Cheap e-bike? £600?

Max1980

Pedelecer
May 28, 2022
36
3
Hi guys, great forum!

I'm looking for a cheap e-bike option to get back into cycling. The plan is to do little day trips around London with my gf who just got a VanMoof. It won't be for commuting but it would be nice if I could swap some journeys. For reference I'm 5'7 and 140lbs. I would guess the range would need to be between 20-30miles.

Unfortunately I can't really justify spending big money at this point in time so I've narrowed it down to a few options. The goal is to end up with something fun that I can grow with.

1 - Used Carrera, Lombard, Chinese fat bike - These can be had for £600ish but the obvious worry is that they will have no warranty and if anything goes wrong parts could be hard to get hold of.

2 - New Amazon/Chinese bike - Brand new, 1yr warranty, good reviews but what happens if something goes wrong in a years time? scrap heap?

3 - DIY my own bike - If I don't go super high end in theory I could build something pretty cool. I have to admit I'm drawn to the UDX look, retro BMX cruisers etc


Any advice?
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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One can buy dual volatge controllers like Kt with displays the easy bit, what you will have to be careful with though is the hub motor and particularly the winding speed. If you buy a 36v hub it will run 33% faster at 48v so if wanting to climb hills one will need ideally a proper 48v wound hub at 201rpm.
As far as I understand it controllers are DC to DC converters with speed being voltage and current being torque so when you hit a hill voltage drops but current surges in the controller to give a torque boost but at a slower speed. I understand your point about specially wound torque optimised hubs but still any controller can optimise torque more with 48V than 36V can't it? It has more capacity to drop voltage and produce more current plus of course the batteries being setup for 48V will mean the cells have more capacity for current when needed to get up hills.

I've seen some 24V ebike reviews and typically those bikes have very little torque for the hills even with low geared 20" wheel folding bikes which are typically good high climbers because of their low gearing (small wheels). Those ebikes typically have probably only 12-15Nm torque at the motor.
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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Ok gonna sack off that idea!

Bought a new one of these locally for £100

Is it definitely new? I see battery packs for sale occasionally in my area and they may look newish from the advert but many people sell battery packs after they have done 100s of charge cycles and capacity starts to drop. I remember reading a thread somewhere possibly this forum but not sure where someone had bought a ebike for £300, used it for about 18 months with the battery capacity dropping considerably and then sold it on ebay for something like £380 and he couldn't believe his luck it went so high with an end of life battery. Many people don't consider batteries as consumables with a limited life so don't bid realistically on ebay. I've also seen a few threads where people have bought ebikes secondhand only to complain of the short range of the battery many of which were on this forum.
 
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Max1980

Pedelecer
May 28, 2022
36
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Is it definitely new?
Yeah fortunately (or unfortunately!) this one is definitely new. The guy needed the 36v model and was just out of the returns period.

I've seen this one but I don't fully understand the freewheel/cassette differentiation.

What kind of bike setups work with freewheel motors? Should I avoid this setup entirely?

 

Woosh

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May 19, 2012
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I've seen this one but I don't fully understand the freewheel/cassette differentiation.
Freewheel: the motor has thread for a screw on freewheel, usually 6-7 speed, like this:



Cassette: the motor has a freehub and will accept a 8-10 speed cassette, like this:



Motors with cassette fitting (freehub) tend to cost a little more.
Check your rear wheel and buy accordingly.
If you have 11-speed cassette, check with the supplier before buying.
 
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Nealh

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Yeah fortunately (or unfortunately!) this one is definitely new. The guy needed the 36v model and was just out of the returns period.

I've seen this one but I don't fully understand the freewheel/cassette differentiation.

What kind of bike setups work with freewheel motors? Should I avoid this setup entirely?

Oh dear another one who doesn't understand that 1kw kits are;
1. Not legal.
2. Likely not suitable for the inteneded use.
3. Unlikely the bought battery can sustain more then 30a continuous for the kit linked to.
 
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Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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Yeah fortunately (or unfortunately!) this one is definitely new. The guy needed the 36v model and was just out of the returns period.

I've seen this one but I don't fully understand the freewheel/cassette differentiation.

What kind of bike setups work with freewheel motors? Should I avoid this setup entirely?

Well you got a brilliant deal on that battery then but it does restrict you somewhat. Anyway which bike are you aiming to get or are you basing it on the most suitable ebike kit?

If you are buying a cheap new bike then its probably freewheel based anyway. Despite that kit saying includes Shimano 7 speed freewheel it is not pictured in the included items. Anyway if you bought a 6 speed freewheel based bike then you can use the 6 speed freewheel no problem and the bike will come with a 6 speed shifter.

The issue is the legality of the kit but it does include a display and you will be able to restrict it to the legal limit in the settings I'm sure but it will never be fully legal. You will probably want to remove the 1000W sticker on the hub motor too. This sort of bike would be compatible;

https://www.argos.co.uk/product/9308435 or a similar s/hand bike.

The Voilamart 1000W kits used to have a physical wire that limited the controller to lower watts and a 15.5mph speed limit but that kit looks like it would be through the display options to restrict it.

Don't forget there is a yose discount code if you join their mailing list.

Although it looks like the kit is cheaper on ebay and does show the freewheel.


So you will end up with a spare rear wheel and possibly a 7 speed freewheel to sell to help recover some costs. There could be some bonuses and discounts available due to the holiday weekend. That ebike kit shows as 750 nectar points for me which is about £3.75 in real money.

I didn't realise 48V and geared hub motors were so rare. It looks like you are pretty much forced to have a direct drive hub motor with 48V.

I bought a kit of amazon sometime ago which I haven't fitted to a bike yet but its 48V 500W 20" wheel and geared, I didn't realise how rare it was when I bought it.
 
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Bonzo Banana

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Oh dear another one who doesn't understand that 1kw kits are;
1. Not legal.
2. Likely not suitable for the inteneded use.
3. Unlikely the bought battery can sustain more then 30a continuous for the kit linked to.
Not legal of course but don't quite understand the other 2 points why would it not be suitable for the intended use and why would the battery not be suitable. That kit isn't going to need 30A continuous that sounds more like peak figures, 1000W shared by 48V is about 20A but these kits exaggerate their power. Going from the legal mode which peaks around 400W the so called 1000W mode only goes up to about 500W, the 1000W claim must be absolute peak power. That battery will be fine I'm sure but if the display is set to the right assistance speed limit there certainly won't be any problems.

The issue is legality really and its a tough one to answer. How Bosch can get away with close to 800W with their so called legal mid-drive motors and yet others are classed illegal that produce half the torque at half the wattage seems very unfair.
 
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Nealh

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Quite simply by checking the spec's of the kit he linked to !
The controller is 15a rated and 30a max, one in general should always select the battery continuous rating to be greater then the controller max out put as you should know.
If one doesn't then these guys start moaning about how crap hub motors are when they don't spec the correct components. Whether or not he uses the 30a max current is another thing but if wanting a moped as most seem to want to for some reason then the throttle will draw max current, the battery simply I doubt will be capable and will cut out.

We have seen this many times on here in the past, dissapointed buyers buy cheap motor kits and a cheap battery simply not up to supplying the current or able to climb hills. A £100 or £200 battery isn't going to be 30 or 35a capable.
 
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Bonzo Banana

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the disadvantage of those direct drive kits is clear when climbing a steep hill.
Imagine doing that with your car stuck in fifth gear. The motor will not run in its sweet zone, the more you try to compensate for the lack of torque, the more current it will pump until the controller reaches its maximum current. A geared motor with a typical 5 to 1 gear reduction gives you the torque you need while weighing a lot less.
I don't think its fair to generalise like that, I've seen cheap 24V ebikes with tiny geared hubs and even with the small wheels the motors are only producing a peak of around 12-15Nm, some of the direct drive hub motors are delivering maybe 30Nm in restricted mode 250W(400W peak) and 40Nm in unrestricted mode maybe (400-600W and peak of 1000W) or something like that and then you have geared hubs at up to about 45Nm typically as a maximum. Obviously those who use direct drive hub motors at 1500W and beyond go significantly beyond those figures. A huge part in addition is the gearing, you can gear a bike for climbing.

I totally accept that direct drive hub motors are not the ideal hill climbers but still offer huge assistance going up hill and certainly beat many smaller geared hub motors going up hills. They are by far the most reliable of all ebike motors, you have the ability to use regen which if you only use power for going up hills can be a significant boost to range and they have the greatest weight capacity and easiest cooling due to their greater amount of material. There are a huge amount of positives to direct drive hub motors. In fact when you look at Grin Technology its clear its their favourite motor type by far. For long commutes, touring and low maintenance it could be the optimal ebike.

This is essential viewing for anyone wanting full info on hub motors and how actually efficiency doesn't vary that much between different motor types as all have areas where they are more or less efficient over normal use. That could be related to energy losses through internal cogs and belts or through the drivetrain (mid-drive) or through heat loss and poor thermal properties.

 
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Bonzo Banana

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Sep 29, 2019
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Quite simply by checking the spec's of the kit he linked to !
The controller is 15a rated and 30a max, one in general should always select the battery continuous rating to be greater then the controller max out put as you should know.
If one doesn't then these guys start moaning about how crap hub motors are when they don't spec the correct components. Whether or not he uses the 30a max current is another thing but if wanting a moped as most seem to want to for some reason then the throttle will draw max current, the battery simply I doubt will be capable and will cut out.

We have seen this many times on here in the past, dissapointed buyers buy cheap motor kits and a cheap battery simply not up to supplying the current or able to climb hills. A £100 or £200 battery isn't going to be 30 or 35a capable.
Well the battery spec isn't clear on what this battery outputs on that ebay listing but does clearly state compatible with 1000W 48V motors and personally I have no reason to think that is wrong. I don't think these controllers peak at anywhere near what you think they peak at. These 1000W kits rarely go to 1000W more like 500-600W with occasional peak output of 1000W just so they can sell them at 1000W but 30A at 48V is 1440W. I think you are being overly cautious about pairing batteries to controllers or don't realise how over-stated the wattage is on some of these entry level direct drive hub motor kits are. The same direct drive motors are paired with 1500W and 2000W kits just those kits have more capable controllers. Basically the direct drive motor gets what is given, if you can't climb that hill with the provided power then you don't climb it basically.

I guess occasionally I might read a posting on a battery pack where a internal fuse has blown but I think maybe one of the occasional issues with direct drive hub motor kits is the controller not handling the sustained level of current, i.e. the controller box over-heating, sometimes they are housed in a provided bag that doesn't assist at all with heat loss and so the controller gets too hot but that would surely indicate the battery is actually coping very well and providing ample power. Typically then people may replace the supplied controller with a higher rated controller and then I can see a battery issue if they haven't thought about the controller demands on that lower spec battery.
 
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Woosh

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I don't think its fair to generalise like that, I've seen cheap 24V ebikes with tiny geared hubs and even with the small wheels the motors are only producing a peak of around 12-15Nm, some of the direct drive hub motors are delivering maybe 30Nm in restricted mode 250W(400W peak) and 40Nm in unrestricted mode maybe (400-600W and peak of 1000W) or something like that and then you have geared hubs at up to about 45Nm typically as a maximum. Obviously those who use direct drive hub motors at 1500W and beyond go significantly beyond those figures. A huge part in addition is the gearing, you can gear a bike for climbing.
Power = torque * rotational speed.
Let's say your motor No1 is a direct drive and your motor No 2 is geared and has a ratio of 5 to 1 reduction for example. Both climb the same hill at the same speed.
You can see that the rotor of motor No 2 spins therefore 5 times faster than the rotor of motor number 1 and only needs to produce a fifth of the force to get to the same result. It's the same with your car, you shift your gear down on hills to make life easier for your motor.

If the motor stalls, all electrical power you send into the motor will be converted into heat. Your conversion yield electrical energy into mechanical energy is zero.
If you don't put any load on the motor, it will reach a maximum 'no load' speed. Your conversion yield is also zero because of the zero load.
Therefore, it's fundamental for electric motor to have a sweet zone and if you are not running your motor in its sweet zone, you are wasting your battery.
The disadvantage of direct drive motors becomes clear: their sweet zone is at comparatively higher speed compared to geared hub motors and crank drive motors. The sweet zone of a typical 200mm wide direct drive motor is about 200RPM-400RPM, for a typical geared hub motor about 100RPM-250RPM. In the context of street legal pedelecs, direct drive motors are good for small wheels (16"-20") and geared hubs for 26"-29" wheels (crank drive motors are more flexible, between 20RPM-100RPM depending on models). The other disadvantage of direct drive motors is magnetic striction. The magnetostriction acts like a brake. That is because their rotor moves with your wheel, whether it is powered or not. You feel it when you pedal without power. Magnetic striction alone should be a sufficient reason to deter manufacturers to fit direct drive hub motors to their bikes.
 
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Max1980

Pedelecer
May 28, 2022
36
3
Oh dear another one who doesn't understand that 1kw kits are;
1. Not legal.
2. Likely not suitable for the inteneded use.
3. Unlikely the bought battery can sustain more then 30a continuous for the kit linked to.
Still looking into the specifics. Happy to take my chances on 1.
 
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Max1980

Pedelecer
May 28, 2022
36
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Well you got a brilliant deal on that battery then but it does restrict you somewhat. Anyway which bike are you aiming to get or are you basing it on the most suitable ebike kit?
Yes I think I'll be basing it on the kit since they are hard to get 2nd hand! There seems to be a few things I need to balance even when the costs are within the same ballpark.

The choice right now seems to be Freewheel 1000W kit at £200ish vs Cassette 500W at £307

BFSWX02 48V 500W
 

Max1980

Pedelecer
May 28, 2022
36
3
The battery has very little detail on the spec's, no idea of cells used or current rating. Many of these sellers simply plonk a 1000w rating ona 48v battery and often they just aren't up to the job. One simply doesn't just buy a battery on the off chance like has been done and then decide a 1kw chepa hub kit will be fine, I bet the Op doesn't even know how to match a battery and controller together for effective use and safety.
I am the OP.. just trying to learn that's why I'm here!

I've found this kit which includes the same battery so I've got to assume a 500W kit will be OK


And the battery - 30A Max so 20 continuous should be fine?
 
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Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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Power = torque * rotational speed.
Let's say your motor No1 is a direct drive and your motor No 2 is geared and has a ratio of 5 to 1 reduction for example. Both climb the same hill at the same speed.
You can see that the rotor of motor No 2 spins therefore 5 times faster than the rotor of motor number 1 and only needs to produce a fifth of the force to get to the same result. It's the same with your car, you shift your gear down on hills to make life easier for your motor.

If the motor stalls, all electrical power you send into the motor will be converted into heat. Your conversion yield electrical energy into mechanical energy is zero.
If you don't put any load on the motor, it will reach a maximum 'no load' speed. Your conversion yield is also zero because of the zero load.
Therefore, it's fundamental for electric motor to have a sweet zone and if you are not running your motor in its sweet zone, you are wasting your battery.
The disadvantage of direct drive motors becomes clear: their sweet zone is at comparatively higher speed compared to geared hub motors and crank drive motors. The sweet zone of a typical 200mm wide direct drive motor is about 200RPM-400RPM, for a typical geared hub motor about 100RPM-250RPM. In the context of street legal pedelecs, direct drive motors are good for small wheels (16"-20") and geared hubs for 26"-29" wheels (crank drive motors are more flexible, between 20RPM-100RPM depending on models). The other disadvantage of direct drive motors is magnetic striction. The magnetostriction acts like a brake. That is because their rotor moves with your wheel, whether it is powered or not. You feel it when you pedal without power. Magnetic striction alone should be a sufficient reason to deter manufacturers to fit direct drive hub motors to their bikes.
I think the end torque figure is what you need to go by, I think everyone pretty much knows how geared hub motors work by providing extra torque but at a lower speed and thats fine which is why direct drive motors are so large they provide their torque by being physically larger than geared hubs and ultimately you end up with greater weight on the bike but I think you have to look at the whole spectrum of advantages and disadvantages as shown in that Grin video to make an informed and fair choice. Geared motors have the most resistance of all ebike systems so they have a clutch type plate to allow freewheeling however one of the most efficient motor systems I have seen was a geared hub without a clutch plate and with regen enabled. Yes there was more drag more drag than a direct drive motor but then regen was super efficient and the drag was not terrible on the flats. The drag is often over-stated on direct drive motors it is noticeable for sure but its not like it prevents you cycling on flats or slight inclines and when going downhill you can enable regen which adds to overall range. The direct drive assists up hill quite well but you still have to provide some effort, on flats you have to work a tiny bit harder than a normal bike and going downhill you work a little bit harder sometimes if its a slight decline and still have to peddle to enable regen but on steeper hills you can coast although I guess this is down to how aggressive the regen braking is set. Ultimately a direct drive hub motor ebike ends up levelling the amount of effort on the bike for any gradient and makes the world seem a bit flatter. Compare this to a normal bike where going up hills need intensive effort, flats need minor effort and downhill needs no effort at all.
 

Bonzo Banana

Esteemed Pedelecer
Sep 29, 2019
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The battery has very little detail on the spec's, no idea of cells used or current rating. Many of these sellers simply plonk a 1000w rating ona 48v battery and often they just aren't up to the job. One simply doesn't just buy a battery on the off chance like has been done and then decide a 1kw chepa hub kit will be fine, I bet the Op doesn't even know how to match a battery and controller together for effective use and safety.
I think Yose batteries have a good reputation but they are a trading house mainly I think rebranding products manufactured by other companies. My Hailong battery packs (not Yose) appear to be extremely similar. I think mine are also the exact same 624Wh capacity and mine uses the Samsung cells 2500mAh which were good quality cells of ok capacity and the Yose pack might be the same. I saw someone split apart the battery pack I have on either youtube or a web page and they were definitely Samsung cells in there but that doesn't mean every pack has Samsung cells of course. The typical 1000W kits do seem to vary what is the minimum pairing, I've seen the requirement as 48V 10Ah to 48V 12Ah but that is capacity not its sustained current or max current figures. However I think if you put the controller into restricted power mode for reduced legal speed in the EU/UK you can get away with a smaller capacity battery, I have in memory that it was 7-8Ah but not sure as it was a long time since I read it, I'm pretty sure it was a single figure.

I honestly don't think the OP will have any issue with that battery and pairing it to a lower end 48V kit but I could be wrong of course.
 

Bonzo Banana

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I am the OP.. just trying to learn that's why I'm here!

I've found this kit which includes the same battery so I've got to assume a 500W kit will be OK


And the battery - 30A Max so 20 continuous should be fine?
Those links seem to be going to the US Yose site. The kit at the top already includes a battery and it has a built in controller so not suitable for use with your battery. However I have to say it looks like a powerful geared hub motor with 67Nm peak torque. If you could find the same wheel and a separate controller kit that would be suitable for use with your battery. However legally it is 500W and maybe no legal UK/EU restricted mode.

Maybe you should try to focus on a 500W 48V geared hub motor. That could be a good match. Bafang used to do one and I'm sure there are other options, these are super power hub motors right up close to middle spec mid-drive motors for hill climbing performance.

I bought a cheap kit myself on Amazon a while back. I've not fitted it to a bike yet but the paperwork and web page detail was vague, its a 20" wheel with a rear hub of 48V and 500W and when I found something similar on aliexpress they had a chart for torque and the spec similar to mine was 85Nm peak torque in 20" wheel size. The image on Amazon showed a small hub motor but on arrival it was much, much larger there was hardly much length of spoke at all. If you want high torque but the reliability and simplicity of a hub motor then a beefy geared hub motor could be a great option.

I don't know if it will help you but I wonder if this Bafang wheel currently on offer could be over-volted to 48V from its stock 36V? Perhaps someone else knows the model knows. It's the G020 model I believe.

 

guerney

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I am the OP.. just trying to learn that's why I'm here!

I've found this kit which includes the same battery so I've got to assume a 500W kit will be OK


And the battery - 30A Max so 20 continuous should be fine?
I've been using a 36V 19.2ah battery composed of (non-terrible quality, apparently) LG MH-1 cells for (about) 1600 miles on my 250W bbs01b, and it's now only charging to 41.9V, and I've only been drawing 15A. I don't know much about ebike batteries in general, but I'd say your battery will fare worse at 20A, with whatever cells that battery pack contains.

Have you jumped the gun a bit with your battery purchase?
 
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Bonzo Banana

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I've been using a 36V 19.2ah battery composed of (non-terrible quality, apparently) LG MH-1 cells for (about) 1600 miles on my 250W bbs01b, and it's now only charging to 41.9V, and I've only been drawing 15A. I don't know much about ebike batteries in general, but I'd say your battery will fare worse at 20A, with whatever cells that battery pack contains.

Have you jumped the gun a bit with your battery purchase?
It's a 624Wh battery but 20A at 48V would be 960W so you'd be getting less than 40 minutes of assistance time if it was taking 20A all the time or about 12 miles maybe of range. People are getting around 40-60Km range or about 25 to 40 miles with such batteries with direct drive motors, less for hilly areas. So average current is more like a third to a half of that. It does of course depend how you use it. If you have regen enabled and only use assistance for hills with the throttle you could be getting close to 200 miles range. Yes 200 miles is just a theoretical number that I can't prove but it is in theory possible if you only use assistance for steeper hills and use regen where possible. Admittedly regen would mask the average current used because the battery would be getting a charge for maybe 5-20% of the journey.

A quick look shows your motor has peak torque around 80Nm and to achieve that it probably uses a very high current drain from the battery, maybe not as much as Bosch but its likely peaking well above 600W maybe reaching 700W. It's a much more powerful motor than the 1000W direct drive motor despite its 250W rating assuming the 1000W motor comes with a fairly entry level controller that can only peak for short periods at 1000W and rarely does. I guess the issue is how long each motor can sustain its peak power but from what I understand mid-drive motors can peak at higher wattage for longer because they are internally geared and based around a very high rpm small motor. The range of rpm these motors can operate at is well beyond a direct drive hub motor. The hub motor controller will try to increase torque by lowering voltage and increasing current to the motor but can only do so much.

I did a quick google and your motor consumes 630W at 80Nm but there is also mention of a 100Nm version that probably peaks well above 700W probably close to Bosch current levels. So its quite possible your battery is getting a rougher time with regard current draw. Also as the controller drops voltage and increases current a 48V 12.5Ah battery is equivalent of a 36V 16.7Ah or a 24V 25Ah or a 12V 50Ah or a 6V 100Ah etc. So it can produce 8x the current at 6V to create torque. I'm not saying it does that I don't know what is the range of voltage and current it can send to the motor hub but a 48V battery is capable of higher current at lower voltage than a 36V battery of the same Ah.
 

Max1980

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May 28, 2022
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Maybe you should try to focus on a 500W 48V geared hub motor. That could be a good match. Bafang used to do one and I'm sure there are other options, these are super power hub motors right up close to middle spec mid-drive motors for hill climbing performance.

I don't know if it will help you but I wonder if this Bafang wheel currently on offer could be over-volted to 48V from its stock 36V? Perhaps someone else knows the model knows. It's the G020 model I believe.

Wow that is really cheap! £150 for this and that's the whole kit (I think) for £200.



This is the other one I'm looking at. I believe it's from the same line.

BFSWX02 48V 500W - G020.500D/DC mode
https://www.amazon.co.uk/Conversion-Wheel-Electric-BAFANG-Display/dp/B09R7TDWHJ?th=1&psc=1


I guess the question is whether it's worth spending more for the native 48v hub kit?