June 17, 201510 yr It depends which one you're talking about. There's more than ten different 250w motors and about five different 350w ones. The main difference is that some are rated at 250w, so legal and others rated at 350w, which is not legal in the UK. You can get ones rated at 250w that produce more power than the 350w ones.
June 17, 201510 yr 100W. Joking aside, there are two factors that you can use to gauge the raw power of the motor: its diameter and its gear reduction ratio. The BPM for example has 180mm diameter, the SWX like on your Metro 120mm. The BPM can deliver roughly 50% more power than your SWX without overheating. The gear reduction ratio is important for hill climbing, the higher the better. SWX has 4.4 reduction, the BPM 5. Recently, I test rode the Q128H from bmsbattery.com. I think it's the same motor made by Aikema, 128SX. The Q128H has 128mm diameter but a reduction ratio of about 11. The Q128H weighs about 3kgs and delivers about the same power as the BPM albeit more slowly (the BPM can delivery an astonishing amount of power on startup) so it would suit lighter weight riders.
June 17, 201510 yr Getting complicated here. OP asks about Bafang 8 Fun motor. Replies are about BPM, SWX etc.
June 17, 201510 yr SWXes are 8-Fun 250W, BPMs are 8-Fun 350W. They have new models now, revised versions of the above: http://www.szbaf.com/en/components.html
February 11, 20179 yr Is the 8FUN CST HT C02 a 250w or 350w motor ? Yes. Care to elaborate? It depends which one you're talking about. There's more than ten different 250w motors and about five different 350w ones. The main difference is that some are rated at 250w, so legal and others rated at 350w, which is not legal in the UK. You can get ones rated at 250w that produce more power than the 350w ones. [mention=16337]Neil5403[/mention] it gets complicated at times mate.
February 11, 20179 yr Power is controlled by the controller. Run higher voltage and current it's higher power. So it's both. The original motor test specs had a difference. A manufacturer rated the motor at the highest power it could handle and not burn out at. So they could sell a powerful motor.the test proved it could cope. The bike law lets them rate a 1,000 watt motor as 250 watts. They make one motor and rebadge it for multiple markets. And sell it as legal. The 8 fun motors can mostly handle over 500 and even as high as 1,500 watts but reduced life happens at extremes.
February 11, 20179 yr It does sound complicated.. In a nutshell is the 8fun CST HT02 250w motor sold in the Oxy kit able to produce more power and speed than a 'standard' 250w setup? E.G my Halfords Carreras crossfire e-bike..
February 11, 20179 yr Yes the oxidrive is ABLE to deliver more than A standard 250,i.e. Carrera. But you need to be nice to D8veh to get the best out of it. And a standard 250 Could also be more powerful than the oxidrive if it was tweaked. Remember too that higher power makes for slightly higher speed but much reduced range. Is it worth it?
February 11, 20179 yr It does sound complicated.. In a nutshell is the 8fun CST HT02 250w motor sold in the Oxy kit able to produce more power and speed than a 'standard' 250w setup? E.G my Halfords Carreras crossfire e-bike.. It's not the motor that decides how much power you get. It's the battery and controller. The bigger the motor, the more power it can take. That's pretty simple, but has nothing to do with how much power it produces. The same motor can be run at 24v, 36v or 48v. At 48v, it will make double the power it would at 24v, using a controller with the same maximum current. Next, comes winding speed. Often, the same motors are sold with different speeds. A low-speed one will make significantly more torque at low speed than the equivalent high-speed one and the high-speed one will make more torque in the mid range. Then there's internal gearing. The faster the rotor spins, the more torque and power the motor can produce. Nearly all geared hub-motors used to have standard 5:1 internal gearing. Now, there's 8:1. 12:1 and more, plus a few in between. Wheel size also changes the speed at which the rotor spins in the same way. Therefore, we have current, voltage, winding speed, reduction ratio, wheel size and battery that affect how much power (torque) you get at any point in time. This is where all the myths about hub-motors not being able to climb come from. Some combinations can blitz your average Bosch bike in a climbing contest, others would look very sad. Most of the people who say crank-drives are better have never tried hub-motors designed for climbing. Back to your question: The Oxygen and Oxydrive systems are designed for mid-range grunt, so they can sustain relatively high speed cruising. I haven't ridden your bike, nor tested it's system, so I have no idea of the winding speed, controller current or reduction ratio. if you or anybody else could provide that info, I could convert that into a real-world comparison.
February 11, 20179 yr Thanks for that. It is far from simple !! I have a Specialised Crosstrail Hybrid with 700c wheels and am looking for a kit that is 'legal' to the eye but has the ability to occasionally do approx 20mph with pedal assist. My current Carrera has a range of about 30-35 miles with my mixed riding, so as long as it can match that, then I am happy. The Oxydrive kit is a rear 8fun CST HT02 250w, with a Panasonic 36v 14ah battery. Doesn't say spec of intergral controller. Will that suit me 'out of the box' or will it need 'tweaking'.
February 11, 20179 yr The Oxydrive kit is a rear 8fun CST HT02 250w, with a Panasonic 36v 14ah battery. Doesn't say spec of intergral controller. Will that suit me 'out of the box' or will it need 'tweaking'. How heavy are you? What sort of hills do you encounter?
February 11, 20179 yr I am not small. 6'4 and 115kgs Not big hills just the odd one here and there !! I manage 30+ miles out of my Halfords Carrera e-bike.
February 11, 20179 yr Have a word with Woosh. I think they run their kit with slightly more current, which would be better for a heavy person.
February 11, 20179 yr It does sound complicated.. In a nutshell is the 8fun CST HT02 250w motor sold in the Oxy kit able to produce more power and speed than a 'standard' 250w setup? E.G my Halfords Carreras crossfire e-bike.. Are you looking for something with more oomph than a Crossfire-E? If so, be aware that the Suntour Crossfire-E already has a fairly powerful motor / controller combination, so you need to be picky in selecting something that has noticeably better performance. My Crossfire-E has similar performance to my Bafang SWX08 (essentially a slightly less powerful BPM) powered ebike and cuts out assistance at 16.5mph (as reported by Garmin).
February 11, 20179 yr Woosh use the Bafang BPM in our Big Bear, Big Bear LS and Zephyr B. It has more torque at low revs than other popular and smaller geared hub motors making it more suitable for heavy riders. For reference, the BPM weighs 4.5kg compared to the popular bafang SWXH at 2.75kg. We use the BPM code 13 which is marginally slower (no load speed about 230RPM) than SWXH (about 240 RPM) but has much higher torque (about 50NM at 8mph) against the SWXH/SWXK (about 35NM at 8mph). Bikes built with the BPM need to be restricted to be legal.
February 11, 20179 yr The Woosh BPM kit has 20a controller and is pokey with great torque and crusies nicely at 19/20mph (not legal) a 201rpm wind on the road, NLS 230rpm. If you ran it at 48v still legal then you should get a nice 23/24not legal) though expect the FFP to raise their head above the parapet. The LCD if still used is a very simple and basic King meter JLCD, really easy to change parameters. It has speed , wheelsize , odo, trip, battery level and clock. Mine has 1950 miles on it so far and I have replaced a side plate bearing at 1650 miles as it wore and slapped some more grease in at the same time, 10/15 min minor maintenance job otherwise the kit has bee ultra reliable in all weathers. Edited February 11, 20179 yr by Nealh
February 11, 20179 yr The Woosh BPM kit has 20a controller and is pokey with great torque and crusies nicely at 19/20mph (not legal) a 201rpm wind on the road, NLS 230rpm. If you ran it at 48v still legal then you should get a nice 23/24not legal) though expect the FFP to raise their head above the parapet. The LCD if still used is a very simple and basic King meter JLCD, really easy to change parameters. It has speed , wheelsize , odo, trip, battery level and clock. Mine has 1950 miles on it so far and I have replaced a side plate bearing at 1650 miles as it wore and slapped some more grease in at the same time, 10/15 min minor maintenance job otherwise the kit has bee ultra reliable in all weathers. Interesting thanks. I take it the extra power will affect the range? I will always use the pas as want the exercise, so although I would like a little extra speed over 15mph on pas, the range is important and needs to be 30miles plus, at least that of my Carrera E
February 11, 20179 yr My 2 yo 15ah battery has lost some capacity and only now gets 41.4v max charge but still manages 28 mile range if needed, a new battery should get you 45/50 miles. The 2 yo batt with a Q128c only sees 17/20 miles. Tbh derestricting the Bpm will make very little difference on overall range.
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