Lestronic II repair attempt

[coosa]

Originally Posted by Sergio

That means you should listen (read) closely to what JohnnieB says

It looks like you just need a new capacitor and you should be good to go.

Make sure you get a capacitor with the proper voltage rating, typical run capacitors for HVAC are either 370v or 440v and you should get one rated for 660V.

The output voltage without the resonant capacitor installed should be between 55v and 65v

Wow, that's great to hear! I was gonna start stripping it of usable parts and add to my pretty extensive junk pile. It would be great for it to run again, as it is really a fine charger that will charge the cart in a hurry. And I always listen to JohnnieB, but there are times when he assumes that I am smarter than I really am. :)

Johnnie, when you read this, I am gonna ask a big favor. I know that you use Amazon because you have posted links to it before. Would you find a capacitor on there that would work with this charger? You know I will mess it up if try to pick out something myself. Here is the first one to pop up; would it work?

https://www.amazon.com/dp/B01MRXHVVK..._2.ZbGbJX2SBZ9

Thanks to all for the help.

[JohnnieB]

The service manual for the 17090 charger calls for a 6µF - 660VAC capacitor and the one you linked to is only 5µF instead of the 6µF needed.

Here is a 6µF - 660VAC motor run capacitor (Motor run is continuous duty while motor start is intermittent duty.) at Amazon. https://www.amazon.com/GENTEQ-27L601...1088454&sr=8-1

However you can get it a few dollars cheper at Newark. https://www.newark.com/genteq/27l601...ive-Components

[coosa]

Many thanks, Johnnie.

The Amazon one looks like it probably ships from China. I've had a couple of bad experiences ordering from Amazon and not realizing I wasn't gonna get it for 2 months. They may have a presence in the USA, but I couldn't tell from their info, so I bought the one from Chicago.

I will update the thread when it comes in. Hopefully, I will be able to post a picture of it charging the cart.

[JohnnieB]

When you get it, be sure to check the transformer's output with the capacitor connected. Should be 90VAC (Between 83VAC and 97VAC) if it is, then 6µF is the right value.

[jhnmflr]

Bravo !!!!! Bravo!!!!

[coosa]

It lives! It's alive! The Frankencharger works.



I got the new capacitor in last night and set up to install it this morning. Who knows what it was originally intended for, but JohnnieB said it met the specs. It was smaller than the original, so I used a generous amount of duct tape to make it fit the bracket. Johnnie said to be sure to test it with the new capacitor on, so I set up everything to do that. First, I had to take the cables loose from the diodes, or at least I thought I did. I should mention that anytime I test it I have to first convert the cart back to 36 volts. The cart at my house is 42 volts, so I switch it back to 36, turn off all the switches and put it into tow mode, then remove the key. I don't know what would be the result if someone tried to run it on 36 volts, but I don't think it would be good. You can tell that I am careful and meticulous about such things.

So I plugged in the AC and DC cords and tested the output at cables to the diodes - 86 volts. Boom! This thing is gonna work!

I'm always nervous around live electricity, and my senses are finely honed at such moments. I heard a vehicle pull up to my house, which I expected to be the UPS man, so I unplugged the AC cord and went around the shed to meet him. But there was nothing there, and I guess I imagined it.

So I went back to the cart, turned off my meter, and prepared to reconnect the diodes so I could try out the charger. I started tightening the bottom one, let the wrench touch the positive pole on the rectifier, and instantly saw a bright spark that scared me to death - I had forgotten to unplug the DC cord.

I would have bet that I was careful enough that I would never do such a thing, but here is the proof:



This really wasn't my fault. I put all the blame on the UPS guy for interrupting me at a critical time.

I checked and it didn't blow a fuse, so I hoped I didn't damage anything. I finished hooking it up and the charger immediately came on and the ammeter showed it was working. The cart was charged last night, so it shouldn't take but a few minutes for it to cut off. If it will, I will put the cover back on and take it to the farm where it can once again charge the Black Beauty. So it looks like another BGW Success Story!

Many thanks to JohnnieB for guiding almost every step, and also thanks to Sergio for noticing that I had neglected to run one of the tests Johnnie told me to do. Hopefully, this thread not only got my charger going again, but it will also inspire someone equally incompetent to me to try to repair their Lester Lestronic or EZGO Powerwise charger. And maybe it will help someone far into the future when they search the internet on how to make such repairs. I have used a Google search in the past for golf cart issues and it led me to threads on this forum that were many years old, but still had excellent information.

Good carting to all!

[JohnnieB]

[coosa]

To add to the story, when I first plugged it in, it registered 18 amps output on the ammeter, and within 1 minute it had dropped to 12. Output voltage at cart was 46.5 volts, which seemed a little high to me.

Within 10 minutes, the ammeter read 2 amps, and it stayed there for the next two hours. Voltage never changed from the 46.5. I could hear my batteries bubbling away, so I finally took it off charge.

This was on a battery pack that was charged last night with a DPI Accusense charger, so I had expected the old Lester charger to run just a few minutes before cutting off. It would seem that either the Lester is charging too much, or the DPI is not putting enough of a charge on it. The battery pack is Trojan t105 and has always measured good.

I suspect that the board on the Lester may have an issue, but thought I better ask the experts. Since it is gonna run on a generator at the farm and will always be closely watched, I'm not too concerned about it not cutting off. Many times when I leave I put as much gasoline in the generator tank as I think it will need to charge the cart, crank it up and go home, letting it cut off when it runs out of gas. I realize that is not good on any electrical equipment, but I just count it as part of the cost of doing business when you are off the grid.

[JohnnieB]

If your DPI is a Gen-III, it float charges at 39.4V after the regular charge cycle ends. If it is a Gen-IV, it doesn't have float charge mode and the batteries will start self-discharging the moment the regular charge cycle ends.

Does the Lester shut off when you unplug it from the cart while it is still plugged into AC power? (The control board is supposed to shut it off when the output voltage exceeds 45V +/-1V and it'll go well above that when not connected to the battery pack)

Are the batteries in your DVM good? (Some of them read high when the batteries are low.)

Cart batteries gas (bubble) when voltage goes above about 2.35VPC (Volts per Cell), which is 42.3V for a 36V pack.

[coosa]

Johnnie, I have never figured out which generation the DPI is. I think it is a 3, but it doesn't say anything about generation on it. It's probably 4 years old. I had unplugged it after it charged yesterday, and it's been cold, so no doubt it discharged a little.

The Lester did shut off when DC was unplugged.

I think that the DVM batteries are ok. It read the pack at 38.0 before I charged it yesterday. I'm thinking that the Lester is putting out too much voltage. The DPI has always seemed to keep the batteries about where they should be.