# small petrol charging motor...



## ZeffriN (Jan 7, 2008)

Has anyone considered/tried the possibility of having a small petrol motor to recharge batteries if you were ever in need.

My thought is that a small motor say from a lawnmower or whippersnipper could be mounted somewhere like the engine bay, boot, or maybe where the old petrol tank was... it holds just enough fuel to kick over for a few hours..

Idea being that if you wanted to drive the EV longer distances, you could do 500km a day on battery power which is a pretty good drive for one day, 5hours minimum with no breaks and 100km/h with no interuption, can go further on petrol sure but we do the best we can isnt it... but anyway... after my first day driving I pull into a cheap little motel where I wont have any external powerpoints and so run the little petrol motor in the back to recharge the batteries, ready to drive again tommorrow..

and going one step further I wonder if a little motor could produce enough power for highway coasting

Anyone ever seen, heard of or had this idea before... thoughts?


----------



## Mr. Sharkey (Jul 26, 2007)

No, I can't imagine that anyone has ever thought of this before.









If you are considering replacing a vehicles ICE engine, which contains effective pollution controls with a stinky, smelly, noisy lawnmower engine which spews out ten times more pollution than the original ICE while creating 1/10th of the useable power, you should apply at your local government's environmental protection agency, they need original thinkers there.

...Just kidding, but there are at least a dozen reasons that this is an awful idea. No one with a functional EV has yet made any significant progress creating a series hybrid using such "technology" (using the term loosely).


----------



## mattyd (Jan 8, 2008)

There are a few people who have used this idea. Most of them take a small, efficient diesel engine and place it in a very small, lightweight and aerodynamic trailer. You then connect the motor via a gear box to the wheels of the trailer, and the trailer pushes the car along when the batteries are running low. You can then use regenerative braking on the car to charge the batteries, or use the trailer to assist in long up hill climbs that the batteries can't sustain.

With this sort of idea you can use biodiesel fuel, get extremely long range, and can disconnect the trailer for around town trips.

An easy way to make the trailer is to get a complete front cut from a diesel car. Ensure the steering is removed and welded straight, and then weld on the appropriate tow hitch points, add in some "drive by wire" throttle type arrangements and you'll be set.

Do some searching online and you'll find a few companies with this in mind, as well as a few individuals who have made this idea work for their EV conversion.

Matt


----------



## Coley (Jul 26, 2007)

I bought a small homelite style 110 volt, generator for use when the power goes out to keep the house furnace going.

I also thought about hooking it to my electric Yugo to extend the range, but I can't really get myself to do it.

I like the pure electric car concept and the generator would be against that....


----------



## mattW (Sep 14, 2007)

The thing that convinced me about why it wouldn't work is that the engine in the car that you are converting is sized to run at the power levels required on the highway. You don't gain any energy by converting that power to electricity (in fact you lose some) so you come to realise that the most appropriate sized motor for a generator to achieve sustainable highway speeds is the engine you took out in the first place... It takes between 10-15kW to travel 100km/h (60mph) and even the biggest household generators put out about 5kW, you would get about a 50% increase in theoretical range minus the conversion losses and the additional drag of pulling a trailer meaning its just not worth the effort!


----------



## Mr. Sharkey (Jul 26, 2007)

mattyd said:


> There are a few people who have used this idea. Most of them take a small, efficient diesel engine and place it in a very small, lightweight and aerodynamic trailer. You then connect the motor via a gear box to the wheels of the trailer, and the trailer pushes the car along when the batteries are running low. You can then use regenerative braking on the car to charge the batteries, or use the trailer to assist in long up hill climbs that the batteries can't sustain.
> 
> With this sort of idea you can use biodiesel fuel, get extremely long range, and can disconnect the trailer for around town trips.
> 
> ...


What a clever idea. Too bad it would never work.


----------



## Greenflight (Sep 13, 2007)

i.e., Follow the link in his sig...


----------



## mattyd (Jan 8, 2008)

Haha, yeah, the guy who I was referring to is Mr Sharkey. To be honest, I've done so much research in "work" hours that I didn't know where to go looking for those pages I read this in.

I must say that Mr Sharkey has an amazing vehicle. I'm completely jealous. And it was reading his web pages that have helped to convince me to forgoe my petrol 4wd and replace it with a diesel model so I can make my own bio-diseil fuel for it (mostly to save money... ).


But definately take the time to read through Mr Sharkey's pages. At the very least there are some amusing tales of his adventures as he camps out in caravan parks, drives through forest fires, swaps out head gaskets and slowly does up his electric rabbit.


----------



## ZeffriN (Jan 7, 2008)

Ok so the motor uses far too much power for a small generator to keep up with, I think thats fine..

The point is not to use the generator often, the point is just to make overnight recharging possible on long trips when no other source is available..

I'll have to check out that provided link, thanks for that..

and as for the ribbing saying I should apply at the environmental agency... I can deal with burning something on the rare occassion, maybe once a year, that I take a long distance trip (1400km to Sydney)... maybe biodiesel or 100% ethanol engine would be best.

I think there needs to be a realisation on both sides of the fence in regards to electric vehicles. Sure, most commuters doing their day to day travel would be well serviced by an electric vehicle and in fact most of those people might ultimately find more benefit in electric if they'd try it, however... There are certain industries/situations where electric powered vehicles aren't viable at this time, unfortunate as this is.. And in example I point one towards prime movers. We simply cannot provide the power and range needed to transport goods interstate at the rate at which those trucks must work, just in order to cover their registration costs.

I want to have an electric car, partly because of the environmental benefits and partly because I believe battery costs will fall dramatically over the next few years anyway meaning total running costs will fall below that of a petrol engine, especially considering oil looks to continue rising..

However, if burning something means I can use said electric car to make the 1400km journey to sydney by all means I'll do it  Although like I say, I'd definately prefer to be burning a renewable energy such as ethanol and I'd be only doing it rarely anyway.

Thanks for feedbacks though, does anyone here know off hand the math to figure out how long 850W generator would take to recharge a 'normal' EV. I mean, I don't know whats the average capacity people are loading into their EVs but whatever that average is, I wonder how long would a small generator around 850W take to recharge it?

Thanks all!


----------



## Mr. Sharkey (Jul 26, 2007)

As I said there are a lot of reasons that series hybrid is a bad idea, not the least of which is efficiency. There's more reading out there, so I won’t concentrate on that for now.

Small engines are notoriously inefficient, create loads more pollution than a normal vehicle's ICE, and don't have very good longevity. A typical small horsepower engine will have a life expectancy in the several-hundred-of-hours range before it's time for a rebuild. Better quality small engines my go into a thousand or two hours before they're knackered.

To directly answer your last question, I'll use my own EV as an example. (All distances are in miles, convert to km yourself)

A day of shopping, bill paying and work results in a mileage of 30 miles.

My car gets 2 miles per kilowatt hour = 15KwH, or 15,000 watt hours.

Your hypothetical generator is rated at 850 watts. 15,000/850 = 17.6 hours.

But wait, lead acid batteries are only 80% efficient so 17.6*1.2 = 21.1 hours.

In the real world, a 850 watt generator will only put out about 600 watts when charging batteries due to power factor, recalculating: 15,000/600 = 25*1.2 = 30 hours.

How much fuel will that small generator consume while running 30 hours? If it's more than one gallon, then you'd be better off sticking with an ICE.

Yes, you are proposing this so that you can use an EV for your daily use and the generator for special uses, so a bit less mileage is acceptable. But it's a lot of complexity to get from point A to point B. If you had no other choice, of course you'd do it, it would take a long time, still consume resources, and produce excess pollution.

I keep a couple of ICE vehicles for this reason. They cost more to register and insure, and don't have the zero petroleum fuel appeal of the EV, but they are the appropriate choice when it's necessary to travel distances in excess of what the EV is capable of. I don't even use my hybrid trailer for such travel unless there is a need to have the EV at the distant location, a car show, renewable energy event, etc. It just makes more sense to use conventional transportation when an EV is not a logical choice.


----------



## ZeffriN (Jan 7, 2008)

Indeed 17 hours is too long even let alone 21-30.. the trailer is a good idea for when you do shows nice one

Ah well no matter, I guess I will need to use a different car to make the interstate trip, its not like I go often anyway, infact I haven't been in the last 2 years at all :\ My friends and family probably can't remember me hehehe

Thanks for the infos, much appreciated.. I'm trying to get a good feel for whats possible and not now so that I can form more solid plans in my mind.

Good news is I'm starting a new job on monday which should provide enough income to start saving for an EV build.. probably take me at least 6 months to a year but still, at least I'm moving toward my target!


----------



## mattW (Sep 14, 2007)

If the trip is annual and not too long it is probably better off insurance and rego wise to just hire really efficient highway cruiser for that trip. I can't believe you drive to Sydney, that is a huge! Grats on the new job and I hope all the plans go well.


----------



## ZeffriN (Jan 7, 2008)

Thanks Matt

Sydney trip isn't so bad... I do one day from 5-6am stopping for breakky, lunch, and sometimes afternoon rest to land at Coff's in time to check-in at Formula F1 cheapy hotel... grab some sleep and set out early next morning to do it all again... arrive in Sydney that evening.

It is a long drive but it's not that bad, I've only done it once without a passenger though and surprisingly time went by much faster 

I think you're right though, rego and insurance is a killer... these days it'd probably work out about the same cost to just fly down on a cheap flight and rent a car while im there


----------



## Dan Frederiksen (Jul 26, 2007)

well Mr Sharkey, as for the viability of a pusher trailer, J. B. Straubel did just that. he's the current chief technical officer at Tesla motors.

personally I think a pusher trailer is a dreadful design but it can apparently work.

as for series hybrid in general I think you are quite wrong on that too. so much so that this is the design you will see all cars use in the future. The Chevrolet Volt will use this configuration.
as for efficiency, having it as a generator means you can use the motor at its most efficient point rather than using it directly to drive. 

many have thought of having an onboard generator for extending range. it has recently been called a range extended ev or REEV.
and it is a good design.
I would look into motorcycle motors or even scooters as donors. I figure if you can get 10kW it can be enough for a 'normal' car to run 100km/h. and it doesn't have to live forever. hopefully it would only rarely be used. 

I'm not sure about optimal generator design but maybe the Etek PM motor can be used in combination with a not dreadful 250cc motorcycle motor


----------



## Mr. Sharkey (Jul 26, 2007)

Dan Frederiksen said:


> well Mr Sharkey, as for the viability of a pusher trailer .... it can apparently work.


Bah! Crackpot idea! Trying to push an EV from behind with a single point trailer hitch will result in extreme instability that would cause the tow vehicle to get all squirrely and crash into a ditch and overturn in flames, causing the death of the driver and serious injuries to any witnesses. Death trap on wheels.


----------



## mattyd (Jan 8, 2008)

Dan, I think you'll find that Mr Sharkey is being quite sarcastic. If you have a look at his web-links in each of his posts, you'll find that he actually designed a trailer-pusher many years ago - and it worked quite well pushing his little EV car along on longer trips.

So while I don't know him personally, I would suspect that he is just being humourously sarchastic.

Mattyd


----------



## Dan Frederiksen (Jul 26, 2007)

ok. you need to work on your comic timing then Mr Sharkey. holding a position with a straight face message after message is not the way to go..

maybe you thought everyone knew your pusher trailer, I don't know.


and while it probably could be made more safe than it sounds I would not go with a pusher trailer.
rather a motorcycle motor generator as a series config. I think as little as 10-15kW can work in a good glider. especially if not based on 400kg of batteries


----------



## BenNelson (Jul 27, 2007)

I still say that the easiest way to go is have a seperate ICE and EV vehicle. Just use the EV for all the normal, local trips, and the ICE car for long-trips and out-of-town.

Depending on what your travel patterns are, it might even make sense just to rent a gasser every once in a while.

That said, I think experimenting is also quite fun. I am a little afraid of pusher trailers, but apparently they work fine.


----------



## Mr. Sharkey (Jul 26, 2007)

Pusher trailers. Feh. anybody who belives that is a moonbat tinfoil hat wannbe.


----------



## Dan Frederiksen (Jul 26, 2007)

don't quit your day job Sharkey


----------



## Mr. Sharkey (Jul 26, 2007)

No problem there Dan, I'm retired, I have lots and lots of free time to make fun of myself on forums just to upset people like you for no apparently recognizable reason...


----------



## Greenflight (Sep 13, 2007)

Well, for the record, I'm almost falling out of my chair laughing every time I read new posts...


----------



## xrotaryguy (Jul 26, 2007)

sorry to dig up a dead thread, but I just thought that I'd add my research into the mix. I have been tentatively planning on an EV with a range extender. I don't think that the previous poster's 10kwh would work for a normal car. Close though. The EV that I was planning was a Ford Escort and to keep it chugging along at 60mph I would have needed a 15kw generator. I looked at some generators on line, and they are relatively affordable. I am going from memory here, but I seem to recall calculating that one generator could run on 10 gallons of gasoline for 6 hours. At 60mph, that would be 360 miles. That's almost exactly the efficiency of 5 speed gasser Escort. So, not much would be gained on long trips, but the car would still be super affordable around town and would have the added advantage of extended range just in case. As for finding a place on-board an Escort wagon... heh... dunno about that one.


----------



## simy (Jan 26, 2008)

xrotaryguy said:


> I am going from memory here, but I seem to recall calculating that one generator could run on 10 gallons of gasoline for 6 hours. At 60mph, that would be 360 miles. That's almost exactly the efficiency of 5 speed gasser Escort. So, not much would be gained on long trips, but the car would still be super affordable around town and would have the added advantage of extended range just in case.




Did you take into account the generators fuel usage at full output? Ive seen sombody that took a standby/idle time of a generator under no load, and tout 100+ mpg 

Youve also got to consider the weight, rolling resistance, and drag of a trailer (or anything attacked/affixed to the vehile -- temp or perm attached dosnt really matter, if its on, its slowing you down.)

Just my .02 

ps: For the record I did a quick google on some gizmo-gadget that increases your milage XX percent. I think it was one of those hydrogen bubblers, touted 100+ mpg again... But that was assuming you could use electrolisys or hydrolisys at max efficency, and that no (eletrical/physical) power is being used to make it  (Its worth noting Ive used one of these, did get slightly better milage! -- then I wanted an eletric  )


----------



## xrotaryguy (Jul 26, 2007)

simy said:


> Did you take into account the generators fuel usage at full output?


I actually used the continuous usage number supplied by the manufacturer.



> Ive seen sombody that took a standby/idle time of a generator under no load, and tout 100+ mpg


Kinda silly  I geuss with fewer batteries and a smaller motor/lighter car, this could be possible, but then that could be accomplished with just about any underpowered teeny tiny car with just about any drivetrain (outside of a rotary motor of course  )



> Youve also got to consider the weight, rolling resistance, and drag of a trailer (or anything attacked/affixed to the vehile -- temp or perm attached dosnt really matter, if its on, its slowing you down.)


I took into account the weight of the generator in as much as realizing that mounting a generator inside of a Ford Escort wagon that was already laiden with a dozen lead acid batteries was probably a bad idea. To be honest, I don't recall if I calculated the additional weight of the generator when performing efficiency calculations. Again, I planned on having the generator on board. I would probably not keep the generator in its original chassis as it would probably not fit in the car well in that form. I could perhaps use a portion of the Ford's tank and use its fuel pump to supply the generator and then mount the generator motor and generator elsewhere in the car. 

If a trailer were used then mileage would go down big time on the freeway, which is the most likely place where such a thing would be used. Then again, using the heavy 1/3rd of a vw rabbit as a trailer isn't going to provide the efficiency of a gasser rabbit either. I don't think that either design is ideal. For the record, when GM was showing its EV1 around the country, they pulled a trailer with a generator mounted on it to get from city to city.

Another problem with a generator is that it is essentially adding a second large electric motor to the car. Using the traction motor for recharge would be better. I think that Toyota calls this configuration a Prius.  Actually, I did see one design that placed a golf cart axle where the drive shaft of a Model A ford would usually reside. The differential served essentially the same purpose as the planetary set in a Prius. Neat cheap design for a small car. As long as the electric motor and drive train are incapable of turning the IC motor, the design would not even need any kind of flywheel brake. 



> ps: For the record I did a quick google on some gizmo-gadget that increases your milage XX percent. I think it was one of those hydrogen bubblers, touted 100+ mpg again... But that was assuming you could use electrolisys or hydrolisys at max efficency, and that no (eletrical/physical) power is being used to make it  (Its worth noting Ive used one of these, did get slightly better milage! -- then I wanted an eletric  )


too bad hydrogen storage takes up so much space. Otherwise, making hydrogen on board from the grid and off peak when the batteries are full would be neat. The hydrogen could be run through a fuel cell (chaching! $$$) which could be as much as 60% efficient, or through an IC motor at 23% efficiency powering the wheels or a generator. Unfortunately, a plug-in electric is already heavy enough and strapped for space to the point that these ideas are probably impossible.


----------



## simy (Jan 26, 2008)

Bout the hydrogen, Youve got a good point there... I'm gona look into suspension eventually, and I hope to have some space, somewhere...

Sounds like youve got all your ducks in a row, and you seem to know about the drawbacks, and are ok with that... Let me know how it goes, I'ld be very intrested in your milage... 

Speaking of gas, I had to coast to my house just about 1/2 the way to have enough gas to get into the driveway ( Crossing fingers that I make it to a gas station later in the week...

Best of luck to ya though, Gota love how intresting these projects all turn out to be! I hope mine isnt uneventfull but isnt costly eigther =)


----------



## sharp21 (Mar 11, 2008)

Hi gang, this is my first post & ill introduce myself in another thread, but this is the subject that I was looking for when I joined the forum!
Im planning an s10 build & was reading the article on Truck Aerodynamics in the Performance forum. In it, it says something to the effect that if you have an aerodynamic trailer behind an aerodynamically inefficient truck, it can improve your MPG by evening out the airflow.
Here is a link to the page:
http://www.evworld.com/article.cfm?archive=1&storyid=870&first=6362&end=6361
S.


----------

