Personality Plug did not work as expected

[worleytech]

2001 EzGo TXT PDS 36V 1206MX Controller
All stock as far as I know, tires included.
Came with a light kit installed which is good because my town requires them!

Got this cart this past winter, Trojan T-105's dated 2005 were shot.
Got a free set of three 12V 186AH/20Hr Sealed Lead/Acid TEL Service Batteries & used these to see if this cart runs or not.
Swapped out old cables between batteries and to controller with #4 welding cable during battery installation.
Cables from controller to motor looked larger already so I left them alone.
(But that might just be insulation thickness tricking me.)
All cable bolts checked/tightened.
Runs around town all afternoon with no problems.
Added Panel Mount DVM into the ball holder with Velcro.
With these batteries full throttle voltage drops aprox 34V but recovered aprox 36-38V after sitting a few minutes.

Came to me with the Blue Personality Plug.
Cell GPS Spedo shows an average of 15.5MPH on flat ground after an overnight charge.
Swapped out to the Red Personality Plug in TOW mode.
Speed only raised 1MPH, 16, maybe 17MPH downhill, again after an overnight charge.
Not what I expected.
Regen braking went away with Red Personality Plug.
Put the Blue Personality Plug back in and Regen braking came back.
Checked the Personality Plug beep count.
Blue sounded 2 beeps, Red sounded 4 beeps.

Why no major speed increase with the Red Personality Plug when the beep count shows correctly which one is installed?

[scottyb]

Try turning the R/T switch off then back on to refresh the controller?

[worleytech]

Done that.
Thinking that when I switched from Tow to Run after installation maybe it didn't take the first time.
No help.

[kgsc]

4 beeps is the red plug. Could be your batteries just don’t have enough umph to get there or brakes or need some air in the tires.

[worleytech]

Yes, confirmed the beep count with both plugs.
Have not checked tire pressure for the last month or so.
Thinking if the tires were low, how did I get 15.5MPH out of the Blue Personality Plug?
Can't remember what pressure I put in them.
If I over inflated them and increased the circumference of them that might let me see the 15.5MPH.
Did try two different GPS Spedo apps.
Both matched my truck speed on the highway.

[JohnnieB]

The plug with the red jumpers sets the controller to Freedom mode which is supposed to have a top speed in the 17MPH to 19MPH range and does not have regen braking when you lift you foot off the pedal.

The plug with the blue jumper sets the controller to Steep Hill mode which is supposed to have a top speed in the 13.0MPH to 13.5MPH range and has strong regen braking when you lift you foot off the pedal.

Getting 15.5 mph in the Steep Hill mode indicates the tires are about 20.5" tall while stock is only 18" tall.

The combination of the 12% torque loss from the taller than stock tires and low air pressure could limit the max speed in Freedom mode to less than what the specs state.

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What is the tire size stamped on the sidewalls?
What is the actual tire height as measured with a yardstick and level?
What is the max recommended inflation pressure stamped on the sidewalls?

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Attached are charts show the four plug types and the four performance modes

[JohnnieB]

Another thing:
With the low capacity (186AH) batteries, the voltage drop while accelerating may be enough to prevent top speed being reached in Freedom mode.

Try accelerating like there is a red solo cup in the cup holder that is filled to the brim with a very precious liquid, instead of doing a jackrabbit start.

[worleytech]

-----------
What is the tire size stamped on the sidewalls?
What is the actual tire height as measured with a yardstick and level?
What is the max recommended inflation pressure stamped on the sidewalls?
---------

Checked one of the rear tires.
18 x 8.50 - 8 and all are the same. (I believe this is the stock size???)
Max pressure listed as 22PSI.
Currently was 8PSI & 16-1/2" height.
Inflated to 20PSI & got 17" height.

Will have to check the pressure on the rest of the tires later today as time permits.

Still curious how I got 15.5 MPH on the Blue plug.
It might be the low capacity batteries not providing enough amperage with the Red plug not getting the higher actual speed.
Only 40F here today, let it warm up a bit to run it around testing again.
Also the "very precious liquid", can that be Rum & Coke?
No wait, the town regulations do not allow open alcohol in carts, bummer...

[JohnnieB]

Yes the tire labeling indicates stock size, but as you've discovered, the actual tire height can vary an inch or more in either direction from the labeled number.

Getting 15.5 MPH on 16.5" tall tires with stock (12.44:1) differential gears means the motor is spinning about 3928RPM. The blue plug rpm limits the motor to about 3150RPM, which is about 13.5MPH on 18" tall tires and the speed sensor puts out 4 pulses per motor revolution. If the 4 pair of poles magnet disc was somehow modified to 3 pairs of poles, than the speed sensor would only put out 3 pulse per motor revolution and the motor could spin at about 3938RPM with the blue plug inserted. That is the only scenario I can imaging that will up the Steep Hill mode to 15.5MPH on 16.5" tires.


I suspect the max speed in Freedom mode is low due to the low battery capacity (186AH), further lowered by cold temperature (75% at 40°F or 140AH) and almost flat tires.