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Old 07-21-2013, 05:42 AM   #270 (permalink)
NachtRitter
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Join Date: Dec 2008
Location: Placerville, CA
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Helga - '00 Volkswagen Jetta TDI
TEAM VW AUDI Group
Diesel
90 day: 51.85 mpg (US)

Mathilde - '99 Volkswagen Eurovan Camper
90 day: 16.87 mpg (US)
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Quote:
Originally Posted by oil pan 4 View Post
I figure intentionally under sizing, or sizing it to your average power consumption would be best.
That way it can run flat out staying near its best fuel consumption per KWH any time you are going faster than say 55 to 60mph.
Then when you pull into town, stop or otherwise slow down the gen set would be putting out less power in theory, but the natural under size of the gen set would mean that its not too far out side its best FE/watt production even when you are sitting at a stop light.
Correct, you can undersize the genset... but that will limit your range and therefore falls outside our assumptions. Technically, you could undersize the pusher also, and then we'd be down a different path altogether because we'd have to agree on how far we want to go (200 miles? 400 miles?) in order to properly compare one to the other.

Quote:
Originally Posted by oil pan 4 View Post
Best of all you can turn off the gen set.
Problem I see is a lot of FWD vehicles do not recommend flat towing, which is what it would amount to if you tried to shut off your FWD drive train based push trailer and keep driving under electric power.
Should be able to turn the pusher off too... and yes, the Mk4 VWs with manual transmissions may be flat towed. Might actually be interesting to have the axles set up like a bicycle freewheel... only engage when the engine spins the axles forward... not saying that's possible, but it would be cool.

Quote:
Originally Posted by oil pan 4 View Post
What I have observed over the years with diesel generators is if you compare running them in stand by or nearly no load to running them full load fuel consumption doubles.
Then if you run them at half load fuel consumption typically goes up by about 1/3 over running idle at speed or under very light load.
The generator site that I've been linking to provides some consumption charts from no load to full load... most of them are relatively linear. Of course if you're talking about only partly loading a generator, then you'd need to get an oversized generator rather than an undersized one, and then you'd probably start noticing that you're not gaining anything from a fuel consumption perspective for a given kW output.
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