Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Can I use a GENERATOR to power an Electric car directly?

Nerys · 06-14-2009, 11:46 PM

I assumed 60mph and I used EV1 data because thats the only usable real world example I have. and I did specify and ev1 like vehicle.

Watts is watts. that generator WILL produce 27,500 watts in 11 hours AFTER losses. Battery charging of NIMH is close to 90% IIRC.

I ignored speed because it varies. I assumed a consistant 60mph.

I used that figure because THATS the figure GM used. $1 in E for 100 miles. $1 in E is about 8000 watts. So thats the figure I use. As I noted the RAV4EV uses something more like 10,000 watts per 100 miles (heavier and draggier)

Conversion of energy from generator output to wheels turning is 89% efficient. (86% for lithium as some of the power is used for COOLING the battery pack)

100mph is not legal and I will never go that fast in my commuter so I don't really care what the power consumption is at 100mph

Your example of 20% mechnical 80% heat has a major flaw.

that total of 100% is NOT 100% of the energy in gasoline. that is 100% of the gasoline that gets converted to usable energy.

OF THAT energy 20% is mechanical 80% is heat.

We only extract maybe 5-10% of the total energy in gasoline. so its 20% of that 5% 80% of that 5% Thats where i came up with my guess of 2% assuming 10% total extraction and 20% efficiency at using that 10% for an actual efficiency of 2%

My time figure again comes from the fact that the generator will evenly generator that much power over 11 hours so IN REALITY it will in fact generate about 2500 usable output watts PER HOUR regardless of my speed.

I assumed 60mph so 1 hours per 60 miles. As you can see this presents a problem for while the generator can produce enough power to go 340 miles it will take 11 hours to DO THAT.

at 60mph I will reach 340 miles in 5.6 hours at 60mph. But in that 5.6 hours I will have only gotten 14,000 watts from the generator so far.

so while the generator has the power it does not have the ON DEMAND power needed. I would need something TWICE as large (ie a 10,000watt generator so I could get 5000 watts at 50% load for best efficiency)

Thats where I came up with my time energy and watt values. I apologize for not making that more clear.

this is why its a problem. IF I COULD AFFORD a 10,000 watt continuous rated generator I would already be able to afford to build an EV :-)

06-14-2009, 11:46 PM	#57 (permalink)
Nerys Grrr :-) Join Date: May 2008 Location: Levittown PA Posts: 800 Cherokee - '88 Jeep Cherokee 90 day: 19.44 mpg (US) Ryo-Ohki - '94 Geo Metro Xfi 90 day: 50.15 mpg (US) Vger 2 - '00 Plymouth Grand Voyager SE Ninja - '89 Geo Tracker 90 day: 30.27 mpg (US) Thanks: 12 Thanked 31 Times in 25 Posts	I assumed 60mph and I used EV1 data because thats the only usable real world example I have. and I did specify and ev1 like vehicle. Watts is watts. that generator WILL produce 27,500 watts in 11 hours AFTER losses. Battery charging of NIMH is close to 90% IIRC. I ignored speed because it varies. I assumed a consistant 60mph. I used that figure because THATS the figure GM used. $1 in E for 100 miles. $1 in E is about 8000 watts. So thats the figure I use. As I noted the RAV4EV uses something more like 10,000 watts per 100 miles (heavier and draggier) Conversion of energy from generator output to wheels turning is 89% efficient. (86% for lithium as some of the power is used for COOLING the battery pack) 100mph is not legal and I will never go that fast in my commuter so I don't really care what the power consumption is at 100mph Your example of 20% mechnical 80% heat has a major flaw. that total of 100% is NOT 100% of the energy in gasoline. that is 100% of the gasoline that gets converted to usable energy. OF THAT energy 20% is mechanical 80% is heat. We only extract maybe 5-10% of the total energy in gasoline. so its 20% of that 5% 80% of that 5% Thats where i came up with my guess of 2% assuming 10% total extraction and 20% efficiency at using that 10% for an actual efficiency of 2% My time figure again comes from the fact that the generator will evenly generator that much power over 11 hours so IN REALITY it will in fact generate about 2500 usable output watts PER HOUR regardless of my speed. I assumed 60mph so 1 hours per 60 miles. As you can see this presents a problem for while the generator can produce enough power to go 340 miles it will take 11 hours to DO THAT. at 60mph I will reach 340 miles in 5.6 hours at 60mph. But in that 5.6 hours I will have only gotten 14,000 watts from the generator so far. so while the generator has the power it does not have the ON DEMAND power needed. I would need something TWICE as large (ie a 10,000watt generator so I could get 5000 watts at 50% load for best efficiency) Thats where I came up with my time energy and watt values. I apologize for not making that more clear. this is why its a problem. IF I COULD AFFORD a 10,000 watt continuous rated generator I would already be able to afford to build an EV :-) Last edited by Nerys; 06-14-2009 at 11:54 PM..