Greenworks 40v Electric Garden Cart broken - any advice welcome

OffGridInTheCity

OffGridInTheCity

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Hey Folks

I have a Greenworks 40v Garden Cart that is just turned 2 yrs old and the electronics have failed.
1619835582632.png

The electronics started failing after 1 year and gradually got worse until now - 2 years in the motor is unresponsive. It started operating intermittently, then worse and worse... and finally stopped completely. Its has button to 'engage' (like a timer and motor power won't engage unless this is pressed) and a Forward/Reverse and a Throttle.

I'm trying to repair it but I'm a newbie to this. Here's what the electronics look like:
1619835820569.png

The motor is 36v300w....
1619835889971.png


The controller (silver box) is:
1619835855081.png

and then there's a small circuit board with a couple of mosfets inbetween the battery and the rest of the stuff....
1619835964372.png


I ordered a new throttle and it didn't fix things.

Next - I think I've found a controller (with reverse function) - and ordered that.....
1619836035885.png


=========================================
QUESTIONS....
but what the heck is that small printed circuit board? If the new controller + new throttle doesn't make it work... Can I bypass it/remove it? Is it a BMS for regenerative braking (the power light glows when pushing the unit with no throttle)????

Any info/thoughts/speculation about anything trying to repair this would be appreciated. Why did this fail incrementally.... seems like electronics would be more of an all or nothing!!! :)
 
I was going to say the varistor, the throttle, was going bad. But if you replaced it, then the next option would be the brushes in the motor. If this has been kept outside where it can get humidity, then the brushes may have corroded to the brass housing.
If this is the case, pull the brushes out, and use a brass bristle brush to clean the brass housing and then use a knife, razor, fine sand paper, to scrape the outside layers of the brushes down to a smaller size.. This will allow the brushes to move easier in the housing.
You may be able to use the brass brush on the brushes to clean the corrosion off.

From the low light images of the controller board, it looks clean, no corrosion in there. The cap looks good, too. Perhaps pull the board out and check the underside for any corrosion.
 
I had never problems with greenworks, and i have a lot for in the garden.
But like all electric tools, everything is made for a purpose and can not be exchanged.
Especially the more bigger companies.
At least this is my experience with repairing electric tools, they are all connected and can not work without other own products of that particular company.
I hope i am wrong in this one....

I would buy a new one or replace all the electronics.
You can also so give a email to Greenworks, in my understanding if you are the first owner you have a two year warranty.
If not ask them for replacement parts.

Korishan said:
then the next option would be the brushes in the motor. If this has been kept outside where it can get humidity, then the brushes may have corroded to the brass housing.
Click to expand...
Go to a hardware store and get some carbonfiber brushes, they cost over here ~1 or two euro's for four.
Also check the contact wires that are going into the brushes.
Behind the brushes there are a sort of springs, they could be rusted away/broke/tension loss.
Good thinking Korishan!
 
My uncle has a chop saw. It was in storage for awhile, and he got it out and started making cuts. He made probably about 10 cuts and it started acting weird. Wouldn't stay running, get to full speed, or sometimes not even start up.
I pulled the cap off the brushes housing, the brushes had corroded in place. I broke one of them trying to pull it out, so had to get a new one.
That's the experience of why I was thinking about the brushes ;)
The motor will work for a time, until the arcing finally eats away enough of the material that it can't jump the gap anymore.

A simple test to try, and may not work at all depending on how badly they are frozen, is to tap the motor where the brushes are and see if the make contact.

All in all, checking the brushes is the cheapest thing. I do not think that these mower motors have brushless motors. Altho, I could be wrong. If they are brushless, then the driver board in the motor is probably defective, possibly corroded. Not all brushless motors have their own driver board, but some do.
Either way, worth a shot to pull the motor rear housing off and see what's there.
 
Request to the company - no response. These units are all 'unavailable' in the last few months, including a newer "Pro" model - maybe because of supply chain issues.

MOTOR - thank you for this tip. I'll take a look.
 
Its working again.

I took the back motor plate off but I didn't see brushes. I did see a small PC board with 4 x black/square 'things' between the windings and the armature. Couldn't pull out the armature because its attached at the other end into the gear box / differential.
Forgot to take a pic but found one that's pretty close:
1619902196818.png


Gave it a compressed air treatment, wiggled things, and some oil was present - I assume from differential / machine being on it's side.

Tried it while the motor was open and it worked. Put it back together and it now works as it did orginally.

Not sure what made it stop and then start working but it sure seems motor related as discussed above - maybe compressed air cleanout did the trick?! If so - it was easy to do.

I'll report back in a few months and thank you much for the ideas :)
 
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that "almost" looks like a brushed/brushless hybrid.

The sections that go towards the center look like they may touch the top of the rotor. I doubt those would be hall effect sensors as that'd be waaaay overkill.

It's possible that taking it out and blowing it out, you removed a piece of debris that was blocking one of the sensors.

Do you have a part number for the motor itself? The one stamped on the side in the OP image didn't pull up anything.
 
Korishan said:
Do you have a part number for the motor itself? The one stamped on the side in the OP image didn't pull up anything.
Click to expand...
Nothing visible on the outside except that number. I didn't find anything searching either. I should have taken some pics of the inside while it was open - but was focused on the repair.
 
Was cleaning it up and found a label hidden from view on the motor... Model: YVDJ020-300B14 (I think that's a YVD..) but no luck searching...
1619922440644.png
1619920551732.png
 
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looks to me to be YWDJ0120. but even that number doesn't pull up anything, almost literally nothing. And searching only the last portion pulls up a lot of vehicle parts or other non-related components.
Definitely an odd one there.

But, at least that tells you a little bit about the motor. It is brushless, which was determined when you had the cap off. You know that it runs at 11A and 36VDC nominal. You should be able to push this up to 50V fairly easily, tho. But I suppose if the battery packs are working as intended, no since tinkering with it :p After all, you aren't racing this thing :LOL:
 
Yes that is a bit of a hassle with Greenworks, the have 10 pieces in stock and always 10 in back-order and 10 pieces of a new model on there way...
They are continues "renewing/upgrading" there products.

I am glad it is working again,
Best
 
If i remember correctly Greenworks and Kobalt are made by the same company, parts could be interchangeable, I have a dozen Kobalt 40v tools 4 mowers etc not working in need to repair.
 
Update - the Greenworks cart has been / is working perfectly - even in 114F/46C weather! Its so rare that you take something apart, giggle it, and put it back together to have it start working.

Its the magic of the forum :)
 
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