# Small gas generator for extended EV range?



## BoilerUP (Jun 24, 2008)

As a professional pilot, I know that most if not all airliners (even the smaller prop ones) have an auxiliary power unit that provides HVAC and electrical power to the aircraft when the engines are not running. Most mid-size business jets also have an APU. An APU is simply a small jet engine, usually mounted in the tail, that spins a generator. This is often used on the ground, or in the air if there is a generator problem with one of the aircraft's engines.

This got me thinking - how feasible would it be to have a small gasoline-powered generator (say 2000 watt Honda) wired into an EV to provide extended range for those times when it would be needed?

From a technical and physics standpoint, would you be able to simultaneously charge the batteries with the generator while driving the car and discharging the batteries? If you could do that, would there be a heat or battery life penalty for doing so? 

If using the generator as a charger wouldn't be feasible, would one be able to wire the generator directly into the hot wire for the electric motor, allowing it to provide the electrons for movement?

I realize either scenario would likely require a transformer and/or rectifier...I did well in collegiate physics but admittedly electrics weren't my strong suit...


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## ww321q (Mar 28, 2008)

There are some threads on series hybrids on this forum . I myself may end up doing a parallel hybrid for extended range . There has been threads on pusher trailers to . J.W.


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## hardym (Apr 2, 2008)

It is possible. I have a small 4000 watt generator, that puts out 20A at 220V. This is just barely enuf power to drive the Zivan NG-3 charger for my 144V DC Battery pack. (with ocassional circuit breaker interruptions)

Range extension is not quite the best description of use -- it's more of a survival. If I'm going somewhere with unknown distance, or I may get lost, I throw the generator in the back for range insurance.

My EVehicle only goes about 30-40 miles on a charge. The Zivan charger takes 3-4 hours to replenish the pack. So, you can get some amount of range, but you really need to pull over for a couple of hours to recharge. 

Another way to think of it is that the Zivan charger only puts out about 20-30 amps into the pack. Driving down the freeway consumes about 200A. 

Mark

http://evalbum.austinev.org/1352


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## Vwbeamer (Jun 16, 2008)

Without 2k gen set is not going to extend your range much. if my thinking is correct.

2000 watts is a little more than you get from a wall socket. Lets say it takes 6 hours to charge your pack. and that you get 40 miles range at 40 miles an hour.

So with you gen set charging for the one hour you are driving, it will be 1/6 of your normal charge time.

So it will extend your range by 1/6th or 6.6 miles. course in real life this may be more, because batteries don't charge a linear rate and the gen set is charging while you are sitting still at red lights, etc,

But, you had to carry the weight of the genset , so the extra weight will reduce your normal range some what.


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## Coley (Jul 26, 2007)

Getting lost only 40 miles from home, Hmmm

Is that with an 80 mile range (40 miles away from home), or 40 mile range (20 miles from home)?

A cell phone is a lot cheaper.....just kidding...


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## cdbldr (Feb 4, 2009)

Honda has a 1000 watt generator that only weighs 29lbs. 2000 watts for 47lbs. Less wieght than one 12v battery! While that's not much power, it will also run for 8 hours (probably at low-load) on a half gallon of gas. So let's say you're going to go someplace towards the limit of your EV range, you could park, turn on the generator, recharge for hours while you're doing whatever...

Also, and please excuse my technical idiocy, couldn't you just plug your on-board charger into the 120v outlet on the Honda, and be charging as you drive down the road to offset the drain on your battery pack?

I am all for pure EV, but if a Chevy Volt-type system like this could work on conversions, it would expand the number of people who could go EV without fear of the 5% of the time they might need longer range, be away from a plug, etc.


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## drdonh (Aug 8, 2008)

Like cdbldr discussed, my plan is to have a 2KW (1.6 KW rated)invertor style generator on board to extend range. This type of generator is relatively light and compact (and supposedly quiet), and will actually fit not bad in my trunk space. As per EV Consulting's website (http://www.evconsultinginc.com/articles/hybridizing_dc_system.html), I will just plug my charger into the genset, and hopefully get some extended range when required and with a minium of complication. The 1.4 KW charger I plan to use should pretty much max out the generator capacity, so not much point in getting a larger one, unless I get into 240V AC charging systems.

At best, this will push 10-12 amps in my 96V system. A theoretical EV calculation of my current draw at 30 MPH is around 40 Amps. So for just scooting around town, perhaps I might gain 25% more range? Actual driving conditions, with stops and such, might even improve this.

I just wonder if the charger will handle these conditions. Would "smart" chargers that monitor the pack voltage get confused by erratic voltage readings that occur with driving and charging at the same time? These invertor style generators are supposed to be good for preventing surges and have a clean output, so I'm thinking it should be safe with regard to protecting the electronics. So far, I haven't heard of anyone who as actually tried this configuration. 

Don
EV-A40.blogspot.com 

PS In adding the gas engine option, you really notice how smelly and dirty ICE technology is compared to the EV stuff.


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## PhantomPholly (Aug 20, 2008)

BoilerUP said:


> As a professional pilot, I know that most if not all airliners (even the smaller prop ones) have an auxiliary power unit that provides HVAC and electrical power to the aircraft when the engines are not running. Most mid-size business jets also have an APU. An APU is simply a small jet engine, usually mounted in the tail, that spins a generator. This is often used on the ground, or in the air if there is a generator problem with one of the aircraft's engines.
> 
> This got me thinking - how feasible would it be to have a small gasoline-powered generator (say 2000 watt Honda) wired into an EV to provide extended range for those times when it would be needed?
> 
> ...


Just man-up, convert a full-size pickup, and grab a 16Kw generator from Home Depot and put it in the rear (under a hard cover so no one knows you have it...).



What do you fly? Spent a few hours in the sim one day with a friend/instructor for a 737-200, about twice the gross of a Phantom. Boring, no guns or missiles...


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## Bowser330 (Jun 15, 2008)

drdonh said:


> Like cdbldr discussed, my plan is to have a 2KW (1.6 KW rated)invertor style generator on board to extend range. This type of generator is relatively light and compact (and supposedly quiet), and will actually fit not bad in my trunk space. As per EV Consulting's website (http://www.evconsultinginc.com/articles/hybridizing_dc_system.html), I will just plug my charger into the genset, and hopefully get some extended range when required and with a minium of complication. The 1.4 KW charger I plan to use should pretty much max out the generator capacity, so not much point in getting a larger one, unless I get into 240V AC charging systems.
> 
> At best, this will push 10-12 amps in my 96V system. A theoretical EV calculation of my current draw at 30 MPH is around 40 Amps. So for just scooting around town, perhaps I might gain 25% more range? Actual driving conditions, with stops and such, might even improve this.
> 
> ...


To really take advantage of the small genset technology we have to look into higher voltage systems....

With the correct modifications one can make an interpoled DC motor sustain up to 250V...Combine this with the fact that there are some DC controller suppliers coming out with controllers that have Max voltage at 250V.....

If it takes 20hp to move a car at 65mph...that is about 15kw...

using a 144V pack it would take 104Amps to sustain this speed...

but.....

using 250V it would take only 60Amps to sustain this speed...

Now if you were to have the 10kw genset...at 240V charge voltage, you would have about 42 Amps going into the pack...

So net cruising at 65mph, you would only be drawing 18A from the pack...

So in 1 hour you drove 65 miles and used 18AH (Net)..If you have a battery pack that is 90AH and you take it to 70%DOD, 63AH...then...

63AH/18AH = 3.5, 3.5x65miles = 227 miles per charge (to 70% DOD)

Of course the above is all calculations..but what do you see wrong with it? Looking for constructive feedback! Thanks!


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## tj4fa (May 25, 2008)

Then you probably seen a few of these laying around the old flightline. 

30Kw should get you down the road...


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## PhantomPholly (Aug 20, 2008)

Didn't those come bundled with a Solar (company, not as in "from the sun") turbine?

Man, those puppies were loud...


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## cdbldr (Feb 4, 2009)

You guys have way more technical skills and the desire to use them than I do. I wanted to keep it simple and just buy a honda 1kw generator and mount it in my trunk next to the electric motor (old beetle) and use it only as a range extender--like if I knew I had more driving than usual that day, I could start it when I left and leave it running the whole time as I drove, parked, shopped, whatever. And maybe it would give me another 30% in range or so. But then again, someone told me that for long battery life I should drain down to 50% DOD before charging, so maybe charging/discharging like this all day would hurt my battery life?


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## drdonh (Aug 8, 2008)

In the EV Performance section of this forum, there is a posting with a spreadsheet for predicting the range vrs. speed based on battery combinations and such. It has the capability to factor in an APU (i.e. an on-board generator). It is interesting to see even a modest size generator, like around 1600 Watts, can have a significant effect on range at the lower speeds. THe thread is:

http://www.diyelectriccar.com/forum...-performance-and-range-spreadsheet-26286.html

Attached is a graph using values I'm planning for my EV,m, that is, with a 1600 W genset. While this is all theoretical, and I don't expect to get 1400 km range at 20km/h, it is encourgaging to see that big boost in range.

Don
ev-a40.blogspot.com


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## dantheman77 (Aug 3, 2021)

BoilerUP said:


> As a professional pilot, I know that most if not all airliners (even the smaller prop ones) have an auxiliary power unit that provides HVAC and electrical power to the aircraft when the engines are not running. Most mid-size business jets also have an APU. An APU is simply a small jet engine, usually mounted in the tail, that spins a generator. This is often used on the ground, or in the air if there is a generator problem with one of the aircraft's engines.
> 
> This got me thinking - how feasible would it be to have a small gasoline-powered generator (say 2000 watt Honda) wired into an EV to provide extended range for those times when it would be needed?
> 
> ...


LOL


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## electro wrks (Mar 5, 2012)

If this true, it's right down there with the brain-washed people on their Covid virus death bed, getting injected with experimental drugs to try to save their sorry lives, and still refusing to take the vaccine(if they survive), because it is an experimental drug.


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