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ynot

Member
Joined
May 28, 2021
Messages
59
It's an E-tractor the motor has died (24 volt series wound golf cart motor) after serving us well for 10 years.
It is almost impossible to find another used motor out of a golf cart or equal because the newer ones all bolt up to the differential thus do not need a bearing on the output end, the tractor is belt drive.
I have a motor out of a treadmill currently being used on a large sander I use for woodwork. (20" X 118" belt) it has almost twice the power of the current motor but needs about 80 volts, I can replace it with a slightly smaller treadmill motor. Have to keep costs at a minimum as we are on a fixed income and building a house.
Am planning to build an 80 Volt +/- leaf module battery to drive the treadmill motor, anyone have advice or opinions???
Some pics:
Regards, Ynot.
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,278
Cool build I believe I saw your tractor on another forum or maybe another almost like it. my folks have a couple dead lawnmower tractors sitting around. Dammit just what I need another project! :)The forklift mast on the front end is great. I saw a treadmill on the sidewalk on my walk today.
Replacing the LA batteries with leaf cells I suspect you will have to off set the weight difference by adding weights to the rear. What size is the treadmill motor?
Sounds like a cool project.
On your E tractor is it direct drive or does it use the original tractor transmission? What controller did you use? So many questions grrr :) guess I will add it to list.

Later floyd
 

ynot

Member
Joined
May 28, 2021
Messages
59
Floyd, grab the treadmill, amazing what you can do with the parts.
The tm motor I have is about 4 hp at 90 Volts with a max draw of 25 amps.
I will use a pwm to control the speed. The tractor has a 6 speed transmission with reverse, and for the series motor used a Curtis speed control with potentiometer linked to a foot pedal, hope that the PWM will accept the old pot.
Those pics are at least 5 yrs old, the forklift weight tore up the steering gear so we put in hydraulic steering. Also added a sun/rain shade in the form of a 300 watt 32 volt PV panel, so untill I fried the batteries did not plug in the tractor for about 2 years. Has been a work horse for us, & hope we can keep it going, even tho' the heavy lifting is pretty much done.
 

ynot

Member
Joined
May 28, 2021
Messages
59
Floyd, grab the treadmill, amazing what you can do with the parts.
The tm motor I have is about 4 hp at 90 Volts with a max draw of 25 amps.
I will use a pwm to control the speed. The tractor has a 6 speed transmission with reverse, and for the series motor used a Curtis speed control with potentiometer linked to a foot pedal, hope that the PWM will accept the old pot.
Those pics are at least 5 yrs old, the forklift weight tore up the steering gear so we put in hydraulic steering. Also added a sun/rain shade in the form of a 300 watt 32 volt PV panel, so untill I fried the batteries did not plug in the tractor for about 2 years. Has been a work horse for us, & hope we can keep it going, even tho' the heavy lifting is pretty much done.
 

ynot

Member
Joined
May 28, 2021
Messages
59
Took the tractor for a short spin yesterday, on a 5s pack of leaf modules. put in the newer motor a week ago then whipped up a test battery, lo and behold the surging problem is fixed, the motor pulley size (gear ratio) is close enough. Next comes reversing the motor, have to use reverse to go fwd right now, build a 5s 2p or 2p 5s working battery and install a BMS, buy a battery charger 42V max 5 to 10 amp output..
Recommendations for a BMS & or charger would be welcome.
Ynot.
 

ynot

Member
Joined
May 28, 2021
Messages
59
Hey Floyd, I had a series wound 24/36 motor that is in very good shape, it was always my intent to try that first, then if the motor was still pulsing, would assume it was the curtis speed control at fault, but turns out it was the lead acid batteries pulsing, probably my fault because I put a terminal melting dead short on them. The 36V test leaf module drives the new motor smoothly & the motor spins up to a good speed so all is good.
Now for a BMS & a Charger.
Cheers,
ynot.
 

floydR

Member
Joined
Aug 23, 2017
Messages
1,278
what is the max A that your 36v golf cart motor draws?
BMS there are several options.

Tiny BMS 150/750A ebike/light ev has a pc application needed to program the bms current limits, once you have all the pieces needed for the bms to function at high currents the bms runs about $500 low balancing current. Any Chemistry.Some chargers can interface with it.
https://www.energusps.com/shop/product/tiny-bms-s516-150a-750a-36 There is a guy up in canada that sells them on ebay.

Chargery 16t current limits of up to 600A Uses Relays to control charging and discharge up to 1.2A balancing current again some people have had good luck, others not so good luck. Any Chemistry. Several sellers on ebay/alliexpress/alibaba

Daly smart bms's somepeople love them others hate them./non smart bms's I am using a couple 4s models LifePo4 models low balancing current not sure about the relay based daly have only heard about it. Several sellers on ebay/alliexpress/alibaba/Amazon many are chemistry specific


Ant BMS again some people love them some hate them. low balancing current any Chemistry Several sellers on ebay/alliexpress/alibaba/Amazon . many options in the apps

JBD/overkill solar etc. some are chemistry specific mostly good reports.

Prices vary but for high discharge most are $300+
chargers
https://www.ebay.com/itm/313132709291? 1.8A-5A
https://www.ebay.com/itm/203352565873? 5A
https://www.ebay.com/itm/384096151892? 12A
Later floyd
 

ynot

Member
Joined
May 28, 2021
Messages
59
Floyd, thank you for the input.
On the test run with the 5 module pack 40 volts the motor did not blow an 80 amp fuse, but am expecting to use the bms to open a relay if the amps are higher than the bms.
Sources are very helpful, gonna have to do a lot of research I fear.
 

ynot

Member
Joined
May 28, 2021
Messages
59
Well, flipped the tractor on it's side (try that with any other EV) switched the field wires (S1 & S2) to reverse the motor, put the test 10s leaf module test pack back in and took the tractor for it's first drive in quite a while. All seems good, lots of power and in top gear on pavement goes at a very fast walk, moderate jog.
Now building the 10s 2p pack and waiting for charger and bms as well as a buck convertor to power the winch.
Thank all for the help I received, now on to the freighter trike.
Tony
 

ynot

Member
Joined
May 28, 2021
Messages
59
So this morning drove the tractor about 4 kilometers pretty much in top gear, doing laps around the slightly under 1 kilometer block, almost all of the time in top gear, at full speed ( a rather fast walk) each lap stopped and measured the 5 leaf module pack & duly recorded the voltage.
Started out at 40 volts (8 V per module) and ended up after 4K with 38 volts (7.6 volts per module). The voltage drop was very consistent at 0.3 volts per lap, I am estimating .4 volts per Kilometer, and plan on running the pack between 40 volts and 36 volts.
Is it reasonable to expect 8 kilometers from the 5s pack, and 16 kilometers when I built a 5s 2p pack.
The purpose of the test was to help me decide between a 5s 2p, 3p or even 4p for 10, 15 or 20 modules. looks like a 5s 2p pack will be plenty.
 

ynot

Member
Joined
May 28, 2021
Messages
59
Yesterday installed the 10s 2P (10 leaf modules) battery into the tractor, with BMS, should give me an easy18 kilometer range.
Checked the module voltage on the 10s (5 leaf modules) pack and was surprized that all of the modules but one were at 7.6 volts, one was at 7.7. that after a months use with no BMS. Now the big need is for a faster way of charging, may have to build a solar charge station to get things moving a little quicker.
 
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