Which kit is...

[Sacko]

Is suited to me?

I have been out on the bike a lot more lately, and always liked the idea of an Ebike.

Te only drawbacks are that the area I ride is notoriously hilly and I weigh in at around 16 stone and wish to travel a distance of over 10 miles. As the bike will be used solely off road, I am looking at the 48v 100watt kits available online.

Luckily, there seems to be hundreds of kits to choose from out there, but I am completely lost and need some advice if possible which kit to go for.

I have a lot of experience in the RC world and will be using Lipos. Namely 6s 5000mah Lipos in a 4p2s configuration.

Are these kits any good?

48v 1000w Bike Hub Motor Brushless Cycling Conversion F | eBay

Are there any kits out there suited to me? Reliability is crucial, but this is on a tight budget and only looking for a Chinese jobby.

Cheers Paul

 

[NRG]

Used solely off-road....are you sure? Service and support is normally inverse to the amount you pay! LiFePO4, EV Charger, EBike Battery, Bike Conversion Kit, Motor, Controller - BMSBATTERY gets a lot of recommendations on the forum though I've never used them....I would trust them slightly more than anybody selling off ebay and you get to choose the components you need. I would recommend the BPM geared motors and not the direct drive types for hill climbing (Your link is a DD type) they are smaller and lighter and installed in the rear wheel will give good traction.

If using RC Lipos install some LVC cell monitoring alarms, cellogs or similar. Set for 3.2v LVC to be on the safe side.

 

[Sacko]

Thanks for your reply, much appreciated

Of course solely off road, I'm insulted you think otherwise

Just trying to find an all in one solution to monitoring all my Lipos on one screen, I'm sure there is one out there.

Is this the kit?

http://www.bmsbattery.com/ebike-kits/209-cute-1000watts-q-12-frontrear-driving--motor-e-bike-kit.html

I presume you can change the throttle lever to twist and go?

 

[lee.pie]

I was in the same dilemma as you.
I went for one of these in the end:

Xipi Electric Bike Conversions > The Commuter Kit

I weigh 19st and it get me to 30mph (off road). Plus you get a 10% discount for being a forum member.

I'm really pleased with it.

 

[Sacko]

Cheers for the reply, but that's a lot more than I was willing to spend. Looks a cracking bit of kit though.

Any idea how hoe many miles you coverup-assisted by any chance?

 

[Scottyf]

Your pretty much heading down the route I did. Using the same batteries as me also.

Although I only monitor cells at pack level using a turnigy watt meter. I also Cycle alot of it so If I do use electric its only ever for hills or a boost. Majority of the time I pedal.

Anyway...

Plenty of Kits out there, plenty of battery options + fitting options.



A rough breakdown follows :-

Direct Drive Brushless DC Motors - about as simple as it gets, hub motor direct drive.
Pro's - Usually fast top speeds, faster to cool down and more robust to overvolting and amping can allow regen to put power back into the battery.
Neg's - Poor climbing ability, always engaged (Run out of battery hard to pedal, think of pedaling with flat tires)

Geared Hub Motors - Similar to the above but usually gear at 4:1 to 6:1 depending on make
Pro's - Strong Hill climbing ability, Free wheel ability (due to clutch inside motor) slightly more effcient than the direct drive counterparts due to gearing
Neg's - Lower top speed, No regen, takes longer to cool, more complex and more expensive than the direct drives. Less robust to overvolting and amping due to internal gears.

Crank Drive - Drive through the crank or through transmission electric motor
Pro's - Flexibility of gearing, excellent hill climbing due to gearing avalilability and top speed (If system is unrestricted). Very effcient.
Neg's - Kit building alot more difficult than the hub motor counterparts.

 

[Sacko]

Thanks for the detailed reply

Gears seems the way to go I think, and more suited to me.

Dont suppose you could recommend a kit? Preferably the best all rounder. Was initially only looking to spend £200-£220 on the kit itself.

Cheers

 

[Scottyf]

I only have limited experience using the Bafang range of motors so couldn't really give you a good all rounder.

However I have been more than happy with the performance of the Bafang BPM 350w Rear Kit I brought from BMS Battery. This cost £150 inc shipping. Delivery from China was slow and I never got import tax.
Communication is willing but limited from China.

This included the motor laced into a wheel / controller / pedelec sensors and brake sensors.
The wheel later chewed up the spokes which i had to replace but has been ok ever since.

For £150 you can't go wrong if you have the time to spare and patience with China.




I started with a much smaller kit and progressed and now using lipo because of the flexibility it gives me. (Voltage / amps and range)

With hub motors remember :-

Volts = Speed
Amps = Torque

In a cut down way. With Lipo you get the ability to chew up loads of amps at the expense of range though. However @ 44v and 20amp my bike has no problem with any hills if I need it. However I never really use it.

 

[Sacko]

Cheers. Do Bafang do a geared 48v 1000w rear system?

Can't seem to find one anywhere.

 

[NRG]

The Bafang BPM comes as either 350w or 500w, see the BMSBattery web site...this is the continuous power rating, the peak power the motor will produce will be well in excess of this.

 

[Sacko]

Ah, ta.

Apologies for all the questions, but what does the higher Wattage mean? What extra would I see from 1000w?

 

[lee.pie]

Cheers for the reply, but that's a lot more than I was willing to spend. Looks a cracking bit of kit though.

Any idea how hoe many miles you coverup-assisted by any chance?

I've done about 20 miles on one charge de restricted mode and that's with hills, it will go further restricted i would have thought.

Normal use i do 11 miles each way to and from work but i do charge after each single journey.

You're right it's not cheap but at least i know that if anything goes wrong it just a quick phone call away from getting it sorted.

I'm sure what ever you choose you will be pleased with it.
Happy hunting.

Edit: My kit de restricted is 1500W.

 

[Deleted member 4366]

I sent you a pm

 

[Sacko]

Cheers for the info, pm replied

 

[Scottyf]

Becareful on ratings of electric motors.

Electric motors will draw anything they can pull electrically until they burn out or stop functioning.
There was a detailed report on how the ratings continous report worked for electrical motors but is buried within the search function here.


Most system that are continous rated 350w / 500w will be quite happy hitting 3x that as their peak.
This peak figure is usually at half the top speed or when the motor is drawing the most amount of Amp's.

Even the legal 250w systems you can buy off the shelf would generally have a peak of 400watt at 7-8mph.

768w = 1HP (I think from memory excuse me if I am wrong)

Which on a bike is alot of power considering most people generate 200w continous - 300w peak and the average bike weighs in at 14kg.

 

[NRG]

Exactly, to give the OP some idea I've been running a 250w Bafang at 21amp peak battery draw for a while from 12s2p Lipo on my Peugeot, I charge to ~4.1v / cell so 49.2v x 21amp is just over a 1Kw draw from the battery (1033w to be precise). Big guess at 100w due to losses (controller, windings, wire etc) so 933w drawn x motor efficiency at peak power drawn (60~70% lets say 65%) gives approx 600w at the wheel.

This is probably the top power I would want to put through the 250w motor so you can see peak power is quite a bit higher and the 350w/500w BPM would be capable of handling a fair bit more...

EDIT: BTW nice to see D8VEH post again, I hope he comes back and contributes to the forum once more...

 

[Scottyf]

Interesting I'm using a similar lipo pack with the batteries at pull about 960 watts @ peak (20amp controller) and to be honest its loads in a hybrid bike and the speed if i leave it on full tilt with me pedalling up a hill is quite scarey.

To put it into context, I went up a hill twice as quick as another electric bike that was romping up there. Followed by someone not assisted.

Nice to see the little 250watt can cope with the 1kw being push through them in bursts.

 

[Sacko]

I'm slowly getting there, many thanks to D8VEH for all the info and answering my endless amount of questions

These are the 2 I am currently looking at;

Bafang BPM 48V500W Rear Driving Bike Conversion Kit - BMSBATTERY

And
36v 350 or 500w and 391rpm
bike conversion kit

..but I do want to run 48v Lipos.

 

[NRG]

391rpm 36v motor in 26" wheel is 30mph unloaded. 48v would spin the wheel up to 40mph!...I suggest you buy a moped! You loose torque, hill climbing ability with the faster wound motors so maybe a lower rpm would be better to make sure you get up those off-road hills.

 

[NRG]

....Oh another thing, please could you share with the forum the advise / answers d8veh gave to you so others new to e-bikes with similar questions may also benefit, thanks!