GEM won't go over 29 mph

GEM Forum
1

Hello,

I’ve been working with some great board members Kinghappy, Old Houseboater and Inwo who have been very helpful. Checking to see if anyone else might have any ideas for this set-up. Heard a few get to 40-45, but I can’t get close.

I purchased a Forklift program kit for my 2005 GEM ES with GE 5 hp motor, Deka 8G31 Gel batteries, 10.35 gear ratio and T3 controller. It has 195/50/16 tires with a height of 23.7 inches. Travel is all flat no hills.

I originally tried the MM built by Inwo, but it wouldn’t work in my GEM, it did increase the speed of my brother-in laws Club Car with early GE IQ motor by 5 mph.

I tried different controller settings such as;
#3 Controlled acceleration from 12 to 10
#4 Max Armature Current from 218 to 235 to 245
#13 Rolling Radius from 104 to 95 to 120 with 104 working the best.
#20 Pedal Up Regen Decel Rate from 128 to 75
#21 MPH Overspeed from 245 to 255

The fasted combination was #3 at 12, #4 at 235, #13 at 104, #20 at 128, and #21 at 255. It also seem like when I back off the accelerator it picks up some speed, not like when fully depressed and feels as if it’s holding back.

Set tire air pressure to 38 psi

Also checked battery voltage at full charge

13.05,13.12,13.11,13.11,13.09,13.02

After 12 miles of testing they read;

12.2,12.3,12.3,12.3,12.3,12.2

Checked Delta Q the 80% light flashed 6 rapid blinks which should be the algorithm for charging Gel batteries.

Thanks in advance for your interest.

Greg

2

Greg

You only have 5 Hp so 40 is not going to happen. The large Diameter tires are holding you back. You need more motor.

The probable reason that the MM didn’t work is that you don’t have enough available HP to make it go any faster than stock with the over size tires…

Take a GPS reading with the present set up. How fast will it go? What is the speedometer reading? If the speedometer reading is 26 the limiter is shutting you down. If it isn’t you are running out of HP

If the Speedo doesnt hit 26 bump the Amps to 255 and RR to 86, If there is no change then you have run out of power and and will have to go with a bigger motor.

Note: the 5 horse is going to get hot in a hurry with these settings. Beware.

Since your on flat ground suggest you deprogram regen.

Rodney

3

Rodney,

Now I’m confused, I was told that the low profile tire I had on before which were 18.5 inches tall would slow my car down which it did. I couldn’t go faster than 22mph (GPS) with the speedo hitting 25.

So I changed them to the taller 23.7 inch tires and got to 28mph (GPS) with the speedo registering 25 mph.

My current set-up is doing 28/29 mph (GPS) with the speedo blinking 25/26 mph.

What program numbers do you suggest changing the count numbers too for the Regen changes.

Thanks Greg

4

Your speed limiter is controlling your speed at this point.

Try setting 16 to 124 and see if you gain You can also try 147 leave your tire size at 107

Setting 16 tells the computer what gear ratio you have Telling it you have a 12.44 or 14.76 lets the motor spin faster before it hits the limiter. At these settings I think you might hit 33 or more.

Put regen settings back to original for now.

Rodney

5

[quote=spider445;29217]Rodney,

Now I’m confused, I was told that the low profile tire I had on before which were 18.5 inches tall would slow my car down which it did. I couldn’t go faster than 22mph (GPS) with the speedo hitting 25.

So I changed them to the taller 23.7 inch tires and got to 28mph (GPS) with the speedo registering 25 mph.

My current set-up is doing 28/29 mph (GPS) with the speedo blinking 25/26 mph.

What program numbers do you suggest changing the count numbers too for the Regen changes.

Thanks Greg[/quote]

greg ,

some can get a little more top speed out of there carts by dropping #7 parameter . unfortunately on a t3 controller you don’t have that option. the number 7 parameter drops the min field current which allows your motor to spin a higher rpm . with the smaller tires your motor would have hit max rpm’s at to low of a speed . with the bigger tires at max rpm your getting a higher top speed .

if your consistently showing 26 on your speedo . either drop #13 back down to 90-95 or raise #16 to 124 . they both have the same effect . they wont give you more power but well lower your speedo and allow your gem to faster before the limiter kicks in .

you can also take your # 4 all the way to 255 . this is where the new cars are set to . this sends max amps to your motor , it may help .

6

Would there be interest in an auxiliary field weakening function?

The project has been on hold while ramping up MM project.

I wasn’t aware that T3 lacked minimum field current function.
First thought was for those who didn’t want to reprogram. Seems T3 users might benefit.:confused:

7

My feeling is there is no lower threshold on the T3 so it would be mote. This could probably be verified by amp mapping and comparing the profile against a T4.

At this point I believe that the MM didn’t show any increase in speed in the initial installation was because the reserve power, in the stock programming, was over come by the Large diameter tires.

The programming changes we have suggested currently will more than use up the HP in the 5 HP motor. A 7HP will require the MM or Hi Speed magnet to fully utilize it’s potential. In any case all 40 MPH carts have R4F or equal performance motors.

NOTE: In a stock cart with virgin programming you gain 2 mph changing from a 5 to a 7Hp motor. This is first hand experienced base from change outs on 3 distinct carts.

8

maybe . the problem is that just field weakening wont do it . you have to change multiple parameters to get higher speed. in gregs case he changed all of them but it appears cant adjust his field weakening . for him it might work . but remember t3 was only made for a short time . there is not a lot of them out there.

what was the feed back on your mm’s with no other adjustments ? how was the top speed.

9

I know we talked about #7 being a different scale reading on the T3 vs the other controllers, so what would happen if I dropped it to a 3 or 2 count vs the 4? Getting out of my pay grade at this point. Also is it possible to replace the T3 with a T4 or T5.

When I installed the MM in my GEM it had no effect and wouldn’t go faster than 22 mph with smaller tires, or 25 with the larger tires. It read half scale on my speedo and the adjustable one read up to 22 then half scale. When I put it on an early GE IQ motor that has the pressed in magnet, it gained 5mph so the MM does work but not on my GEM.

I will try changing setting #16 and may even bump up #4 to 255, but Rodney cautioned about the motor getting hot very quickly. Thanks all!

Greg

10

Greg at this point in time your being held back by the speed limiter. Do the 16 bit, you probably have a power reserve just waiting to be freed.:clap2::clap2::clap2:

11

[quote=kinghappy;29229]maybe . the problem is that just field weakening wont do it . you have to change multiple parameters to get higher speed. in gregs case he changed all of them but it appears cant adjust his field weakening . for him it might work . but remember t3 was only made for a short time . there is not a lot of them out there.

what was the feed back on your mm’s with no other adjustments ? how was the top speed.[/quote]

About 5mph.
I did get this feedback from one in Italy.
Works great, no speed limit, with 7,5 hp arrived 60kmh!! Good!!

12

Not in time for Greg, but still might continue with a test of fw. mod.

13

[quote=spider445;29234]

When I installed the MM in my GEM it had no effect and wouldn’t go faster than 22 mph with smaller tires, or 25 with the larger tires. It read half scale on my speedo and the adjustable one read up to 22 then half scale. When I put it on an early GE IQ motor that has the pressed in magnet, it gained 5mph so the MM does work but not on my GEM.

Greg[/quote]

That is exactly how they should work. Just a more convenient fix than magnet change.
Hope to learn from this!:confused:

14

Rodney made the change to #16 setting it at 124, took it for a ride on fresh charge and the speedo flashed 20/21 then held at 21 with a GPS speed of 26 mph.

Then kept the same setting and bumped up # 4 to 255, car seemed to be holding back some and only reached 25mph on GPS,

Put settings back to #4 at 230, #13 to 103 and took it for a ride, speedo flashing 25/26 with GPS speed of 29 mph.

At this point it seems strange that removing amps from 255 or 245 to 230 under #4 position would make it faster. I would assume that adding power should have the opposite result.

Anyway I guess either my motor is tired or the T3 controller sucks and has limited adjustment. If you happen to come across a RFF turbo motor I just might take a trip out to see you, might even trade in my 5 HP. Thanks again for all your help.

Greg

15

[quote=spider445;29239]Rodney made the change to #16 setting it at 124, took it for a ride on fresh charge and the speedo flashed 20/21 then held at 21 with a GPS speed of 26 mph.

Then kept the same setting and bumped up # 4 to 255, car seemed to be holding back some and only reached 25mph on GPS,

Put settings back to #4 at 230, #13 to 103 and took it for a ride, speedo flashing 25/26 with GPS speed of 29 mph.

At this point it seems strange that removing amps from 255 or 245 to 230 under #4 position would make it faster. I would assume that adding power should have the opposite result.

Anyway I guess either my motor is tired or the T3 controller sucks and has limited adjustment. If you happen to come across a RFF turbo motor I just might take a trip out to see you, might even trade in my 5 HP. Thanks again for all your help.

Greg[/quote]
greg,

did you try lowering your #7 ? would it allow it ? if so try the smallest increment you can . lowering your minimum field current allows the motor to spin higher . don’t know if t3 well allow it . even if it did you are only talking a few mph more then u have now .

if you want it to go a lot faster you are going to have to get a RFF motor .

16

Haven’t played with position 7 yet, not sure what the scale reading is and there appears to be limited information available. Was hoping Marlon was available, he seems to be the GEM guru and might have some answers.

17

Conflicting information.
T3 manual = not used.
Stock setting = 4 :confused:

18

Try the MM again with the power settings you have now.

I read some where that GE had some fail safes for over revving. Looks like we found them.

Your the only T3 I have run across. Interesting.

I have 2 GE 7hp and would steal your 5 in trade

Rodney

19

You may be on to something.:clap2:
As controller has access to actual RPMs, it would make sense to have a hard coded red line. Regardless of function settings.

20

[quote=OLD HOUSEBOATER;29243]Try the MM again with the power settings you have now.

I read some where that GE had some fail safes for over revving. Looks like we found them.

Rodney[/quote]

I could send him a tach.
Run car with no load to see RPM maximum.