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Old 07-24-2011, 09:16 PM   #121 (permalink)
home of the odd vehicles
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Join Date: Jun 2008
Location: Somewhere in WI
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Originally Posted by Nerys View Post
yeah well this is NJ not some sane portion of the country. if a NJ cop see's me going buy on an electric hybrid bike doing 45-50mph with an aeroshell he is going to pull me over and the ticket/fight is harsh in NJ.
Around here if you encounter that you just go over their head to the state DOT, get a handbook and register your 25+ year old car as a hobbiest vehicle. Cop gives issues explain ignore and go to court if need be.

Problem solved.
As for genset
Slow-Turning 5 kW Yanmar Diesel Generator

Get that jobber in a 48v head, it looks quite promising.

I ran through the calculations, my system voltage under load varies from 46-52v in NORMAL circumstances, if the DC head would be wound to operate in the 50-90% load in that region (thus offsetting more than enough at lower speeds or 90+% of my usage at max speed)
(my batteries will output 10 amps for 21hours so I doubt I would run out of juice)

My MPG would be about 90-94mpg steady state.

My example vehicle is a 2005 Miles ZX40 that weighs in at 2400lbs (without Me and cargo) It draws about 65amps (with me, two others and cargo) if my top speed reaches 28mph (it usually is better), and about 95amps with field reduction once it reaches 35mph. I occasionally do better, if my batteries are freshly charged I reach 36/37mph and draw 90 amps or 30mph @ 55amps w/out field reduction.

Running through the math for the real world fuel usage of the genset and the real world amp usage of my car I end up in the 90mpg plus area at steady state.

I am not saying that I couldn't do this if my car were to come as a diesel from factory with hypermiling but I believe if I wanted to make due that isn't bad plus it is probably easier.

A good thing to remember is that when accelerating I try to draw 50amps as long as possible moving up to a max of 125amps if I am in more of a hurry.
So I don't think I would overtax or drain my batteries easily.

I think anyone who already owns an EV and knows its energy usage at different speeds, can get an info sheet for a genset that lists its fuel consumption at different wattage levels. This can give a fairly good real world estimation because besides the wire losses a decent DC rewind would only output exactly what you need so the battery loss would be minimized and the genset load levels are shown on the fac sheet.

But even if the genset were to only be charging batteries my EV would still get at least 45mpg (however) my batteries are low resistance gel type that have a very high charge efficiency for lead and at low SOC charge at about 80-90% EFF depending on charge rate according to the data sheet. The charge eff drops to about 75% at about 80% SOC.

My guess is smaller cars that aren't real aero will probably look decent FE wise at the low speeds on a decent diesel genset, the bigger cars at higher speeds will probably look rather lackluster but we would only know if you have the amp draw and wattage needed to drive a speed and compare to a genset like the one I linked that provides its fuel econsumption at a given wattage. The trouble would be finding DC genset heads.


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