# Adding gas powered generator to an ev



## subliminalrich (May 11, 2011)

Okay I'm totally new to this site, so bear with me a little. Maybe this has been answered a thousand times before, but if so, I haven't found it yet.

I've got a 1978 VW Van. Its a Westfalia with the pop top, sink, etc. It doesn't run, and I'm thinking rather than spending the money to restore it to it's original condition, I can spend about the same amount to convert it to an ev. I'm looking at using the warp9 motor as I've seen others do with their typeII buses. The consensus is that I'm only going to get about 50 miles per charge. That's fine as a daily driver for me, but I really want the _option_ to take it on an occasional trip. I've seen several threads where people say it is not feasable to extend range with a gas powered generator because it would only about provide 1/4 of the wattage needed to charge if you tried to run it while you were on the highway. Assuming that we are using about 10-14kw on the highway (maybe at 55mph) and most generators only produce about 2.6kw, seems like it wouldn't really work out.

But then I found a honda generator that produces 11.7kw continuously. It's not really terribly large or heavy, it claims to run off of gasoline, propane, or natural gas, and it claims to use only 1.4 gallons per hour at full load. It's a little pricey at $3000, but seems like it could be worth it in the long run. Here it is:
http://www.generatorsales.com/order/H11000E5.asp?page=H11000E5

The math suggests that if I could make it 50 miles in one hour and the generator only burned 1.4 gallons, that's theoretically 35 mpg. And even if it were less, it would be much better efficiency than the original ice in the van. I would have 3 options on a fuel source for the generator, which is kind of cool. Plus, I'd still be able to run around town without using the gen at all. In fact, there would be no need to cart it around unless I was planning to go further than my batteries could carry me. But I'm not so optimistic to think that everything will work out exactly as I envision. So basically, I want to know what would be wrong with such a set up??

Thanks in advance everyone!


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## DIYguy (Sep 18, 2008)

There are a few threads on this. His is one that I commented on (Comment #14 or 15 I think). 
http://www.diyelectriccar.com/forums/showthread.php/generator-controlleri-56966p2.html


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## normalmitra (May 11, 2011)

I sure am glad you asked this. I'm also curious...

If you were to take a 25hp Briggs & Stratton motor, connect it to a Lynch motor (or similar), add a diode and plug it into your charger, would your batteries get 19kW (approx.) ?

That would potentially give you a nice compact generator at around 85lbs - easy to put on a trailer or even on one of those hitch buddy racks.

The engines are easy to find at $500, a Lynch is $1500, but other options are in the $500-800 range. A Harbor Freight light utility trailer is $200. I think that a $1200 range extender has appeal.

Is it really that easy, or am I missing something?


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## aeroscott (Jan 5, 2008)

normalmitra said:


> I sure am glad you asked this. I'm also curious...
> 
> If you were to take a 25hp Briggs & Stratton motor, connect it to a Lynch motor (or similar), add a diode and plug it into your charger, would your batteries get 19kW (approx.) ?
> 
> ...


good idea, pm motors work .how about a 3 cylinder geo metro engine ( cheap, certified )


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## frodus (Apr 12, 2008)

an agni/mars/PMG won't run continuously at that sort of power, and still not very high without forced air cooling.

Even then, your charger would need to take in a DC input, at a fairly low voltage (48V-72V). These motors won't go much over 5krpm if that, and even then, the motor output would be about 60-70VDC.

could use a 48V system and a solar inverter, but still, why convert mechanical, to electrical, electrical DC to electrical AC, then back to mechanical. Just build an engine that pushes...... its more efficient.


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## MN Driver (Sep 29, 2009)

I agree that an engine that pushes is ideal if you are carrying a trailer.

...if you insist on a generator I did some searching for larger generators. I found this site on Google so I can't vouch for it.

15kw
http://www.electricgeneratorsdirect.com/Generac-5734-Portable-Generator/p2683.html
17.5kw
http://www.electricgeneratorsdirect.com/Generac-5735-Portable-Generator/p2685.html

It's cheap but its going to be LOUD! My experience from seeing construction sites with Generacs of a smaller size is that they are loud. I'm not sure how loud that sounds when near it but is 60% louder than a Honda EU6500iS, which is a 5500kw continuous generator. Too bad you can't gang two of these 5.5kw together as that would be about the quietest option. Two, using two isolated chargers would work but at $4500 per generator plus compatible chargers to use, the best option is expensive. I'll take my gas car when required, its cheap enough to keep the insurance for a second car, I know people paying more for the registration and insurance on one car than I am for both of mine.

I had the thought of using the 6kw $600(when on sale) Harbor Freight generators but can't fathom the noise level thoughts involved with two running, if I can keep them running before they turn into another hammer like other Harbor Freight stuff I've used. I just don't have a use for a hammer that big though. -Sorry, off-topic rant.


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## DIYguy (Sep 18, 2008)

I find this topic to be a bit of a slippery slope. The more you think about it, the more you want to do it. . . but the more experience you have with it.... the less you want to do it. Some things you just have to try yourself. 

Couple of points to consider.... when looking into this, it's easy to get lured into an inexpensive genset. Just remember, if you really do actually end up doing this for any length of time.... you need one that is going to last. After all, you are going to driving around all the time with this thing running. Many hours of service. Get one that will make the journey.
Next, is the noise thing. I had this vision of a small Honda sitting there making little if any noise. NOT. Just Google generator noise etc.... and you will see that there are a ton of ppl trying to make these things quiet and I learned that it is not the muffler. A new Honda, has a pretty darn good muffler. There may be a few gains to be had, but not what you might think. There is a ton of noise coming from the rest of the generator. I didn't buy a cheap one, but I'd be willing to bet they are louder than a good one with a Honda engine. 
I ended up spending a couple grand on this idea. I also planned from the beginning to have a 240V capable charger that matched the output from the genset I wanted to use. I had a need for a backup power plant for my house anyways so, I justified it this way. That said, if I had forgone the genset and the lead-acid, I would have had half the money needed for the lithium.  (which is where I am now at anyways) lol


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## normalmitra (May 11, 2011)

So is there commercial possibility for a trailer mounted genset? It could even be dual purpose - home power backup/range extender.

I envision a liquid cooled motorcycle (250cc) engine connected to a liquid cooled Bus/RV alternator (or three, or a custom high output alternator). Mount that to a light utility trailer, add electronics to control engine speed, power output, etc... The trailer would then connect to the battery charger. 

Or i could use an ac generator head and have it connect directly to the charging inlet on the car. Can the cars electronics handle this?

Sorry if my inexperience is taking me down an impossible path, I'm passionate if not very knowledgeable.


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