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DIY Trike

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    DIY Trike

    Hi guys, new to the forum and looking forward to what is available. I have just built a fat tire trike for the woods and would like to change my controller to one with pas. What I have now beside very little knowledge and experience is: a trike I built out of two fat tire bikes, one 48v 1800w motor driving one rear wheel and 30aph lithium battery. The trike is probably 70 lbs and I am 250, thats why the 1800 motor and large battery. The motor is one from Amazon with a twist grip throttle. I have geared it down through a jack shaft system, it runs about 13 mph on the road (no pedaling) this is fine but hard to keep at a steady speed off road. I hope a new controller with PAS will correct this issue. I have found a number of controllers for up to 1500 w motors but not much for an 1800w, any suggestions where to find a controller like I think I want?

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      1800w at 48v is only around 40 amps. 60 amp controllers seem to be around and have come down in price. I haven't really looked that close into them so I can't give any specifics.

      I too would like some photos and details about the build. Heard of people joining 2 bikes but never seen one up close. The 1 wheel drive must be interesting at times too. Do the pedals drive the same wheel?


        jack shaft makes it sound like a three wheel gokart...drift mtb?


          I agree basically with post #3.

          To expand on that: Basic Electricity: Volts x Amps = Watts


          1800 Watts (your motor's rating--assuming this is max-continuous rating, not a peak-rating)

          divided by

          48 Volts (your system-voltage)


          37.5 Amps (the minimum number for maximum-continuous-output you'll need to seek in a controller).


          Your controller's maximum-continuous output-rating must exceed the maximum-continuous-rating of your motor. But no worries--there are tons of controllers on the market.

          In your case, a 40A controller would do fine; so would a 45A controller. Again--maximum-continuous output ratings--never base anything on "peak" or "max instantaneous" ratings.

          Keep in mind your battery must also be able to provide enough current to adequately supply your controller. So, your battery's BMS also needs to have a maximum-continuous-output rating which meets or exceeds the maximum-continuous-output rating of your controller.

          See how that all works? Battery, controller, motor--everything is meant to be matched. Get all three's "Max Continuous Ratings" lined up--and you'll be good to go.


          Now: To be honest? I think you're way too low on power. I feel if you could approximately double what you're working with--you'll be happy.

          A couple things:

          A trike is hugely expensive in terms of energy-consumption already--and your total project weight (including rider) is considerable.

          For motors like yours, pulling high-amperage, many have found temperature-sensing/overheat-protection to be invaluable in extending the life of their components. Esp. in light of the stress you're putting yours through, and how you describe its inability to keep up off-road, I'm willing to bet you're building up a lot of heat in your motor (and likely your current controller). If you have none, get some temp-sensing/overheat protection.

          Next, let's be realistic here:

          You've chosen for a trike. Okay--so just to be clear--that means we're all beginning with the assumption that weight isn't an issue--right?

          I'm assuming that's already obvious to you--or you'd not have chosen "trike" for your platform... But it's better to be sure we're on the same page--follow me?

          Okay--so now that whole "keep it light" idea has been flushed down--and is no longer on the table; we can examine a very helpful option:

          You may wish to consider multiple motors. My three-wheeled bakfiets is AWD--and it works (for me) fantastically. In my case, I use a 4KW mid-drive to power the single rear-wheel, and two 1.5KW direct-drive hub-motors to power the front-wheels.

          I'm not worrying about weight either. Complete with rider, my machine likely tips the scales somewhere near 250 kilograms. Yet no amount of mud or sand has deterred me yet. My only "off-road" concern (as is true with all trikes) is tip-angle.

          But let's get back to that simple math, to see why I think you're currently underpowered: To achieve acceptable performance-levels (in my case) --where I'm also running 48V, I find by monitoring my own power-consumption, I'm tending to run at or below a max-continuous of around 65A (which comes out to 3120 watts). No, I don't pull that much current all the time, but with my current settings, that's what mashing "full-throttle" will give me. Note: That's way below my own "max-continuous" tolerances--I'm never pulling 6,000 watts--and that's intentional--for minimizing overheat, and therefore maximizing component service-life.

          Each front-motor has its own 40A controller. Both my front-motors' controls are linked together and they operate in unison. The rear-wheel's mid-drive motor is powered by its own 60A controller. On the handlebars, I'm set up to operate the front and rear systems either independently or synchronously via separate but linkable hall-sensor throttles.

          Of course I can't get inside your head; and I do not really know what exactly you're wanting or expecting in terms of performance--but I've got pretty decent intuition--and I get the feeling that in order for your project to feel "satisfactory" to you, you'll probably need to be boosting your power-output into similar ranges as I've got working.

          And, well--your currently-installed single-motor cannot handle that kind of amperage (obviously).

          But you're one of the lucky folks who picked a trike for a project--so you're blessed with extra options. If you like, you can add motors (and upgrade your battery if needed) in order to boost your output--whereas that's not so doable on a "keep-it-featherlight" two-wheeler.


          Best of luck with your project!

          Last edited by tklop; 10-14-2020, 12:25 AM.


            Having only one rear wheel driven on a two rear wheel (single front wheel) trike would make it very hard to steer wouldn't it? Whenever you accelerate, it would want to do a U turn? Why not power the other wheel as well? Unless I am not understanding correctly, that is?

            Driving only one rear wheel might work on tar or concrete, but I doubt it would work off road. Do you have any pics?