Powerwise charger problem

[wolfejeremy24]

Here are some more pictures.

I did make sure to take pictures before I removed the old board so I would be sure where everything plugged in on the new board. And the charger did work fine for me last year. This happened the first time I plugged it in just a few days ago from sitting all winter in my garage.

The MOV that is blowing from what I can tell is between the GRN terminal (where the ground from the AC cord connects) and the top terminal of the relay (where the black wire from the AC cord connects).

I also did check the wall outlet voltage and It was reading 123vac. There were a few times that i stuck the probes into the outlet and the initial reading read up close to 150vac before dropping back to 123. Not sure if this is because of the digital multimeter that I was using or if the voltage is spiking as soon as i plug something in, which is when both MOVs have blown, right as soon as the plug touched the receptacle. I didn't know if the problem could be something to do with the ground or a short in the charger. This is definitely not my expertise. I'm just trying to be able to fix this charger if possible cause they are definitely pricey to replace.

A couple of these pictures are of the new board (which is a bit different than the old one), but I think the picture of the bottom of the circuit board is from the old board.

[JohnnieB]

I'm also pretty sure the bottom shot is the old board.
Wouldn't happen to have a bottom shot of the new board, or a top shot of the old board without all the wiring in the way.

It doesn't matter for the problem you are having. Quite honestly, it's got me stumped.

If I was doing to, I'd replace the MOVs on the new with S20K250s and give it a try, or just clip the leads to the blown MOV on the old board and plug it in.

The only thing I can think of at this point is both boards had bad MOVs.

[wolfejeremy24]

The first two are of the old board the second two are the new board.

Yeah Im stumped also. I guess at this point Im going to try and use the good MOV from the old board and put it on the new board and try a different outlet and see what happens. If that doesnt work then Ill try ordering the S20K250s and see if that makes a difference.

[wolfejeremy24]

Alright, so I took the good MOV from the new board and replaced the bad MOV on the old board with it. Plugged the charger into a different outlet and NO loud bang! But I still dont really know if the charger is fixed or not cause my batteries on my cart are too dead for the charger to turn on.

A question I do have though is this. After I replaced the MOV I tried testing for continuity across the MOV to make sure that I got a good connection when I soldered it, and there is NO continuity across the MOV. I have continuity from the GRN terminal to first prong of the MOV and from the second prong of the MOV to the top terminal of the relay, just not across the MOV. It this correct? I there is supposed to be continuity across the MOV then the other two that I thought were good are really bad too, just not blown out like the other two are.

[JohnnieB]

If it shows conductivity, it is bad. If it doesn't measure any conductivity, it might be good.
Without some specialized test equipment, you cannot determine if a MOV is good.

The easy way to test MOVs by holding them at arm's length above a waste basket and dropping them.
If they bounce, they are bad, if the shatter, they were good.

[yurtle]

Originally Posted by JohnnieB

The easy way to test MOVs by holding them at arm's length above a waste basket and dropping them.
If they bounce, they are bad, if the shatter, they were good.

I like it. Kinda like the way we used to test for witches.

Is that true?

[Volt_Ampere]

The green wire should be ground. Sounds like you may have a grounding or other wiring problem on your outlet that blew the Mov. You should never see 150V when you test that outlet. Since you blew two of these, I suspect the outlet. Try running from another one with an extension cord and get your charger working. But then I would check out that suspect outlet! MOV's almost always blow from an over voltage situation. They are intended to handle only a very momentary over voltage condition not a long lived one.