1989 EZGO speed issues and charge question

[Derekfarm]

Kernel. Yes sir. Looks like that. I welded new battery supports in. I can only tell 2 speeds.

[kernal]

First look at all connections especially the wires connected to the resistor box. Next look at the speed board. The bottom lug is the resting position where the wiper stays when accelerator is at rest. the other 4 lugs are the speed. Each should have a solid wire connection and the lugs should look good. No deformation and such. After than you will need advice from a pro as that is not me. I used to own one of these. They are relatively simple and cheap to repair vs a modern solid state cart.

[Derekfarm]

Thanks gents for the reply. I will look up the wiring when I get home tomorrow and make sure it’s not wired backwards.

[Derekfarm]

Ok fellas don’t laugh at me but after two weeks of 60+ hour weeks installing medical equipment I tried to troubleshoot this thing. It looks as if everything is wired good. Only issues I can tell visually is maybe nuts in motor bolts need replacement and a few wires. They don’t look bad but there not new. After that I took for a ride and you gents stated I should feel 4 speeds. I could only feel two. Jacked up the cart and put a meter across it and when it starts I got 6.3 volts across the old speed slide and pushed all the way and only got 8 volts at the top speed. I realized I was taxing it with not weight so I hooked to the lug on the motor that came out of the resistor lug that was no resistance when pedal floored and floored going 8mph got 17vdc max. My batteries full charged!! Ok Is my brain mush from work and I’m troubleshooting wrong? New solenoid bad or motor bad? Or should I start with new slider solid speed control assembly and wires? Thanks for any feedback

[JohnnieB]

Here a schematic for a resistor drive.

With the pedal on the floor (position-4) the battery pack is connected directly to motor, so if you only got 17V on the motor's A1 stud, either the battery pack is dropping to 17V, or there is excessive resistance somewhere in the high amp circuit.

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What type medical equipment were you installing?

I repaired medical equipment for 35 years before retiring in 2009.

I also taught troubleshooting in the Air force BMET school.

[Derekfarm]

JohnnieB. That’s awesome you were on this field. I worked on Inhouse imaging equipment for 10 years till jumping over to GE Healthecare. Been with GE 6 years. Im and FE3 that services, pm and installs Cath labs, vascular labs, mammo, rad and RF rooms. This is why this golf cart should be easy but GE running the hell out of me with 60-70
Hour weeks installing labs and running repairs. I think I’m just tired and need to sit down and go through it slowly. So any help appreciated. Xray repair now days is windows 10 with firewall networking with wireless Bluetooth footswitches and low dose high resolution images. A lot different than when I started in 2001 with my mentor and I working on old tetorde and pulse tanks and manual techniques.

You do biomed, imaging, lasers,??

[JohnnieB]

I've worked on most everything that existed up until I retired as the Director of Clinical Engineering at a modest sized hospital in a small town. I was a shirtsleeve manager with a Jensen toolkit that got his hands dirty just about every day.

Didn't have an dedicated Imaging Engineer, so I did first call on X-ray, CT, MRI, Nuke Med, US, Laser and Lab to get better pricing on service contracts (which I also negotiated and managed) and backed up the BMETs as needed. In addition to the HR, Budgetary and Risk Managment stuff I also involved with equipment planning and procuring. Helped design the physical plant for an MRI suite, when the hospital's accountants finally figured out having their own system would be less expensive than renting a mobile one.

Ironically, teaching troubleshooting back in the 70's is what allowed me to work on such a diverse array of devices and fields. No matter what they are applied to troubleshooting and problem techniques are the same.

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Back to the cart.

EZGO wired their resistor drive two ways. I posted the schematic for the one with throttle position #4 connected to A1 on the motor. Make sure your cart is wired the same.

If you have two DVMs, measure from B- at the battery pack to B+ at the battery pack. And measure from B- at the battery pack to A1 on the motor, or position #4 on the wiper assembly.

The two voltages ought to stay about the same.

If they do, you have a battery issue.
If they don't, you have a cable/contact/connection issue. (See attached schematic with high current circuit highlighted with F/R in R)

[Derekfarm]

Update. Was reading about a volt let’s at my motor vs the batteries. I changed the majority of the wires, terminals and nuts out to 2 guage and now I got same voltage and got to 11mph on flat ground. I really think this is all this cart will do and motor starting to wear.

[JohnnieB]

Increase in top speed is directly proportional (almost) to the percentage of voltage increase applied to the motor. If the battery voltage is 37.0V when at top speed and motor voltage is 36.0V, then with perfect conductors connecting the battery to the motor, the top speed would be roughly 11.3MPH, or a gain of about 3%.

You're right, 11MPH is probably about all that cart is going to do without dumping a lot of money into it.

[Derekfarm]

Johnnie B. Great chatting with you about this. I am the type of guy that will read and watch video and get personal feedback by asking it of questions. I have another two questions if you have a minute to reply. So I got $1300 in this EZ go. Not To bad IMO but seen video where guys are saying you can Temp put 48volt to a 36 volt motor to make it faster if you build a circuit where it doesn’t feed back. With that said have you see this and is it hard on the motor? I thought maybe going up hillS loads down with kids I could kick it in? Is this stupid of have you seen it?

Question 2. A lot of people around here like riding in the parades. I thought about hooking up my old lawn mower trailer to haul kids on a flat road down a parade. It’s it ok to put 2-3 extra batteries in the trailer wire in series and hook up with and Anderson plug in parallel with the golf cart batteries?

Thanks for more conversation.