What I have vs what I need

EzgoNewbie305 · 06-23-2018, 09:50 AM

I recently bought a 2001 txt that looked pretty stock. Bright it home, put some old batteries that were on their way out and it runs pretty decent. I am going to have to replace the batteries soon so I think I’m going to step it up to 6x8 48 volt pack. I have been gathering parts cheap locally and I now have a Jakes 5” lift, and some rims and tires 23x10x14.

The motor was replaced previously. It is a GE 297? It is rated for 4400 RPM, and 4 HP. The wires look to be 4 gauge, everything else looks to be stock. I can’t really find info on the specs though.

My plan is
5” lift
23 inch tires
2 gauge wires
HD solenoid
500 amp controller
Convert to 48 volt

From what I read 22/23 inch tires reduce your torque about 20%, and a rear seat+weight are another 10%. And a 500 amp controller would add about 40% torque. Does anyone see a problem with that plan?

JohnnieB · 06-23-2018, 10:27 AM

Get an Alltrax SR48500 controller, it is user programmable.

The F/R switch is the weak link in your system. Ought to be upgraded with a true HD F/R (Most being sold as HD aren't) or a Reversing contactor.

Here are links to the good stuff:
http://www.cartsunlimited.net/f---r--switches.html
http://www.cartsunlimited.net/reversing-contactors.html

Also, attached is a chart showing speed gains and torque losses vs tire height.
(Speed is based on circumference while torque is based on radius, so the %gain and %loss aren't the same for each tire height.)

BTW: Going from 36V to 48V is a 33.3% increase in both speed and torque.

EzgoNewbie305 · 06-23-2018, 01:01 PM

Thanks for that advice. That’s the controller I had my eye on.

My question no is, if the motor is rated at 4400rmp with 48 volts that’s the max right? I have it running on a 36 volts does that mean it’s running at 66.6%.

JohnnieB · 06-23-2018, 01:27 PM

I'm pretty sure that motor will spin faster than 4400RPM at 48V. From the way I read the specs, it yields 4HP @ 4400RPM with 36V applied. That means it is a high speed motor and has less than stock torque.

Yes, running it at 36V, it only has about 66.6% of its max RPM and Torque.

EzgoNewbie305 · 06-23-2018, 02:26 PM

Ok, so I’m not sure what’s holding it back. Old batteries or small cables. But I’m only going about 14 mph.

kernal · 06-23-2018, 04:16 PM

I have that motor. Should run faster than that so you have an issue somewhere. I don't believe it will be happy with 23" tires but I haven't tried that either.

EzgoNewbie305 · 06-23-2018, 08:48 PM

Kernal, what kind of setup do you have and what kind of performance do you get out of it?

kernal · 06-24-2018, 06:29 AM

My cart is a 2000 TXT series configuration (not sepex). It is technically called a shuttle 2+2 which means it's a factory built 4 passenger cart. Not a standard golf cart with a rear seat kit bolted on. I only mention this to point out that in context this cart is heavy. I'm the only owner.
Originally 36v with a factory installed Curtis 400 amp (24-36v) controller, 200amp solenoid and a 1.87KW motor vs the standard golf cart motor at the time of 1.49KW.
Years ago (at least 7) I installed the D297 motor and 4 ga cables and no other changes. Cart would now run 20mph on the flats (driver only) on 17" tall tires.
Later on I installed an Alltrax SPM 400amp controller and 400amp solenoid. No changes in performance as expected. Controller change was in preparation for eventual 48v conversion.
After 48v conversion cart will run 22-23mph and gets there faster. (still on 17" tires). Big change at 48v was the torque. Handles additional weight (passengers ) much better than at 36v.

One time we loaded this cart up with 4 big people. All 230# at least. Went to a destination ~8 miles distant and after a several hour rest returned. The motor clearly was not happy about it. Got very hot. Thought I had damaged it. This is why I'm suspicious it won't like the 23" tires even with relatively low passenger weight.

YMMV

EzgoNewbie305 · 06-24-2018, 07:52 AM

I see, I might just keep it low. But I’m going to have to go thru my system a bit to see what the holdup is.. thanks for that info. Are you comfortable now taking people with you? Have you made any changes, because I do plan on putting a back seat on it, and would hate to be worried about the added weight.

kernal · 06-24-2018, 08:39 AM

I don't worry about this cart at all. Multiple people use it. Extended family and house guests. Normal routine is to cruise in an extremely golf cart friendly environment sometimes with lots of little people on it (grandkids). Many times for 15 or more miles at a time. Over the last 18 years it has been very reliable. What I don't do anymore is load it up with ~900-1000lbs of humans for a high speed long distance run. I have another cart (RXV) that can do that no problem.

If I were to do this again with this cart I would go with a motor optimized for torque and gear it up or run 20" tires (no lift required). There are "off the shelf motors" that will do this better than the 297 and if you are really serious about this a custom wound motor is an option.

Over the years on this forum I have observed people seem to get better speed AND RELIABILITY with torque motors and larger tires or actual gear changes than with the high speed motors. Again, an observation as I have no scientific proof.

06-23-2018, 01:01 PM	#3
EzgoNewbie305 Gone Wild Join Date: Mar 2017 Location: Miami Posts: 157	Re: What I have vs what I need Thanks for that advice. That’s the controller I had my eye on. My question no is, if the motor is rated at 4400rmp with 48 volts that’s the max right? I have it running on a 36 volts does that mean it’s running at 66.6%.

06-23-2018, 01:27 PM	#4
JohnnieB Techno-Nerd Join Date: Jun 2011 Location: West Virginia Posts: 19,654	Re: What I have vs what I need I'm pretty sure that motor will spin faster than 4400RPM at 48V. From the way I read the specs, it yields 4HP @ 4400RPM with 36V applied. That means it is a high speed motor and has less than stock torque. Yes, running it at 36V, it only has about 66.6% of its max RPM and Torque.

06-23-2018, 02:26 PM	#5
EzgoNewbie305 Gone Wild Join Date: Mar 2017 Location: Miami Posts: 157	Re: What I have vs what I need Ok, so I’m not sure what’s holding it back. Old batteries or small cables. But I’m only going about 14 mph.

06-23-2018, 04:16 PM	#6
kernal Gone Wild Join Date: Jul 2010 Location: Peachtree City, Ga. Posts: 2,759	Re: What I have vs what I need I have that motor. Should run faster than that so you have an issue somewhere. I don't believe it will be happy with 23" tires but I haven't tried that either.

06-23-2018, 08:48 PM	#7
EzgoNewbie305 Gone Wild Join Date: Mar 2017 Location: Miami Posts: 157	Re: What I have vs what I need Kernal, what kind of setup do you have and what kind of performance do you get out of it?

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06-24-2018, 06:29 AM	#8
kernal Gone Wild Join Date: Jul 2010 Location: Peachtree City, Ga. Posts: 2,759	Re: What I have vs what I need My cart is a 2000 TXT series configuration (not sepex). It is technically called a shuttle 2+2 which means it's a factory built 4 passenger cart. Not a standard golf cart with a rear seat kit bolted on. I only mention this to point out that in context this cart is heavy. I'm the only owner. Originally 36v with a factory installed Curtis 400 amp (24-36v) controller, 200amp solenoid and a 1.87KW motor vs the standard golf cart motor at the time of 1.49KW. Years ago (at least 7) I installed the D297 motor and 4 ga cables and no other changes. Cart would now run 20mph on the flats (driver only) on 17" tall tires. Later on I installed an Alltrax SPM 400amp controller and 400amp solenoid. No changes in performance as expected. Controller change was in preparation for eventual 48v conversion. After 48v conversion cart will run 22-23mph and gets there faster. (still on 17" tires). Big change at 48v was the torque. Handles additional weight (passengers ) much better than at 36v. One time we loaded this cart up with 4 big people. All 230# at least. Went to a destination ~8 miles distant and after a several hour rest returned. The motor clearly was not happy about it. Got very hot. Thought I had damaged it. This is why I'm suspicious it won't like the 23" tires even with relatively low passenger weight. YMMV

06-24-2018, 07:52 AM	#9
EzgoNewbie305 Gone Wild Join Date: Mar 2017 Location: Miami Posts: 157	Re: What I have vs what I need I see, I might just keep it low. But I’m going to have to go thru my system a bit to see what the holdup is.. thanks for that info. Are you comfortable now taking people with you? Have you made any changes, because I do plan on putting a back seat on it, and would hate to be worried about the added weight.

06-24-2018, 08:39 AM	#10
kernal Gone Wild Join Date: Jul 2010 Location: Peachtree City, Ga. Posts: 2,759	Re: What I have vs what I need I don't worry about this cart at all. Multiple people use it. Extended family and house guests. Normal routine is to cruise in an extremely golf cart friendly environment sometimes with lots of little people on it (grandkids). Many times for 15 or more miles at a time. Over the last 18 years it has been very reliable. What I don't do anymore is load it up with ~900-1000lbs of humans for a high speed long distance run. I have another cart (RXV) that can do that no problem. If I were to do this again with this cart I would go with a motor optimized for torque and gear it up or run 20" tires (no lift required). There are "off the shelf motors" that will do this better than the 297 and if you are really serious about this a custom wound motor is an option. Over the years on this forum I have observed people seem to get better speed AND RELIABILITY with torque motors and larger tires or actual gear changes than with the high speed motors. Again, an observation as I have no scientific proof.