under powered motor???

[Portdawg]

Happy fathers' day weeked to all the dads out there!

My cart: 2006 EZGO TXT PDS converted to 48v, alltrax xct 400 amp controller, D&D 8.4 HP high speed motor #170-500-0001, 6" lift, 23" tires, all 2 gauge cables, new led light kit.

Issue: After/during carrying a heavy load (4 riders/couple of coolers) the cart slows down to a slow creep. after letting it sit for 30-60 min, it's back to normal.

Did D&D send me the wrong motor, as suggested by JohnnyB...should've been a high torque? Could there be another power issue?

I've checked/cleaned/tightened battery connections. As a very novice electrical guy, I'm not sure what else to check. Any help/suggestions would be extremely helpful. thanks!!!!!!

[JohnnieB]

The D&D 170-500-0001 has higher than stock speed, but less than stock torque while your cart has 23" tires and a rear seat, so it needs a motor with more than stock torque.

In a nutshell, you need 27.8% more torque with 23" tall tires to apply the same amount of force where rubber meets road that you'd get with stock height (18") tires and the D&D motor you have produces 10% less than stock torque, so your cart has upwards of a 40% torque deficit compared to a stock 36V PDS and with 4 people onboard plus coolers, it is doing about twice the work it normally does. On the other hand, going from 36V to 48V, upped the torque by 33%, so the net deficit is only about 7% or so and the net results is overheating.

The XCT controller is most likely overheating. When it misbehaves, stop, lift the seat and look at the LED. It ought to be blinking an error code.

The fan is optional on the XCT48400-PDS, did you get one or are you trying to run without one?

Record a data log (continuous sampling rate). It'll show the motor amps being drawn as well as the controller temperature and a ton of other stuff.

[Portdawg]

Copy Johnnie B.
I did purchase controller fan couple of months ago. Quite often it turns on very soon after starting operation…the 90 degree+ temps may be impacting that.
Think an extra fan near the controller would help (USB computer type fan)?
I’ll run a data log next time Im riding.
Thanks!

[JohnnieB]

More fans won't hurt, but probably won't help much either.

[Portdawg]

So follow me here....a motor rated at 10% over a stock motor would be a 20% swing from my current motor. By my simple math that would cover the 7% shortage in torque needed correct?

again...simple math for simple minds like mine.

[JohnnieB]

Math is right, baseline is wrong. A stock cart carries two golfers and their clubs. If you want to do more than that, you have to upgrade from stock.

First you what to figure out what you want for a top speed, then find the highest torque motor you can lay your hands on that will reach the need RPM to move your cart at that speed with 23" tall tires, 12.44:1 gears and a 48V battery pack.

The D&D motor I'm running has stock speed with 30% more than stock torque. My cart has tiny tires (17" tall) and I can spin the motor at 7000RPM with a 42V battery pack, but I have it RPM limited at 6500RPM.

Contact Vic or Eric at D&D and tell them about your cart (23" tires, 12.44:1 gears, rear seat, 48V battery pack) and your desired top speed. They ought to have something that'll work for you.

Also, contact Chuck at EMP. He custom designs cart motors to match the cart.

[Portdawg]

Neither Vic or Eric were available and the guy who answered just told me to look on the site. Site suggested 500 amp controller and sole solenoid for #170-502-0001. Would my 400 amp set up work for that engine?

[JohnnieB]

Originally Posted by Portdawg

Neither Vic or Eric were available and the guy who answered just told me to look on the site. Site suggested 500 amp controller and sole solenoid for #170-502-0001. Would my 400 amp set up work for that engine?

Yes, your 400A setup will work with that motor. In fact it ought to work very well.

That motor will give you about 40% greater than stock torque, which is about what your cart needs.

The laws of physics dictate the faster a motor spins, the fewer amps it is capable of drawing, so the performance difference between a controller that will pass 400A and one that will pass 500A only exists below the max RPM at which the motor is capable of drawing 400A.

I don't have a dyno printout for that motor, but my best guess is that RPM is in the neighborhood of 1500RPM, or 8.3MPH on 23" tires. In other words, there will be little, if any, performance difference above 8MPH.

[Portdawg]

Just talked to Vic for a quick min….they are jobbing at d&d. He suggested I get the ES-9B-50. Said it would be plenty of torque plus another $100 more than 502-0001. In your honest opinion, is it worth the money? Would you know if the 9B would be longer/require any additional modifications for install?
Figured I ask here before stopping Vics production again.
Thanks a million!!!

[JohnnieB]

Originally Posted by Portdawg

Just talked to Vic for a quick min….they are jobbing at d&d. He suggested I get the ES-9B-50. Said it would be plenty of torque plus another $100 more than 502-0001. In your honest opinion, is it worth the money? Would you know if the 9B would be longer/require any additional modifications for install?
Figured I ask here before stopping Vics production again.
Thanks a million!!!

Vic knows his stuff and the ES-9B-50 is worth the extra money.

The motor will fit in the space provided.