Science Faction
1 W
- Joined
- May 18, 2009
- Messages
- 59
Hi All,
I have been thinking about small range extenders.
I recently went on a ride on an Santa Cruz Bullit ebike I built for a friend,with his partner on a Giant Trance ebike I built and him on a Giant Glory Ebike he just bought.
The bikes all do around 55kph top speed on the flat.
We we riding in Koonyum Range outside of Mullumbimby NSW through dirt roads and awesome single track.
We planned to ride for under an hour as the bikes have about 1kW hour stored each.
It's just so much fun that an hour is not long enough.
The third bike that a another friend built sold it so he could buy a KTM dirt bike and stop messing with spending more time battery charging than riding.
The two bikes i built feel great with 7.5 kg of battery (6x 6S nanotech 8AHr 18S2P) and 7 kg of HS3540.
I wouldn't really want to add much more weight.
However the thought crossed my mind about going to 18S1P saving over 3kgs and running a 1kW range extender.
I have researched for many hours to finding a suitable power plant to produce the 1.2kW of mechanical power necessary to get 1kW of electrical power assuming a consertvative 85% conversion efficiency.
The Bladon jets that jag use came up, but they have a minimum of 5kW and run exhaust energy recovery heat exchangers to make them more efficient.
A 12kW domestic genset Tata have commissioned from Bladon is powered by a radial turbine and apparently the whole unit is as big as a fridge.
The larger jets such as the 70kW units in the jag are an axial arrangement.
There are many rc motors that produce around 1.2kW and weigh about 300gms but they are not made for long hours of constant running.
For that I had to look at UAV engines.
The one I think is most suitable is the Cubewano Atom.
It's an advanced aircooled single rotor motor that produces 1.8kW, weighs under 3kG, runs EFI on multifuels and if reved lower to only produce 1.2kW would get 500hrs TBO with 100 hour Service intervals.
It's quoted at 0.8lb/hp/hr which I worked out to produce 1kW of charging power would sip 0.75litres/hour.
As our bikes use about 1kW to run at 50kph on flat road, I figure that we'd use 1.5L/100km or 156mpg(us).
So with a 1.5l of fuel being about 1kg and allowing 1kg for the generator and electronics I figure there is a good chance of the unit weighing under 5kgs. Adding only 1.5kg to our current config if we go to 18S1P.
Obviously the noise would need to be very carefully silenced to make the units attractive on an ebike and I believe this is achievable as the motors will be running at constant load and rpm.
I reckon the single exhaust could be split and tuned to cancel out the sound pulses.
The only problem is the motors are currently $18000(us).
However...
In order to get them down $1000 I need to order 3000 units.
Probably have to spend over $100k in development too.
If they were $1000 I'm figuring the whole genset would be about $2200.
Which sounds like a bit but its the equivalent of 2kWhrs of Nanotechs.
With this genset 1.5l of fuel would be the equivalent of adding 2kWHrs of batteries, in Australia at the moment that will cost you about $2.40.
Then when you run out you fill it again in under a minute.
My questions are have I got the Maths right?
And
Would anyone here be interested in the lightest, smallest 1kW genset potentially available at a price point of $2200?
I figure that the market is huge, charging EV's.
Especially if the units are designed to be modular and Combine in parallel for more amps.
Also in Camping, boats, worksites and unfortunately military.
Is 3000 units ridiculous or if I was to raise the 100k to fund this product and float it on Kickstarter do you reckon it is an achievable figure?
Thanks for reading
Paul
I have been thinking about small range extenders.
I recently went on a ride on an Santa Cruz Bullit ebike I built for a friend,with his partner on a Giant Trance ebike I built and him on a Giant Glory Ebike he just bought.
The bikes all do around 55kph top speed on the flat.
We we riding in Koonyum Range outside of Mullumbimby NSW through dirt roads and awesome single track.
We planned to ride for under an hour as the bikes have about 1kW hour stored each.
It's just so much fun that an hour is not long enough.
The third bike that a another friend built sold it so he could buy a KTM dirt bike and stop messing with spending more time battery charging than riding.
The two bikes i built feel great with 7.5 kg of battery (6x 6S nanotech 8AHr 18S2P) and 7 kg of HS3540.
I wouldn't really want to add much more weight.
However the thought crossed my mind about going to 18S1P saving over 3kgs and running a 1kW range extender.
I have researched for many hours to finding a suitable power plant to produce the 1.2kW of mechanical power necessary to get 1kW of electrical power assuming a consertvative 85% conversion efficiency.
The Bladon jets that jag use came up, but they have a minimum of 5kW and run exhaust energy recovery heat exchangers to make them more efficient.
A 12kW domestic genset Tata have commissioned from Bladon is powered by a radial turbine and apparently the whole unit is as big as a fridge.
The larger jets such as the 70kW units in the jag are an axial arrangement.
There are many rc motors that produce around 1.2kW and weigh about 300gms but they are not made for long hours of constant running.
For that I had to look at UAV engines.
The one I think is most suitable is the Cubewano Atom.
It's an advanced aircooled single rotor motor that produces 1.8kW, weighs under 3kG, runs EFI on multifuels and if reved lower to only produce 1.2kW would get 500hrs TBO with 100 hour Service intervals.
It's quoted at 0.8lb/hp/hr which I worked out to produce 1kW of charging power would sip 0.75litres/hour.
As our bikes use about 1kW to run at 50kph on flat road, I figure that we'd use 1.5L/100km or 156mpg(us).
So with a 1.5l of fuel being about 1kg and allowing 1kg for the generator and electronics I figure there is a good chance of the unit weighing under 5kgs. Adding only 1.5kg to our current config if we go to 18S1P.
Obviously the noise would need to be very carefully silenced to make the units attractive on an ebike and I believe this is achievable as the motors will be running at constant load and rpm.
I reckon the single exhaust could be split and tuned to cancel out the sound pulses.
The only problem is the motors are currently $18000(us).
However...
In order to get them down $1000 I need to order 3000 units.
Probably have to spend over $100k in development too.
If they were $1000 I'm figuring the whole genset would be about $2200.
Which sounds like a bit but its the equivalent of 2kWhrs of Nanotechs.
With this genset 1.5l of fuel would be the equivalent of adding 2kWHrs of batteries, in Australia at the moment that will cost you about $2.40.
Then when you run out you fill it again in under a minute.
My questions are have I got the Maths right?
And
Would anyone here be interested in the lightest, smallest 1kW genset potentially available at a price point of $2200?
I figure that the market is huge, charging EV's.
Especially if the units are designed to be modular and Combine in parallel for more amps.
Also in Camping, boats, worksites and unfortunately military.
Is 3000 units ridiculous or if I was to raise the 100k to fund this product and float it on Kickstarter do you reckon it is an achievable figure?
Thanks for reading
Paul
