Electric BCS - technical details walkthrough

A longer and more detailed description of the technical details of our farm's electric-powered BCS 2-wheeled tractor and explanation of how the conversion was carried out. Apologies to any and all who sit through the whole duration but it was faster and easier than writing a 20 page manual and hopefully it'll answer a bunch of technical questions for anyone who feels inspired to pursue a similar project.

[@mathieulamaure1487]

I was tilling some new beds yesterday with our two wheel tractor (a grillo not a bcs but close enough)And I was thinking it would be so nice to electrify the damn thing. And here you are! Thanks for the video, it is very inspirationnal and helpful. If you ever feel like writing an instructable page, that would be much appreciated.

[@reidallaway]

I'm pretty sure someone else will soon do an easier-to-duplicate build using easy-to-find parts. Mine is too much based on what I already had on hand and while it's a good and functional one-off it's not a great template for others to copy from. I am happy to answer questions and provide guidance if you decide to tackle such a project yourself.

[@paulbrowne5049]

You'd think BCS would bring out an electric version direct from the factory themselves. This makes so much sense as you are not alone in wanting to use an emissions free machine in a confined space like a polytunnel.

[@reidallaway]

I do hope that BCS or Earth Tools will tackle this in the years to come. The lack of emissions and noise is what initially appeals but the control, performance and improved safety of the machine have even more staying power. Long after we've forgotten what a gas engine even sounds like we are still appreciating the control and precision of the electric drive because it's not just less bad, it really is better.

[@MsSomeonenew]

Well since BCS really only packages some other companies engine with their kit I'd say we just need someone to make a complete electric pack that can swap in.

[@qorje]

Thank you! I'm enjoying your videos very much, going through them at the moment! I hope to build my own some time in the future!

[@tomlampros7122]

*Very* comprehensive! Lots of great info here. Thank you

[@ronaldpasilan8636]

Reid Allaway, your Two Wheel Tractor is impressive. I am currently now searching for a Research Proposal regarding Two Wheel Tractor. Design, Fabrication and Performance evaluation. By your permission sir" I would like to conduct your innovative design in my Research Proposal Sir Reid Allaway and study more on the Design, Fabrication and Performance on this machine, since i've never seen in my place (Philippines) one of this kind invention. Thank you for sharing your videos.

[@reidallaway]

You are very welcome to include my tractor in your study but I am unable to provide significant support or time for collaboration as it is currently summer and our farm is very busy. Note that commercial electric models now exist in Europe and many are surely in development. In Europe you can look up Rapid brand and there's another in Germany that I can't remember. I've heard that BCS in Italy has machines in development but no public présentation to date that I know of. Contact me via our farm "Tourne-Sol co-operative farm" if you need more info.

[@lelanddyke8386]

I'm in love with those battery packs

[@bigdaddy470]

Great build! Your design and implementation is pretty much perfect in my opinion as far as a balance of robustness, availability of parts, cost, performance, simplicity (in a good way). It's an amazing time in the world that as I was thinking of this conversion I was able to find your video posted only a few days ago. Especially since I'm not so mechanically inclined and would be mystified about some of the details you showed. I do have a few questions if you care to answer: 1) Have you considered leaving the clutch installed? It seems this would give you a mechanically controlled ability to modulate torque, otherwise the motor controller acts as a speed control rather than torque control (though speed control is ideal for most applications). 1a) If you left the clutch installed, then would the custom-fabricated interface be DC motor Clutch input (which looked like a keyed shaft in the video but i'm not confident about that). Would that be an easier to build or find parts for? 2) Regarding keeping the tractor balanced, you mentioned intentionally designing for compactness to match the weight balance w/the honda. (Maybe this is also one reason you removed the clutch). Could you also keep the balance by moving the batteries closer in to the wheels, either mounting them sideways so the tractor is wider, or mount the batteries up higher almost in between the wheels? Basically what happens when the heavier person scoots towards the center of a seesaw/teeter-totter. Do you have any mass or center-of-mass measurements for the electric and/or gas drivetrain? 3) I'm a new owner of a used BCS and I haven't used it that much yet. I noticed there is a mechanical interlock to prevent PTO engagement when the transmission is in reverse. When adding the electric reverse, is there any risk of damaging certain implements somehow? Or is that only a safety measure to prevent me from tilling my toes?

[@reidallaway]

Thanks for the kind words of encouragement and the great questions. First off I would say that if your BCS isn't going to be used indoors or has engine problems it's probably not worth the time and effort to convert to electric - especially if you have a Honda engine. In our case the BCS is currently used almost exclusively inside greenhouses (though I used it in the field yesterday) and that, along with my interest in the conversion challenges, was enough justification to shelve a perfectly good Honda GX340 in favour of something more expensive and unproven. 1) Re: clutch removal or not. I don't know about newer BCS or models with the hydraulically actuated "Powersafe" clutch but on the older models the clutch is just about the only flaw in the BCS design. It's a conical clutch that tends to grab and the size and strength of the operator's hands largely determine if it is pleasant, safe and useful or the just the opposite. Women farmers with smaller hands have been complaining about BCS clutch operation for years and this frustration was targeted for elimination as part of the conversion process. Also, the conical clutch is not a very good clutch for modulating power or torque as I believe it's designed to prevent slip. The clutch isn't terribly heavy but it is bulky, filling the volume of the bell housing. Thus, keeping it intact would make the machining/fabrication of the adapter shaft trickier and might require shifting the electric motor further away from the bell housing, increasing forward weight which I wanted to minimize. All told the clutch had very little in its favour as a keeper and go the axe. It also simplifies the control systems to have no clutch which makes it easier to train employees on the BCS. Many people never really “get” how to use a clutch anyway. 2) The compactness of my overall assembly is going to be hard to improve on except by using a physically smaller battery and changing them more often. There’s only about 2 cm clearance between front of the wheels and rear of battery cradle. If the batteries are set in the other orientation (wider L to R) it would make them the widest point on the machine, compromising manoeuvrability and preventing it from fitting in certain narrow walking paths, maybe even doorways. if the batteries were stacked above to motor and clutch housing it might prevent swinging the handlebar to reverse operation position used for mowers and other front-mounted implements. I’m pretty happy with the balance result of this setup and don’t like the compromises of the others. That said my friend François Handfield converted his BCS with a slightly smaller motor at 48V and used a larger Volt 12S battery module mounted above the motor - and he can still reverse his handlebars. 3) I toyed with several solutions to the PTO-reverse interlock. I liked the idea of using a 24V solenoid or magnetic acuator to pop the PTO to neutral whenever reverse was engaged but I didn’t want to spring for the parts and ran out of time. I assembled a lock-out switch that would prevent reversing until PTO was disengaged but ultimately decided not to fit it (again time and perhaps tedious in operation). I don’t think many implements would be damaged by reverse operation but It’s a valid question. For a mower I definitely think an overrunning clutch would be in order if there isn’t already one integrated into the mower - I don’t think you’d want the mower’s blade inertia to keep spinning the electric motor for no good reason after power is removed, though I suppose you could recover the energy with an appropriate controller. Having now logged some time with the tiller I find it convenient to not have to disengage and re-engage the PTO drive for brief reverse movements but when I’m backing up significant distance I do disengage. Maybe an audible alarm would be a good solution for this so you don’t do it much but have the option of doing it briefly, as when correcting your path with a quick reverse to the side. Thanks for the great questions and please share other ideas as you ponder the pros and cons for yourself.

[@wiredforstereo]

Thank you so much for posting this. This is exactly the sort of tour that this nerd was looking for. So rarely do people get into much detail. Maybe I missed it skipping around, but what is the capacity of the batteries? How much time do you get out of them say, tilling? It was interesting to do the math on your amperage, seems tilling only uses like 2 hp continuous and max power is under 8. This is an outstanding project, an excellent explainer, and one I would love to do myself one day.

[@reidallaway]

Solomon Parker there's another video on my channel somewhere from a stress test where I finally had enough work to run the batteries down one after another. They last about 30 minutes at sustained 60-100A load - which makes sense for 1kWh pack at 24V.

[@reidallaway]

Solomon Parker thanks for the geek praise. You're fully the second person in two years to really enjoy the details and say so 😆. The other guy was a friend of mine but at least it means we're not alone.👍

[@reidallaway]

And yes Solomon you're right about the power figures. 7kW Power in makes quite a lot of torque through a DC motor. I might worry about the drivetrain with more. The only change I'd make with a do over would be to go up to 48V for lower amperage and higher motor speeds at same power - but that posed more challenges for battery pack design, at least with my budget.

[@tiagomesser993]

Congratulations! Nice work. It is inspiring.

[@jamesquinn2650]

you are a f@#%@%ing genius!

[@reidallaway]

Hah! Not true but thanks anyway Jamie.

[@wiredforstereo]

Does the reverser also reverse the PTO or just the wheels? It seems one would want to retain that for some of the reversed implements.

[@reidallaway]

The original mechanical reverser in the BCS gearbox does not affect PTO direction but it is set up so that it disengages the PTO when you flip into reverse (using the clutch to disengage the gas engine during shift). My new setup with electric reverse simply reverses motor direction and drives everything backwards, including the PTO. I considered using a solenoid or other actuator to pop the PTO out of gear when switching to reverse but just ran out of time and patience to implement it. For a commercial version you'd have to make some similar provision for safety (anti toe-nibbling security for folks who don't wear steel toe boots). A bypass to deactivate this function would make sense when the handlebar is reversed for front PTO implements like mowers or snowblowers because you wouldn't want to interrupt their power when reversing. I think they'd need an over-running clutch too or stick with the mechanical reverser rather than reversing the motor. I'll figure that out when I get a mower.

[@garciasgardens3981]

Cool beans. Is there clearance to flip the handlebars around?

[@reidallaway]

Yes. loads of clearance. The handlebar and controls rotate just as they did originally and there's actually more clearance than with the Honda engine. The control cable layout is also much simplified as I've now got just one bundle of wires in a heavy sheath and only the diff-lock cable (clutch, throttle and reverser cables were all deleted during conversion). The wiring layout with upper and lower junction boxes was also chosen to facilitate adjusting and reversing the handlebar. The lower junction box is securely mounted to the transmission on a little mounting plate I fabricate and there's just a tidy and flexible bundle of wires from the lower junction box to the upper one. The upper junction box provides a place to tidy some wire connections and also a convenient spot for the emergency stop button.

[@phalmantha141]

Hi Reid, My name is Phal Mantha, I work with developing sustainable agronomic models to be used in various places including the Chesapeake Bay, Puerto Rico, and in the Pacific (Hawaii, American Samoa, Palau.) I am very interested in utilizing an all electric converted BCS and Power Harrow combination to perform secondary tillage in our production systems. I couldn't find an email anywhere on your channel to send you a private message. I am hoping to rope you in as a consultant or at least have a phone call with you to see if you could share some pointers with us. Please send me an email if you are interested in assisting us in this endeavor. I believe that your experience with this conversion would be invaluable to our efforts. My email is [e-mail]. I have also included a link to my linked in as it may give you some background on my work as well as what our organization does- Thanks so much for your assistance, I look forward to hearing back from you. Warm Regards, Phal Mantha www.linkedin.com/in/phalmantha/

[@ProxyLimit]

Did you study engineering in college? How did you figure this all out?!

[@reidallaway]

Nope not enough math patience for engineering. I studied agriculture and environmental science but I've always liked taking things apart and I have a lot of patience for reading manuals and trying to figure things out.

[@ProxyLimit]

@@reidallaway That is great, you have inspired me to give it a try. I'm very thankful for the videos you have posted thus far, and can't wait for the day I can say I've converted a gas powered tiller to electric.