Serial Hybrid Cycle with ICE Generator Onboard

Serial Hybrid Cycle with ICE Generator Onboard.

Inspired by the Selsyns and Amplidynes Thread

A serial chainless bike where the pedals run a generator is intrinsically less efficient than a direct chain driven one. However, if you have such a setup, you could, instead of using large batteries to store/complement the pedal-generated juice (which has a weight penalty), you could use a very small glo-plug model aircraft engine attached to a small tiny generator to boost charge a small auxiliary battery. Such small generators (e.g. http://www.m-dot.com/page8.html and http://www.dstarengineering.com/piston.html) could be used to augment the power of pedaling when coupled via a DC-DC converter. These small engines rev very fast, maybe 10000 rpm, so to direct drive a bike they have to be heavily geared down in 2 or 3 stages, each stage of which adds friction and hence inefficiency (see Matt Schumaker's project). However, by using the system described, a battery just big enough to act as a buffer between the generator and the motor would be all that was needed. Then, since we know from the title of this thread "11,000 watt-hours equal about a gallon of gasoline" it's better to carry gas, we can carry a litre or two of gas as our auxiliary power supply.

If anyone knows of a generator that is commercially available attached to a 1-10cc motor, let's hear about it.
What do you think?

My smallest genset, a 700 watt honda puts out about 3 amps of 12 volt dc. I don't know what sise engine it has, but it will run about 6 hours on a gallon, and holds 2 gallons. Someday I need to throw it in the trike, along with my 4 amp charger and just see how far I get. The problem is it weighs like 100 pounds or something. So to make the range infinite I'd need to ride at a 4 amp draw, and packing 100 lbs that could just be less than 5mph. And polluting about as good as a tire on fire all the way. Your Idea of a reallly light generator has merit for sure, especially if you could get say 8 amps of 36 volt out of something that weighed 25 pounds. Maybe burning pure ethanol. But what I want to do eventually is have about 100 ah of lithium battery in the trike so I really could do cross country rides if time is not an issue. In winter, It would be quite pleasant to ride to LA. The cowboy calculation for my trike is about a mile range per amp hour. If you could ride about 3 or 4
hours in the morning, bum a charge for 3 hours, and ride some more in the afternoon I could get there in about 3 or 4 days. You'd need to make a friend about every 75 miles or so ahead of time to charge.

Oh, and if you find that generator that makes 11,000 watts out of a gallon of gas, let me know. Now that I think about it, at full load, that little gennie only runs about an hour and a half on a gallon. So thats about 1,050 watt hours on a gallon. So about 4 bucks a killowat hour. Vs 11.5 cents to plug in.

Dogman, did you look up the URLs I gave you? Those motors are nothing like a 700 cc Honda genset. We are talking 1 to 10 cc glo-plug motors type of size. See http://www.m-dot.com/page8.html and http://www.dstarengineering.com/piston.html)

Yes I understand, and as you can see it would really be a big improvement over the current state of the art. My post was to illustrate how poorly it would work with what you can go buy at the hardware store today. I should have made that more clear in my post. I did not mean it to criticise the idea, just show how much the general idea needs tec improvement. I don't think generator makers have given a rip about efficiency.

I looked at this idea a few month ago and reckon it's quite do-able with a bit of adapting. It looks like making a small ICE generator is the best option, but the challenge is finding the bits. Luckily we have a few rather neat options around for potentially useful components.

Both Honda and Robin make some very lightweight, small, four stroke engines intended for use in strimmers (weedwhackers in US-speak). These are around 22 to 35cc, put out about 1 to 1 1/2hp and are fairly cheap to buy. Being four stroke they tend to be clean and economical, plus they're a bit quieter than their two stroke brethren. The GX22 from Honda looks to be a good bet, as 1hp is plenty for this application.

For the generator I'd look at using a big brushless RC type motor. The big, relatively low kV models are getting to be pretty cheap now and will be fairly happy when spinning at the sort of speeds that one of these small engines operates at, so could be directly coupled (simple, cheap and lightweight). The motor will generate three phase AC, which can easily be rectified and used to drive the battery charging/motive power systems.

The total cost, provided you shop around a bit (eBay for the engine, etc) could be comparable to that for a much heavier four stroke gen set, plus it could be built to integrate into the bike, perhaps by being fitted in a sound insulated box on the rack.

jeremy

I think you could make it work. A brushed motor would be easier electrically, but perhaps not as efficient. Here's my mockup using a Honda GX-31:


The generator could also be used to start the ICE when the battery voltage drops. The generator could automatically switch off when the battery voltage gets up to full charge.

I've been thinking about this subject for awhile. I came across a Honda EU 1000W generator a few years ago and was impressed with how quiet and small it was. It can also be paralleled with another EU generator

It's rated at 8.3A at 12v DC and 120v AC and when run at half throttle it runs 8.3 hrs on .6 gal of gas. so then it would be 4.15A @12v DC it's also quiet at 53 to 59 db. 29 lbs (dry)

The next up is the EU2000 its 12v DC output is the same but the AC amps is 16.7. it runs 15 hours on a gal. It weighs in at 47 lbs.

Instead if we ran the AC current into our own battery charger we could get better amps at higher voltages.

My thinking has been when I do my next bike I might get a trike and put the generator in the back. If I can go 20 mph with a little pedaling then 8.3 hrs X 20 = 166 mi at 276 mpg

this would make a bike hybrid to compete with the Prius.

An existing generator seems to me to a better "plug and play" then cobbling something together, though, that sounds like fun also.

If you were going cross country then a generator could also be used to run the lights at your campsite

I prefer the idea of a steam driven generator

STUART TURNER
Generator Set
Single cylinder enclosed vertical engine, c1940's.
Belt driven 25/35 Volt dynamo.
Designed to produce 750 Watts @ 1200 r.p.m.

After a bit more thought, the honda EU 1000 specs out quite a bit better than my honda, which now that I think about it, may be from the 80's, I bought it used. The problem with the one i have laying around is basicly weight, It's pretty dang heavy. And it may be able to run a much bigger 36 volt charger than the biggest one I own. I really don't know, All I know is it puts out 700 watts continuous and 800 surge. If that would run a 36 volt 10 amp charger, you just might be able to get down the road, though not too fast on that. Its a good idea, but maybe not so hot with the junk I have laying around. My 3500 watt genset and a golf cart charger would do the trick though! But then I'd be carrying at least 200 pounds of weight. Maybe I could put wheels on the generator and tow it.

It would still pollute about the same as ten of my subaru though. That is the rub with all the serial hybrids in my opinion, more than anything else. An ethanol burning superlight generator that puts out 48 volts is what we need. I may just put my gennie on the trike with my 4 amp charger this weekend and try it. If I do, I'll post how it goes here. All I'll be able to measure is distance. If I go more than 6 miles its a winner. I think the weight is going to kill the gain of only 4 amps. I don't want to try more than one charger simultaneosly.

Miles said:

I prefer the idea of a steam driven generator

Click to expand...

Who gonna stoke the fireboxx??? :lol:

Ah ha... we can burn Oil Executives.

But they make greasy smoke.

Although using the 12V DC output of a conventional small AC generator could be made to work, you still need a DC - DC converter to step the voltage up to a level that's useful for charging the batteries, plus the DC out from these small generators is low, typically only around 100 to 150W. Using the higher power AC output to drive a conventional charger would be fine, except your then adding weight and losses to the system.

The little Honda GX22/25/31 engines weigh around 3kg or so (about 7lbs). A suitable PM motor as a generator would be around 1 to 1.5kg (2.2 to 3.3lbs). I'd guess that a complete home made genset, that would charge at maybe 600W or so, would weigh around 4.5 to 5kg (about 10 to 11lbs).

The Honda EU1000 generator mentioned weighs around 13kg (29lbs), so is about three times heavier, before you add in the weight of the charger or DC - DC converter that would also be needed.

The idea of building your own gen set (as Fechter has shown so well with his neat system, which is pretty close to what I had in mind) is that you can have a lighter unit with a much better efficiency for charging bike batteries, as you don't need to do any voltage conversion on the output. If you match the PM motor (being used as a generator) kv rating properly, then you'll end up with a DC voltage that would be right for charging. The other advantage is that, with a bit of simple switching, the motor being used as a generator might be used as an electric starter for the ICE. This opens up the possibility of building a fully autonomous hybrid system, where the ICE kicks in whenever needed to top off the battery pack. All that's needed to make such a system work is a bit of fairly straightforward control electronics to sense battery state and switch the ICE in or out as needed.

Jeremy

Hi Paul,

As Jeremy says, an RC type motor makes a good generator to drive from a glo-plug engine. They are both made to do the same job, so they are similar size and rpm. And possibly similar MTBF.

You would then have a compact method of turning liquid hydrocarbon into electricity. I say liquid hydrocarbon rather than gas/petrol as these glo-plug engines run on a mixture of methanol, nitromethane and castor oil. Even though that escapes the duty for road fuel, its still not very cheap. I don't think they are fuel efficient either. The benefit would be that its small and lightweight.

Nick

Jeremy Harris said:

...
For the generator I'd look at using a big brushless RC type motor. The big, relatively low kV models are getting to be pretty cheap now and will be fairly happy when spinning at the sort of speeds that one of these small engines operates at, so could be directly coupled (simple, cheap and lightweight). The motor will generate three phase AC, which can easily be rectified and used to drive the battery charging/motive power systems.

Click to expand...

All the ideas on this page are TOO BIG! I reckon you are much more technically savvy than me, Jeremy, but I've got to get you guys thinking much smaller! Think of the induction system in a toothbrush charger! That's the scale I'm thinking of. Now if you are climbing volcanos, then that isn't big enough, but if we think in terms of generating 15 watt hours per mile that should be doable with a very small generator, n'est-ce pas? This isn't going to REPLACE a battery, but top it up at the rate that it used for climbing the occasional hill, while using leg power to cope with loads needed for flat terrain. Now, do you get what I'm driving at? Or am I trying to defy the laws of physics again? :lol:

I agree, too big, or at least too heavy. I would never want to pack more than 50 pounds, and look how far that would take you with Lifepo4, like 65 amp hours. I'd need to give my ass a long break by then anyway even in a comfy recumbent. But somthing really light and small purring away, that would put about 2or 3 amps into your battery while you had a bite to eat, or shopped would be really cool. No skulking around trying to steal a few watts or trying to park by the plug you got permission to use. When really quick charge batteries get affordable, most folks will be able to cruise around with 6 pound batteries all day, stopping for 10 minuites here and there for a recharge. By then the quickie mart will sell you a drink and a charge.

While researching this I came across:
http://www.adaptivematerials.com/products/amie25.php
runs on propane. Haven't got dimensions yet, but I emailed them to find out.

dogman said:

When really quick charge batteries get affordable, most folks will be able to cruise around with 6 pound batteries all day, stopping for 10 minuites here and there for a recharge. By then the quickie mart will sell you a drink and a charge.

Click to expand...

MAKE IT SO!!!!!!!!

Here is a pretty cool little alternator. http://www.sullivanuav.com/home.html

...

[/quote]
All the ideas on this page are TOO BIG! I reckon you are much more technically savvy than me, Jeremy, but I've got to get you guys thinking much smaller! ...This isn't going to REPLACE a battery, but top it up at the rate that it used for climbing the occasional hill, while using leg power to cope with loads needed for flat terrain. Now, do you get what I'm driving at? Or am I trying to defy the laws of physics again? :lol:[/quote]

Hmm, interesting. Yes i think carrying around a 20lb generator that comes on 15% of the time to keep up a charge, versus a 7 pound generator that come on 40% of the time, the latter would be preferable.

In other words, quadruple my range for only doubling my weight is a nice payback.

Could this also be enabled manually on hillcimbs-- decreasing the inevitable battery drain.

At some point one approaches the human/butt endurance level, rather than the e-assist limitations; ie, ever ridden a bicycle for 3 hours without getting off for a significant break? This is not a comfortable area for the average person on a DF. But a faired 'bent could be nice.

Try this for 3 lbs and $1600, plus conversion to Propane and a high efficiency voltage converter.
http://www.fuelcellstore.com/en/pc/viewPrd.asp?idcategory=54&idproduct=1107#details

Those little engines I've mentioned aren't big at all, they are often used in model aircraft. Their advantage is that they are four stroke and run on ordinary gasoline, not fancy (and expensive) model aircraft fuel. Stripped of the fancy casings and stuff, pull start etc, they weigh around 4 to 5lbs, apparently (that's according to a model aircraft site that sells these engines see here and scroll down for the Honda 4 stroke kits: http://www.carrprecision.com/Pages/prod02.htm). Add in another couple of pounds for a suitable small motor and you have a tiny genset that might well weigh in at around the sort of weight you're looking for.

The best way to use an engine like this might be to trade off some battery capacity for the genset weight. A 36V, 10Ah LiFePO4 pack weighs about the same as a stripped down genset, so this might be the sort of trade in battery capacity needed to keep such a system weight neutral.

At a guess, I would think that the trade in range terms would be around 20 miles or so of battery range for perhaps a hundred or more miles of hybrid range.

Jeremy

Sorry, Jeremy, I got taken in by Fetcher's pic of a GX31, which doesn't weigh 4-5 lbs; it's much bigger. Even though the motor you mention might be a good proposition, I'm still wondering if one could get away with something smaller.
sxi6 has pointed to http://www.sullivanuav.com/home.html which shows devices that look of the size I'm aiming at. And they are already alternators. What do you think?

View attachment Poorus hybrid..JPG Ok guys here is some cowboy data on my Poor-us Hybrid.

800 watt honda generator weighs 55 pounds with one gallon of fuel onboard.
36 volt 4 amp charger.
12 ah 36 volt sla battery pack 33 pounds.
BD 36 hub on schwinn meridia trike.

Normal range for the trike with empty basket is 6 miles at full throttle no peadling.
I just rode 11 miles at full throttle, no peadling except to get past 5mph. More or less flat ground, equal uphill and down.
It used so little capacity of the generator that I could not hear a difference when I plugged it in.
Test completed when the low battery light stays on while riding full speed.

By cracky it sorta works! With a 10 amp charger it would really work.

Wow I'm suprised. I thought a 4 amp charger might be close to the generators limit. I'm guessing by how it sounds running that it was using only 100 watts. I sota have a feel for this by experience running different stuff, the gennie will porpise if pulling less than 100 watts and it was. A dinky 4 amp charger doubled the range, and did it packing an extra 55 pounds. Its slower for sure, like 12 to 16 mph depending on slope. and forget a big hill. Basicly it slowed the trike down to its fastest safe speed, at 25 mph it is actually pretty scary. So range increased due to less speed for sure. But nevertheless, it still was running full throttle for more than twice as much time, almost double the distance.

So you guys are definitely on to something here. My guess is if you shoot for something that will put out 8 to 10 amps of 48 volt dc and you would get down the road just about infinitely. One thing to take note of, my test took place at 95 degrees farenheight and I would not want to push my hub more than that in this weather so if you took a break every hour of riding, the battery could catch up while the hub cooled. riding like that you could get by with an even smaller gennie.

For someone wanting to just do it from avaliable stuff, look for the lightest possibe generator. You will only need about 400 watts. And a 6 to 10 amp charger that is durable enough to take the bumps. The trike is cheap, $250 at wallmart, buy it onlline and they ship it to your local store free.

Does anybody know if you can run two chargers into one battery pack at the same time?

dogman said:

Does anybody know if you can run two chargers into one battery pack at the same time?

Click to expand...

I believe identical soneil sla chargers can be paralleled.

d

Fechter's pic IS of one of these engines, the photo is deceptive. That one weighs about 7 1/2lbs I believe, complete with all the fancy casing etc. Stripped of it's casing stuff I believe that the GX31 weighs in at about 5lbs.

One of those small UAV alternators looks like a good option, but I bet they are expensive. A cheaper alternative would be to use a model aircraft electric motor run as an alternator, or perhaps as a dynamo if it's a brush type motor.

Jeremy

Miles, your comment about a steam engine reminded me of this.

Click on the steam motorcycle and follow the links to the end and there is a video to see it in action.
http://www.lindsaybks.com/gallery/Jorg/index.html