more torque needed

[scottyb]

12.44 Xs 10% gives 13.68

Plus 20% is closer (14.92) to the workhorse gear ratio.

20% is a pretty significant change.

[720Deere]

JohnnieB was talking about the effective ratio difference between the 12.44 w/23" tires vs. the 14.7 with 25" tires. No matter the final outcome, I just don't value ground clearance that much! The most economical change may be to sell the PDS and start over with a series cart taking as much of your goodies as possible along with you.

[JohnnieB]

Originally Posted by scottyb

12.44 Xs 10% gives 13.68

Plus 20% is closer (14.92) to the workhorse gear ratio.

20% is a pretty significant change.

True, but I was crunching the torque loss from going from 23" tire to 25" along with the torque gain going from 12.44: to 14.7:1 to get a net gain of about 10%.

23" -> 25" = -8.0%
12.44:1 -> 14.92:1 = +20.0%

(23" -> 25") + (12.44:1 -> 14.92:1) = +10.0% net gain over previous Tire height and gear ratio.

Thanks for the exact gear ratio.

Looks like it ought to be +12%, but you have two percents, so simple adding and subtracting (or multiplying and dividing) doesn't yield the correct percent of change. Learned that one in Accounting rather than Physics.

[Kydog]

The reason for going with 25" tires was more of a selection issue than anything. The tire and wheel combo i purchased originally were 10 x 8 rims with 23" tires and the tires were crap, dry rotted and split the side walls withinn 2 years and also had a bad bounce to them. The choices for 23" tire were terrible, it was either go back to the kind i had or something similar and they were junk. The 25" sze had more choice's since they were standard ATV tires.
JohnnieB, it is a GE D1162 motor and i am running map #4 i believe. i had called Alltrax for correct map when i built it. I'll have to check the pack voltage the next time at the farm.
How much voltage will these motors take? how do i increase the amperage to the motor?
The cables seem fine, the motor does get hot under these circumstances.
When i built the cart i copied a beast 48 build i had seen for sale on the net, this cart is used on the farm and for hunting so speed was not an issue.
Thx KyDog

[JohnnieB]

Originally Posted by Kydog

1. The reason for going with 25" tires was more of a selection issue than anything. The tire and wheel combo i purchased originally were 10 x 8 rims with 23" tires and the tires were crap, dry rotted and split the side walls withinn 2 years and also had a bad bounce to them. The choices for 23" tire were terrible, it was either go back to the kind i had or something similar and they were junk. The 25" sze had more choice's since they were standard ATV tires.

2. JohnnieB, it is a GE D1162 motor

3. and i am running map #4 i believe. i had called Alltrax for correct map when i built it. I'll have to check the pack voltage the next time at the farm.

4. How much voltage will these motors take?

5. how do i increase the amperage to the motor?

6. The cables seem fine, the motor does get hot under these circumstances.

7. When i built the cart i copied a beast 48 build i had seen for sale on the net, this cart is used on the farm and for hunting so speed was not an issue.
Thx KyDog

1. You do what you gotta do. Going up 2" in tire height did cost you about 8% in torque, but I think that should have just slowed you down on steeper hills rather than stalling. But I'm just speculating, so I might be wrong.

2. That is the high torque one. Something like 12 HP at 1300 RPM @36V, so at 8 MPH om 25" tires with 12.44:1 gears you are turning about 1338 RPM and should be developing close to max HP.

3. Ask then if field map #55 might be better for your application, or if the have one that produces the best low end torque without regard for top speed.

4. From what I've been able to find on a GE D1162, it is a 36V motor, but DC traction motors (cart motors) can take a lot more voltage than they are rated at. The problems going higher than 48V are finding the controllers and solenoids that work at the higher voltages.

5. Except when the motor is stalled, or turning just a few RPM while accelerating from a standstill, or bogged down to walking speed or less on a hill, it cannot draw all the amps a DCX500 will allow it to draw.

Connect a laptop to the controller and log that data while driving. That will tell you how many amps it draws, or at least what the armature draws, The column labeled Battery Current is the average current to the armature. The Output current column is peak amps.

To answer your question, Higher Ampacity controller, Heavier gauge high current cables, Higher rated Solenoid, Higher AH capacity battery pack. Also the motor work on Watts rather than Amps, so increasing the pack voltage would increase the motors torque at any given RPM.

6. The cables and connections should not get more than about 10°F above ambient air temperature. The motor will get HOT, but should be kept under 239°F measured at the case surface.

7. Looks like you are duplicating the Beast 48V 2WD cart pretty well, including the 25" tire height.

Their website doesn't give the AH of their battery pack, but other than that and the tire type, the appear to be about the same.

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

I believe what the battery pack drops to under load is going to be a significant factor.

[sportcoupe]

Kydog's cart would be an excellent candidate for a lithium battery conversion. Lighter weight, a tad more voltage (59v) and very little voltage drop under load. He would gain an impressive amount of torque.

[HiTechRedNeck]

Anyone say hills?

Might look at RXV's
48v AC drive climbs hills very well.
Madjax has wheels that look and ride great.
Wheels that fit under UN LIFTED RXV's dont seem to hurt hill climbing or brake performance.
Speed is set by computer (MAX @20mph) no need to sacrifice/trade off speed and torque.

Would not go with 20 inch or larger tires or more than a small (3 inch) lift on RXV's.
Brake performance may not be up to safely stopping from the speed cart would go with that large a tire.

I live in very hilly area,Customers LOVE RXV hill climbing ability.

Johnnyb-- have you driven a RXV up a hill?
Would love to hear your opinion of their performance. I have limited
experience with upgraded motors and controllers.The ones i have seen
in this area do not impress me.

[HiTechRedNeck]

Apologies for typo JohnnieB.

[sportcoupe]

Put 25" atv tires on an RXV and tell me how much torque it has then.

[HiTechRedNeck]

No-- No bigger tires than fit under Un Lifted cart.
25" not recommended -- Loss of torque = Loss of braking power on RXV's.
25" would put RXV's well over 20mph legal speed for golf cart in my state.
12" or 14" look good on RXV's -- safe & legal speed (@20mph)
Great hill & climbing good speed.
No mods needed to motor or controller.
RXV's DO like good batteries and upgraded cables!

No dog in this fight-- Just saying Motor/controller/gears =$$$
Might be cost effective to trade in ,go with what works for you-
--------------Looking is free.---------