Invacare RWD Field Load Test Figure, Using Hydrometer to Check Battery Cells Lead Acid Figure

TROUBLESHOOTING PROCEDURE 2

This Procedure Includes the Following:

Field Load Test

Using Hydrometer To Check Battery Cells (Lead Acid)

Motor Testing

Motor Brush Inspection Electro-Mechanical Parking Brake Testing

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.

Oldbatterieslosetheirabilitytostoreandreleasepower,due to increased internal resistance. This means that as you try totakepowerfromthebattery,someofthatpowerisusedup intheprocessofpassingthroughthebattery,resultinginless voltage at the posts. The more power drawn, the lower the voltageavailable.Whenthislostvoltagedropstheoutput1.0 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.

Useadigitalvoltmetertocheckbatterychargelevelatthecharger connector. It is located on the base of the wheelchair frame.

4.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.

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 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

T R O U B L E S H O O T I N G

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.Remove the footrests from the wheelchair and per- form one (1) of the following:

A.RWD MODELS - place the CASTERS of the wheelchair against a wall, workbench or other stationary object.

B.MWD MODELS - place the STABILIZER wheels of the wheelchair against a wall, work- bench or other stationary object.

C.FWD MODELS -place the DRIVE wheels of the wheelchair against a wall, workbench or other stationary object.

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 chemical goggles or face shields is recommended when working with batteries.

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