Box Bike Conversion advice please!

waggonsroll

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May 4, 2021
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Hi! I wonder if anyone here could help me with some questions about converting my box bike to an electric one. It's from the Cargo Bike Company, and has 2 wheels at the front and a single at the back.

I think I should probably be going for a mid drive kit, as they generally have higher torque, and are less likely to overheat.

But beyond that, I'm pretty clueless. I have a limited budget, but also want reliability, so keen for a trusted brand.

I am pretty handy, so would look to do the conversion myself, unless this is just asking for trouble!

Can anyone help, please? Thanks!
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
Hi! I wonder if anyone here could help me with some questions about converting my box bike to an electric one. It's from the Cargo Bike Company, and has 2 wheels at the front and a single at the back.

I think I should probably be going for a mid drive kit, as they generally have higher torque, and are less likely to overheat.

But beyond that, I'm pretty clueless. I have a limited budget, but also want reliability, so keen for a trusted brand.

I am pretty handy, so would look to do the conversion myself, unless this is just asking for trouble!

Can anyone help, please? Thanks!
Please show photos of your bike that show the whole thing, then ones that show the area around the bottom bracket, the chainwheel and the back wheel.

Your assumptions about a crank motor are incorrect. There are hub-motors that can work very efficiently, though it doesn't mean that a crank motor might not be the best solution. what sort of loads will you carry? What sort of hills do you have to go up? How fast do you want to go? What sort of brakes do you have?

Please answer all the questions if you want to get the best advice.
 

Woosh

Trade Member
May 19, 2012
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wooshbikes.co.uk
you would need a high torque motor.

If you like a road legal rear hub motor, go for the Woosh kit DWG22C.
https://wooshbikes.co.uk/?hubkits#dwg22c-48v-kit

If you like a crank drive, go for the high power Bafang BBSHD.
The BBSHD isn't road legal though.
 

waggonsroll

Just Joined
May 4, 2021
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Thank you both very much for responding. Photos attached and answers below, @vfr400

Loads: the bike is rated to carry up to 100kg, and the box itself is approx 25kg, so I'd like a motor capable of around 130kg.

Hills: minimal - the worst is approx 7%. We're in London so it's all pretty flat!

Speed: this is for getting around with the kids / dog at a safe pace, speed is not something that matters.

Brakes: standard V brakes

Distances: unlikely to do more than 20 miles in a trip, and most often far less than that (<5 miles).

IMG_5807.JPG
 

Attachments

vfr400

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Jun 12, 2011
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the first thing i noticed is that your frame is not a normal shape, so there's a small chance that it will not accept the common crank-drives. If I were to guess, i'd say that there's just enough room, but, as always, your pictures are all from the wrong angles to see the important things. The only way to be sure would be to try one or take measurements and compare the dimensions on the various drawings:

Another possible solution would be a large slow wind geared hub-motor, like a 201 rpm Bafang BPM that you can get from BMSBattery, but it's rated at 500w so not legal. The 48v 201 rpm one would be perfect. It's a very strong and robust motor.

The 48v hub motor from the kit that Woosh mentioned would be good if you ran it at 36v with a 36v controller and battery. I think a 22 amp controller would be good in that situation. The standard 48v Woosh kit would work, but it might be a bit fast for your loads, in which case it would run inefficiently and over-heat.
 

waggonsroll

Just Joined
May 4, 2021
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Thanks very much for your advice, @vfr400

I will check out the various options.

Assuming the crank-drive will fit, would you choose it above the hub driven options?

Can the Bafang BPM be limited to 250W with a controller, similarly to the Woosh one?
 

Woosh

Trade Member
May 19, 2012
15,853
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Southend on Sea
wooshbikes.co.uk
The 48v hub motor from the kit that Woosh mentioned would be good if you ran it at 36v with a 36v controller and battery. I think a 22 amp controller would be good in that situation. The standard 48v Woosh kit would work, but it might be a bit fast for your loads, in which case it would run inefficiently and over-heat.
the DWG22C that I stock can take 25A on 36V but the optimal speed would be too low. It's optimised for 15mph on 48V.
 

vfr400

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Jun 12, 2011
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Thanks very much for your advice, @vfr400

I will check out the various options.

Assuming the crank-drive will fit, would you choose it above the hub driven options?

Can the Bafang BPM be limited to 250W with a controller, similarly to the Woosh one?
The regulation is on the rated power of the motor, not the power that you put through it, so no, you can't make it legal even if you had a 1w controller. Lot's of people have used these motors. Nobody is checking, but anything can happen in the future.

If you want legal, the BBS01 would probably be your best choice if it fits, in particular the special high torque version that ou can get from Brighton ebikes.
 

Benjahmin

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Nov 10, 2014
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This rated power malarky really is a pain in the butt. As Tony said above his DWG22c is capable of taking 900w max, but it's still rated at 250w, so it's legal.
Perhaps motor manufacturers could supply a choice of non-removeable labels with their motor, so that the one appropriate to the country of use could be applied. Then we would be free of this bureaucratic humbuggery.