Conversion kit with 36v 17AH or 20AH battery

Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
Hi,

Can anyone please recommend a bike conversion kit UK road legal(easy to unrestrict and restrict for offroad use), front or rear hub with a very large capacity battery? 20AH or bigger? Would like to do as little pedalling as possible and get as far as possible with the bike on one charge.

Thanks
 

Woosh

Trade Member
May 19, 2012
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wooshbikes.co.uk
how about fitting one battery on the downtube and one on the rear rack?
 

Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
I intend to get a vintage bike and add a front or rear hub motor and have a very sturdy leather pannier made to hold the battery and controller and have it mounted in the frame fuel tank style not too dissimilar to this photo:
http://i1081.photobucket.com/albums/j350/tanksalot5/DSC05932.jpg

or this:
http://www.fleamarketinsiders.com/wp-content/uploads/2015/07/Ascot-Vintage-Electric-Bike-018.jpg

The rectangular rear rack type batteries seem to be about the right shape to fit in the space and I was really wondering if there are any of the shelf kits with that shape and large capacity.

I'm really not very educated in the ways of elastictriggery and don't know how I would go about connecting two batteries to the controller and motor.

What combination kit did you have in mind?
 

Woosh

Trade Member
May 19, 2012
19,407
16,387
Southend on Sea
wooshbikes.co.uk
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Deleted member 4366

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If you're going to make a leather case, you don't need a proprietary ebike battery. Instead, you can get Jimmy (BGA Reworking) to make one exactly the size and shape you want with the very best cells. Cost would be about £425 for a 21 Ah with Panasonic GA cells, or he has his preferred long-life Boston Cells for about the same amount. That's for a 48v one (recommended). A 36v one would be less.
 
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Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
W
If you're going to make a leather case, you don't need a proprietary ebike battery. Instead, you can get Jimmy (BGA Reworking) to make one exactly the size and shape you want with the very best cells. Cost would be about £425 for a 21 Ah with Panasonic GA cells, or he has his preferred long-life Boston Cells for about the same amount. That's for a 48v one (recommended). A 36v one would be less.
What controller, motor .... would you pair the custom battery with?
 
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Deleted member 4366

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What controller, motor .... would you pair the custom battery with?
36v 201 rpm Q128H frpm BMS battery

https://bmsbattery.com/ebike-kit/776-q128h-48v800w-rear-driving-e-bike-motor-wheel-ebike-kit.html

Q128c if you're not happy with a 7 speed freewheel.

Elifebike.com also list the Q128 under their own designation, but I'm not sure that theirs is the high power version.

Elifebike (AKA PWSpower.com) for the controller. Eithe 17 amp for the Q128C or 20 amp for the Q128H:

http://www.pswpower.com/peng/iview.asp?KeyID=dtpic-2016-3F-33C0.50CGS
 

Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
36v 201 rpm Q128H frpm BMS battery

https://bmsbattery.com/ebike-kit/776-q128h-48v800w-rear-driving-e-bike-motor-wheel-ebike-kit.html

Q128c if you're not happy with a 7 speed freewheel.

Elifebike.com also list the Q128 under their own designation, but I'm not sure that theirs is the high power version.

Elifebike (AKA PWSpower.com) for the controller. Eithe 17 amp for the Q128C or 20 amp for the Q128H:

http://www.pswpower.com/peng/iview.asp?KeyID=dtpic-2016-3F-33C0.50CGS
Are the motors restrictable to be legal on UK roads using the controllers/lcd?
 
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Deleted member 4366

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Yes. if you use the controller i mentioned, you can set the maximum speed in the LCD.
 

Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
Trying to start to get my head around the calculations around the ebike electrics - can you recommend a simple tutorial to get me started?

Is this right?
15Ah 36V battery is capable of delivering 540 watt hour
15Ah 48v battery is capable of delivering 720 watt hour

So the 48v motor will be more powerful as it is able to use more watts hour?

Or is it a case that two similar motors one 36v and the other 48v moving the same weight rider, bike over the same distance will require the same watts hour so the 48v kit will have an additional range given by the remaining 720 - 540 =180watt hour?
 
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Deleted member 4366

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It's not as simple as that. Those figures are for the battery, which determines how far you can go, or better still, how long yor power will last. The more watt-hours you have, the further you can go with the same motor running at the same power.

How much power you get depends on two things: how the motor is wound, which affects it's speed; and how much current the controller allows. A 20 amp controller will allow 33% more power than a 15 amp one for the same motor and battery.

Electric motors do not give out constant power. The power you get depends on the speed you're travelling compared with the motor's winding speed. You get maximum power at about 75% of it's maximum RPM, so it's very important to choose a motor that matches your own riding style.

The same motor will give 33% more maximum power when run at 48v than when run at 36v with the same current, but it will also speed up by 33%, which would make it less efficient at low speed.

To summarise, how much power you get depends mainly on the controller, but also on the motor's winding speed and size, and the battery voltage.

If you're thinking of a crank drive, motor speed means cadence.

If you have a specific motor or system in mind, I can tell you more specifically, what the differences are.
 

Chris.mitu

Pedelecer
Jun 21, 2015
63
6
Kent
How would you estimate the difference in how far you can travel on this kit: Look at this on eBay http://www.ebay.co.uk/itm/222477630015
250w motor with 14A controller and 9Ah 36V battery

The battery has 324 watt hour but the controller is able to feed the motor at 504 watt hour? How much of it is the motor able to use in one hour? How long will it run for at full power?

Vs
https://bmsbattery.com/ebike-battery/766-36v145ah-case-02-panasonic-battery-pack-battery.html
https://bmsbattery.com/ebike-kit/632-q100h-36v350w-front-e-bike-motor-wheel-ebike-kit.html?search_query=Q100H&results=5

14.5 Ah 36v battery, 18A controller 350W motor.

Can you please share the formula or how you work it out - give a man a fish .... :)
 
Last edited:

Benjahmin

Esteemed Pedelecer
Nov 10, 2014
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P=IV Power(watts)= Current(amps) x voltage.
So a 10Ah battery at nominal 36v has 360watt hours capacity. So, nominally, can give 36w for 10 hours or 360w for 1 hour.
It is reckoned that the average e biker will consume between 10 - 20 watt hours per mile.
However rider effort, terrain, wind speed, road speed, tyre pressure, overall weight, aerodynamics, all affect range.

Motor rating (250w, 350w etc) are merely manufacturers stamp of what power the motor can run at continuously without overheating. If the controller is max. 20A then (P=IV) max power at 36v would be 720watts.
An 18A controller at 48v would give 864watts max. This would be less on lower power settings. These are all nominal figures for guidance only. For instance a fully charged Lion 36v battery is actually a little over 42v, but will sag during periods of heavy current draw or over the period of a ride. So there are no absolutes.
So, buy the biggest battery you can to aleviate range anxiety but balance this against the pain of notes flying out of your wallet:D
 
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A couple of things first. The Q100H is listed with two speeds: 201 rpm and 260 rpm. 260 rpm is what you want. I think 201 rpm is the basic Q100, not the H version. It has a lower reduction ratio and doesn't spin as fast internally, so it makes less power.

The other motor looks like a Tongxin. It could be the later Outrider motor, but whichever it is, they don't like to run with high power or torque, though they are very quiet. Only buy that one if you're light and want a light efficient bike.

The BMS battery kit is running at 18 amps and the other with 14 amps so you get 28% more power with the BMSB kit, but that's about the same as the difference in capacity of the batteries, so they'll both last the same time, but you'd be going faster on the BMSB kit, so you'd go further.

Both of the kits have KT controllers that use current control with 5 levels. On both of them you'd be unlikely to be using maximum assist (level 5) except maybe on hills. 18 amps is quite a lot, so you'd probably not use the extra power that often, but it's very useful for hills..

If you're trying to decide between those kits, I think I'd rather pay the extra for the 260 rpm Q100H, which is a sensored motor, so it can use the sine wave controller, which is much smoother and quieter than the S06P. It gives good power and efficiency around 15 mph, so is ideal for a legal bike. It maxes out at about 22 mph, though not much power after 19 mph. That's in a 26" wheel. Also, those cylindrical bottle batteries are not noted for their long life or waterproofness.
 
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