04-11-2012, 12:29 AM
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#11 (permalink)
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Go with as high of voltage as you can if you're trying to make a highway capable vehicle. The less voltage you have the more amps you're going to need to pull and the greater the peukert effect which even lithium is effected by. That all adds up to less range and less battery life. You also have to take into consideration hills which require quite a bit more power to go up than just cruising on a flat road.
You can definitely hypermile an EV, just not to the extent you can with a ICE powered vehicle. There is less inefficiency in the system, so there is less to take out. Basically the faster you go in an EV the more wh/mile you're going to pull period. The only exception will be if you're mashing your brakes in town a lot. Regenerative braking will negate this to some extent but its not nearly 100% efficient, so you're still loosing power by using it.
There is such a thing as regenerative shocks, however I don't believe they're readily (perhaps not even commercially) available.
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04-11-2012, 12:40 AM
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#12 (permalink)
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Add it all up and then see if getting a room makes more sense.
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04-11-2012, 01:24 AM
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#13 (permalink)
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Master EcoModder
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The faster you go the more watts per mile you will use, part of the reason that gas cars get lousy mileage in town is the starting and stopping and the sitting with the engine running while the car is not moving, that is why you see the city mileage of some hybrids being higher then their highway mileage.
Is there a reason why you are living so far from school?
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04-11-2012, 02:07 AM
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#14 (permalink)
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EcoModding Lurker
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Free rent, and I go to 2 schools.
I needed a few classes before pro school and they were either not available or full...
I will be going to Oregon State full time next year (where I am currently driving to.)
Today I found cafe electric (has anyone heard of them?)
They make controllers for DIY EV's and more. I wanted to see if I could shadow or intern there, but I can't find the building
This project isn't because of my drive;
For me it's about the experience and knowledge I will gain. On a side note, I think our whole road system needs to be reworked. People are very wasteful, and I would really like to start my life trying to be self sufficient. I feel the governments of all nations are taking more and more freedoms away from us.
I figured this might be a good starting point.
It's not efficient to drive 40 miles to and from school, but I only drive 3 times a week.
I won't lie, I also drive to salem on the weekends etc because that is where my girlfriend lives. (about 60 miles away)
I can recharge there and also at my house.
At my other school in Eugene, they do have charging stations, and they might have some in Corvallis too, but I am not really sure...
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04-11-2012, 02:10 AM
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#15 (permalink)
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some of the vendors I have been emailing are asking me some questions that I need to pass along to you guys, because I do not know the answer.
"And please confirm the working current and peak current you want, thank you.
We have to confirm all the details so that I can show you a well performance Li-Fe battery to your project, is it?
"
could someone please explain the two currents she is speaking of?
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04-11-2012, 09:54 AM
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#16 (permalink)
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Master EcoModder
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Quote:
Originally Posted by joejoe317
"And please confirm the working current and peak current you want, thank you.
We have to confirm all the details so that I can show you a well performance Li-Fe battery to your project, is it?
"
could someone please explain the two currents she is speaking of?
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Your electric motor will draw a set number of amps while cruising, but also under acceleration it will draw more, so you want batteries that can handle that sustained output but also something that can handle a 10 second or so peak output, that peak output can also be limited by your controller.
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04-11-2012, 10:00 AM
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#17 (permalink)
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Get an electric motorcycle with the range you need and build some aero fairings to improve it's efficiency.
regards
Mech
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04-11-2012, 03:24 PM
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#18 (permalink)
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Quote:
Originally Posted by Old Mechanic
Get an electric motorcycle with the range you need and build some aero fairings to improve it's efficiency.
regards
Mech
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I have 2 things against that;
1) I was in a roll over accident.
2) I live in Oregon, it rains a lot... But you are right a motorcycle can do it.
How much would it take in batteries for a motorcycle?
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04-11-2012, 07:13 PM
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#19 (permalink)
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Master EcoModder
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Quote:
Originally Posted by joejoe317
I have 2 things against that;
1) I was in a roll over accident.
2) I live in Oregon, it rains a lot... But you are right a motorcycle can do it.
How much would it take in batteries for a motorcycle?
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I was thinking about that 6 months of rain as well, granted it's not heavy rain, but it's rain and it's annoying and cold and can get slippery on a motorcycle.
In my own research on sizing a battery for my electric motorcycle, I figure I can get 75 to 150 watt hours per mile, at 45mph 75 watt hours per mile seems to be pretty standard, so a much smaller battery pack! about $25-$50 per mile of range, where a full car is closer to $80-$120 per mile of range.
There are some decent EV charging station finder maps out there, along with EV clubs, but personally I like the idea of an EV that can handle the full range that you need in an average day, then charge mid day so you are coming home with a full charge again and if done well, this $8,000 investment in lithium batteries should last you 100,000's of miles, after all, the average person is going to spend over $275,000 in their life time on gasoline if they are getting 20mpg.
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04-19-2012, 07:06 PM
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#20 (permalink)
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Electric MG Midget
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Quote:
Originally Posted by joejoe317
some of the vendors I have been emailing are asking me some questions that I need to pass along to you guys, because I do not know the answer.
"And please confirm the working current and peak current you want, thank you.
We have to confirm all the details so that I can show you a well performance Li-Fe battery to your project, is it?
"
could someone please explain the two currents she is speaking of?
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I have been reading your post, and I think you can get the range you want with a pack at 108 volts, and 180Ah. I would recommend using the new Sinopoly cells, which are Thundersky cells under new management. I have finished converting an MG Midget that has 120 volts and 160ah Thundersky cells. I just measured my range with driving around town and 40 to 50 mph stretches at 112 miles. This was right down to 2.7 volts on the cells. Really it was the BMS saying one cell dropped below 2.7 volts. My measured range (wh/m) at 50 mph is 83 miles to 80%, or 100 miles to 2.7 volts. The currents that you need to worry about are maximum current used during acceleration. For me it is 500 amps. The cells I’ve mentioned are rated at (3C) 3X 180=540 amps for the Sinopoly, for me it is 480 amps. This is claimed for continuous current, but I wouldn’t want to do that for long. The other current would probably be peak, and that is 5C, but you wouldn’t need that. Your hyper milling techniques are perfect for an electric car, and would mean you can go with DC motor system. People who coast to a stop don’t gain much from regenerative braking. For around town range improvement, you’ll want to reduce weight. For your highway performance just use the techniques for reducing drag found on this site. The A123 cells look good at first, but containing them and hooking them up, and hooking up a BMS to that many cells will be an issue. The Sinopoly cells are easy to handle. I’m measureing 200 wh/m for my around town driving, and did measure 183 wh/m for 50 mph on a 80 deg day. My Midget weighs 2020lbs, and isn’t known for having a good Cd. I do live at 5,000 ft, so I have 15% less dense air than you do. Check out my site electricmgmidget.com. (I can't post a link yet, I have one more post to go, then I can) I have pictures and articles that you can learn from. Please feel free to ask questions, I’ll be happy to try to help out.
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