EZGO Txt Upgrade cont

[IRwynn]

Scotty, 6 8 volt Band new batteries fully charged

[JohnnieB]

What are the make/model of the batteries?
What is the battery pack voltage 12 hours after charger shuts off?

Lack of speed is often a voltage problem, so step-1 is identifying the batteries' storage capacity and their SoC (State of Charge)

-------------
Were all 13 high current cables upgraded to 4Ga?

[IRwynn]

Scotty, double checked the LED, I do get 4 green flashes but once throttle is engaged the LED is green and stays green even at full throttle

[IRwynn]

JonnieB, the batteries are Golden Eagle GEGC-150, pack voltage is currently 50.63 volts . I have attached the CSV log from the controller

[IRwynn]

Could this be the F&R switch? Still the original from the 36v.

[JohnnieB]

On the data log, Battery voltage was 50.2V as measured at the controller's B+ terminal when the solenoid closed and went down to a minimum of 47.0V at the end of the log.

Lowest voltage during pedal time was 47.7V, but max Battery Current was only 34.7A. That is a voltage drop of 7.2V/100A, which is 3 to 4 times the typical voltage drop per 100A being drawn from battery pack, so something is amiss with either the battery pack's ability to supply amps, the high current circuit's ability to deliver amps or the motor's ability to draw amps. The controller's ability to pass amps is also a factor, but it appears to be going to 100% duty cycle since the Battery Current equals the Motor Current when the throttle % is at 100 and Battery Voltage equals Motor Voltage.

You 8V batteries are only 150AH while the standard capacity 8V batteries used in 48V packs are 170AH. So you only have about 88% of the storage capacity that your 36V pack had. (Ironically, you are running the equivalent of a 4x12V battery pack instead of the standard 6x8V.)

The temperature at the time the log was recorded was about 53°F, so the storage capacity was further reduced by about 15%, bring it down to about 130AH. Also, when new, lead-acid, deep-cycle batteries only have about 75% of their rated storage capacity until they are broken in, so depending on where they were at in thei break-in process, they may have had less than 100AH of capacity.

However, low storage capacity alone won't prevent the motor from drawing a lot more amps than was seen in the log, so there is excessive resistance in the heavy cables and their connections, or the F/R contacts. Are any of the thick cables or the F/R switch getting hot?

What gauge high current cables? All 13 ought to be 4Ga or thicker.

The motor might be sick also, may need new brushes and a thorough cleaning inside. Ought to be drawing 200A or more during acceleration and it's only drawing about 1/5th of that.

-----------------
I suspect that all of the above is keeping your top speed down.

------------

Question:
Did you slowly press pedal to floor over several seconds, or push it to floor rapidly?
The log shows it took 7 seconds from 0% throttle to 100% on the first run and 4 seconds on the second.

[IRwynn]

JohnnieB, Great information, I looked at the Alltrax file and did not know how to interpret the data. I saw the motor draw only 50 amps at full throttle was not sure if this was correct . Will check to see if there is any heat coming from cable F&R switch. All 13 cables are 4ga welding wire see below.
Alos I will pull the motor tonight and break it down, check the brushes and clean.




# 4 Awg HD Golf Cart Battery Cable 13 pc GREEN TXT E-Z-GO Set U.S.A MADE
BUILT AND MADE IN THE U.S.A
EACH CABLE IS HYDRAULIC CRIMPED WITH 5/16" TINNED COPPER LUGS ON EACH END.
BUILT FROM CENTER TO CENTER OF LUG HOLES.
CABLE USED FOR BUILDING IS HEAVY DUTY EPDM 105C WELDING CABLE MADE IN U.S.A.
EACH CRIMPED END IS COVERED IN 3:1 HEAT SHRINK
STRANDING IS: 624 STRANDS OF BARE COPPER
RESISTANCE TO (FLAME, OIL, GREASE SOLVENTS, OZONE AND ABRASION.(ROHS COMPLIANCE)
600 VOLTS.

[JohnnieB]

Originally Posted by IRwynn

JohnnieB, Great information, I looked at the Alltrax file and did not know how to interpret the data. I saw the motor draw only 50 amps at full throttle was not sure if this was correct . Will check to see if there is any heat coming from cable F&R switch. All 13 cables are 4ga welding wire see below.
Alos I will pull the motor tonight and break it down, check the brushes and clean.

I'd like to see a data log taken when the cart accelerated from a standstill on level pavement after the pedal was slammed to the floor and held there until cart had been at top speed for 50 yards or more. The throttle should go to 100% withing a couple lines of the Relay going to a "1" and the battery amps should be well in excess of 100A (Possibly 200A or 300A or more) and then decrease down to about 50A or so as motor RPM reached it maximum for the voltage applied and mechanical load imposed.

For some reason, your motor isn't drawing the normal number of amps and it appears the controller isn't the bottleneck. The 4Ga cables appear adequate, but need to be checked for hot spots.

That sorta leaves both ends of the chain. Motor and Batteries. (and F/R in the middle)

[IRwynn]

Johnnie, I will try this test this evening before I take out the motor.

[scottyb]

Note too that if the LED is not changing to orange at full throttle the controller is not getting a full throttle signal - the monitor will allow you to see what percentage of throttle the controller is being asked to deliver and - you can compress the graph so that the controller accepts the max pedal signal as 100%.
This can help resolve speed issues