[ausev] Small On-Board Generator

Sun Nov 25 19:35:37 GMT 2007

AC Propulsion, Inc. gave a presentation to the CARB on Range Extending using 
a generator in a trailer.
A lot of groundwork is in that document.  First, you have to use a generator 
engine that is low in emissions, if you plan to charge "on the go", making 
the EV a series (aka: serial) hybrid.

http://www.acpropulsion.com/reports/Low_Emiss_Range_Ext.pdf
Since I have a daily round-trip commute of 72 miles, this discussion 
interests me.

John in Seguin

----- Original Message ----- 
From: "Chris Robison" <chris at ohmbre.org>
To: "AustinEV News Announcements and General Discussion" 
<ausev at austinev.org>
Sent: Sunday, November 25, 2007 11:15 AM
Subject: Re: [ausev] Small On-Board Generator

> On Sat, November 24, 2007 9:53 pm, Sarah & Erik wrote:
>
>> There are a couple new things to take a look at before you use a
>> generator to run your EV. Generators can have messy electrical outputs
>> that can fry your charger (unless you can get one to straight DC
>> output which is great, but hard to find off the shelf). They can have
>> voltage spikes or not a true sine wave which your charger counts on.
>> Some are fine, you just have to check.
>
> I recall a Manzanita PFC charger getting toasted by a cheap generator. A
> while back, don't remember details (make, model etc)
>
>
>> Some generators are really
>> nasty smelling too - I understand Honda generators run fairly clean. A
>> cheap generator can put out the emissions of dozens of cars in a short
>> time.
>
> One of the reasons I feel that Wilderness EV's promotion of small
> generators is highly irresponsible is that in reality, *all* generators
> are this way, because the laws that govern their production and sale don't
> have the same requirements for emissions. There are no catalytic
> converters or decent mufflers, there are no EGR valves or evaporative
> emissions systems (charcoal canisters, etc) or control computers on small
> generators -- and no manufacturer will add these components until they're
> forced to. Like any appliance employing a small gas engine, they put out
> orders of magnitude more non-CO2 emissions than cars sold today.
>
>> Another thing is that if you have a generator powerful enough to
>> keep you driving for a while you need to keep an eye on your motor
>> temperature. My motor can get pretty warm in the summer after a run,
>> but I only go so far at once.
>
> True. EV motors are rated for continuous horsepower, and the short range
> of most EVs means you can in most cases ignore these ratings.  As your
> range increases by way of lithium batteries or auxiliary generators, you
> have to size your motor at least to the average power required for the
> maximum speed you want to drive, or increase the motor's rating by adding
> forced air cooling. Not a dealbreaker, but something to consider.
>
>
>> understand the concern about running out of juice. It takes a pretty
>> stout generator though to be useful for anything but a true emergency
>> and those get heavy. One of the handheld ones will take a good while
>> to charge you up full.
>
> Consider the numbers. It takes somewhere in the neighborhood of 20hp to
> keep a small vehicle going at 55-60mph depending on aerodynamics, tire
> rolling resistance, brake drag, etc -- as a convenient rule of thumb, this
> ends up amounting to somewhere around 20kW minus motor and drivetrain
> losses. 20kW is a big generator; you'll likely not find one with a small
> gas engine. I've seen one up to 15kW, and that wouldn't fit in most cars.
> Some time ago Northern Tool used to sell a huge 20kW generator head which
> would be adequate, but at full output it required a 50hp engine, which
> puts you in motorcycle or small car engine territory. That's a lot of
> weight, which means you need a trailer and a bigger motor.
>
> The sensible (but difficult) way to do this is to custom engineer an
> engine and generator to spin at crazy speeds, so you win the battle with
> RPM instead of engine displacement and generator size. Capstone
> microturbines were one example of this, and I believe that GM may be
> working in that direction for the Volt. AC Propulsion ran a horizontally
> mounted twin cylinder Kawasaki motorcycle engine at very high speed
> (10,000+ rpm) for their experimental Long Ranger trailer. Something you
> can't even find mentioned on their site today, though they have some
> archive pictures that show it.
>
>  --chris
>
>
>
>
>>
>> Erik
>>
>> On Nov 24, 2007 6:55 PM, John Penry at Texrocks <jpenry at texrocks.com>
>> wrote:
>>>
>>> I ran across a website a while back that listed some common gas
>>> generators.
>>> http://www.e-volks.com/hybridconversion.html
>>> Beware of the noise and emissions created by these.
>>>
>>> John in Seguin
>>>
>>>
>>>
>>> ----- Original Message -----
>>> From: Casey Martinez
>>> To: ausev at austinev.org
>>> Sent: Saturday, November 24, 2007 8:23 AM
>>> Subject: [ausev] Small On-Board Generator
>>>
>>> Dear EVers,
>>>
>>> I am in the market to buy an EV soon and I would like to know if there
>>> are
>>> any for sale that this group may know about. I am considering all
>>> options
>>> right now.
>>>
>>> Also, how practical would it be to keep a small generator in the trunk
>>> of my
>>> future EV so that when my batteries are low on juice I could stop and
>>> get
>>> some hydrocarbons and charge my battery bank? I understand the charge
>>> may
>>> take some time and that it would be stupid to store liquid fuel on board
>>> due
>>> to weight factors but I wanted to hear what this group would have to say
>>> about this idea.
>>>
>>> Thanks everyone for reading and have a happy holiday season. I have
>>> enjoyed
>>> reading these messages over the last year or so and I look forward to
>>> seeing
>>> yall at the Sustain A Ball on the first.
>>>
>>> Sincerely,
>>>
>>> Casey Martinez
>>> 512-797-7518
>>>
>>>
>>> ________________________________
>>>
>>>
>>> _______________________________________________
>>> AusEV mailing list
>>> AusEV at austinev.org
>>> http://www.austinev.org/mailman/listinfo/ausev
>>>
>>>
>>>
>>> _______________________________________________
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>>>
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