EZGO many things ok but something ain't.

[Old MXer]

Thanks for joining in johnnieB.
Will be ordering a controller then.

I'm am still concerned about the motor maybe taking out the controller.

I'm showing less than 1 ohm resistance between A1 & A2. Same for S1 & S2. No readable continuity between the S & the A sides, or to the case from any motor post.
( I'm beginning to mistrust my new meter on low resistance readings.)

So, with the pack neg cable & S2 cable removed & FR in neutral, I jumped pack pos ( 31.9 V this way ) to the S2 post & got the full 31.9 volts at S1. I thought I'd get a voltage drop across the coil...? Can you guys help me with a motor test?

[Old MXer]

I probably did that wrong. I didn't have a load on the coil.........

[JohnnieB]

The actual DC resistance of the armature windings or stator windings is in the low Milli-Ohms range.

I have a data log from a fellow member's SR48500 that show 501.2A being drawn from the battery with 34.4 V between the controllers B- and B+ terminals, so his motor's impedance is 68.6 Milli-Ohms. However, the multi-range Ohmmeters most of us have will read as follows:

A1 -> A2 = 0.2Ω to 2.0Ω
S1 -> S2 = 0.8Ω to 3.0Ω
A1 -> S1 = OPEN
A1 or S1 -> motor case = 5,000,000Ω or more.

--------------------
You have to have amps flowing in the high current circuit to read the voltage drops across the armature, the stator and the MOSFETs.

-------------
Attached is how to test a series motor.

[Old MXer]

Extra detail appreciated.

I miss my old Fluke meter. It succumbed to the display problem many of them had. ( After about 20 + years.)

I'll do the motor test tomorrow & start looking for parts.

I'll update the result when installed & tested. I hate it when threads are left open ended.

Just FYI, this cart was one of a group a local cart shop bought from a golf course. It looked well cared for & came with new batteries & battery cables. I suspect the controller & solenoid may have been replaced at one time because one of the solenoid bracket mounting bolts was twisted off.

[Old MXer]

Thanks to all for getting me this far.

Motor checked OK forward & reverse with 12 V jumpered using JB's diagram.

New 350A controller & new solenoid installed & the cart is running OK, but not the way I expected.

There's about a 25 to 30 degree slope, about 100' long, in our driveway. With only the driver on board & with the old controller, the cart wouldn't maintain top speed going up that slope. It would slow & maintain a reduced speed.
From a dead stop on the slope it would accelerate but not to top speed.
With the new controller it acts pretty much the same way.
I expected the new 350 A controller to put out a little more torque & make a difference on that slope.

I mentioned earlier I suspected the controller might have been replaced before, so maybe the cart already had a 350 A in it. Were the originals around 275 A? The removed controller has a EZGO cover & a small decal on the alum backplate that reads P331906.

The pack has Continental 2GC11-110 batteries & 4 ga cables, all this is about 4 or 5 years old. They were newly installed when we got the cart. They've been well maintained since, & the pack charges to 38.2 V. The rest of the high amp wiring is 6 ga.

I'd like to gain a little more performance on that hill if you guys have any low $ ideas.

[JohnnieB]

Being inside of a magnetic field created by amps passing through the stator windings, a motor's armature spins and because the motor's armature is spinning within the magnetic field created by the stator windings, it also generates electricity and the electricity generated has the opposite polarity of the electricity causing the armature to spin. Therefore, the faster the armature spins, the amps the motor can draw.

Since the torque a motor produces is proportional to the amps flowing through it, the faster the armature spins the less torque is produced. When traveling on a level surface, the armature's RPM will increase until the mechanical load being imposed on it is equal to the torque produced by the amount of amps the motor is capable of drawing at that RPM.

When the mechanical load increases, the motor's RPM decrease until once again the amps needed to offset the new mechanical load can be drawn by the motor. Going uphill increase the mechanical load on the motor and a series wound motors slow the most of any motor design.

---------
The max recommended incline for an EZGO cart is 14°, so it is most definitely going to slow considerable going up a driveway with a 25° to 30° slope. (See attachments)

-----------
Replacing all 13 high current cables (14 cables if controller has an A2 terminal) with 4Ga of thicker cables will help.

Going to a 48V battery pack (requires a controller and solenoid upgrade also, so not cheap) will help.

Going to a motor with higher torque throughout RPM spectrum will help.

Stay with stock height (18" tall) tires since taller tires will reduce torque where rubber meets road.

Other than moving to house will flatter topography, not much else can be done.

[Old MXer]

Well, a different house & location probably isn't gonna happen. This one isn't quite done yet even though we've been living in it for three years. The boss says, "It's good enough. Let somebody else finish it.".

I think I misjudged the slope angle by a bunch after looking at the charts. Probably closer to 15/20, still, your point is well taken.

The boss & the dog will enjoy, never the less.

I'm outta here. Thanks for everything! And I'll probably be back with another thread. Just started working on my brother-in-laws G22E.