Motor size?

Do It Yourself (DIY)
21

[QUOTE=frodus;2620]actually its got 3, one ICE and 2 motors that operate differentially.

why, are you drag racing?[/QUOTE]

I have been known to drag race from time to time.

[QUOTE=frodus;2620]no, its per mile, you were right.[/QUOTE]

275WH isn’t per hour, it’s per minute, because you need that to go 1 mile, and traveling at 60MPH, you are moving 1 mile per minute. So, you need to generate 275WH/minute, or 16,500 watt hours, to travel 60MPH. Believe me, I wish it weren’t so, but it is. A generator also runs best when it is not run over half capacity, so you should ideally double the requirement for the generator. And that makes for a huge generator. Just the generator head is 38 inches by 18 inches by 22 inches, or thereabouts, way too big to fit under the hood and still have a 200HP engine to turn it.

22

I have been known to drag race from time to time.

all depends on budget and pack capacity.

275WH isn’t per hour, it’s per minute, because you need that to go 1 mile, and traveling at 60MPH, you are moving 1 mile per minute. So, you need to generate 275WH/minute, or 16,500 watt hours, to travel 60MPH. Believe me, I wish it weren’t so, but it is. A generator also runs best when it is not run over half capacity, so you should ideally double the requirement for the generator. And that makes for a huge generator. Just the generator head is 38 inches by 18 inches by 22 inches, or thereabouts, way too big to fit under the hood and still have a 200HP engine to turn it.

where did the 275 come from anyway? I thought you were talking about the 240Wh/mile specification from Tesla. Stick to one number, and preferably the correct one. Also, it IS 240Wh/mile, not minute. You can’t just start throwing miles per hour at it and expect to get the data you want. You need to get the associated units to cancel out.

On wikipedia “Dynamometer testing in August, 2007 of a Validation Prototype on the EPA combined cycle yielded a range of 221 mi (356 km) using 149 W·h/km (4.17 mi/kW·h) battery-to-wheel and 209 Wh/km (2.98 mi/kW·h) plug-to-wheel.[9][38]”

Since we want Wh/mi, its 1000/4.17, which is 239.8Wh/mile. If you had a 239W load, and ran it for an hour, it would be equivalent in power useage to what the tesla uses in one MILE.

Lets say we wanted to go 60 miles. (Average 60 miles per hour) and it takes an hour.

240Wh/Mile * 60 miles= 14,400W is what it uses in that distance over the course of an hour.

So you would need to generate 14.4kW in an hour, which is 14.4KWh. Now, yes, you could do this:

14400kWh * 60min/1hr = 240Wmin, but I’ve NEVER seen any generators rated per minute, its always per hour.

I know you went from A to Z, but again, its hard to follow when you tell me 275Wh/mile is actually minutes… that is ONLY true when you ASSUME that you’re going 60 miles in an hour. Which you only JUST said, so how would I have known?

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Sorry, no need to get touchy here. :smiley: The 275 watts came from my previous post. Yes, I failed to add specifically that the vehicle was traveling at 60MPH, was working at my regular job at the same time I was making that post, AND dealing with disappointment when I realized my error meant this was a no-go. The realization that I was figuring power needed per mile without recalculating to figure power needed per mile per hour was like finding out I’m the 25th guy in line for a case of beer. Frustrating.

I know generators are measured in KWH, it’s also recommended that no generator ever carry more than half its rated power on a continuous basis. Because of this, we’d need a generator twice as large as needed to run the motor at 60MPH. That’s a huge generator.

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Oh, sorry, I’m not meaning to be touchy, just wondering where you were getting the calculations from… it seemed all unrelated, so I kinda drew it out…

End result:

thats one HUGE f’in generator needed :slight_smile:

25

http://www.endless-sphere.com/forums/viewtopic.php?f=16&t=2264&st=0&sk=t&sd=a

might post there too :slight_smile:

26

Yup. I want to use my truck as a truck, not generator transport! Heh heh… I’m not sure what I’m going to do now. Guess I’ll just let it percolate for a bit longer, then see what other wild-hair idea I come up with. Thanks for the help.

27

Hey Telco. Where are you at with this project? I have considered doing a similar project, which is what brought me here. I would ultimately like one diesel geni and four motors (4 wheel drive w/ no tranny). This would also give me the ability for a non mechanical differential, full time 4x4 or I could even shut down to one motor at cruising speeds (depending on drag). One big difference, besides multiple motors, I’m planning on doing this in a 90-94 Ford F250 Crew Cab 8’ bed. It WILL be a truck, meant to pull a boat or work trailer( ~ 3-5k, not necessarily the original rated 12,000lbs) and primarily a daily driver for commuting.
I agree, it seems it should be possible, however, after reading your posts, my balloon is mostly deflated.
So, bottom line, did you ditch the project, or have you attempted it?