05-03-2012, 10:30 PM
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#11 (permalink)
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EcoModding Lurker
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Location: USA
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Thanks to all.
To sgtlethargic and fb_bf: I posted the same message on the DIY site, and sure enough gottdi responded. If interested, go here:
Newbie saying HI from Savannah, GA - DIY Electric Car Forums
To Ryland: I'm planning on asking if I could charge at work (I don't think it's possible). I'd still be cutting it close, though... with about a 27 mile one-way trip to work. Gottdi mentioned that using lead-acid batteries in real world driving could maybe get me a 25 mile range.
From what I've seen on evalbums.com, most people with a 144V system or less, using lead-acid, get the lower 25 - 35 mile range... but a few guys claim 60 miles or more. I find the significant difference very interesting!
It seems that I must choose to deal with the ~30 mile if I stay with the lead-acid batteries. OR wait until next year to go lithium. If I do the former, the car will be used mainly to run to the grocery store, church, friend's house, and to drive the kids around locally. Not bad, but a little bummed about not being able to drive to work. If I go with lithium, then it would be more practical. I just don't have the cash right now. How much would I be looking at for a 144V lithium system, anyway?
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05-04-2012, 12:00 AM
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#12 (permalink)
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Master EcoModder
Join Date: Jan 2008
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People in our local EV club did a group buy of GBS batteries so they got a better price and I'm not sure what that price was, but if you buy a smaller quantity of them it looks like $6,000 worth of batteries should give you around 50 miles, around $120 per mile of range that you want to drive, there are of course cheaper batteries out there, A123 system pouch batteries directly from china are almost half the price before shipping, but they also are just in plastic pouches... no hard cases and if you don't compress them then they swell and stop working, the pouches also just have flat foil tabs on top, so you would need to figure out a way to bolt cables on to them.
In comparison, quality lead acid golf cart batteries are going to cost you about $30 to $45 per mile of range that you want to drive, but to get the kind of range you are looking for you are going to need 1,600 pounds of lead acid batteries stuffed in to an 1,800 pound car! those GBS batteries are going to weigh about 5.3 pounds for each mile, lead acid... 28.9 pounds per mile of range, so when I said you would save a ton of weight I was a little off, it's only half a ton!
Figuring out how many batteries you need for a given range is easy, you make an educated guess based off what others are getting as to how many watt hours per mile range you can get, then you look at the capacity of the batteries you are looking at, lead acid don't last very long if you drain them past 50% so you cut the capacity of lead acid batteries in half so they last longer, that way you still have good range as they age as well, a common mistake that people make with lead acid is to drive to 80% depth of discharge and wear their lead acid batteries out really quick.
Most lithium batteries do just fine to 80% depth of discharge, of course shallower discharges and they are happier and could end up lasting the rest of your life, but if you drain them to 80% don't freak out like you would with lead acid batteries.
If or when you do go to talk to someone at your job about charging, remind them that it's not going to cost a lot of money, around 2 cents per mile that you drive, so for 27 miles one way $.54 per day.
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05-08-2012, 03:13 PM
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#13 (permalink)
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Electric MG Midget
Join Date: Apr 2012
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I would wait on the LiFePo4 cells. When I was considering all of this, I decided that an electric car with LiFePo4 batteries would be much more sellable if I had to sell it. What pushed me over the edge was finding a car that was already started for me. I also felt that I could cut the cost by selling my gas midget when I was done with the conversion. It worked out that I bought my electric midget with warp 9 impluse with mounting done for $400 more than what I sold my gas car for. That included $800 for shipping the car in from California. Had I started wih my car it would have cost more. If you want to do the Karmen, then it will be hard to find one already started, but there are some good deals on cars people have given up on.
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05-08-2012, 03:57 PM
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#14 (permalink)
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Master EcoModder
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I agree with fb_bf completely, if you want to build a low cost EV then find someone's project that they gave up on, a friend of mine is building an electric Nissan 300ZX that he bought for $1,000, it already had the motor adapter, battery boxes and the engine was already pulled, figured he got around $5,000 worth of car and parts for his $1,000 investment, then another $1,000 bought him a brand new motor, speed controller and some contactors from someone else's project that they gave up on because the motor was to long for the car they had in mind, so he got another $4,000 worth of brand new, high end parts leaving him leaps and bounds ahead of where he would have been if he had started from scratch.
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05-09-2012, 10:32 PM
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#16 (permalink)
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EcoModding Lurker
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Thanks for the continued feedback.
Here's the latest on my side... I spoke with my son and wife (it was actually my son's idea to take the EV conversion project on), and we decided to wait to save money for Lithium batteries. The more I read, the more I become convinced that going this route would make the vehicle more practical (and valuable, as fb_bf mentioned) in the long run.
About the donor car... good and not-so-good news. I live in a non-environmentally-friendly area, where giant, gas-guzzling trucks dominate. Walking, biking, and even less EVs are not very popular. Trying to find someone locally willing to sell an abandoned project would be a waste of time (I guess I never considered having one trucked from elsewhere). Anyway, it's too late... now the for good news.
I did find a donor car. A 1973 Karmen Ghia, in surprisingly good shape. The previous owner was going to do a full restoration on it, but changed his mind (he now wants a new Porsche). He claims to have bought it for $4,500 - but the important part is that I got it for $1,500. Not bad, I think, considering that it's in good condition. Also, almost EVERYTHING is removed from the car: engine, transmission, full interior, wiring, lights, etc. That's good and bad. On one hand, he did a lot of hard work for me. On the other hand, he went a little overboard for what I meant to do (perform the conversion). Still, the nice thing is that I can build and install my own wire harness, check for rust, etc., etc. So, more work than I originally anticipated, but my son and I talked it over before buying it, and we're committed now.
So we have plenty of work to keep us busy in the meantime, giving us time to save for the Lithium batteries.
By the way, Cd, I did follow that link and they have some awesome concept cars. Good inspiration.
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05-23-2012, 03:20 PM
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#17 (permalink)
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Electric MG Midget
Join Date: Apr 2012
Location: Colorado
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This sounds like a great start. The deal on the car is fantastic. If you start figuring out what motor and volts you'll end up using, you can as find different controllers that will work. From there keep your eys open for used parts. They don't sell for a whole lot lower than new, but you'll still save money. Once you have picked a motor, can you start with getting the adapter plate done and the motor installed. That is a big part, and taking your time on doing all of this is a good idea. Best of luck and keep us informed on how it goes.
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05-30-2012, 02:30 PM
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#18 (permalink)
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home of the odd vehicles
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Quote:
Originally Posted by nicman
Thanks. I thought it looked too optimistic... Can you or anyone comment on how to estimate the actual range for a setup like I described previously?
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How slow are you willing to go?
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