Toro Workman MDE conversion

Electric cars, trucks, ATVs, NEVs - things bigger than a motorcycle.
Ribfeast   100 mW

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Re: Toro Workman MDE conversion

Post by Ribfeast » Feb 19 2019 7:17pm

Batteries have arrived, I've made up a temp bus bar out of some aluminium flat bar for the initial balance charge. 3.2V 1600Ah, wouldn't want to drop a screwdriver on it!

https://imgur.com/a/6o6j5A8

Just waiting on BMS and charger. Charger might be a few weeks :(

Looking at mounting the box to the kart frame with these (or similar) to reduce damaging vibrations as I bounce over the old ex-vineyard humps on the property.
https://www.bunnings.com.au/goliath-30- ... r_p4230094

Ribfeast   100 mW

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Re: Toro Workman MDE conversion

Post by Ribfeast » Feb 24 2019 4:58pm

Battery box built :)

https://imgur.com/a/IlTpuF9

Have configured as 4S4P temporarily and attached to a gel charger for a few days while I wait for the variable power supply to arrive. It's just hit the country so hopefully I'll see it soon. Will then reconfigure to 16P and finalize the balance charge.

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Re: Toro Workman MDE conversion

Post by Ribfeast » Feb 27 2019 5:48pm

Power supply has arrived and I have been performing a balance charge for the last few days. Have the power supply set at 3.45V and it has been hovering at around 8-10A output without dropping (bank is wired as parallel, ie 1600Ah). Pack is sitting around 3.35V.
Around 1.7kwh has been sent to the pack plus whatever I put in with the 12V car charger before I started metering it, may stop the charge soon and do a final 3.65V charge just before I finalize assembly (don't want to leave it fully charged for too long).
Pack is 5kWh and I'm not sure what percent charged the cells arrived at, but they arrived with 3.275V each, am worried about overcharging it, even at such a low input voltage.

https://imgur.com/a/uNbcTN5

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Re: Toro Workman MDE conversion

Post by Ribfeast » Mar 01 2019 8:35pm

Wired it all up yesterday with BMS etc and took it for a spin, runs like an absolute animal now, goes up hills like they aren't there, seems to peak at around 185A draw with just me in it on a moderate 30 degree hill. Drove it to a mate's place and we took it up a 45 degree hill together and hit 300A and it went up without breaking a sweat.
Continued on to the horse feed shop (5km round trip) and loaded around 100kg of feed bags in the back and drove it back home, still sitting on 79% charge.
I'm giving it another full charge to confirm it is actually full, BMS seems to be doing a good job of keeping cell balance in check.
Will put up some photos and videos soon once I have prettied things up a bit.

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Re: Toro Workman MDE conversion

Post by Ribfeast » Mar 03 2019 5:35pm

Some pictures :)

https://imgur.com/a/pH8l9tN

Just need to do a few tweaks to the voltage limits for charging etc, currently it is set a bit conservative. I'd also like to upgrade the white battery monitoring wires to thicker ones so that the current shunting works better, I think they are a bit thin.
All in all a successful project, thanks everyone for their advice!

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fechter   100 GW

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Re: Toro Workman MDE conversion

Post by fechter » Mar 04 2019 2:30pm

Nice. That should stop the corrosion around the battery box too.
"One test is worth a thousand opinions"

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Re: Toro Workman MDE conversion

Post by Ribfeast » Mar 14 2019 4:50pm

Cheers :)

I've picked up a 2000W pure sine 48V inverter (4000W peak), it appears to run my compressor, power tools, heat gun and other items easily, problem is it is so big I can't mount it anywhere on the kart!

But it could run the 650W server rack, or a fridge for many hours if there is a power outage, as it has a 5kwh pack.

https://imgur.com/a/jpPw2rc

Also mounted some 72W LED spotlights on top for when I need to cut firewood etc at night.

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Re: Toro Workman MDE conversion

Post by Ribfeast » Apr 02 2019 10:19pm

Finally mounted up the inverter, here's a quick video of the BMS and inverter doing their thing, with the air compressor running off it.

https://imgur.com/a/Kux2ZZB

Next step is to install some LED headlights, 6x4 inch. Something like this:
https://www.aliexpress.com/item/HJYUENG ... st=ae803_4

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Re: Toro Workman MDE conversion

Post by Ribfeast » Apr 30 2019 5:20pm

My girlfriend parked up the kart yesterday and then went to use it later in the afternoon, it makes all the right noises (reverse beep etc) but the main contactor doesn't click on, and getting 4 flashes on the dash.
Tried bridging the 2 large terminals on the contactor to allow current flow but this didn't work.
Applied 48V to the contactor and it clicked over fine and reads 0 ohms when energized, so it appears OK. So it seems the Sevcon isn't outputting a contactor charge to energize it. It's now just giving 3 flashes which indicates it is likely faulty :(

So it appears that I have a faulty Sevcon Millipak controller. Does anyone know where I can get one of these affordably? Most seem to be around $700-1000US :(
It's a model 633T46301.
Are some of the other visually similar models interchangeable?
I think these work by switching things to ground, vs switching to positive, so not sure if I can change to another brand of controller.

If I was to buy a new Sevcon, would it need to be programmed also?
Does anyone maybe have a good one they are selling?

I've pulled it apart and it's full of that black potting epoxy, so I'm going to have a hard time getting to the innards to try and repair it otherwise. Has anyone repaired one successfully?
Might cross post this in a general area too.

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fechter   100 GW

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Re: Toro Workman MDE conversion

Post by fechter » Apr 30 2019 7:28pm

I tried looking it up. All I could find was MILLIPAK, MOTOR CONTROL, 500 AMP, 48 VDC

Do you know if the motor is separately excited or permanent magnet? There are many compatible controllers, like Alltrax or Kelly.

But check all the sensors and switches before giving up on it. There should be a way to find out what the fault light is indicating.
"One test is worth a thousand opinions"

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Re: Toro Workman MDE conversion

Post by Ribfeast » Apr 30 2019 10:12pm

It's a Sevcon Millipak 633T46301. Toro's heavily marked up version is 110-2569.

I'll check the motor brushes tonight, and double check the resistance of the contactor coil to confirm it is 126 ohms. The contactor does work when energized manually though. I've already removed the controller from the kart but I might reinstall it to facilitate testing.

Have a suspicion it is the diodes in the controller that manage the contactor, but it's going to be a major undertaking to open the unit due to the potting compound they used.
Pricing for a new controller is $2700Aus so unless I import one I'm up the creek :(

There is no magnet in the motor, it's a brushed DC model I believe. Has F1/F2 and A1/A2 connectors on it.

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Re: Toro Workman MDE conversion

Post by Ribfeast » May 01 2019 5:25am

Just rechecked, only getting 1 volt between Pin 8 (contactor) on the Controller, and the 12V switched pole. The controller is supposed to drop pin 8 to ground when ready, and it doesn't seem to be doing this, it just floats up to positive voltage. Tried fooling it with a resistor but no luck.

Going to have to try and get the potting out and disassemble :(
Motor brushes look good and contactor reads 123 ohms on the coil, within spec.

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fechter   100 GW

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Re: Toro Workman MDE conversion

Post by fechter » May 01 2019 11:12pm

Motor is a separately excited from the description. These are quite common on golf cars, so your local golf car repair place may have one that's reasonably priced and compatible.

If the potting is the hard epoxy kind, heating to around 80-100C will make it like rubber and you can dig it out with a small screwdriver.

Any luck with decoding the blinking LED code? There must be a manual that describes it somewhere.
"One test is worth a thousand opinions"

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fechter   100 GW

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Re: Toro Workman MDE conversion

Post by fechter » May 02 2019 9:18am

I looked around a bit. Kelly does not make a sep-ex controller. Alltrax does though. XCT 48500 would be a 48v, 500A that would work with your motor. It would take some rewiring to fit the connector on the Alltrax.

Here's one I found on Amazon. $630.00usd. Still expensive but maybe less than the OEM Sevcon.
https://www.amazon.com/Alltrax-XCT-4850 ... B016V10UZQ

Similar Sevcon $750.00usd:
https://www.electricmotorsport.com/ev-p ... -500a.html

But I found a manual for a similar Sevcon:
http://www.thunderstruck-ev.com/Manuals ... opaK_M.pdf
10.2.5Diagnostic LED - This is mounted between the connectors on the front of thecontroller. It serves as a simple diagnostic tool as explained below:
Constant illumination - No fault, normal condition
LED extinguished- Internal controller fault
1 flash- Personality out of range
2 flashes- Illegal start condition or illegal steer switch inputs.
3 flashes- MOSFET Short Circuit
4 flashes- Contactor fault or Motor Open-Circuit
5 flashes- Not used
6 flashes- Accelerator, Steer Pot or Speed Probe wire off fault
7 flashes- Low or High battery voltage or BDI cut-out operating
8 flashes- Over temperature
9 flashes- Contactor coil s/c12 flashes- CAN bus fault

I'm pretty sure the codes will be the same on yours. The controller is sensing open circuit on the motor. You tested the contactor already so you might just have worn out or dirty brushes on the motor. Sometimes just spinning the motor by hand a few turns can get it going.
"One test is worth a thousand opinions"

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Re: Toro Workman MDE conversion

Post by Ribfeast » May 02 2019 6:13pm

I bridged F1 to A1 one last night and then hooked up F2 and A2 to a bench power supply dialed to 50V 20A, and the motor spun, and upon inspection the brushes look OK, almost new judging by the amount of meat on them.
Measuring A1 to A2 is less than an ohm, same for F1 to F2, so everything seems normal there.
I've started removing the epoxy with a conical burr tool and some acetone. Tempted to try the oven method however the unit is rated to 70C (non operating) and I'm not keen to bake it at 150-200C. Steam is another method I have considered too.
I've ordered another identical unit from overseas for around $700, just waiting for them to confirm they have received my order. Hoping it doesn't need to be reprogrammed to suit any field characteristics for the motor, or any Toro-specific stuff etc.

I contacted Alltrax yesterday but they said they didn't have anything suitable. I think the link you just sent is not suitable for series wound motors. I was looking at the Alltrax SR-48500 but it would involve adding a big 2-way contactor to handle forward/reverse, after taking a detailed look at the wiring diagrams. The Sevcon handles that internally.
https://www.cartszone.com/alltrax-sr-48 ... controller

Was initially getting 4 flashes on the controller, but this progressed to 3 flashes once I manually energized the contactor. Suspect I fried something in the circuit when I did that as the magic smoke was released. I'd say there are dead diodes in the contactor circuit, and dead mosfets which would have been the original fault.

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Re: Toro Workman MDE conversion

Post by Ribfeast » May 09 2019 9:51pm

New controller has arrived at work, can't wait to get home and fit it! It's a generic one with the same model number, hopefully there is no Toro-specific programming in the old one.

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Re: Toro Workman MDE conversion

Post by Ribfeast » May 14 2019 5:31pm

Installed the controller in the kart last night finally, great to have it up and running again! Had to adjust the accelerator stop button to eliminate a 2-flashes issue.
For some reason this new controller appears to draw a bit more current than the old one, so maybe it has some different motor parameters in it. It also seems to have less regen, likes to coast a bit more gently to a stop, but maybe it will self adjust over time.

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fechter   100 GW

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Re: Toro Workman MDE conversion

Post by fechter » May 15 2019 8:04am

Great you got it running again. No risk in trying to tear apart the old controller. My experience is most of that potting stuff gets like rubber when heated to 100C and that should not be hot enough to damage any components. Boiling water is one way. A heat gun and IR thermometer is another way.
"One test is worth a thousand opinions"

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Re: Toro Workman MDE conversion

Post by Ribfeast » May 15 2019 5:41pm

Yeah might give that a try sometime, nothing to lose now.
The controller seems to have recalibrated itself and now drives the same as the old one. Must be some pretty clever electrickery going on inside.

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