. Turn the power On and carefully push the joystick forward, trying to drive the
wheelchair through the stationary object.
NOTE: Performing STEP 6 puts a heavy load on the batteries as they try to push through the
stationary object. If the wheels spin, have two individuals (one on each arm) apply as much
downward pressure as possible on the arms of the wheelchair.
7. Read the meter while the motors are straining, no longer than 3-4 seconds, to
determine the voltage under load.
NOTE: If the voltage drops more than 2 volts from a pair of fully charged batteries while under
load, they should be replaced regardless of the unloaded voltages.
Pronto® Series
WARNING
30
Part No. 1125075