Hi all
I have a project under progress which is a stand-up paddle board (SUP) conversion to a go-kart for the water with hopes for a 3 m per second cruise speed under human power using an electric transmission. The sup is being setup to wear four wheels with pneumatic tyre tubes for enhanced roll resistance. Traction is being applied via the rear wheels wearing bladed fins over the tubes in the way of tyre treads
I would like to turn the rear axle with a small BLDC motor geared very low. For power, I am wondering if it is feasible to run a larger BLDC with a foot crank and use that as a generator to get the voltage and current needed by the smaller motor
To start out, I have some RC aircraft and truck motors to try for the axle and ordering a discounted hoverboard to get a pair of hub motors out of it for the generator side. These are rated 250w each. These will run a small sprocket and driven from a bike crank. I am hoping to create enough power with this to run the RC truck motor well enough for 3 m per second cruise speed at an easy rhythm. A battery will also connect to the system for aux power against wind and such
May I please have some assistance on the electrics. I think I am good with hooking things up, but there are certain things that I am struggling with a bit. One is how to convert the output from the generator side to DC. I have 10x shotkeys rated 3A. Would I be able to use these? What would you guys recommend?
Thanks and regards
Randy
I have a project under progress which is a stand-up paddle board (SUP) conversion to a go-kart for the water with hopes for a 3 m per second cruise speed under human power using an electric transmission. The sup is being setup to wear four wheels with pneumatic tyre tubes for enhanced roll resistance. Traction is being applied via the rear wheels wearing bladed fins over the tubes in the way of tyre treads
I would like to turn the rear axle with a small BLDC motor geared very low. For power, I am wondering if it is feasible to run a larger BLDC with a foot crank and use that as a generator to get the voltage and current needed by the smaller motor
To start out, I have some RC aircraft and truck motors to try for the axle and ordering a discounted hoverboard to get a pair of hub motors out of it for the generator side. These are rated 250w each. These will run a small sprocket and driven from a bike crank. I am hoping to create enough power with this to run the RC truck motor well enough for 3 m per second cruise speed at an easy rhythm. A battery will also connect to the system for aux power against wind and such
May I please have some assistance on the electrics. I think I am good with hooking things up, but there are certain things that I am struggling with a bit. One is how to convert the output from the generator side to DC. I have 10x shotkeys rated 3A. Would I be able to use these? What would you guys recommend?
Thanks and regards
Randy
What voltage are those motors and diodes meant for?
A BLDC motor used the other way around is essentially a three-phase generator. You can rectify it with a bridge consisting of six diodes. It's been a while since I looked into this stuff, but 3 A seems rather small for 250 W unless the voltage is unusually high.
A BLDC motor used the other way around is essentially a three-phase generator. You can rectify it with a bridge consisting of six diodes. It's been a while since I looked into this stuff, but 3 A seems rather small for 250 W unless the voltage is unusually high.
If I'm not mistaken, you could in principle also just connect one motor to the other without rectifier or motor controller, but then the ratio of the rotation speeds is fixed by the ratio of the numbers of poles, and there is no battery.
Hello Marcel
Thank you for your interest and attempting to help. I know a tiny bit more than since I started the project. Glad to be able to deliver the right info now that I have worked on this a bit further. I did the testing with a larger RC boat prop using a BLDC 18v cordless drill and a large RC prop shaft to get some benchmarks
I can provide further details on the craft and build if there is any DIY interest from anyone here. The motors being used are a pair of BLDC hub motors rated 36v 250w each for hoverboards. I have been wondering if one can be used to drive the other with electrical transmission rather than belts and chains from the front to the back of the craft. One as crank and one as the driven motor. Eager to test this once they arrive sometime next week
If the hoverboard to hoverboard motor transmission works well, then it might even be worth running two motors from a second hoverboard without messing around with the washing machine and diodes
These are the few thoughts that I am running with at the moment
Thank you for your interest and attempting to help. I know a tiny bit more than since I started the project. Glad to be able to deliver the right info now that I have worked on this a bit further. I did the testing with a larger RC boat prop using a BLDC 18v cordless drill and a large RC prop shaft to get some benchmarks
I can provide further details on the craft and build if there is any DIY interest from anyone here. The motors being used are a pair of BLDC hub motors rated 36v 250w each for hoverboards. I have been wondering if one can be used to drive the other with electrical transmission rather than belts and chains from the front to the back of the craft. One as crank and one as the driven motor. Eager to test this once they arrive sometime next week
If the hoverboard to hoverboard motor transmission works well, then it might even be worth running two motors from a second hoverboard without messing around with the washing machine and diodes
These are the few thoughts that I am running with at the moment
I have been working away on this since the thread started. It is the pet project for recreation purposes. The fun thing to work on during downtime.
In the year since, I have learnt a lot and this thread can discuss BLDC tech, the controllers and implementation and such. The uses can cover PA transport trolleys and active wheels and such and their DIY
I will include my use case as well, but the discussion is open to all applications
There is an active reverse e-trike project that I am cancelling in favour of this project. I will only do the kids size in that design for now as a one-off for my kid. The issue is that it is the kart format that is appealing, and I would rather focus on this then 3 wheels. The feeling of delivering forces from 4 points and feedback....once in the ZONE
This is becoming very difficult to take part in due to rules and regs. Hence, the return to try to find the karting experience on the water. Initially I envisioned a 4 wheeled setup running fins to retain the ambience of the kart, but there are substantial efficiency issue there
I have been very lost trying to come up with the ideal craft and thought up many ideas and refined it to the following thoughts and observations to try to find a water based emulation
1 - A waterkart wouldn't really be a boat in the traditional sense
2 - If a quadcopter is akin to a kart, then a speed boat is like a plane
3 - Aero, fairing and body work is relevant on the bitumen, in the air or on/in the water
4 - A quadcopter controller can provide differential drive with four props or hub motors for water wheels. Combined with an actual turning mech via a steering wheels to a pair of props or wheels or rudders. AWD type experience
5 - A pair of rear waterwheels would allow drifting if run against forward rudders
It is more about the ambience than speed. Thoughts on recreating the kart experience on the water. Some fun can also be had with RC models. This is directed towards like-minded audio nuts who are also into BLDC tech, vehicles and RC
In the year since, I have learnt a lot and this thread can discuss BLDC tech, the controllers and implementation and such. The uses can cover PA transport trolleys and active wheels and such and their DIY
I will include my use case as well, but the discussion is open to all applications
There is an active reverse e-trike project that I am cancelling in favour of this project. I will only do the kids size in that design for now as a one-off for my kid. The issue is that it is the kart format that is appealing, and I would rather focus on this then 3 wheels. The feeling of delivering forces from 4 points and feedback....once in the ZONE
This is becoming very difficult to take part in due to rules and regs. Hence, the return to try to find the karting experience on the water. Initially I envisioned a 4 wheeled setup running fins to retain the ambience of the kart, but there are substantial efficiency issue there
I have been very lost trying to come up with the ideal craft and thought up many ideas and refined it to the following thoughts and observations to try to find a water based emulation
1 - A waterkart wouldn't really be a boat in the traditional sense
2 - If a quadcopter is akin to a kart, then a speed boat is like a plane
3 - Aero, fairing and body work is relevant on the bitumen, in the air or on/in the water
4 - A quadcopter controller can provide differential drive with four props or hub motors for water wheels. Combined with an actual turning mech via a steering wheels to a pair of props or wheels or rudders. AWD type experience
5 - A pair of rear waterwheels would allow drifting if run against forward rudders
It is more about the ambience than speed. Thoughts on recreating the kart experience on the water. Some fun can also be had with RC models. This is directed towards like-minded audio nuts who are also into BLDC tech, vehicles and RC
Lots of forced idle time for things like this, atm. Trying to do some maintenance around the place while recovering from leg burns ended up in a big ouch
Thinking about how to get the kart feel. The flat surface of a SUP might allow drifting with RWD and forward rudders if there is a forward planing pad similar to a seaplane float
This is the e-hub from my reverse trike project. I am thinking about taking the hub out of the spokes and using that as the motor. A belt can run from its centre groove to a cog on the rear axle. The karts forward, reverse, human hybrid and braking will come from the e-hub and its controller. I don't know how 1500w and 70NM from the e-hub will go, but will be a lot faster than a human paddled SUP. I also have a 1.8m kite to harness wind power for some boost
1.5kw e-hub
I am thinking wheels on the rear only and a pair of floats bearing rudders on the forward axle (x-beam) similar to a hydroplane. An upgrade to a dual motor controller and using the outputs meant for a bike front wheel to drive a prop mounted to the forward planing pad should enhance the AWD feel. I found some motors suitable for such a thruster that feature hall sensors and would mate well in the e-bike system
Thinking about how to get the kart feel. The flat surface of a SUP might allow drifting with RWD and forward rudders if there is a forward planing pad similar to a seaplane float
This is the e-hub from my reverse trike project. I am thinking about taking the hub out of the spokes and using that as the motor. A belt can run from its centre groove to a cog on the rear axle. The karts forward, reverse, human hybrid and braking will come from the e-hub and its controller. I don't know how 1500w and 70NM from the e-hub will go, but will be a lot faster than a human paddled SUP. I also have a 1.8m kite to harness wind power for some boost
1.5kw e-hub
I am thinking wheels on the rear only and a pair of floats bearing rudders on the forward axle (x-beam) similar to a hydroplane. An upgrade to a dual motor controller and using the outputs meant for a bike front wheel to drive a prop mounted to the forward planing pad should enhance the AWD feel. I found some motors suitable for such a thruster that feature hall sensors and would mate well in the e-bike system
Motors are about 80% efficient, cranking one motor to drive the other means you are 0.8*0.8 = 0.64, or 64% efficient.
Look at what electric scooters in India and China do for circuit ideas.
Many types of drives and voltages are used.
500W is 2/3 horsepower, and at 64% you need 1 HP to crank the generator, meaning you need a horse, or be physically strong as a horse to crank the device.
I don't think it is a good idea.
Look at what electric scooters in India and China do for circuit ideas.
Many types of drives and voltages are used.
500W is 2/3 horsepower, and at 64% you need 1 HP to crank the generator, meaning you need a horse, or be physically strong as a horse to crank the device.
I don't think it is a good idea.
Yeah man, I did the tests mentioned earlier in the topic and found it to be inefficient and put it away. This time running the 1.5kw ehub via regular chain and crank in PAS mode. The electric transmission thing is not happening anymore
I want to keep this to one motor, mid-engine AWD with forward steering type experience. This means a pair of props in the water in place of the forward wheels. It will be a challenge to design a marine grade mechanical distribution system, splitting the power to a pair of rear wheels and a pair of forward props!
https://en.wikipedia.org/wiki/Ford_GPA
https://en.wikipedia.org/wiki/Amphibious_vehicle
Look at them for ideas.
https://en.wikipedia.org/wiki/Amphibious_vehicle
Look at them for ideas.
To distribute 1.5kw to 4WD. The 1/5 scale RC systems run up to 7HP and use 8-9mm shaft setup and can be borrowed from. Will use industrial 10mm shaft systems for the rear axle, a chain to transfer power to the forward 10mm axle. This forward axle will be shorter and couple 1/5 scale front CVDs to its ends to rotate the front wheels or props. The 10mm shaft systems feature gear, cog and pulley sets in 90 degree and differential too. Makes the transmission feasible. The bite of the fins will set the loads and the 10mm system makes it easy to mess with ratios
The rear is a live axle and all the way to almost the front hubs is very simple mechs. The driven front wheels or props will be that cheat using the grafted on RC CVDs
Another challenge will be to transfer power from the e-hub to the rear axle. I think a belt can run from its groove to a pulley on the axle. Also considering 5hp 4 stroke as 'final ratio'. Shifting to that would mean backing off the e-throttle and that will engage regen as the e-hub will keep turning, but its bike hub system will not feed the petrol engine back into the foot crank. Shifting to that would also turn the engine on. The engine will power the wheels and props once engaged and also top the battery back up. A go-kart engine and gearbox with reverse can serve. A scale model V8 would be nasty 😀
The rear is a live axle and all the way to almost the front hubs is very simple mechs. The driven front wheels or props will be that cheat using the grafted on RC CVDs
Another challenge will be to transfer power from the e-hub to the rear axle. I think a belt can run from its groove to a pulley on the axle. Also considering 5hp 4 stroke as 'final ratio'. Shifting to that would mean backing off the e-throttle and that will engage regen as the e-hub will keep turning, but its bike hub system will not feed the petrol engine back into the foot crank. Shifting to that would also turn the engine on. The engine will power the wheels and props once engaged and also top the battery back up. A go-kart engine and gearbox with reverse can serve. A scale model V8 would be nasty 😀
A 5kw e-hub would be better performance than a 7hp petrol and be a drop-in replacement type of upgrade, but power options are pretty flexy
I know there are dedicated forums out there for RC and buggies and such, but I struggle to feel at home on them as there is a distinct disconnect to full scale. Better amongst like-minded geeks in audio
Another 'philosophical' thought on the kart experience for the water would be that props are more appropriate in a place of the wheels. Would love to see a discussion on AWD or RWD water wheels vs props such as quad prop drive with front props turning for steering analogous to four car wheels. With the debate keeping in mind that the bias should be towards more kart like and less boat like
I know there are dedicated forums out there for RC and buggies and such, but I struggle to feel at home on them as there is a distinct disconnect to full scale. Better amongst like-minded geeks in audio
Another 'philosophical' thought on the kart experience for the water would be that props are more appropriate in a place of the wheels. Would love to see a discussion on AWD or RWD water wheels vs props such as quad prop drive with front props turning for steering analogous to four car wheels. With the debate keeping in mind that the bias should be towards more kart like and less boat like
Selected these bearings for the axles. Let's see if stainless can survive the usage. Will prolly need 4x per axle and also some in the steering mech
I think I am well sorted with BLDC systems now. Have invested a lot of time and effort in learning the use of these. The kart is a viable project now and the training ground for learning and developing systems for the Bass Shelter project. This thread is done