Cycling UK Forum

Hi folks,

My wife and I are regular cyclists and I would really like to reduce our car usage, particularly for short local journeys. However when we do use the car locally it's because we need to carry more than our bikes can handle. I've therefore been thinking of a cargo bike with electric assistance. I have looked at what's available off the shelf and prices are prohibitively high. However s/h cargo bikes can be had for reasonable prices. What sort of conversion kit would be best suited to this? I can't see a front wheel motor being any good. Also would a road legal 250W motor be powerful enough to get up a steepish hill with a week's load of shopping? Another option would be a normal bike with a motor and a trailer but I tend to think a dedicated cargo bike might be better suited to our needs.

I appreciate your collective wisdom.

Ian

I fitted a Woosh XF07 front hub conversion http://wooshbikes.co.uk/?hubkits to a tandem & it gets up hills OK, not fast, but steady. All up weight around 180kg with the wife & little kiddie on board. I still put a fair bit of effort in myself but it will go up pretty much on it's own with the throttle only I'd imagine (maybe have to turn the cranks a bit to get the pedal assist if the hill's too steep for the throttle only). Therefore I'd imagine it would get you, the cargo bike & the weekly shop home without too much problem. There are better (more powerful) hub kits available from the same supplier. Woosh were very good to deal with.

If you went for a mid drive motor then its ability to hill climb is limited by the gears.

I fitted a bafang mid drive 10,000 miles ago on mine, took a couple of hours one evening and most of that was removing the old stuck bottom bracket.
(Mine was from Woosh)

We've also got an XF07 on a tandem; also from Woosh. It does need low gears and quite a lot of help on what passes for a steep hill here (White's Hill, Owslebury, about 1 in 10?), but the help it gives just makes all the difference. We haven't had any issues from the front drive; and found Woosh very helpful.

Woosh are short of most controllers at the moment (36V hub kits are delayed again until 20-October. Factory sent the wrong parts, our apologies.) Their rear hub SWX02 is really powerful and is available; they suggested it for the tandem but couldn't supply in 700C wheel at the time.
http://wooshbikes.co.uk/?hubkits#swx02-48v-kit

The Woosh 48v swx02 kit is 250w and marked on the casing as so. The advantage of 48v over 36v is the motor will have 33 more torque and speed if you wanted to have it. Also a 48v 12ah battery will have the same range as a 36v 16ah one as both will have similar watt hours.
The swx02 is marked as code 16 which means it is a slow wound 190rpm high torque it will manage maybe about 17mph, it will excel at load lugging and hill climbing.

Thank you all for the replies - all really helpful. The 48V Woosh rear wheel kit looks particularly interesting. Is there any reason why this couldn't be used with for 12V motorcycle batteries wired in parallel to increase range as fitting/stowage wouldn't really be an issue on a cargo bike?

iandusud wrote:Thank you all for the replies - all really helpful. The 48V Woosh rear wheel kit looks particularly interesting. Is there any reason why this couldn't be used with for 12V motorcycle batteries wired in parallel to increase range as fitting/stowage wouldn't really be an issue on a cargo bike?

No reason at all, you'd need 4 in series to get your 48v.

Looking at the battery on my motorcycle that would give you around 12Ah for I'd estimate two to three times the weight and size.
That would only give you a similar range though, to increase the range you'd need another 4. That's 8 at £50 each.

The other consideration is they're not really designed to be continually charged and run near flat. They're meant to sit trickle charging at near full charge with the odd heavy pull for starting.
You might be better looking at deep cycle batteries which are designed for that sort of use.

Then you need 8 x 12v charger - although you might be able to find a specialised 48v lead acid charger (or make one, they're fairly simple).

Bought a Nihola Flex cargo trike for wheelchair transport without an electric motor and fitted a 250W one myself with a 5 year old and well used 612Wh battery.
It climbs 10% hills slowly with me providing about 200W as well but I avoid steeper hills if I can.
Done 35 miles in rolling countryside, battery might last for 40. It's fine without battery power on the flat at 15 mph.
Also fitted a http://www.electric-bike-conversions.co.uk/ 250W kit to another trike and it was fine and much cheaper than sophisticated set up on the Nihola.
I reckon the Nihola all up weight is in the region of 220kg!!!!!!!
If you can afford it pick a cargo trike with proper front wheel steering, handles much better than the hinged frame versions!

Hi Pedals2slowly,

Thanks for your thoughts on this matter. The more I read about conversion kits the more I come to realise that not all 250W motors are the same! The Bafang 48v SWX02 Woosh supply would appear to ideal for low speed grunt and with the 17A controller should produce in theory 816W max (48x17). Of course there are losses but even so Woosh quote 750W max. I don't really understand how the 250W nominal designation is arrived at but clearly not all 250W motors are the same!

Ian

iandusud wrote:Hi Pedals2slowly,

Thanks for your thoughts on this matter. The more I read about conversion kits the more I come to realise that not all 250W motors are the same! The Bafang 48v SWX02 Woosh supply would appear to ideal for low speed grunt and with the 17A controller should produce in theory 816W max (48x17). Of course there are losses but even so Woosh quote 750W max. I don't really understand how the 250W nominal designation is arrived at but clearly not all 250W motors are the same!

Ian

Strictly speaking anything over 250W is illegal, though if used judiciously I doubt you'd ever get stopped.....but with the ever increasing number of e-bikes being used by incautious folks you might be unlucky. https://www.gov.uk/electric-bike-rules

Anything above 250W and 15.5 mph powered and you need CE marking, registration and insurance seems totally unfair that I have to lug twice the weight around with 250W
https://www.bike-eu.com/home/nieuws/201 ... 1540472345

The 250W is approximately the power a reasonably fit person can sustain for any length of time - it does make sense for solo e-bikes but not for tandems etc.

250w isn't a max wattage rating, it is a test criteria that it won't over heat during a constant test period of 1 or 2 hrs at that wattage so is merely a nominal rating that conforms an agreed criteria. If it passes it is given a 250w rating. Any 250w rated hub will have a higher peak wattage output just depends on how many amps you throw it, the more amps then the more it will heat up. Most 250w hubs are happy with 17-20amps after that they get hot and internal nylon gears melt.

The important bit is that the hub is marked as 250w. Only OEM complete bikes can have a CE mark, kit not so.
Kits are a bit in no mans land as they aren't catered for in eapc reg's, but appear as long as they comply they are accepted.

Hence my statement, not all 250W motors are the same.

iandusud wrote:Hence my statement, not all 250W motors are the same.

Interestingly though 250, 500 & 750w motors can all be the same.

The cargo bike project is coming along nicely. All the major welding is done and I hope to find the time this week to fit wheels, bars etc to test ride it. I then need to build the box and weld up the supports and make up a centre stand. Then it's a strip down and paint and we're done. That will still probably take a few weeks of spare time.

I have been in touch with Tony at Woosh who is very helpful. I asked his opinion on whether I should go for a SWX02 48v rear hub or a Tongsheng 48V 250W TSDZ2 mid drive, which looks very tempting. He is of the opinion that I should go for the SWX02. This did surprise me as I stressed my concern that it should cope with hills with a full load, but he is confident that it is up to the job. This is good news as I prefer the simplicity of the set up and the ability to retain a useful range of gears (ie triple front with a wide range freewheel). I also suspect that reliability should be better with a hub motor but time will tell.

Cheers, Ian

Hello

I have a Nihola Family cargo bike (http://www.nihola.com/products/family.html) which I would like to convert to electric. I carry two children (4 and 7) and live in Flat Cambridge. Can anybody suggest me a) which e-kit to buy b) could I install it myself c) can anybody do it for me? d) where do I buy the kit (is this the one http://www.electric-bike-conversions.co.uk/).
I have looked all around Cambridge but cannot find a place thaat offers the service

I look forward to your replies

Luana