June 10, 20223 yr Hi guys! Just got a 250w fatbike that I feel is to slow. Is there any way to increase the top speed without buying a stronger motor? I've done a ton of research and found noting that works on the bike i own. Any ideas? I got the Volta VB2: https://volta.com.tr/product-category/electric-bicycle/vb2-en/?liste=vb2-en&nam=154&desc=on Most important specs: Motor: Rear hub 250W Battery: 48v Controller: DC48V Display: AK47 Just tell me if you wanna see pictures of controller, or cables or anything else. My general feeling is that the 250w motor is too weak to bring the bike to a higher speed than 25 kph. I cannot find any speed limiter wires on the controller. I already set the display settings to 41 kph, but doesn't seem to make any notisable diffrence. I don't want to install a throttle. Seems like the speed is measured internally in the motor because i can't find a magnet for a speed sensor anywhere. Could that be right? What can I do to make it go faster for as small amount of money as possible? Thanks! Edited June 10, 20223 yr by snillet1992
June 10, 20223 yr Author Speed is likely hard set in the programming. Yeah, but do you think that the motor is what limits me or can a 250w motor be able to travel faster on a 20" fatbike like this? I mean i did set the display to 41 kph which was the maximum speed in this display.
June 10, 20223 yr As I said programming may be holding the speed back. If it isn't programming then one would need to know th motor rpm winding rpm to know if it is the hub motor. I have displays that go to 70km/h but doesn't mean I can.
June 10, 20223 yr Author As I said programming may be holding the speed back. If it isn't programming then one would need to know th motor rpm winding rpm to know if it is the hub motor. I have displays that go to 70km/h but doesn't mean I can. Ok thanks. Then I guess it could be worth trying to change the controller?
June 10, 20223 yr One can't just change the controller as a paired matching display is also needed. As I mentioned one needs to also know the motor rpm winding, the motor won't electrically run faster then it's terminal load speed unless higher voltage is applied.
June 10, 20223 yr Author One can't just change the controller as a paired matching display is also needed. As I mentioned one needs to also know the motor rpm winding, the motor won't electrically run faster then it's terminal load speed unless higher voltage is applied. Yes, ofc I would change the display too. I just watched this video that explains how you find hidden functions on your controller: Watch from 8:55 Maybe I can solder a button on the controller to use the 120% speed feature? How do you know what motor rpm winding you have?
June 10, 20223 yr Seconding Neal's comments, it's rare for a hub motor to have a wind that can exceed 16 mph in a 20" wheel. I only recall one offhand, an A2B 20" wheel model that had a wind for 20 mph. With your's already on 48 volts it's unlikely you'll achieve more with that motor. As a general rule with wheel hub motors it's always best to buy with the speed you want in the first instance. Trying to increase the speed later is invariably complicated and expensive. .
June 10, 20223 yr Author Seconding Neal's comments, it's rare for a hub motor to have a wind that can exceed 16 mph in a 20" wheel. I only recall one offhand, an A2B 20" wheel model that had a wind for 20 mph. With your's already on 48 volts it's unlikely you'll achieve more with that motor. As a general rule with wheel hub motors it's always best to buy with the speed you want in the first instance. Trying to increase the speed later is invariably complicated and expensive. . Yes, I can see that now. Would just be nice to be able to have a 250w motor that can run that fast. But I understand that it's complicated, that's why i came to this forum. Seems like there is alot of people here that know what they're talking about
June 10, 20223 yr One expects your hub is wound for 260/270rpm which would equate to a max 25km/h speed for a 20" wheel, If the same hub motor was placed into a 26" wheel then one would see 28 km/h or up to 31 km/h in a 26" wheel.
June 10, 20223 yr Yes, I can see that now. Would just be nice to be able to have a 250w motor that can run that fast. But I understand that it's complicated, that's why i came to this forum. Seems like there is alot of people here that know what they're talking about Theoretically you can achieve the big speed increase you want by changing to a 72 volt battery. BUT and it's big but, that voltage is illegal, you'd have to buy a controller that could handle 72 volts and replace your battery with a 72 volt one. So costing a huge amount, the bigger battery having to go on the carrier. making the bike tail and top heavy, and a lot to lose if the law confiscated and destroyed it, as they are entitled to with the laws on assist speed, power and voltage all broken. .
June 10, 20223 yr One expects your hub is wound for 260/270rpm which would equate to a max 25km/h speed for a 20" wheel, If the same hub motor was placed into a 26" wheel then one would see 28 km/h or up to 31 km/h in a 26" wheel. Reminds me of the Ezee Quando and Torq, both using the identical electrical setup. With no controller limiting, the 20" wheel Quando's assist speed ranged from 16mph down to 14 mph as the battery discharged. The Torq with the motor in a 27" wheel (700c) would spin to 26 mph with the motor wheel lifted off the ground, but could only assist to 22 mph at best in calm level ground conditions. .
June 10, 20223 yr It's the same old story someone wants a legal pedelec then want to make it illegal by increasing the speed. Yesterday I was able to reach 33km/h with my 250w hub motor but that was using my own power only, my cut off speed is set for 22km/h so I get a bit more range from the battery. Edited June 10, 20223 yr by Nealh
June 10, 20223 yr Theoretically you can achieve the big speed increase you want by changing to a 72 volt battery. BUT and it's big but, that voltage is illegal, you'd have to buy a controller that could handle 72 volts and replace your battery with a 72 volt one. So costing a huge amount, the bigger battery having to go on the carrier. making the bike tail and top heavy, and a lot to lose if the law confiscated and destroyed it, as they are entitled to with the laws on assist speed, power and voltage all broken. . Flecc, can you clarify the laws on the voltage you are allowed to use? I thought it just had to be stated on the battery, but I have not seen a limit anywhere, or for example whether it's breaking the law to run a 36V battery at 48V.
June 10, 20223 yr Flecc, can you clarify the laws on the voltage you are allowed to use? I thought it just had to be stated on the battery, but I have not seen a limit anywhere, or for example whether it's breaking the law to run a 36V battery at 48V. I dont remember the exact figure in the regulations, but it's a design regulation. Its over 50 volts, but 72 volts isn't permitted on these light applications. It's an EU regulation but we retain all of those via the Great Repeal Bill which wrote them into UK law. 48 volts or it's peak voltage when fully charged isn't any problem. .
June 10, 20223 yr Some comments on battery voltages here; https://www.pedelecs.co.uk/forum/threads/legality-of-battery-voltage.38104/
June 10, 20223 yr 48V is a bit of a difficult one for lithium batteries, in terms of getting a nominal voltage of 48. If the voltage limit is based on the EU Low Voltage Directive, it seems the limit for AC is 50V, but 75V for DC: https://ec.europa.eu/growth/sectors/electrical-and-electronic-engineering-industries-eei/low-voltage-directive-lvd_en Have I missed something?
June 10, 20223 yr Ok, have found this pdf of the BS EN15194-2017 regs. It does seem to mention max rated voltage of 48V. Then the charger is covered by the LVD regs if it is over about 42V.BS EN15194-2017 Cycles_Electricallypowerassistedcycles_EPACBicycle.pdf
June 10, 20223 yr If the voltage limit is based on the EU Low Voltage Directive, it seems the limit for AC is 50V, but 75V for DC: But of course a 72 volt lithium battery fully charged will be at almost 82 volts, way over the 75 volt DC limit. .
June 10, 20223 yr But of course a 72 volt lithium battery fully charged will be at almost 82 volts, way over the 75 volt DC limit. . Well, I was mainly thinking about the 48V nominal for lithium cells, so you'd be at 46.8 with 13 cells, but one more cell would push you over the limit. Is this the get out clause? "...voltage up to and including 48 V d.c. or integrated battery charger with a nominal 230 V a.c. input." So if the charger is integrated into the battery, could 72V be ok?
June 10, 20223 yr Well, I was mainly thinking about the 48V nominal for lithium cells, so you'd be at 46.8 with 13 cells, but one more cell would push you over the limit. Is this the get out clause? "...voltage up to and including 48 V d.c. or integrated battery charger with a nominal 230 V a.c. input." So if the charger is integrated into the battery, could 72V be ok? It depends what that means. It could mean only when running connected to the mains, as some TV sets and laptops are, battery voltage supplied but run while connected to the mains. Others in here have been adamant that 72 volts is not acceptable. Anyway, who would want to cycle a 72 volt battery around. Not me for sure. .
June 10, 20223 yr It depends what that means. It could mean only when running connected to the mains, as some TV sets and laptops are, battery voltage supplied but run while connected to the mains. Others in here have been adamant that 72 volts is not acceptable. Anyway, who would want to cycle a 72 volt battery around. Not me for sure. . Not sure if a pedelec with a cable attached would be much use...would need a very long extension cable A 72V bike need not be dangerous if it is properly implemented. Electric cars run at much higher voltages.
June 10, 20223 yr A 72V bike need not be dangerous if it is properly implemented. Electric cars run at much higher voltages. Yes, my Nissan Leaf e-car has a 400 volt 100Ah battery under my seat. But that is very different from pedelecs in numerous ways. Pedelec batteries are more exposed to damage, removable for charging indoors, easily tampered with and don't have the accepted connector standards and very sophisticated chargers and software that chargers and e-cars have. .
June 10, 20223 yr Not sure if a pedelec with a cable attached would be much use...would need a very long extension cable No problem. Where I used to live at one time, all the municipal buses were trolleybuses, quiet, very powerful and connected to the mains all the time. The chumps got rid of them in 1969, in favour of diesel buses. I bet they are kicking themselves now! .
June 10, 20223 yr No problem. Where I used to live at one time, all the municipal buses were trolleybuses, quiet, very powerful and connected to the mains all the time. The chumps got rid of them in 1969, in favour of diesel buses. I bet they are kicking themselves now! . Would those have been bright blue trolleybuses by any chance
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