Technical Specifications
Testing Charging Circuit
Tools Required: Electrical tester (multimeter) capable of measuring the following ranges;
- A.C Volts 0 - 20 or greater,
- D.C Volts 0 - 50 or greater,
- D.C Amps 0 - 10 or greater
- Ohms (continuity) 0 - Infinity
Great care must be taken when measuring certain voltages that the meter is set to the correct setting otherwise the wrong reading will be given or possible damage to the meter could result.
Before testing for a charging problem it is necessary to establish that there is power to the wall socket. This can be tried by simply trying another appliance in the socket such as a power tool or table lamp. If there is no power at the socket it is probably a fuse blown or a circuit breaker tripped.
It is also necessary to check that the battery voltage is good, as batteries that are too low will not power up the onboard charging system. Test the battery voltage by removing the red plug, set the meter to D.C volts and insert one lead into the socket (female part) and the other lead to ground (metal part of the chassis, like the seat post). The reading on the meter should read 25 - 26 volts for fully charged batteries. If the batteries read less than 15 volts they will need replacing or giving a booster charge using a 12 volt battery charger.
Once it has been established that there is power to the wall socket, and that the batteries are in serviceable condition the necessary checks can be made to the charging system. If the charging circuit is OK and a routine check is just to be made, go to D.C amps test.
Ohms (continuity) test
Remove the transformer from the wall socket. Move the lift off the charge point and remove the red plug. Remove the plastic end cap from the top end of the rail. Pull out the wires from the end of the rail to gain access to the connector block. Remove one of the transformer wires from the connector block; this will take the transformer out of the circuit to avoid false readings. Set the meter to ohms and check it displays a 1, open circuit. Connect the two leads of the meter together and check it displays a 0, closed circuit. If the display on the meter does not show correctly check the meter setting, leads are correctly plugged in and meter battery is OK.
Connect one lead to the blue wire at the block and the other lead to the metal of the rail. The meter should read 1 (open circuit). Repeat this again with the brown wire. Next check between the blue and brown wire, the meter should still read 1 (open circuit). If the meter reads any less than 1 this indicates a short circuit in the rail wiring which will result in transformer failure. If a short circuit is found it will need to be located and rectified before any voltage checks can be made. Likely places for the wires to short are behind the charging strips and at the joint in the rail. Once any repairs are made it will need to be re-checked with the meter.
Connect the transformer wire back into the terminal block.
A.C volts test
Plug the transformer back into the wall outlet and switch on. Set the meter to A.C volts. put the meter leads between the blue and black wires at the connector block. Take a reading from the meter, which should show 15 - 18 volts A.C . This shows that the transformer and wire is OK. If no voltage (or very low) is showing, the transformer requires replacing and re-testing.
Next locate the top charging strip on the rail and test between the two brass strips, the meter should read between 15 - 18 volts A.C . Repeat this test at the bottom charge strip. This will show the rail wiring is OK. If no voltage shows at one or both of the charging points, it indicates a break in the rail wiring. This will need repairing and re-testing.
With the lift parked on a charge point and the body cover removed locate the brown and blue wires that plug onto circuit board. Remove the plug and test between the two wires in the plug; the reading should be 15 - 18 volts A.C . If the reading were 0 then this would indicate a pick-up problem. The likely cause would be one of the plungers stuck in or the pick-ups are out of line with the charge strips.
Re-connect the plug to the circuit board.
D.C amps test
The correct way to check the charge output from the circuit board is to check the amperage (current) and not the voltage. The meter will need to set to D.C amps. Depending on the meter used one of the leads will need to be located in a different socket on the meter to obtain the correct reading and prevent damage to the meter (refer to meter instructions).
With the lift parked on a charge point remove the red plug; connect one lead from the meter to the plug and the other lead to the socket in the cover. If the cover is removed connect from the red plug to the red lead that goes to the B+ on the circuit board. The meter should now be bridging the circuit between the board and the batteries. The reading should be 0.25 amps for 8 - 10 seconds (higher readings will be observed for batteries that are heavily discharged) then should read 0 for a couple of seconds, this should cycle like this and shows that the batteries are receiving a (pulse) trickle charge.
If no readings are obtained and all connections are good this would indicate charging failure of the circuit board and it will require replacement.