PROCEDURE 2 | TROUBLESHOOTING |
T R O U B L E S H O O T I N G
This Procedure Includes the Following:
Field Load Test
Using Hydrometer To Check Battery Cells (Lead Acid)
Motor Testing
Motor Brush Inspection
FIELD LOAD TEST (FIGURE 1)
NOTE: The following test can also be performed through the controller of the wheelchair along with a remote pro- grammer. Refer to the individual CONTROLLER MANUAL supplied with each wheelchair.
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 volt- age drops the output 1.0 volts under load (2.0 for a pair), replace the batteries.
Testing under load is the only way to spot this problem. 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 base of the wheel- chair frame.
NOTE: READ the instructions CAREFULLY before us- ing the digital voltmeter.
NOTE: Invacare recommends that ONLY qualified ser- vice personnel perform this test.
1.Ensure that power is OFF.
2.Make sure battery is fully charged. An extremely dis- charged battery will exhibit the same symptoms as a bad one.
3.Place a one (1) piece of wood taller than the axle of the drive wheels between the wheelchair and a wall, workbench or other stationary object.
4.Remove the footrests from the wheelchair and place the stabilizer wheels or the front of the wheelchair against the piece of wood.
5.Place the voltmeter leads into the charger plug on the wheelchair. Most digital voltmeters are not affected by polarity, however, analog meters (meters with swing- ing needles) can be and should be used carefully. A good meter reading should be 25.5 to 26 VDC.
6.Have two (2) individuals (one [1] on each arm) apply as much downward pressure as possible on the arms of the wheelchair.
7.Turn the wheelchair ON and push the joystick for- ward, trying to drive the wheelchair through the sta- tionary object. This puts a heavy load on the batteries as they try to push through the stationary object. Read the meter while the motors are straining to determine the voltage under load.
NOTE: If the voltage drops to less than 23.5 volts from a pair of fully charged batteries while under load, they should be replaced regardless of the unloaded voltages.
Battery Charger | |
Connector |
|
(+)
Digital Voltmeter 
FIGURE 1 - FIELD LOAD TEST
USING HYDROMETER TO CHECK BATTERY CELLS (LEAD ACID) (FIGURE 2)
NOTE: Perform this procedure when a digital voltmeter is not available.
WARNING
NEVER smoke or strike a match near the batteries. If the caps of the battery cells are removed, NEVER look directly into them when charging the battery.
The use of rubber gloves and safety glasses is recommended when testing the battery cells.
When reading a hydrometer, DO NOT al- low any liquid to come in contact with your eyes or skin. It is a form of acid and can cause serious burns, and in some cases, blindness. If you do get battery acid on you, flush the exposed areas with cool water IMMEDIATELY. If the acid comes into contact with eyes or causes serious burns, get medical help IMMEDIATELY.
The battery acid can damage your wheel- chair, clothing, and household items. Therefore, take readings cautiously and only in designated areas.
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