Ebay motors

[Hugh Morris]

As a winter project I'm building an electric trike. I'm thinking of using a go-kart motor to power it on the rear axle. An ebike front wheel conversion 26" 250W was not successful. Some Ebay motors seem to make fantastic power claims of 1800W or even 3000W on what looks like a very small unit of 150mmL x 100mm Diameter. The make is Vevor (American). Any thoughts?

 

[telectrix]

take an average of those claims , say 2400watts. on a 24A battery that would equate to 100A, typical 17Ah battery would be totally flat in about 6 minutes.

 

[DPG]

The 'watts' used by people selling motors and amplifiers on Ebay (or similar sites) are a very unusual unit which you won't find in any textbook. I believe the formula is to take a regular watt and then multiply it by a large, but fairly arbitrary, number.

 

[Lucien Nunes]

The ratings are probably rather optimistic, but in any case that would be an instantaneous peak power at 4500rpm and for a given size of motor the power increases approximately in proportion to the speed. These 3-phase electronically commutated PM motors with rare earth magnets can be surprisingly powerful, having been developed extensively for drone use in recent years. And yes, the batteries have to go some to power them. The charging stations I made up to support a multirotor that carries a 40kg payload each have 1.8kW DC charging output for six 14Ah 6S LiPo packs rated to 45C (630A) peak current. The craft carries two packs giving about 15 minutes max flight time under average conditions, leaving enough juice in each pack to make a controlled landing if the other fails.

 

[DPG]

The ratings are probably rather optimistic, but in any case that would be an instantaneous peak power at 4500rpm and for a given size of motor the power increases approximately in proportion to the speed. These 3-phase electronically commutated PM motors with rare earth magnets can be surprisingly powerful, having been developed extensively for drone use in recent years. And yes, the batteries have to go some to power them. The charging stations I made up to support a multirotor that carries a 40kg payload each have 1.8kW DC charging output for six 14Ah 6S LiPo packs rated to 45C (630A) peak current. The craft carries two packs giving about 15 minutes max flight time under average conditions, leaving enough juice in each pack to make a controlled landing if the other fails.

Amazing how battery technology keeps improving in recent years.

And that's some payload! Delivering kegs of beer?

 

[telectrix]

40kG is about right for a 9 gallon keg.

 

[James]

Anyone that wants to practice dropping beer kegs full of beer to a remote site, I will send you the coordinates of my back garden!!

 

[telectrix]

Anyone that wants to practice dropping beer kegs full of beer to a remote site, I will send you the coordinates of my back garden!!

you don't drop them, youlower them gentlyto the ground. tap to the bottom.

 

[Hugh Morris]

Thanks folks. Thought it was too good to be true