August 1, 20232 yr I select the hub motors so that they don't exceed 21mph even when derestricted and get twitchy everytime someone is interested in running those motors at 48V instead of 36V to give themselves 30% extra speed. Cardiff police confiscated 17 bikes, they are all capable of 30+mph. Let that be a warning. its a token effort like all these things they take a few bikes yet in reality they will be replaced in 24hrs it just cost you in sales like ebike shop selling dongles with bosch motors and honors the warranty. even curry's sell e scooters now and will sell them to anyone that walks in the door same as halfords yet nothing saying they are not road legal. i have a dongle on my bike and know what laws i am braking selling something like this to someone thinking it is road legal when it is not is just wrong and could land them in prison for being told a lie to sell a product.
August 1, 20232 yr Author well i have had my bike for ten years now and still not dead I hope it stays that way, but riding drunk at the speeds you can travel.... You are stacking the odds against. they was the rear speakers for town house studios in london from the main studio with the 5.1 setup. 60kg each I've just done some reading up on Town House Studios. Them speakers must have had some very famous people listen to them over the years. I still wouldn't want to be your neighbour.
August 1, 20232 yr A mate derestricted his Levo which I tried out on a flat/level road. Speed was ridiculous. Okay you had to peddle, but it was so fast ..... Acceleration was incredible. He burnt out that motor, so didn't derestrict the replacement. And burned out that one too, which is why I am reluctant to buy anything "integrated". brose has the worst reliability of every ebike motor bar shitmano dongles dont destroy motors there made not to last in the first place. all the new gen 4 smart motors are going bang atm at 1000 miles i have one job try and blow my motor up, and if i do i get it fixed for free
August 2, 20232 yr I'd be very happy with 21mph. I'd be happy with 15mph. I want the grunt for hill climbs, not speed. So you pick a motor with the rpm to get you that speed (+ about 10%), in your sized wheel, under no load conditions. That way, when loaded, it should give the legal requirement but still give enough torque to climb. If you can maintain 50%+ of top rpm when climbing then the motor remains efficient enough not to overheat. So that means climbing at 7-8mph. My own Ezee motor has a top speed of 19mph on the stand (if the cycle computer is anywhere near accurate). It has done many years up and down the hills of west Wales without issue. I have had the controller thermally cut out on hot days though.
August 3, 20232 yr Author So you pick a motor with the rpm to get you that speed (+ about 10%), in your sized wheel, under no load conditions. That way, when loaded, it should give the legal requirement but still give enough torque to climb. If you can maintain 50%+ of top rpm when climbing then the motor remains efficient enough not to overheat. So that means climbing at 7-8mph. My own Ezee motor has a top speed of 19mph on the stand (if the cycle computer is anywhere near accurate). It has done many years up and down the hills of west Wales without issue. I have had the controller thermally cut out on hot days though. Like this? (Thank goodness I didn't need to calculate it myself.) The rpm figures seem a bit low given others I've seen referenced elsewhere, though it does tie up, or is pretty close to what you have at 19mph. It's also in the ball park of what Woosh has mentioned at 250rpm. That said, if your wheel diameter is smaller, your wheels will be rotating faster to achieve the same smph figures. Mine is a 47x622 Road Tour with a diameter of circa 70cm. Which is the same diameter as my 650b bike with its fatter tyres. Seems unusually, I'm not interested in 20-30mph speeds where rpm's might be up in the mid 300's. I've no doubt at all, 250w at 36v would be perfectly adequate for long 50 mile journeys on the flat. Possibly I would use some help on the outboard journey, but I certainly would want some during the return leg and would not be contributing much for the last 15 or so miles. What I'd be really happy with, is the full 15mph assistance going up nasty hills, or the 8th or 9th hill and all those after. That's the time when 48v seems attractive. Not for speed in my case, but the "grunt" I might hope to get from it. Windings, can affect all this, but I can't remember where I read up about 'windings for torque', not speed.
August 3, 20232 yr a bosch motor is rated 250w, its not because under this speed a motor can pull as many amps as it wants and gets you up the hill. you want a motor with a 20a controller and set it to the speed you want and a bafang 750w mid drive will give the same power i have to climb any hill if i remove my dongle both wont be much different bar my bike is a money pit
August 3, 20232 yr Author you want a motor with a 20a controller and set it to the speed you want and a bafang 750w mid drive will give the same power i have to climb any hill if i remove my dongle both wont be much different bar my bike is a money pit I'm not going the mid-drive route. Apart from anything else, I may want to use the hub motor on different bikes. I've got about 4. "Technically" 5 if you count the one I'm building for someone else. Are you saying if I can get enough amps into a 250w motor, it would climb hills?
August 3, 20232 yr https://www.alibaba.com/product-detail/10000W-20kW-Peak-power-Brushless-DC_62504652397.html?spm=a2700.7724857.0.0.241b3c96RaYJGS you can limit it to 15mph but at 110 amps the motor will rip the frame in half and over take you. a controller with 20-25a is what you want
August 3, 20232 yr https://www.youtube.com/watch?v=xtZpmyOLfFQ:147 no one will let me review any ones bikes
August 3, 20232 yr https://www.electricbike.com/12-ebikes-that-used-a-hubmotor-as-a-non-hub/ https://www.youtube.com/watch?v=sEaH_lAp8Jk:366 Edited August 3, 20232 yr by lenny
August 3, 20232 yr Are you saying if I can get enough amps into a 250w motor, it would climb hills? Yes ! A 48v controller in the max assist setting (let's call it 17A) will give a notional 816w. Lets allow a massive 20% for various inefficiencies. That still leaves you at 652w. Having watched the Tour de France, they sometimes show a riders power output and this is the sort of wattage a fit, young professional develops when out of the saddle launching an attack on a mountain. I don't think you're going to have any problems !
August 3, 20232 yr Yes ! A 48v controller in the max assist setting (let's call it 17A) will give a notional 816w. Lets allow a massive 20% for various inefficiencies. That still leaves you at 652w. Having watched the Tour de France, they sometimes show a riders power output and this is the sort of wattage a fit, young professional develops when out of the saddle launching an attack on a mountain. I don't think you're going to have any problems ! Bear in mind the all up weight for a young fit professional cyclist on a road bike is probably less than half the weight of the average ebiker on an ebike. They also aren't always going as fast as 15mph uphill. I can hold either of the ebikes I have had (one Yamaha, one Shimano) at max power output so about 600W plus my input and can't hold anywhere near 15mph on a steep hill. Your idea of hills is probably completely different to my normal riding though.
August 4, 20232 yr Author So, after hours of searching (mostly with head banging a wall) I've discovered a motor that probably many here will be familiar with the Bafang 36V 250W RM G020.250 At first I thought this table referred to the maximum rpm, but I've worked out, they will be the controller shut-off speeds at reaching maximum legal assistance. The motor also seems pretty tolerant to 48v too. Is it any good though?
August 4, 20232 yr So, after hours of searching (mostly with head banging a wall) I've discovered a motor that probably many here will be familiar with the Bafang 36V 250W RM G020.250 At first I thought this table referred to the maximum rpm, but I've worked out, they will be the controller shut-off speeds at reaching maximum legal assistance. [ATTACH=full]53196[/ATTACH] The motor also seems pretty tolerant to 48v too. Is it any good though? Is it not identical to the RM G020.500 - they just stamp 500 on it when they are marketing it as part of a 500w kit ? (with 48v battery rather than 36V) e.g. here (I just ordered the kit and it had RM G020.500 stamped on it , without the battery for a second hand 26" wheel Carrera Vulcan - it came with winding code 12 - which I think is what Woosh sold as the 36V SWX02 - but was stamped with G020.250) Review here and here (take it with a pinch of salt - but think it's fine - bog standard rear hub) Edited August 4, 20232 yr by Peter.Bridge
August 4, 20232 yr Author Is it not identical to the RM G020.500 - they just stamp 500 on it when they are marketing it as part of a 500w kit ? (with 48v battery rather than 36V) e.g. here (I just ordered the kit, without the battery for a second hand 26" wheel Carrera Vulcan - it came with winding code 12 - which I think is what Woosh sold as the 36V SWX02 - but was stamped with G020.500) At the start of this enquiry (I think) I asked about 250w x 36v motors becoming 350w motors if used with a 48v battery. I don't recall getting an answer, and in hindsight, possibly I can understand why. The "500" hub package may well be the same as the "250", but I'd be surprised if the windings were identical if the ratings are actually different. I'm sure there are others here who are better able to specifically identify the differences. I'm very new at this e-motor stuff, and I'm finding it a bit like swimming around in treacle. I wouldn't be surprised to find a 500 case was used on a 250 motor, or vice versa. Could be as you suggest, what's stamped on the outside may well be to do with what it's being sold as? Meaning the only difference between a 250w motor and 500w motor, is what is written on the casing?
August 4, 20232 yr the copper wires inside the 48V version is upgraded to take on 30% more power. You also have more spires per Volt, giving you better torque.
August 4, 20232 yr the copper wires inside the 48V version is upgraded to take on 30% more power. You also have more spires per Volt, giving you better torque. what's a spire per volt !
August 4, 20232 yr what's a spire per volt ! turns per volt. More turns / volt = stronger magnetic field for the same voltage = more torque
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