Change motor in cargo bike

nilsroar

Just Joined
Jul 25, 2020
4
0
75
Oslo
Hi! I have aquired a three-wheeler front box cargo bike, sold by Biltema Norway. It is a sturdy and well buildt bike - fairly heavy though, around 60 kg. Components are OK, 13 Ah 36V battery, rackbased with controller in battery box somewhere. Freewheel rear hub motor, 100 mm dia, julet connector in 26" wheel. It is an OEM motor, maybe Bafang or copy, nominal 250W 36V. Speed is fine, does 25 km/h on the flat. Problem is that it runs fast out of steam on inclines - it is a struggle to get it up to the house, 50 m on a 1:8 slope -without load. And Oslo is a hilly city. So it seems I need more torque. 500W rated motors are allowed on this type of cargo bikes in Norway. My initial plan was to change to a low RPM BPM2 500W 36 V, but I am afraid it will not go well together with the 160 mm disc brake, and I would like to keep as much as possible of the original components. Woosh mentions 180 mm disc for the BPM.
So, questions: Will the BPM work with 160 mm disc - if not, will the SWX02 do? Other alternatives?
Is it likely that these upgrades will work with the existing controller? Guess I'll by one for use with the existing motor anyhow, but it would be nice to keep the existing cabling.
Gratful for any input!
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
12,976
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West Sx RH
Do you know the hub model ?
Do you know the hubs winding speed/rpm ?
And the current rating of the controller in use ?

60 kg bike dead weight is heavy for a hub to shift up hill, let alone load it with rider and cargo.
For more torque one needs a low wound hub and more current if using 36v.
The you will need a better battery actually capable of delivering the load asked and I doubt you exsisting battery is really up to it.
Do you know which cells are used in the battery and the continuous current it can supply ?

BPM needs a 180 or 201mm rotor other wise the calliper will rub on the hubs casing, a calliper adapter will be needed to use a larger rotor.
 
Last edited:

vfr400

Esteemed Pedelecer
Jun 12, 2011
8,439
3,381
Basildon
You should change to 48v at the same time as upgrading the motor because you get 30% more torque for the same current. A 48v 201 rpm Bafang BPM will be perfect for what you want. 22 amps should be enough, or 25 amps for ultimate climbing.

If you run at 36v, you'll need 30 amps, which means you're going to need a special battery and large controller.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
12,976
5,058
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West Sx RH
The specs give not much away except the battery and deducing the cells used for the battery which isn't very inspiring for such a heavy bike.
At most Samsung very mediocre 26F or J cells are used , not up to the task.

As vfr has mentioned a new battery and hub will be needed if op goes to 48v.

What ever the Op does a decent celled battery will be required.
 

nilsroar

Just Joined
Jul 25, 2020
4
0
75
Oslo
Do you know the hub model ?
Do you know the hubs winding speed/rpm ?
And the current rating of the controller in use ?

60 kg bike dead weight is heavy for a hub to shift up hill, let alone load it with rider and cargo.
For more torque one needs a low wound hub and more current if using 36v.
The you will need a better battery actually capable of delivering the load asked and I doubt you exsisting battery is really up to it.
Do you know which cells are used in the battery and the continuous current it can supply ?

BPM needs a 180 or 201mm rotor other wise the calliper will rub on the hubs casing, a calliper adapter will be needed to use a larger rotor.
Thanks! No specifications with the bike when it comes to hub nor controller. The sticker on the hub says 36V 250W 26" M3, and AN (Article Number?) 101 140 0021-0. I have not opened the controller/battery case yet. There are molded rotation arrows on the casing which might give a clue to the producer.IMG_20200727_125923369_HDR.jpgIMG_20200727_130319615.jpg
 

nilsroar

Just Joined
Jul 25, 2020
4
0
75
Oslo
So the way to go is 48V 201 RPM BPM, 22 amp controller, top rated 48V battery, LCD, 180 mm rotor and caliper adapter? Use the leftovers to convert my hybrid. Sounds good.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
12,976
5,058
57
West Sx RH
So the way to go is 48V 201 RPM BPM, 22 amp controller, top rated 48V battery, LCD, 180 mm rotor and caliper adapter? Use the leftovers to convert my hybrid. Sounds good.
Yes that's about it, battery wise you need at least v.good 10a cells to be used.
LG MJ1, MH1, M29, M36?
Samsung 25R.
Sony VTC5/A or VTC6.

Speak to Woosh because if out right speed is not important they may have a very high torque hub kit of about 180 rpm.
 

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