Sudden loss of power and where does this wire go?

[Racerjoe56]

New here today.
Cart lost most of its power all of a sudden, Was told to replace potentiometer and I did but that did not fix it so I learned quickly that I cant just buy parts with people guessing so I need your help.

From what I gather this is a 1992 EZGO 36 volt Marathon

Earlier this summer when we pulled this cart out it had 3 bad batteries and I replaced them, The cart ran great, I later noticed that the battery tray was almost rotted out so I brought it home and welded in all new angle.

I put everything back together and drove the cart around the block here at the house (several large hills) and it ran great. I pulled up in the yard at a decent sized hill (it has gone up it many times before) and it simply quit pulling, It would hold itself on the hill but would not go. I worked my way up to the driveway and that is where I am now.

Neighbor told me it was the potentiometer so I replaced it... no difference.

It will pull itself forward and back on level ground.. throttle must go a good ways down before it moves (1/3 to 1/2 throttle)... it cant pull even up the slightest hill now.

Wanted to know the first place I should look based on my description..?

Note: I am not very good with wiring so take that into consideration when responding. :)

I plan to go back and clean all connections (they are tight - I just put all the batteries in and have re-snugged them twice.

Also when looking at the wiring I noticed this wire that isn't connected to anything... It looks like it would be a jumper of some sort (it is a rigid wire)?? See circled in red in pic. Could that be a capacitor or something that is broken and gone or burned up?

Thanks for any advice!! Very much appreciated!

Thanks
Les

[cgtech]

It used to be a MOV, but it either crumbled away or blew up. Cart will do just fine without it.

[Racerjoe56]

Thank you … so that rules that part out...

[coosa]

>>>Earlier this summer when we pulled this cart out it had 3 bad batteries and I replaced them<<<

It sounds like you replaced 3 batteries and kept the other 3 in use? I've always replaced the entire pack at the same time. If 3 were bad, the other 3 were probably about done too. I would start by checking the old batteries. Good luck getting it going again!

[cgtech]

Yep, mixing new & old batteries is flushing battery $ down the toilet.

[Bama Brad]

Yea, test each battery under load and the bad ones will show up. Best to replace all at once (even if some "seem" OK). They are like kids, the bad ones will turn the good ones bad :).

Sounds like battery capacity problem, I bet it clears up when you replace those bad 3. Also good time to evaluate your cables, they don't last forever either.

[Racerjoe56]

Ok I have tested the batteries and the older ones show slightly weaker than the ones I put in a couple/few of months ago. The battery numbers are just the numbers I have them listed in my chart so I can keep up with all the test numbers. These reading were taken the day after the cart was charged.

Battery pack voltage was 38.4

Battery # 1 (Date of manufacture 10/17) 1 of 3 older batteries
hydrometer reading of cells were 1.250, 1.250, 1.260
Voltage reading was 6.38
Load reading was 5.55 volts

Battery # 2 (date of manufacture 4/18 ) 1 of 3 older batteries
Hydrometer reading of cells were 1.250, 1.250, 1.260
Voltage reading was 6.38 volts
Load reading was 5.70 volts

Battery # 3 (date of manufacture 3/20)
hydrometer reading of cells were 1.270, 1.275, 1.275
Voltage reading was 6.40 volts
Load reading was 5.75 volts

Battery # 4 (date of manufacture 3/20)
hydrometer reading of cells were 1.250, 1.270, 1.270
Voltage reading was 6.40 volts
Load reading was 5.80 volts

Battery # 5 (battery manufactured 3/20)
hydrometer reading of cells were 1.275, 1.275, 1.275
Voltage reading was 6.41 volts
Load reading was 5.80 volts

Battery # 6 (date of manufacture 5/17) 1 of 3 older batteries
hydrometer reading of cells were 1.260, 1.260, 1.260
VoltAge reading was 6.38 volts
Load reading was 5.50 volts


Do these readings show that the 3 batteries that are older need to be replaced? If so I will try to go get them tomorrow and see if that fixes it.

Question: what does the resister on the solenoid do? Could it cause anything like this?

A side note... I put a D&D motor and a new controller on the cart back 3 or 4 years ago.

Thank you for any and all input... it is greatly appreciated... these parts cost too much to just guess and throw parts at it... thanks for your help and advice.

Thanks
Les

[Bama Brad]

I think those readings look ok, I would clean every think up. Disconnect each cable, clean and reattach. Run it and see if any of the cables get hot. Sometimes cables can deteriate inside the casing and you can't see it. If everything looks/feels good, start checking selaniod, etc.

[Racerjoe56]

It runs fine and quick on level yard but it stalls on the slightest incline ( not even a hill just slight incline)..... when it stalls it does not buck and jerk like it has in the past when a battery was bad or it had a loose connection it simply stops moving.... it is still pulling just not enough to move the cart... pushing just a slight amount with my foot while sitting in the cart and it’s enough to make it up this little incline.... also the little battery gauge I have had in the dash does not show very low when it stalls (I have seen and ridden around with it lower in the past).... I connected a volt meter to the battery pack and let it stall and it showed 36 volts when it stopped going.... I ran it across the yard a few times and stalled it twice on that incline going into garage, did 2 load tests on each battery, then tested them all again - voltage ranged from a high of 6.27 (on 3 batteries) to 1 battery with 6.21 and the last 2 at 6.20 volts.... the 3rd load test showed 1 battery at 5.6, 1 battery at 5.5, 3 batteries at 5.4, and the lowest at 5.3 volts....

So... the motor runs, the cart goes pretty quick and the throttle seems to be working in relation to speed/pedal position... I hope to be able to work on it some tomorrow and plan to take all cables off and clean every connection again. I guess while the leads are off I may take the forward and reverse switch off and clean all the contacts in it.

From what I have been seeing in this forum the battery numbers while not great seem to be within what most folks are saying they should be... 6.3 - 6.1.... I have not seen any specs on what the load test voltage should be... the hydrometer readings seem to be within acceptable range....

???

[Racerjoe56]

Originally Posted by coosa

>>>Earlier this summer when we pulled this cart out it had 3 bad batteries and I replaced them<<<

It sounds like you replaced 3 batteries and kept the other 3 in use? I've always replaced the entire pack at the same time. If 3 were bad, the other 3 were probably about done too. I would start by checking the old batteries. Good luck getting it going again!

Yes I keep thinking the batteries since it runs good But has just very very little pulling power at all but the battery test readings seem “ok” I think. The batteries were between 2 - 3 years old. They were mistreated when we left the cart sitting (without a charger) for 6 - 8 months while we were staying at the hospital with mom on a ventilator and then rehab then at my house.... once we finally got back to the lake and got the cart out... it ran around a little bit then started jerking after a little bit of driving....I tested them all (I don’t remember the numbers but 3 were noticeably worse so they got replaced.... it ran great)... can you take a look at the numbers from testing the batteries From the past 2 days that I posted below and let me know your thoughts?

Thank you for your thoughts and input!!