Any interest in a "Hybrid" gasoline kit? Supercaps?

Howdy,

I've been tinkering with a small 1HP weedwacker motor and a brushless DC motor as a generator. This thing can easily mount to the back rack of my eBike and provide 800W of charging power. I've also been considering using a generator + supercapacitor only setup (batteryless) for experimentation.

I imagine it'd be useful for extended offroading trips, cross country trips, etc. I'm a fulltime RVer and often use my eBike in the country. I'm not going to be a douche and give eBikes a bad name by using it in the city. I also wonder how quiet I could make the exhaust.

It could also be used as just a portable generator for when you run out of juice. But then why not just carry extra batteries.

This may be a dumb idea, but it's fun to experiment!

Lastly, what about regenerative breaking? Would it make sense to come up with a supercap storage method? Can most Lithium batteries charge quickly enough to make the most use of regen, or is some of the power lost due to charging rates?

zorrobyte said:

I've been tinkering with a small 1HP weedwacker motor and a brushless DC motor as a generator. This thing can easily mount to the back rack of my eBike and provide 800W of charging power.

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Little APU's like this could be a way to ameliorate the bad decisions people make about batteries. "Well, my commute is 6 miles but someday I might want to go 50 - so I'm going to get this 26ah battery just in case."

The future belongs to free-piston generators, but for now small devices like the one you mention might make sense. (BTW 1 hp = 746 watts. So your 1hp weedwacker _might_ give you 500 watts if everything is matched perfectly and you can avoid overheating.)

Lastly, what about regenerative breaking? Would it make sense to come up with a supercap storage method? Can most Lithium batteries charge quickly enough to make the most use of regen, or is some of the power lost due to charging rates?

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Batteries are usually fine with regen braking. You can generally set your regen level to match your battery.

Hey Bill! Thanks for the feedback and the regen advise.

I found these 1HP gensets on Aliexpress:
https://www.alibaba.com/product-detail/Best-price-1-hp-portable-mini_60747759092.html?spm=a2700.7724857.main07.1.6dc42570339w6F&s=p

Good advise on nominal watts. It'd be more efficient to use a DC->DC converter.

I wonder how most OEM chargers handle undercurrent on the 110V side. If they would simply output less current, or shutdown. Hmm.

I wonder if anyone would buy one if I made them. I could use inexpensive Chinese engines, all the way up to Honda 4 stroke engines.

Looks like I have some soldering and more tinkering to do.

zorrobyte said:

I found these 1HP gensets on Aliexpress:

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I don't trust Alibaba or Aliexpress any farther than I can throw them. Also, that's 22lbs - and 22lbs seems like a lot for 800 watts. And I suspect you'd need to do a lot of work to make that thing less than deafening when you use it.

Good advise on nominal watts. It'd be more efficient to use a DC->DC converter.

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I don't think you need a DC/DC for anything.

I wonder how most OEM chargers handle undercurrent on the 110V side. If they would simply output less current, or shutdown. Hmm.

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Why would "undercurrent" be a problem?

While my initial reaction is negative, the reality is that such a scheme is probably more "green" than riding a regular bicycle - assuming that you are riding thousands of miles.

What I personally would be interested in is something that could supply around 300 watts of charging power and that would be about half the size of that charger you linked to and is pretty quiet. My thinking is that for long distance touring you would reduce battery capacity and pause a couple times a day to take a break and recharge the batteries. It would be fun to see how many miles you could travel on one gallon of gasoline with such a setup.

I like the direction of this kind of device.

https://newatlas.com/go/6245/

wturber said:

I like the direction of this kind of device.

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Wow. I can't imagine how loud that thing would be - and at 8khz! But if the efficiencies are high, the noise suppression might be worth it.

While my initial reaction is negative, the reality is that such a scheme is probably more "green" than riding a regular bicycle - assuming that you are riding thousands of miles.

What I personally would be interested in is something that could supply around 300 watts of charging power and that would be about half the size of that charger you linked to and is pretty quiet.

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My thinking is that if you buy it as a "range extender" to make you feel better about a small battery bike, then 1) you'll almost never use it and 2) your increased efficiency/lower cost due to the smaller battery is probably a net plus overall.

However I have always thought it made more sense to just drive one of the wheels with the IC motor directly. On a direct drive setup you can still recharge this way, and during normal travel it's a lot more efficient to go motor -> wheel than motor -> generator -> battery -> motor -> wheel. (And lighter.)

billvon said:

My thinking is that if you buy it as a "range extender" to make you feel better about a small battery bike, then 1) you'll almost never use it and 2) your increased efficiency/lower cost due to the smaller battery is probably a net plus overall.

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I would have it as a range extender not in order to feel better. I'd have it to actually go farther. I already have far more battery than is typical (over 1000 watt hours). Buy I need more (or some other solution) if I want to cover over 100 miles in a day.

billvon said:

However I have always thought it made more sense to just drive one of the wheels with the IC motor directly. On a direct drive setup you can still recharge this way, and during normal travel it's a lot more efficient to go motor -> wheel than motor -> generator -> battery -> motor -> wheel. (And lighter.)

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I've been toying with the idea of doing some long distance touring that would take me across some long stretches of Southwestern desert. So I've been bouncing around the trade-offs of larger batteries, solar panels and finding places to "plug in." The right kind of micro generator is interesting in that context. I wouldn't need or use it for my city commuting.

Yes, the direct drive ICE is more efficient. But there are other considerations besides efficiency. For instance, how pleasant it is or isn't to actually ride (noise) and having motor input that responds smoothly to pedal input. And in AZ, my maximum allowable speed will be 28 mph for electric in August but will remain 20 mph for the direct drive ICE. So I see good reasons to consider a lower efficiency use of an ICE.

I believe Dogman hauls a portable generator around with him on long trips. He uses it at the campsite. I have a foggy memory of him quoting something like 25lbs. 25lbs is only about 2000 watthours of lipo battery according to my math (not sure where I'm going with that info). It's a viable approach though because there is value to keeping your bicycle a nice quiet on riding trails whereas a generator is tolerable at camp.

I've been toying with the idea of doing some long distance touring that would take me across some long stretches of Southwestern desert. So I've been bouncing around the trade-offs of larger batteries, solar panels and finding places to "plug in."

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I personally found the "find a place to plug in" method to be annoying and solar a huge breath of fresh air comparatively. It's much nicer to re-charge next to your camp tent than it is to awkwardly hang around at around at a gas station for a few hours. Places with power plugs are often not great places to lock-up so if you have concern about your stuff getting jacked you are stuck hovering around your bike for a while.

I had a successful mini cross country where I approached it from the angle that the solar panels would provide 100% of the vehicle's energy while in motion and the battery just kind of a "middleman" but due to how obnoxious my 450 watt panel is I am considering having a go at it this time with a 50/50 approach, a large battery and a smaller panel. Personally I am thinking of making a solar trailer using my current HQST flexible 50 watt panels and I would have only 150 watts deployed while riding (a 22inch x 66inch panel) and have another 150 watts stashed that I could pull out and use when parked.

Getting off topic now but I have another mini XC planned, a 110 mile out and back. Utah just completed the Jordan River Bridge thus making it the longest continuous bike path in the United States west of the Mississippi. If I did the Golden Spoke Route (Vivian Park to Rainbow Gardens in Ogden Canyon) that would be about 110 miles one way and I personally would bring 20ah with me on the weedy side or 40ah with me on the... shall we say "less confident" side. :lol:
Edit... with a 150 watt solar trailer in tow.

Huh, I just found this:


It claims to be a 70cc 5HP/3728.5W engine.

Hmm, they claim it's 20% more efficient (than pistons), no vibrations and doesn't need a muffler:
http://liquidpiston.com/wp-content/uploads/LiquidPiston-XMini-Specifications.pdf

I bet it's expensive.

Haha, nevermind. "dev kits" are $30,000
http://liquidpiston.com/dev-kit/

I wonder how reliable R/C engines are:
https://hobbyking.com/en_us/turnigy-30cc-gas-engine-w-cdi-electronic-ignition-and-genuine-walbro-carburetor.html

zorrobyte said:

Haha, nevermind. "dev kits" are $30,000

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And time between overhauls - 3 hours.

parajared said:

I personally found the "find a place to plug in" method to be annoying and solar a huge breath of fresh air comparatively. It's much nicer to re-charge next to your camp tent than it is to awkwardly hang around at around at a gas station for a few hours. Places with power plugs are often not great places to lock-up so if you have concern about your stuff getting jacked you are stuck hovering around your bike for a while.

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Thanks for the insight and perspective. One of the things I'd like to do it ride to the coast (San Diego or LA or perhaps both.) I've been toying with the idea of doing it on a regular bike for years. But doing it on an ebike has brought the idea more to front of mind. I'd like to be able to cover 100 miles per day and hopefully do that without the need to find civilization and services. But I haven't mapped it all out yet and given all the options a thorough vetting.

wturber said:

Thanks for the insight and perspective. One of the things I'd like to do it ride to the coast (San Diego or LA or perhaps both.) I've been toying with the idea of doing it on a regular bike for years. But doing it on an ebike has brought the idea more to front of mind. I'd like to be able to cover 100 miles per day and hopefully do that without the need to find civilization and services. But I haven't mapped it all out yet and given all the options a thorough vetting.

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Most routes through there have a lot of civilization on the way such that you wouldn't have 100+ mile stretches where you couldn't charge. But getting up the mountains could be a problem - there are places where you'd have to go 30-40 miles between stops, and with a 4000 foot elevation change even a 100 mile range bike might not make it.

During most times of the year solar would be a great option on that route, too.

Ha! I found exactly what I was looking for:
https://www.kickstarter.com/projects/1013014272/worlds-first-900w-48v-dc-generator-kit-for-honda-g/?ref=kicktraq

billvon said:

Most routes through there have a lot of civilization on the way such that you wouldn't have 100+ mile stretches where you couldn't charge. But getting up the mountains could be a problem - there are places where you'd have to go 30-40 miles between stops, and with a 4000 foot elevation change even a 100 mile range bike might not make it.

During most times of the year solar would be a great option on that route, too.

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Yeah. I've got to map it out. I was looking at an alternate route to LA that takes lesser known roads to the north of I-10 for a possible LA trip. I'm not sure if I want to ride along I-10 or not with all that traffic. My first survey suggested a 100+ mile stretch with no apparent services. A southern trip to San Diego through Yuma seems less problematic.

As for elevation, I think my first step will be a day trip up and pack from Fountain Hills to Payson. That's about 67 mile one direction and includes over 7000 feet of vertical climbing with a net gain of a bit over 3000 feet. If I add two more hoverboard packs I should have about 1500 watt/hrs which should get me one way comfortably in less than 5 hours averaging a use of 20 Wh/mi or less. Then I'd have to plug in somewhere for a few hours.

This is the closest I've found to a ready made generator that might be reasonably carried along. But I'd rather have half the capacity and half the size - or not carry one at all.
https://www.amazon.com/Sportsman-1000-Watt-Inverter-Generator/dp/B01M8L2RTS/ref=cm_cr_arp_d_product_top?ie=UTF8

The thing that is so attractive about the solar is the independance. The negative is the size and bulk.

zorrobyte said:

Ha! I found exactly what I was looking for:
https://www.kickstarter.com/projects/1013014272/worlds-first-900w-48v-dc-generator-kit-for-honda-g/?ref=kicktraq

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That looks pretty close. Many years ago I looked at doing something similar. Mine used a brushed motor as a generator which simplifies a bunch of stuff and makes it easier to use the generator as a starter motor for remote starting. The motor is a Honda GX-31 four stroke. I still found the noise of the motor to be unacceptable.

That little gen set ever make it out of kickstarter? THAT'S exactly what I have been looking for. 11 lbs I can handle/justify. As far as the noise, I'd just charge away from my camp site, there is no one around to bother or worry about where I camp.

craneplaneguy said:

That little gen set ever make it out of kickstarter? THAT'S exactly what I have been looking for. 11 lbs I can handle/justify. As far as the noise, I'd just charge away from my camp site, there is no one around to bother or worry about where I camp.

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Oops, never mind..... so we are back to the lightest readily available gen set being being over 20 lbs., pass. I used my 1000 watt Yamaha two days ago to pump some water in the boonies, at 27 lbs. it's "light" but not light enough, besides I don't need 1000 watts, I need 2 or 300.

Right now I have harbor freight 800w generator. It could be hauled in a trailer with the bike, but I use it to recharge the house battery in the van, which does leave enough power left to also run my current e bike charger. Its much louder, but much lighter than my very old honda 1000w was. About 25 pounds or something like that on the HF cheapie.

Everything e-bike kind of on hold at the moment though, my "good" batteries burned last year, and my lipos are now over three years old. Puffed to hell, and a bit scary to charge em now. Back when I had 2000wh of battery, I could just carry that. This year its back to pedaling near the house, I can't pedal far with my health problem, and hauling the gas scooter to the woods, once they stop burning for the year.


But yes, like crane plane guy, a 48v 200w generator would be ideal, and preferably no more than 15 pounds, and much quieter than the 60 db two stroke I have now. Better still, 200w of solar. Then with an always full house battery, I could just run my charger off the van. I still like the idea of a 100w 48v panel on a trailer to tow behind the bike. Then a 500wh battery would run as far as 1000wh, if ridden very slow.

Yep. 10 lbs and around 200-400 watts seems to be the target and also doesn't seem to exist. Here's another close but no cigar generator. It is four stroke and supposedly quieter. But it still weights over 20 lbs.

As Amberwolf outline to me a while ago, with solar you probably need at least twice the rated solar panel rating as the watts that you need. So if you need a 200 watt charging rate, you probably need around 400 watts of panels ... or more. And all the info seems to suggest that most charging while riding is fairly inefficient. Of course the counter point to that is you don't need to make sure you have gas and it is pretty quiet.

https://www.walmart.com/ip/Lifan-Energy-Storm-ESI-860i-CA-Digital-Inverter-Generator-40cc-OHV-4-Stroke-Recoil-Start-TDI-Ignition-700-watt-Surge-Power-600-Watt-Continuous/100034043?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227150058922&wl0=&wl1=g&wl2=c&wl3=262136426874&wl4=pla-431234127540&wl5=9030084&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=100034043&wl13=&veh=sem

wturber said:

Yep. 10 lbs and around 200-400 watts seems to be the target and also doesn't seem to exist. Here's another close but no cigar generator. It is four stroke and supposedly quieter. But it still weights over 20 lbs.

As Amberwolf outline to me a while ago, with solar you probably need at least twice the rated solar panel rating as the watts that you need. So if you need a 200 watt charging rate, you probably need around 400 watts of panels ... or more. And all the info seems to suggest that most charging while riding is fairly inefficient. Of course the counter point to that is you don't need to make sure you have gas and it is pretty quiet.

https://www.walmart.com/ip/Lifan-Energy-Storm-ESI-860i-CA-Digital-Inverter-Generator-40cc-OHV-4-Stroke-Recoil-Start-TDI-Ignition-700-watt-Surge-Power-600-Watt-Continuous/100034043?wmlspartner=wlpa&selectedSellerId=0&adid=22222222227150058922&wl0=&wl1=g&wl2=c&wl3=262136426874&wl4=pla-431234127540&wl5=9030084&wl6=&wl7=&wl8=&wl9=pla&wl10=8175035&wl11=online&wl12=100034043&wl13=&veh=sem

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When I did my solar build I built it so 100% of the energy goes back into the battery during the ride but that equated to one very large solar panel. A little 100 watt solar trailer build sounds like it would be pretty neat; just a little solar panel to make a "lid" to a cargo trailer box, nothing too gargantuan. Geometrically a 100 watt "trailer lid" would work out to 44" long and 22" wide to fit nicely on a standard trailer.



Assuming you want to go crazy and travel 100 miles per day that would be maybe...
15wh/mi= 1500 watthours
20wh/mi= 2000 watthours
25wh/mi= 2500 watthours

You would want a little "solar farm" capable of deploying out and getting yourself back up to full charge in just one sitting. To get yourself charged up in just the dwindling evening light and just the morning light again my math says you want at least a good 400 watts of panel in the cargo hold. That would equate to about 23 lbs and 22inch x 22inch x 5 inch of cargo space.

parajared said:

Assuming you want to go crazy and travel 100 miles per day that would be maybe...
15wh/mi= 1500 watthours
20wh/mi= 2000 watthours
25wh/mi= 2500 watthours

You would want a little "solar farm" capable of deploying out and getting yourself back up to full charge in just one sitting. To get yourself charged up in just the dwindling evening light and just the morning light again my math says you want at least a good 400 watts of panel in the cargo hold. That would equate to about 23 lbs and 22inch x 22inch x 5 inch of cargo space.

Click to expand...

Well my general target would be to travel 100 miles per day. I've done back-to-back 75 mile/day two day trips on leg power alone. Sure, I was younger then, but frankly I think my fitness isn't that different. My recovery is surely slower, but then that's where the electric motor comes in. So 100 miles doesn't seem too crazy to me.

I'd probably approach things by riding early. It seems to me that a good plan would be to take an extended rest in the middle of the day, That not only splits things up nicely for rest, recovery and eating, but it should provide the best time to deploy a small solar farm for optimal charging.

If a person stopped for a couple hours mid-day and a couple hours before sunset, do you still think they would need 400 watts of panels. If not, how much would you estimate they'd need. I understand that this will vary depending on time of year, location, weather, etc.

In the 100 watt trailer scenario I'm making a lot of assumptions.

1) I assume 10 watthours per mile is really legging it for you whereas 25wh/mi is reasonable enough. The math I guessed on was 2000 watthours of deficit because 25wh/mi x 100 miles = 2500wh. Subtract about 500 watthours that you would recharge from 6 hours of a 100 watt solar panel being in the sun while you ride. If you can XC at 10wh/mi you don't need as much solar.

2) I assumed you would want to camp/charge when the sun is not at peak; here in AZ 10:30-ish to 3-ish gives the best numbers. My solar panel, a 450 watt panel yields about 4 to 5 amps early morning/late afternoon so only 240 watts out of 450 so I calculated for about 50-60% efficiency to charge up during "camp hours".

3) I assumed you would ride for about 5 or 6 hours and then set up camp charge for about 7 hours of fair to middling sunlight (afternoon/morning). If you spend less time in the saddle, more time camping your requirements go down.

4) I assumed you would want to ride with 100 watts exposed. If you can ride with 200 watts exposed your stowed panel size requirements go down.

I guess I can't make as precise of a prediction as you would want. You will have to strap a bunch of camping gear to your bike and see how much energy you consume on average then decide how you want to re-charge that energy you have consumed to get the very best estimate possible.

100 watts when riding, 500 watts of panel when camping is my best (fairly wild) guestimate. My WAG

Also sorry for de-railing the thread a bit.