EZ-go electric cart question
 

My wife is about to kill me. We have an '03 36V electric EZ-Go for her
excursions around the property.

It's developed a "no climb" problem. With the throttle down, the cart
goes about 1/4 speed on flats, and won't climb a 2% grade.

It's accompanied by a near-silent gentle vibration. Close listening
discovers that the motor is running full-speed, but the wheels aren't.

I took off both rear hubs and inspected the splines. I've seen them go
on EZ-Gos before. But they were fine, and that problem is usually
accompanied by a fairly loud growling noise.

The motor input/diff-case is a unitized, sealed affair, and I cannot find
any drawings for it -- electric cart, not gas; found the gas diagrams.

There _may_ be a belt inside the case, or a clutch to prevent overloads.
This feels just like a slipping friction element. But I have to pull the
whole rear axle assembly and both axles from the case to do that
inspection -- ain't a small job. So I'm looking for hints first before I
shoulder into that job.

On-line help is scant except for one site that is down right now.

Has anyone here seen this problem specifically on an electric EZ-Go?

Lloyd

EZ-go electric cart question
 

On Tue, 26 Jun 2012 14:41:16 -0500, Lloyd E. Sponenburgh wrote:

My wife is about to kill me. We have an '03 36V electric EZ-Go for her
excursions around the property.

It's developed a "no climb" problem. With the throttle down, the cart
goes about 1/4 speed on flats, and won't climb a 2% grade.

(...)

Has anyone here seen this problem specifically on an electric EZ-Go?

Is the manual any help?
http://www.ezgo.com/warranty_custome...t_manuals.html

http://server1.buggiesunlimited.com/...p?f=13&t=64854
HarryT says sometimes the brakes lock up on those.

--Winston --PocketaPocketaPocketa

EZ-go electric cart question
 

"Lloyd E. Sponenburgh" wrote:

My wife is about to kill me. We have an '03 36V electric EZ-Go for her
excursions around the property.

It's developed a "no climb" problem. With the throttle down, the cart
goes about 1/4 speed on flats, and won't climb a 2% grade.

It's accompanied by a near-silent gentle vibration. Close listening
discovers that the motor is running full-speed, but the wheels aren't.

I took off both rear hubs and inspected the splines. I've seen them go
on EZ-Gos before. But they were fine, and that problem is usually
accompanied by a fairly loud growling noise.

The motor input/diff-case is a unitized, sealed affair, and I cannot find
any drawings for it -- electric cart, not gas; found the gas diagrams.

There _may_ be a belt inside the case, or a clutch to prevent overloads.
This feels just like a slipping friction element. But I have to pull the
whole rear axle assembly and both axles from the case to do that
inspection -- ain't a small job. So I'm looking for hints first before I
shoulder into that job.

On-line help is scant except for one site that is down right now.

Has anyone here seen this problem specifically on an electric EZ-Go?

Lloyd

Since you will have to dig into it to fix it, does it really make sense
to procrastinate on digging into it to find out what you need to fix?

EZ-go electric cart question
 

On Jun 26, 2:41*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
My wife is about to kill me. *We have an '03 36V electric EZ-Go for her
excursions around the property.

It's developed a "no climb" problem. *With the throttle down, the cart
goes about 1/4 speed on flats, and won't climb a 2% grade.

It's accompanied by a near-silent gentle vibration. *Close listening
discovers that the motor is running full-speed, but the wheels aren't.

I took off both rear hubs and inspected the splines. *I've seen them go
on EZ-Gos before. *But they were fine, and that problem is usually
accompanied by a fairly loud growling noise.

The motor input/diff-case is a unitized, sealed affair, and I cannot find
any drawings for it -- electric cart, not gas; found the gas diagrams.

There _may_ be a belt inside the case, or a clutch to prevent overloads.
This feels just like a slipping friction element. But I have to pull the
whole rear axle assembly and both axles from the case to do that
inspection -- ain't a small job. *So I'm looking for hints first before I
shoulder into that job.

On-line help is scant except for one site that is down right now.

Has anyone here seen this problem specifically on an electric EZ-Go?

Lloyd

No experience, but maybe this helps:
http://www.ordertree.com/docs/1047/E...8,610987-A.pdf

EZ-go electric cart question
 

Winston fired this volley in news:jsd7e81uo4
@news1.newsguy.com:


Is the manual any help?

I have it. No. They do not show an exploded view of the transaxle. It's
considered a "replacement item" only.

It's not locked brakes, either. Had both drums off to inspect the hub
splines.

LLoyd

EZ-go electric cart question
 

"Denis G." fired this volley in
:

http://www.ordertree.com/docs/1047/E...Service/dana%2
0electric%20transaxle,2008,610987-A.pdf

Yes, thanks. I've been looking for that all day. There are no friction
elements or drive belts, so it's obviously not a tranny problem -- no
grinding noises.

Since the motor sounds like it's running, I'm next going to suspect that
it's an electronic problem with the controller that is "ringing" the
windings without actually making it go.

I've got a 'scope. Next check is electronic. Batteries are good.

Lloyd

EZ-go electric cart question
 

"Pete C." fired this volley in news:4fea4649$0$14540
:

Since you will have to dig into it to fix it, does it really make sense
to procrastinate on digging into it to find out what you need to fix?

Didn't, actually, Pete. I got the wrenches out right after I posted. It
takes a while just to get down to the motor/tranny.

I can chock the machine and put it in forward, and the motor sounds like
it's running, but it doesn't have enough torque to move against the chocks.

Hmm...

LLoyd

EZ-go electric cart question
 

On Tue, 26 Jun 2012 19:11:19 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Pete C." fired this volley in news:4fea4649$0$14540
:

Since you will have to dig into it to fix it, does it really make sense
to procrastinate on digging into it to find out what you need to fix?

Didn't, actually, Pete. I got the wrenches out right after I posted. It
takes a while just to get down to the motor/tranny.

I can chock the machine and put it in forward, and the motor sounds like
it's running, but it doesn't have enough torque to move against the chocks.

Hmm...

LLoyd
Bypass the controller and see what happens. Put jumper cables from
one 12 volt battery to the motor directly - motor should run. If id
doesn't you have motor trouble. If it does you have controller or
battery/cable problems. My bet is on a blown controller.

EZ-go electric cart question
 

wrote in message
...
On Tue, 26 Jun 2012 19:11:19 -0500, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:

"Pete C." fired this volley in
news:4fea4649$0$14540
:

Since you will have to dig into it to fix it, does it really make
sense
to procrastinate on digging into it to find out what you need to
fix?

Didn't, actually, Pete. I got the wrenches out right after I
posted. It
takes a while just to get down to the motor/tranny.

I can chock the machine and put it in forward, and the motor sounds
like
it's running, but it doesn't have enough torque to move against the
chocks.

Hmm...

LLoyd
Bypass the controller and see what happens. Put jumper cables from
one 12 volt battery to the motor directly - motor should run. If id
doesn't you have motor trouble. If it does you have controller or
battery/cable problems. My bet is on a blown controller.

If you jack up one wheel how easy is it to turn by hand? Does it spin
the motor?

jsw

EZ-go electric cart question
 

"Jim Wilkins" fired this volley in news:jsdr2n$hfk$1
@dont-email.me:

If you jack up one wheel how easy is it to turn by hand? Does it spin
the motor?


If I jack up both, you can see that the diff works.
If I jack up one, I can turn it pretty easily, but it's only 6:1 to the
motor. You cannot see if the motor is turning. It's a DANA tranny, and
the motor mounts entirely into the tranny case input side.

LLoyd

EZ-go electric cart question
 

EZ-go electric cart question
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
fired this volley in
:

Bypass the controller and see what happens. Put jumper cables from
one 12 volt battery to the motor directly - motor should run.

Yup. Only way to "bypass" on this machine is to disconnect both the field
and armature connections and do it manually. Tomorrow. It took me a while
this afternoon just to get to the motor -- taking off accessories, bag
holders, baskets, body panels...

LLoyd

Another possibility is the motor coupling to the transaxle is slipping.
Art

EZ-go electric cart question
 

On Jun 26, 7:09*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Denis G." fired this volley :

http://www.ordertree.com/docs/1047/E...Service/dana%2
0electric%20transaxle,2008,610987-A.pdf

Yes, thanks. *I've been looking for that all day. *There are no friction
elements or drive belts, so it's obviously not a tranny problem -- no
grinding noises.

Since the motor sounds like it's running, I'm next going to suspect that
it's an electronic problem with the controller that is "ringing" the
windings without actually making it go.

I've got a 'scope. *Next check is electronic. *Batteries are good.

Lloyd

If you don't have it, there's another manual on this page:
http://mrcarts.com/cat_ezgo_technical_info.cfm
Download -- Technician's service and repair manual electric carts

Diagnostics on pg 74 (F-8) indicate that it might be a problem with
the speed sensor (fault).

EZ-go electric cart question
 

"Artemus" fired this volley in news:jsdsmu$oah$1
@dont-email.me:

Another possibility is the motor coupling to the transaxle is slipping.
Art


There is no such. There is a heat-shrink-fit spline coupler on the nose
of the motor shaft that engages a splined shaft on the input side of the
transmission. The output gears of the diff drive the axle shafts through
heavy splines.

If that one shrink-fit coupler were to be loose enough to cause what I'm
hearing, it would make a ton of noise, and would have filled the pumpkin
with metal. Neither happened.

LLoyd

EZ-go electric cart question
 

"Denis G." fired this volley in news:054f7966-
:

Diagnostics on pg 74 (F-8) indicate that it might be a problem with
the speed sensor (fault).

It's not a PDS cart, so it has no speed sensor.

This controller is a "dumb" PWM type, without regenerative braking or
automatic speed controls.

LLoyd

EZ-go electric cart question
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Denis G." fired this volley in
news:054f7966-
:

Diagnostics on pg 74 (F-8) indicate that it might be a problem with
the speed sensor (fault).

It's not a PDS cart, so it has no speed sensor.

This controller is a "dumb" PWM type, without regenerative braking
or
automatic speed controls.

LLoyd

Can you put a volt meter somewhere on the motor leads, or measure the
battery current or voltage drop under load?
http://auctionpix.co.uk/members/jqg1541461.jpg

Mine is a cheap plastic model with a +/-75A scale for the alternator
and a +/-400A scale for the starter.

For those who don't know, non-contact current meters work only on
single cables carrying current in one direction, not pairs with both
power and return such as from the controller to the motor. That
applies to AC clamp-on meters too.

jsw

EZ-go electric cart question
 

"Jim Wilkins" fired this volley in news:jseuc7$t66
:

Can you put a volt meter somewhere on the motor leads, or measure the
battery current or voltage drop under load?
http://auctionpix.co.uk/members/jqg1541461.jpg

It's a PWM controller, Jim. My DVM does a pretty bad job of showing the
average voltage of a square wave.

Nonetheless, I was able to determine that the motor was not actually
rapidly spinning; it was creeping at about 100rpm, but "singing" or
"ringing" at the PWM switch frequency -- just without any real power or
speed (full throttle). I checked the brushes, and they're like new.

Likely it's a controller issue. I have a spare PDS controller, but will
have to spoof a speed pickup signal to make it work. There are no
provisions on my motor for the PDS speed pickup.

Another hour or so of digging ought to get to the problem. I have a
'scope, but can't bring the cart indoors, and I'm not taking my scope out
in the misty drizzle that's blowing into the shed right now (aftermath of
TS Debby). Maybe when the sun comes out this afternoon.

LLoyd

EZ-go electric cart question
 

On Wed, 27 Jun 2012 08:32:30 -0500, Lloyd E. Sponenburgh wrote:


(...)

Nonetheless, I was able to determine that the motor was not actually
rapidly spinning; it was creeping at about 100rpm, but "singing" or
"ringing" at the PWM switch frequency -- just without any real power or
speed (full throttle). I checked the brushes, and they're like new.

'Sounds like the controller is current - limiting; narrowing it's
PWM pulses because it thinks the motor is shorted.

--Winston

EZ-go electric cart question
 

"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
. 3.70...
"Jim Wilkins" fired this volley in
news:jseuc7$t66
:

Can you put a volt meter somewhere on the motor leads, or measure
the
battery current or voltage drop under load?
http://auctionpix.co.uk/members/jqg1541461.jpg

It's a PWM controller, Jim. My DVM does a pretty bad job of showing
the
average voltage of a square wave.


I know. It's easier when you have another known-good machine in the
shop to compare the reading to. Flat-out acceleration should briefly
show full DC voltage, though.

jsw

EZ-go electric cart question
 

On Jun 27, 6:01*am, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Denis G." fired this volley in news:054f7966-
:

Diagnostics on pg 74 (F-8) indicate that it might be a problem with
the speed sensor (fault).

It's not a PDS cart, so it has no speed sensor.

This controller is a "dumb" PWM type, without regenerative braking or
automatic speed controls.

LLoyd

So no circuit feedback.

Oh well, it always pays to check the simple things first. Maybe the
board won't be too complicated if you have to figure it from scratch.
I understand the basics of PWM, but don't have practical experience.
I would now guess a bad SCR or the oscillator circuit went kerflooey,
but I'm mostly a hex head.

EZ-go electric cart question
 

"Denis G." fired this volley in news:8b707822-
:

I would now guess a bad SCR or the oscillator circuit went kerflooey,


The couple of cart controllers I've taken apart (after scrapping) didn't
use GTO SCRs, they used really husky MOSFET drivers. I think GTOs are
still extremely expensive compared to large, paralleled SmartFETs.

Back in the mid-80s, before carts generally had PWM controllers, my dad
and I designed one from scratch, using bipolar transistors (at the time
large enough MOSFETs weren't commonly available). It ran the motor fine,
but we could never find big enough flyback diodes to protect the
transistors from inductive kickback, and slow switching would overheat
everything. We faced other impediments, like not having the right motors
for that sort of control.

The first commercial ones were about the size of a LARGE loaf of sandwich
bread, and used banks of TO-3 bipolars to do the switching.

Now they're about 4" square, with lots of IR FETs and big "pellet" style
diodes mounted on TO-220 frames -- even have thermistor sensing on the
heat sink!

I finally elicited from my wife that this problem "comes and goes". I
think it's time to pop the cover on the controller.


LLoyd

EZ-go electric cart question
 

On Wed, 27 Jun 2012 08:33:49 -0700 (PDT), "Denis G."
wrote:

On Jun 27, 6:01Â*am, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Denis G." fired this volley in news:054f7966-
:

Diagnostics on pg 74 (F-8) indicate that it might be a problem with
the speed sensor (fault).

It's not a PDS cart, so it has no speed sensor.

This controller is a "dumb" PWM type, without regenerative braking or
automatic speed controls.

LLoyd

So no circuit feedback.

Oh well, it always pays to check the simple things first. Maybe the
board won't be too complicated if you have to figure it from scratch.
I understand the basics of PWM, but don't have practical experience.
I would now guess a bad SCR or the oscillator circuit went kerflooey,
but I'm mostly a hex head.
No SCRs any more - better than 90% are MosFet units - I suspect one
side of the unit, either high or low, is bad, but that's just a guess.
If one side is shorted the control would go into current limit.

EZ-go electric cart question
 

On Jun 27, 12:09*pm, "Lloyd E. Sponenburgh"
lloydspinsidemindspring.com wrote:
"Denis G." fired this volley in news:8b707822-
:

I would now guess a bad SCR or the oscillator circuit went kerflooey,

The couple of cart controllers I've taken apart (after scrapping) didn't
use GTO SCRs, they used really husky MOSFET drivers. *I think GTOs are
still extremely expensive compared to large, paralleled SmartFETs.

Back in the mid-80s, before carts generally had PWM controllers, my dad
and I designed one from scratch, using bipolar transistors (at the time
large enough MOSFETs weren't commonly available). *It ran the motor fine,
but we could never find big enough flyback diodes to protect the
transistors from inductive kickback, and slow switching would overheat
everything. *We faced other impediments, like not having the right motors
for that sort of control.

The first commercial ones were about the size of a LARGE loaf of sandwich
bread, and used banks of TO-3 bipolars to do the switching.

Now they're about 4" square, with lots of IR FETs and big "pellet" style
diodes mounted on TO-220 frames -- even have thermistor sensing on the
heat sink!

I finally elicited from my wife that this problem "comes and goes". *I
think it's time to pop the cover on the controller.

LLoyd

You're more experienced with electronics than I. I'm taking my beer
and I'll watch from the sidelines.