Go big or go a little?

[Lehman_GT]

Here is the Cart - Used strictly on a golf course
2005 EZ-GO Freedom SE TXT PDS (F/R switch on dash, run/tow switch below seat, no regenerative braking)
No Lift kit
12" wheels with tires (18-19 inch diameter total)
Freedom plug/chip in controller
Aftermarket In Dash Radio with Subwoofer mounted under basket
36V (6/6v Trojan T-105's) Roughly 6-7 years old
Stock: Motor, Controller, Solenoid
2ga. Cables (Battery and Motor)

The good:
- Cart runs great on flat ground like parking lot and cart paths. 16-18mph. Seems to run okay elsewhere but really picks up pace on flat smooth ground
- Still a great cart just has a few performance qualities lacking from personal preference

The Bad:
- Acceleration seems to be pretty mild as compared to what it used to be.
- When going up a hill in a fairway, almost all torque seems non existent so it slows way down and struggles to go up the hill when on grass. Still slows down on up hill cart paths but not as dramatic. (used to climb up hills in fairways with no problem)
- When driving in the fairway, the max speed drops to around 12mph
- The vertical battery gauge used to only drop 1 bar after playing 18 holes. Now after 9 holes its about half way down.

Any ideas as to why the sudden drop in performance? Motor? Controller? Batteries? Batteries all tested around 6.2v-6.3v fresh off a full charge.

Was tossing around the idea of the following for an upgrade:
OPTION 1
- Alltrax XCT500 PDS Controller
- H/D Solenoid
- FSIP 48V Speed Motor
- 48V (6/8v Trojan T-875's)

Do i need to upgrade to 48V or can i still see a boost in performance again by doing the same upgrades but all compatible for a 36V set up.
OPTION 2
- Alltrax XCT400 PDS Cotroller
- H/D Solenoid
- FSIP 36V Speed Motor
- New 6/6v Trojan T-105's

Back to the title of the post, Do i go big and do the 48V swap with option 1? or Go a little and stay 36V with option 2?
Pros and cons of both?

Thanks!

[cgtech]

Go 48v, no one ever said "I hate this speed and power, I wish I would have stayed 36v".

[TexTurbo]

for what Cg said....

Scottyb (site sponsor & all around nice guy) is the man you nee3d to "see" !!

[kernal]

Agree on the 48v for sure. EZGO and pretty much everyone else quit making 36v carts years ago.

Suggest doing the upgrades except for the motor first. For just golf you may find the motor upgrade unnecessary.

48v was the best thing I ever did for my old 36v cart.

[yurtle]

Originally Posted by Lehman_GT

<snip>

Any ideas as to why the sudden drop in performance? Motor? Controller? Batteries? Batteries all tested around 6.2v-6.3v fresh off a full charge.

</snip>

Voltage needs to be reported to two decimal places, as there's a pretty wide swing between what you stated. Also, "fresh off a full charge" is meaningless. You need readings 12 hours or more after charge completes. 6.37 is what a good T-105 should read.

My guess is that your T-105s are reaching the end of their useful life. Since you're there, I concur with all comments recommending you go to 48 volts. Realize that your battery interconnecting cables may not fit with eight volt batteries.

[DaveTM]

Go 48V. Before I did the Lithium swap my 8 6V T-105's were 7 years old. Run time was getting shorter 'n shorter.....but I likely could have squeezed another year outta them.

Keep your new batts watered and terminal's clean. Don't run 'em lower than the recommendation and they will last a long time....and you will like the performance!!

[Sir Nuke]

FIRST OFF, considering the age of your batteries, this is most likely your drop in performance, its time for new ones.

WITHOUT A DOUBT....make the jump to 48v. and since you are going to get a new controller, the price difference between 400 and 500 is negligible, so get the 500a even if you don't think you will need it, ya never know, you want to upgrade in the future and your already set this way....and anyway, you really can't have to much POWER!!

AND do the drive system upgrade without a motor change, seeing you will be getting a 33% increase in speed and torque just by going to 48v, that may be all you want/need at this time, you can always go with a bigger motor after you get the rest of it done.

[JohnnieB]

There is an option-3.

42V (7x6V) was the sweet spot for PDS carts with a stock PDS motor before Alltrax introduced the XCT sepex controller. However, with an XCT controller you can limit the motor's max RPM, so over revving is now longer as much of an issue as it was with the Alltrax DCX controller.

Go with the XCT48500-PDS with a MZJ400 solenoid and turn it down to 400A if you run the stock PDS motor for a while, then crank it back up when you replace the motor.

[bronsonj]

Originally Posted by JohnnieB

There is an option-3.

42V (7x6V) was the sweet spot for PDS carts with a stock PDS motor before Alltrax introduced the XCT sepex controller.

Hi Johnnie, I've seen you mention 42v as the sweet spot for this motor before, does it have longevity issues at 48v?

Makes me wonder about my TXT48 if it will have longevity issues at the higher lithium voltages...

[JohnnieB]

Originally Posted by bronsonj

Hi Johnnie, I've seen you mention 42v as the sweet spot for this motor before, does it have longevity issues at 48v?

Makes me wonder about my TXT48 if it will have longevity issues at the higher lithium voltages...

The stock PDS motor has a couple upgrade issues.
1. Heat issue. It can't handle a steady diet of more than 400A for very long, so turn down controllers with greater than 400A throughput.

Tall tires, hi-speed gears, hilly terrain, jackrabbit starts, heavy loads and towing stuff all shorten its life.

Since it is more efficient at higher voltages, it runs cooler at higher battery pack voltages than it does at 36V. In a nutshell, 400A at 36V is 14.4kW while 14.4kW at 48V is 300A and heat is generated by the square of the amps flowing through the resistance (I²R=W), so the 25% fewer amps to do the same amount of work generates far more than 25% less heat.

2. Max RPM is determined by applied voltage. On level pavement with stock height (18") tires a stock PDS motor will spin about 5600RPM when power by a 36V battery pack. Go to 42V and the motor will spin at about 6535RPM and at 48V it'll spin about 7465RPM. The maximum recommended RPM for a stock 36V PDS motor is about 6500RPM, but some suggest 6000RPM max.

The Alltrax DCX controller didn't use a speed sensor, so running a PDS with stock height tires at 48V could get you into trouble, especially going downhill with your foot on the throttle. I was running a stock PDS motor at 42V through a DCX controller and it was spinning about 8000RPM when it exploded. Of course, there were factors other than RPM involved.

Since the XCT uses a speed sensor and max RPM is user programmable, the over-revving issue of running a stock 36V PDS motor at 48V has more or less been eliminated.

---------
As for the TXT48 motor on the slightly higher lithium pack voltage. Not to worry, it is designed to run on 48V at about the same RPM a 36V PDS motor runs on 36V. Remove the RPM limiting of the stock controller (1206HB) and it'll spin at about 5600RPM. At 56V, it increases to about 6500RPM, or about the same as a PDS motor does at 42V.

Not really an issue since you can limit the RPM to a save value with a XCT controller.