Powerwise Charger

[mr.sky]

Hello, I have a Powerwise charger that stays stuck at 5amps, but after 8 hrs or so the Charger does shut off on its own. Could the guage be defective.

[cgtech]

Capacitor or diode is bad most likely. Both tests are done with charger unplugged! Diodes can be tested with a digital meter set to its diode setting or its smallest ohm setting, wires should be removed. Test both directions, should get a small number in one direction, no reading in the other direction. Any other reading is suspect. Capacitor can be tested with largest ohm seting on meter (this is a go-no go test, not super accurate), remove wires, discharge by touching both terminals with screwdriver. Meter should start at zero, slowly increase to 19.99 Mohm, then infinity.

[yurtle]

Since the amp gauge is an electro-mechanical device, and not sealed really well, it's possible that it is reading low (dust or crud). Charging time might indicate whether a diode is blown, doubling the charge time, or whether it's the gauge.

The fact that it does move probably eliminates my theory, but when on charge, try tapping on the gauge and see if it moves up or down.

[radioman]

My charger had the exact symptoms. yurtle has some good suggestions. If that don't work I would suspect the capacitor is partially open. I tackled one of those power supplies (the only one) and everything checked out checking best I could with a ohm meter. I happened to have a fluke 75 meter with the ability to check capacitance and found it was half capacitance it should be. Substituted a AC fan run capacitor of the same and that fixed it. Open capacitors are the most overlooked items technicians overlook troubleshooting power supplies.

[JohnnieB]

Does the charger start out at 5A when it first turns on, or does it start out higher and drop down to 5A and stay there until it shuts off?
(Decending to a 5A reading later in the charge cycle is, or may be, normal.)

There are three major parts to the charger, Transformer, Capacitor and diodes.
(The control board just turns it on and off and the ammeter just tells you how many amps are flowing)

If you are using a Digital Multimeter to check the diodes, set to the function that has a picture of a diode. They should have continuity in one direction and no continuity in the other. Replace both if either is bad. 1N1184 diodes will work.

Attached is how to test the transformer and capacitor.
The attached PDF file is the manual

[yurtle]

8 hours isn't an unusual amount of time for charging. Do they get a full charge? Measure pack voltage at or near cut-off, then again 12 hours later.

[mr.sky]

Originally Posted by JohnnieB

Does the charger start out at 5A when it first turns on, or does it start out higher and drop down to 5A and stay there until it shuts off?
(Decending to a 5A reading later in the charge cycle is, or may be, normal.)

There are three major parts to the charger, Transformer, Capacitor and diodes.
(The control board just turns it on and off and the ammeter just tells you how many amps are flowing)

If you are using a Digital Multimeter to check the diodes, set to the function that has a picture of a diode. They should have continuity in one direction and no continuity in the other. Replace both if either is bad. 1N1184 diodes will work.

Attached is how to test the transformer and capacitor.
The attached PDF file is the manual

Johnnie, yes it starts at 5amps and stays there. I also have another charger
same make, it starts at 0 and within 35 50 seconds it jumps to mid point and
stays there till next morning.

[mr.sky]

Originally Posted by yurtle

8 hours isn't an unusual amount of time for charging. Do they get a full charge? Measure pack voltage at or near cut-off, then again 12 hours later.

When you say measure pack, does that mean take a measurement 1 battery at a time and write down results, and then add the 6 measurements. Correct?

[mr.sky]

Thanks for all the inputs, I will do test tomorrow, and post my results.

[yurtle]

Originally Posted by mr.sky

When you say measure pack, does that mean take a measurement 1 battery at a time and write down results, and then add the 6 measurements. Correct?

You could do that, but I'd start with the full 36 volts. You could have a bad battery or cell, but let's do the easy stuff first. If a borrowed charger works differently, I'd guess a dead diode.