Which motor/battery combo.

William of wigan

Finding my (electric) wheels
Nov 19, 2021
12
-1
I know nothing about ebike kits. Im looking to convert my 2008 trek fuel 8.ive been looking at bafang motors,but there's so much choice.i have M.S. and suffer from fatigue in my right limbs especially. The only thing I know I really need is a thumb throttle I can use with my left hand,and the ability to use throttle only to get me going. What difference does a bigger watt motor make? And do diffrent volt batterys work better with diffrent watt motors?
Sorry if this is confusing.
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
3,814
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Winchester
First and most important thing is to avoid the cheap big wattage direct drive motors advertised on ebay and the like. The are very inefficient and need a large (expensive) battery, and aren't very good on hills.

To be legal the motor should be a maximum of 250w nominal continuous power. They all give much more than that peak, between 400w and even up to 800w or more. Unless you have very steep hills are a very heavy most of the legal motors should be fine.

Higher voltage gives more torque which can be really helpful; most motors will take it but you must be sure the controller is good for the higher voltage. It will be simplest to go for a complete kit from the likes of Woosh; you'll know all the bits work together well, and you'll get excellent advice and customer service. https://wooshbikes.co.uk/

One difference between systems is torque or cadence sensors. Torque sensors sense power/pressure on the pedals and behave more naturally, but you always need to put in power even on their highest settings. Cadence sensors sense pedals turning (they mostly don't sense speed of turning) and will let you ghost pedal, where you need to keep the pedals turning but don't need to put in any effort. That can be important for certain conditions; especially if you are liable to get suddenly tired on the way home.

Mostly hub kits have cadence sensors and crank motor kits have torque sensors, but that is far from always the case.

The rules about throttles are confusing; they are certainly allowed for helping you get going. Probably best to discuss details with Woosh or whoever you buy you kit from. Most Woosh kits include throttles.

Good luck in your search.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
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West Sx RH
Are you looking at hubs motors or mid motors ?
What type of riding will it be ?
 

vidtek

Esteemed Pedelecer
Mar 29, 2015
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74
Bournemouth BH12
I know nothing about ebike kits. Im looking to convert my 2008 trek fuel 8.ive been looking at bafang motors,but there's so much choice.i have M.S. and suffer from fatigue in my right limbs especially. The only thing I know I really need is a thumb throttle I can use with my left hand,and the ability to use throttle only to get me going. What difference does a bigger watt motor make? And do diffrent volt batterys work better with diffrent watt motors?
Sorry if this is confusing.
@William of wigan Welcome to the forum.
There are a few of things we need to know in order to be able to assist you.
  1. Your weight
  2. How much effort you are able to apply yourself on a scale of 1-10 where 1 is a fit 20 year old, and 10 is an 80 year old with arthritis...to give us an idea of your physical capabilities.
  3. The sort of journeys you anticipate doing. Bear in mind that as you progress you will probably want to explore further both your area and your own capabilities.
  4. The terrain you will be using. Tarmac paths, gravel or rough terrain. The sort of inclines you will encounter have a large bearing on range.
All 3 types will perform well on tarmac, a front hub drive can feel skittish on gravel, especially uphill. A mid-drive torque sensor requires more physical input from the rider, so my advice would be to look at rear hub drive kits. As @sjpt suggests, talk to Andy or Tony at Whoosh Bikes, they will put you on the right track.

Cheers Tony.
 
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William of wigan

Finding my (electric) wheels
Nov 19, 2021
12
-1
Thanks for the replies. To answer some questions I'm 14stone.not fit at all...probably an 8 or 9 .I want a mid drive motor ideally,and I want to ride a mix of tarmac and dirt,with lots of towpaths.a range of 30-40 ,miles would be good.

I saw a set up on youtube.bafang hd 750w with a 48v battery and a egg display i think.my short term memory is not good.
 

vidtek

Esteemed Pedelecer
Mar 29, 2015
423
243
74
Bournemouth BH12
Thanks for the replies. To answer some questions I'm 14stone.not fit at all...probably an 8 or 9 .I want a mid drive motor ideally,and I want to ride a mix of tarmac and dirt,with lots of towpaths.a range of 30-40 ,miles would be good.

I saw a set up on youtube.bafang hd 750w with a 48v battery and a egg display i think.my short term memory is not good.
OK If you want a mid-drive do talk to Whoosh first and get their advice on the amount of effort you will need to put into your pedals. No 1 is to get a throttle, with your physical condition you will definitely need that for the initial start up, especially when starting up an incline. Bear in mind you will need to put more effort into your ride with a mid-drive, but it is definitely a smoother and also a more natural ride than any hub motor.

Be sure to get at least a 48v battery, a 52v would be better, but in any case get the biggest battery with which you can justify the cost.
Best of luck, Tony.
 

William of wigan

Finding my (electric) wheels
Nov 19, 2021
12
-1
Thanks for that info Tony so a mid drive bafang with 48v battery and a throttle.what difference does the motor wattage make?

Looks like woosh don't have any motors until February.
 

vidtek

Esteemed Pedelecer
Mar 29, 2015
423
243
74
Bournemouth BH12
Thanks for that info Tony so a mid drive bafang with 48v battery and a throttle.what difference does the motor wattage make?

Looks like woosh don't have any motors until February.
It depends on who you talk to about it. The cheaper motors on fleabay and malibaba have either engravings or stickers on them sometimes the same motors with different stickers/ratings. If you get a Bafang or Tongsheng from a UK supplier you probably can't go wrong. I found when I was looking to buy mine, by the time I'd paid carriage and import duties the difference in price between a UK based supplier with great after sales service and a fleabay merchant who couldn't give a toss after the sale was fairly marginal, averaging £30-40 on a £680 deal.
 

William of wigan

Finding my (electric) wheels
Nov 19, 2021
12
-1
I have seen some deals on ali express,good reviews,with a 3 day delivery time from within the UK. Be good if I could find a supplier in the Manchester/Liverpool area,but I'm not finding any.
On another note, the company that modified my car for me have also done bikes for disabled ppl.might be worth a chat with them.
 

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
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West Wales
Motor wattages are confusing and mostly meaningless.
The specified wattage is merely the continuous rating, that is what the motor can take continuously without over heating.
So a higher wattage motor is not more powerful. The motor will take whatever the controller gives to it - guess that's why it's called a controller ! So a controller with a !7A rating, working at 36v, will give a maximum 612W. This does not mean that a '250W' motor will overheat as the 612w is a peak wattage, not continuous, on the flat in a low/medium setting the motor will only be taking around 100w.
So, a good combination would be a !7A controller (max, rating) coupled with a battery capable of delivering 20A continuous. This gives plenty of headroom in battery capability meaning less stress and longer battery life.

As an M.S. sufferer, with it's sudden fatigue, I would definitely recommend a pas system over a torque based system. Also would fit a throttle.
From long observation on this forum it appear to me that mid drive systems give more hiccups in the fitting (particularly chainline issues) and are not as robust as hub motors.

In the past I have bought of Yosepower (pre Brexit) and would recommend Woosh. Also Brighton e-bikes have a fair rep on here.
 
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vidtek

Esteemed Pedelecer
Mar 29, 2015
423
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Bournemouth BH12
William, it seems I am not alone in my misgivings about the suitability and practicality of a mid-drive motor for your particular circumstances.
Although I personally am a great fan of them, they are really not as practical for you as a rear hub drive would be. I earnestly urge you to re-think your intentions and reconsider the pros and cons of these different motor solutions.
Wishing you all the best in your endeavours, Tony.