EZGO PowerWise II charger problem

[TaylorMade]

I just replaced the batteries in a 2006 EZGO 36V cart, because the 5 yr old ones were not taking a charge anymore and I thought they were dying. My cart has the indicator light that shows how full or empty the battery charge is. After a few uses on the new batteries, the light showed half empty, and I plugged the charger in. It charged overnight, but still didn't take a charge. When plugged in, the charger clicks on and makes the humming noise as if it's charging, but the amp meter on the charger jumps up to 5 or less amps, and slowly goes down overnight. I borrowed a friends charger and it jumped up to 20 amps and charged the batteries completely, with the indicator showing full. So it appears that my charger is not charging or charging very little, even tho it sounds like it's working.

I would appreciate any help or ideas on this, thank you

[rabbitreborn]

The Powerwise 2 was actually made by Lestronic. open it up and check the Diode Board (test each diode seperately) you likely have a bad board (one or both Diodes are bad) and will need to replace it. They're fairly inexpensive so it's an easy fix.

[TaylorMade]

Thanks for the response. When you say test the Diode Board, what should I be testing exactly? Volts? Ohms? What is a good reading vs. bad reading?

[JohnnieB]

Download manual 28646 in the "Sticky" labeled "Basic Ezgo electric golf cart wiring and manuals"
Section K is on the charger and Page K-5 (141/228 according to my Acrobat Reader) shows you how to check the diodes.

In a nutshell, using an ohmmeter, measure the resistance across each diode in one direction, reverse the leads and measure it in the other direction.
One direction should be very high, the other should be very low (10:1 ratio or more).
If not, the diode is bad.

Safety Tip: Always check with a Voltmeter to be sure the circuit is dead before using an Ohmmeter.
Ohmmeters make bright flashes, loud noises and a produce a lot of smoke when attached to a live circuit. Don't ask how I Know.

[TaylorMade]

So I tested each diode and each tested good (resistance one way, and no resistance the other)

Any ideas?

[rabbitreborn]

I can't remember off the top of my head if that charger has a Capacitor or not, but if it does, that would be my next point to check.

[scottyb]

Quote Safety Tip: Always check with a Voltmeter to be sure the circuit is dead before using an Ohmmeter.
Ohmmeters make bright flashes, loud noises and a produce a lot of smoke when attached to a live circuit. Don't ask how I Know. End Quote

That's funny chit right there I don't care who ya R

[JohnnieB]

Originally Posted by rabbitreborn

I can't remember off the top of my head if that charger has a Capacitor or not, but if it does, that would be my next point to check.

The cap would be my next guess also.

I'm new to carts, but I've been troubleshooting electrical/electronic gadgets for more years than I care to remember and I enjoy reading technical stuff.
Here's what I've gleaned from what is available on and through this forum, with a bit of previous knowledge mixed in.

The Powerwise II charger is a Ferroresonant Transformer type, so its output current is regulated by the voltage of the battery it is charging.
Without getting overly technical, the third winding of the transformer and the capacitor in parallel with it, both senses the battery voltage and regulates the amount of charging current.
When the battery voltage is low, the charging current is high.
As the battery voltage increases, the charging current decreases.


If the diodes are good and none of the wires/connectors to the battery are getting hotter than normal, I would replace the capacitor.
NOTE: High resistance in the output circuit would also cause a low reading on the ammeter.
Transformer center tap to negative battery terminal should measure very close to zero ohms, but from diode cathodes to positive terminal may show an ohm or two due to the ammeter and fuse(s) in series.

Correct me if I am wrong, but from what I can determine, the control board only does two things. (And probably should be called the Start/Stop board since that is all it controls)
1. Senses the voltage of the battery and if it is greater than some predetermined voltage, it activates the relay that applies AC power the the primary winding of the transformer. (IE: 28V)
2. Starts a timer that limits the relay from being activated more than a predetermined number of hours (IE: 16 hours)

[JohnnieB]

Originally Posted by scottyb

........That's funny chit right there I don't care who ya R

Au contraire mon fraire!
Or at least, I didn't think it was funny at the time.
Yes, I checked my underwear, it was a rather spectacular pyrotechnical event.
Fortunately, I didn't need to change them.

[TaylorMade]

It turned out the capacitor was bad. It was a 4 micro farad capacitor, but only tested 1.8 MFD. So $30 later and I'm back in action! The amp meter now jumps to 20 amps when I plug it in. Thanks everyone for all the advice!