12HP petrol Lawn Tractor conversion to 36VDC electric

[B4D2USA]

One more... http://www.hustlerturf.com/products/zeon.html

[B4D2USA]

Jack, current exchange is about 1$ to 0.65 pound. Also, we don't deal with VAT or whatever the extra taxes are (so far). We do have to pay local sales tax, but internet purchases are exempt in most states. That won't last though. Lots of noise being made in a lot of gov't spending parlors on how to tweak a few more coins out of our pockets.

That second mower is a profession quality machine whereas the first one I posted sounds like a typical Chinese cheapie.

[jackpreacher]

It moved

I had 20 minutes on the project today and hooked up 24 Volts onto the motor......the beast moved...although the motor is rotating the wrong way. It's a series wound DC motor so it'll be dead easy to wire up to run in reverse.

I'll finish it this Friday and post more photos.

[jackpreacher]

Motor Wiring

After a bit of messing around with jumper cables and the like I came up with these two motor/battery configurations:


Motor wired in forward configuration.jpg

Motor wired in reverse configuration.jpg

As this conversion relies on the gearbox for reverse I only need the motor to rotate in one direction, either Clockwise [CW] or counter-Clockwise [CCW].
The motor drive can be taken from either end as the driveshaft goes right through the motor. One end is splined for a hydraulic pump and the other is a shaft with a key.
The pulley was fabricated for the shaft end and, if wired up in the configuration of the first diagram it rotated the wrong way. After rewiring as per the second diagram the motor rotated in the opposite direction......et voila, Bob c'est le oncle yet again.....

[B4D2USA]

Oh that crazy ole Uncle Bob. He was crazier when he got his wires mixed up. Never been the same since he rewired the buck/boost transformer...

[mogman]

Just read this thread very interesting project but as for the highwayman with the lathe it's an hour tops on a lathe job done.........but if you don't have one you are always going to be open to abuse

Mogg

[jackpreacher]

..new welder first, then a lathe .......am going to have to go back to playing gigs to pay for it all

Still, today was a red letter day......my much better half mowed the lawns (acres of 'em)....too tired to upload pictures - will do tomorrow. It's the end of an (petrol) era......thank god

[jackpreacher]

Oh, it's 48v not 36...

PS: Finally settled on a 48v system - lower amps, faster blades, less copper.

[jackpreacher]

Le finished product - not a "STOCK" production though...

Kill Switch Installed.jpg
This is the backend view of the kill-switch which has a key operated from the dashboard side. Basically all this switch does is to manually break the connection between the batteries rendering the motor, contactor and foot pedal inoperative.

Motor installed and wired up.jpg
This is the motor fully wired up with the jumper between A2 & S2.

Contactor installed and wired - note the professional battery tray.jpg
This is the 48V single pole contactor installed and wired under the highly professional battery tray. The contactor is energised from a 48V line run through a foot switch, similar to a pedal used to operate a guitar FX board - simply 'on' or 'off'


Front battery tray.jpg
The front end has to support 2 batteries weighing around 37kg each....that's 82lbs in old money, and 164lbs in total, plus the other 2 batteries. Total battery weight is 148kg, or 328lbs.

So viewer, what research did this exacting engineer carry out to see if the chassis could hold the weight?.......
..errrrrr......ummmm.....errrrr...ahhhh........... .


.....moving on......


All batteries installed.jpg
Batteries loaded up. Originally I had these grand plans to fabricate a pretty battery tray and clamp system, but since my welder packed up a few weeks back I decided to just bolt it together and use loading straps to secure everything.

Parky is finished.jpg
Finally, the grass cutter is slung underneath. This is operated via a belt driven by the main [expensive] pulley....

......and a warm welcome for 'Parky' as he joins the rest of the family

[jackpreacher]

Exhaustive testing procedures.....

The testing schedule was thorough and punishing - a 30 second hop around the car park.

After the testing was completed the cutter deck was slung on and it was 55 minutes of full on mowing.

[jackpreacher]

The test drive

[mogman]

All looking good so far will be interesting to know if it'll cope with the full 3 acre cut

how will it be charged I see a 24v charger in the back ground or will you be finding a 48v FLT charger?

Mogg

[jackpreacher]

..how will it be charged I see a 24v charger in the back ground or will you be finding a 48v FLT charger?

Well spotted Mogg.....a 48V charger was too expensive for what turned out to be an expensive conversion so the 24V charger is suffice. To charge up I have to rewire the four 12V batteries into two 24V parallel arrays and then hook up the charger [with off peak timer] and leave it to charge overnight. As it's a 50A charger I cut up some old, old jumper cables that had dodgy crocodiles on and used them with new crimp connectors.....it takes around 5 minutes to sort out so I'll live with that.



Next job will be to strip it all down, smooth off the metal cuts, clean everything, degunk where the old engine sat, prime and paint everything, then add bespoke decals.......

[mogman]

Will be good to see the finished job.........well done mate for sticking with it but like you say once it's out on the webb you have to see the project to the end or you my look a

Mogg

[jackpreacher]

All looking good so far will be interesting to know if it'll cope with the full 3 acre cut

Hmmmmm, here's my Macro Maths on the subject:

Motor: 6kW 48VDC, rated for 60 minutes.

Current @ Full Load [estimate]: 6000/48 = 125A

Actual Load required based on hope, faith and an approximation of power conversion factor derived for ICE to Electric and other conversions: 50% of full load = 62.5A

Battery Bank Capacity [Total]: 70 minutes @48V@75A, so therefore around 80/90 minutes. This should give 50% Depth of discharge.

Usual time to mow and collect 3 acres of lawns: 1.5/2 hours

Therefore, with a 60 minute top-up charge interval the lawns should be manageable. It all depends on the amperage. I haven't got any meters installed yet.

Ideally I'd like to deplete the batteries to around 80% of capacity and then recharge so that would mean splitting the mowing across two periods, but even if the batteries get hammered down to 20% they'll still survive at least 200 recharges. The lawns are mowed around 25/30 times a year so they should last between 6 & 8 years.