Ok, it's not like I have time to actually build one, but a couple discussions about electric cars got me to thinking. A lot of electric cars on the market wouldn't be a good fit for a long commute - I've heard of Nissan Leafs apparently running out of charge after 60 miles under non-ideal conditions, and that could get me stuck if I take the interstate. I know, the real answer would be to move closer to work, if the housing market were better.
But I've sometimes daydreamed about building a homemade electric car. I didn't exactly think the 20 hp electric Miata would be a good choice for merging onto I-285, though - if I were to build an electric car, I'd like it to be more like the Deliverator's car from Snow Crash. For those of you who haven't read the book, here's an excerpt:
Neal Stephenson's book
The Deliverator's car has enough potential energy packed into its batteries to fire a pound of bacon into the Asteroid Belt. Unlike a bimbo box or a Burb beater, the Deliverator's car unloads that power through gaping, gleaming, polished sphincters. When the Deliverator puts the hammer down, E36 M3 happens. You want to talk contact patches? Your car's tires have tiny contact patches, talk to the asphalt in four places the size of your tongue. The Deliverator's car has big sticky tires with contact patches the size of a fat lady's thighs. The Deliverator is in touch with the road, starts like a bad day, stops on a peseta.
Ok, so a battery pack that big is probably cost prohibitive, and ion thrusters are something you can really only get away with on public roads in a cyberpunk anarchy dystopia. But I am curious about whether there have been any long range (150 miles or more), fairly high powered homebuilt electrics out there, and what it took to build them.
There was a kid who built an electric S2k with A123 li-po cells - with help from his dad's wallet of course. Performance was very good, in the same ballpark as a Tesla Roadster, but so was the range.
The energy density isn't there to propel an average streetable vehicle much more than 100 miles right now. You could get lots of range with a Solar Challange-type streamliner.
There are a few new battery technologies coming up that could take a car 200 miles easily, like lithium-air batteries. Those have about the same energy density as a tank of gasoline.
Nashco
UberDork
3/31/14 12:18 p.m.
The short answer is that you can't possibly build it yourself cheaper than you can buy it. If you really wanted a project, getting a totaled OEM EV car from an insurance auction and transferring all the important bits to a first generation Honda Insight will be your best bet for a reliable, cost effective, 150+ mile commuter. I'd highly recommend a Nissan Leaf due to the simple batteries and wide availability.
Bryce
In reply to Nashco:
So there's a significant difference in an EV battery pack than a Hybrid one?
Your answer is kind of surprising, since you built a challageable Hybrid. But I also had thought that the hybrid battery packs you used would be applicable to full EV, too- which I honestly know nothing about.
alfadriver wrote:
So there's a significant difference in an EV battery pack than a Hybrid one?
I know the size of the pack is a big difference.
Nashco
UberDork
3/31/14 2:42 p.m.
alfadriver wrote:
In reply to Nashco:
So there's a significant difference in an EV battery pack than a Hybrid one?
Your answer is kind of surprising, since you built a challageable Hybrid. But I also had thought that the hybrid battery packs you used would be applicable to full EV, too- which I honestly know nothing about.
Huge difference. First and foremost, energy storage. A Prius battery has enough usable energy to allow low-medium power for short periods of time. An EV needs medium-high power for long periods of time, which has drastically different requirements. Secondly, my DIY hybrid pack build was 5 years ago when you couldn't get a wrecked Nissan Leaf or whatever...it was a very compromised solution I created to deal with the constraints I had. It required lots of manual intervention, was unreliable, wasn't as safe as I would prefer, and longevity was poor. Such is the nature of nearly free high voltage batteries! If you're talking daily driver instead of occassional hot rod, then you want a modern battery management system, charging system, electrical connectors, safety monitoring, etc. Doing this with aftermarket/DIY parts is nowhere close to the quality or cost of high volume parts that come from OEM efforts like the Nissan Leaf (etc.).
An insurance auction Nissan Leaf is less than $10,000. A non-running Honda Insight is less than $2,000. Putting the two in a garage and mating them will probably run you another $3,000 (+/- $3,000 depending on how handy you are). So, for the same price as a new Nissan Leaf or less, you would have the most efficient EV on the road with 150+ mile range. I don't believe you can do it any cheaper with a "daily driver" quality build, especially in any reasonable amount of time.
For reference, to put together enough junkyard Prius packs to have the same amount of usable energy as a Nissan Leaf would cost you something like $5000-$6000 and would weigh 50-100% more than the Nissan Leaf batteries. Add in all of the charger, powertrain, safety monitors, high voltage cables, etc. and you see what a bargain the wrecked Leaf is in comparison. That's the difference between current technology and 15 year old technology.
Bryce
Thanks! I figured it was a pipe dream, but wanted to check to see if anyone had build such a thing.
I had a joke about locomotive traction motors that had used a strikethrough tag in the original post - unfortunately, it didn't post correctly, but I do wonder if anyone's used one for an EV project.
In reply to Nashco:
Thanks, as well. I had to ask, as I recall that there were "kits" that changed many of the hybrids into plug in hybrids. I didn't read how much straight electric mileage they were getting, but was assuming it was better than nothing. But even that doesn't sound much more than nothing.
I've got less than 8 years from my hoped retirement, and honestly don't expect to really learn much before I leave.
The way I would build it on paper would use:
-Soliton 1 350 volt 1000 amp DC motor controller
- WarP 11" HV DC motor.
-2-3 Leaf salvage packs arranged in 350 Volt 180 AH configuration
-transmission adapter, wiring, charger, etc...
You are still looking at 15-20k in parts and a moderately heavy conversion because of all the batteries. The upside is you would have 300 ft lbs of torque and over 300 hp and a minimum of 120 miles of range.
A fun option would be two complete leaf or spark setups for an awd vehicle but getting the computers to do what you want is beyond most people. I would guess they spark might be easier because chevy often uses similar ecu' s on all their vehicles and people have been hacking chevy ecu' s forever.
Vigo
PowerDork
3/31/14 10:41 p.m.
My ideas for homebuilt EV stuff all have to do with dual-power or 'range-extended' type stuff. I dont seriously consider building a long range BEV for the reasons already stated.
Realizing that current technology is a limitation, and that there are two major use cases (daily short range vs occasional long range), one solution is to equip a COTS EV with a trailer hitch and extended power pigtail, to enable a tow-along energy pod for long range use.
The energy pod could be surplus Leaf salvage packs, auxiliary motor-generator set, or some hybrid of the two.
Build it on a cheap HF trailer platform, and wrap it in a low drag envelope. Suggest VERY robust security hardware to prevent the pod from theft.
Hell, I see a business model where such pods could be rented for occasional long distance use (hello U-Haul, opportunity calling).
I really need to check in with a local college that has been working on a little hybrid car. Last I saw they had just picked up a pallet of brand new Lithium batteries for laptop computers. These guy wind their own motors and have access to CNC machines and foundries and such so might be out of the typical homebuilders reach, but it is still some amazing stuff!
erohslc wrote:
Realizing that current technology is a limitation, and that there are two major use cases (daily short range vs occasional long range), one solution is to equip a COTS EV with a trailer hitch and extended power pigtail, to enable a tow-along energy pod for long range use.
The energy pod could be surplus Leaf salvage packs, auxiliary motor-generator set, or some hybrid of the two.
Build it on a cheap HF trailer platform, and wrap it in a low drag envelope. Suggest VERY robust security hardware to prevent the pod from theft.
Hell, I see a business model where such pods could be rented for occasional long distance use (hello U-Haul, opportunity calling).
There was an Italian electric sports car that had something like this...it was a pure EV with a gas engine trailer that could give you extra range.
There have been conversions posted on the internet.
There was a nice/well done ZX2 featured on their site sometime back.
THIS guy has taken an old Spec Renault chassis and turned it into an all-electric racecar that laps as fast (if not faster) than an SRF. He is trying to get funding to build out enough of them to run a series. He seems extremely enthusiastic about and also seems quite willing to share what he's doing.
I have a friend who built himself an electric car and drives it to work every day. It is powered by a bunch of Chinese lithium cells. His commute is about 35 miles each way but he figures he can probably do two days between charges if needed. But the bonus is his employer put in a charging station by the front door and since he has the only electric car he has premium parking so double win. The car is a Ford Aspire(Festiva). It looks and drives like a typical E36 M3box. No faster and no slower.
Mike
HalfDork
4/1/14 1:01 p.m.
Zelectric is doing some very, very nice conversion work on old bugs. The install is very clean, and doesn't do anything nonreversible to the beetle. I'd have a look at their build.
EvanR
Dork
4/1/14 1:35 p.m.
You can do it old school and convert an S-10 using a crapload of lead-acid batteries.
Electric S-10
This site had some projects including a motorcycle. I have been spending too much time here to keep up.
Nashco
UberDork
4/4/14 9:03 a.m.
Here is your starter platform, a STEAL at $850. If it were here it would already be in my driveway. Alas...Atlanta!
http://atlanta.craigslist.org/nat/cto/4406199342.html
Super light and aerodynamic!
Bryce
+1 for buying that Insight if you want to get started.
In reply to MrJoshua:
Seriously Wow. To get this back to "normal" though a battery and replacement tranny would probably be over a $3k investment, right?
Vigo
PowerDork
4/4/14 12:00 p.m.
That car is ludicrously underpriced. I just bought a higher miles example with a worse battery for $1700 and im fairly happy about it.
If you pay full pop for an aftermarket refurb battery and trans rebuild, you're probably looking at high 2s.
But, i think there's a good chance of fixing the trans for much less.
I guess the Insight is a car that is prone to having synchros ruined since you NEED to downshift frequently and the gears are very far apart. If you dont double clutch rev match your downshifts, yeah, you're going to end up with crunchy gears sooner or later.
^Strictly in terms of trans. wear, only double clutching matters.