# Custom ground up EV build



## electronmonk (Oct 30, 2014)

I'm going to mark this as the "official" beginning of designing an EV, and since it was recommend to include the following, here goes..

Skill level with auto mechanics and fabrication:
With cars, I'm usually good until I have to mess with the deep insides of the engine (I mess one up on a botched replacement of the intake manifold gasket....kept the bent pushrod as a reminder)
As for fabrication, I have some experience in welding, lathe work, and mill work. Recently most of my efforts have been going to converting the basement light fixtures in my house to use CREE LEDs.

Range I'm hoping for:
At least my commute (70 miles round trip) plus some, so conservatively 100-120 miles

Performance:
I really don't see the need to go about 75-80 MPH and even 65 MPH would get me to work just fine. I'd like to have a 0-60 time under 10 seconds and need to be able to climb the hills that seem to be everywhere in Northern Utah.
And as a requirement from my wife: can it pull a small trailer? (<2000 Lbs and not over about 35 MPH)

Budget:
Working on it....(as much as my wife lets me have )

Parts/materials I've considered:
Mostly I've been looking at HPEV's motors and the Curtis controllers for both the simplicity of the systems for forward/reverse and regen abilities (I know I won't get that much back from it, but it'll help on the hills around here).
As for the batteries LiFePO4 is what I've been considering, in particular this one: http://www.electriccarpartscompany....2-in-220-135-30-mm-br-29-lbs-13-kg_p_574.html

For the body, I've considered several different materials including steel tubing, aluminum, and carbon fiber. It only needs to be able to seat two adults (myself and my wife) and possible our dogs.

Other things that I've considered: single/dual motor AWD; fixed ratio final drive; two speed front/rear trans-axles or center transmission; converting either my car (Subaru Impreza) or truck (GMC K2500) instead (not as fun though)

Bottom line is that I'd like to build a lightweight EV that has a decent range for where I live. My original thought was one that I could park in the bed of my truck and haul it up to Yellowstone along with a camper trailer of some kind and use the EV to drive around the park with.

I have some experience with high voltage power systems from my last job testing and trouble shooting a 4kW AC to DC rectifier (140V AC in, 430V DC out). I do know what it's like to be shocked by a capacitor bank that was sitting around 200V, so electrical safety is foremost in my mind.


Any help, insight, advice, or links to similar projects would be helpful, and I'll update regularly as things become more solid on my design (and I become for familiar with Autodesk's Inventor Fusion....)

Thanks!


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## Caps18 (Jun 8, 2008)

http://www.cracked.com/article_19815_the-9-most-insane-vehicles-that-are-street-legal.html

http://www.cracked.com/article_20156_8-insane-vehicles-you-wont-believe-are-street-legal.html

You might want to think about building a kit car of some kind, if you don't convert an existing vehicle.

http://www.zercustoms.com/news/Street-Legal-Ford-GT-Race-Cars.html

Or what would be cool is to make an EV on-road/off-road dune buggy/sand rail.

http://www.acmecarco.com/index.php/berrien-buggy

https://www.youtube.com/watch?feature=player_embedded&v=jHR3a7mCiEk

 That is what I would make. With the amount of work it is to restore and paint the truck I am converting, it would have been smarter to make that. Especially if I still lived in Arizona.

http://www.fly-skyrunner.com/

Or build a flying car. Yes. Not sure how much range you would get in glider mode, but it would be awesome.


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## electronmonk (Oct 30, 2014)

Thanks for the input! I had actually been thinking on and off about a dune buggy like vehicle, so thank you for the link on one place to get a chassis for them.

Thankfully I had looked up the laws in Utah a while ago on building a car, whether from a kit or not, and it seems that as long as you document the build, save your receipts/invoices, and pay your taxes, the process isn't too hard. I haven't found anyone that's gone through it yet, so I don't have any knowledge beyond what's on the DMV's website.


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## electronmonk (Oct 30, 2014)

One of the methods that I've found on how to work with carbon fiber:

https://www.youtube.com/watch?v=VodfQcrXpxc


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## electronmonk (Oct 30, 2014)

Working on an overall design at the moment. Hopefully I'll have something to show on Sunday when I'll have more time to sit at my computer and tweek a few things in autocad.


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## nimblemotors (Oct 1, 2010)

You have to ask yourself the question of WHY do you want to build any car from the 'ground up'? What do you hope to accomplish that isn't possible from a 'ground down' car? 

I am over 50 years old, and have been building cars since I was 17 years old, have built 5 custom cars, and none of them are from scratch, it is VERY difficult and VERY time consuming just to start with one and modify it substantially, let alone build one from scratch where you must reinvent every single detail, from the dome light, the door locks, to the brake line routing.

I just watched a video on a XR3 build, he has been working on it for over 5 years. Even kit cars which are 'simple' to build take many years.


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## Duncan (Dec 8, 2008)

Hi
I built my car from scratch
But I would agree with Nimble - unless you want something that you just can't buy you are better off converting something

I built a 2 seater roadster for use on the road and track
It's simple - no doors - no roof - no glass - no interior
http://www.diyelectriccar.com/forum...-dubious-device-44370p2.html?highlight=duncan

But if you want something more comfortable you would be better starting with a good car and converting it


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## Nathan219 (May 18, 2010)

Our ground up car performs great, but the more OEM parts you can use the better. I also reckomend start designing from you as in your body outward, since the space closest to you is also the most important with regard to your enjoyment. Second make surer you can heat and cool the vehicle unless you are wanting an open air buggy, then I would buy a golf cart and spend the money I would have spent on a ground up vehicle to put lithium batteries in it take a nice vacation, pay off my house, and pay for my kids college.

Www.Illuminatimotorworks.org


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## electronmonk (Oct 30, 2014)

the answer to why is because I haven't found a car to convert that has everything I want in it. Thank you for the words of caution nimble, it is a huge undertaking and I am under no delusions of being able to complete it in a short amount of time.

Nathan, I have been looking at different cars to use as sources for parts and have been intending to use OEM parts where I can. 

I was somewhat inspired to attempt this because of a small company called Local Motors who takes a design and uses off the shelf parts to complete it. Their 3D printed car uses the electric drivetrain from a different production car and is claiming a 100 mile range off a 6.1kWh pack with a top speed of 45 or 50 MPH. 

I'm also doing this for a few other reasons. One is to learn more about cars, the other is to add a large project to my engineering portfolio.

Thanks all for the advice, and I'll keep up on how things are going.


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## electronmonk (Oct 30, 2014)

Well, it's Sunday and I've had a lot of time to mull things over. I came up with three different ways that I could go about my build, and am slightly leaning towards one of them. I could build some sort of small two-seater sporty car, a small SUV, or a truck. Taking in the availability of OEM or even aftermarket parts, I remembered something I saw a number of years ago that I was really interested in: the Jeep Gladiator

jeep_gladiator_side_cs_430.jpg


http://www.jeep.com/jeep_life/news/jeep/gladiator_concept.html

This truck never when to production, but is based on the Jeep Wrangler, which has a huge amount of both information and parts available for it. Now, there are a few issues that have already presented themselves for this, the main one is the weight. At 4000+ pounds, it's quite heavy for my tastes (still doable, but much heavier than I'd like). So, I will likely be using this as a basis for my design. There is also a reason for not just going out and buying a Wrangler and converting it: around here, you either find ones that are rusted out completely for around $1000 or if it's running, they'll want $6000+ (might be able to find one for less, but I don't have the cash right now, which is mostly why I'm working on the design and saving up money).

As always ideas, cautions, and tips are appreciated.


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## electronmonk (Oct 30, 2014)

The Dodge M80 was another that caught my attention

Dodge-M80_Concept_2002_1024x768_wallpaper_1a.jpg


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## nimblemotors (Oct 1, 2010)

Jeep made a cherokee truck. There is also the small vw rabbit truck.
Then there is also the little chrysler rampage truck, which is actually really cool, and of course the subaru's brat.


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## electronmonk (Oct 30, 2014)

That is vary cool looking, and not one that I knew of before.

I had a mechanic that had a BRAT, and have seen a few around here. There are also a few of the Rabbits for sale in the local online classifieds.

Thanks again


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## electronmonk (Oct 30, 2014)

Another week come and gone, but not much progress made. (Overtime and working around the house are a bit more important at the moment)

What I have found out is that a) you do not need an autoclave to make structural carbon fiber parts (aerospace companies are relying less on them)
b) my wife thinks my hobbies are a bit weird
c) that we had an EV in the mid-1990s that was able to do almost 400 miles on a single charge using NiMH batteries

Also, a side note: if I ever post something and the letter "m" is missing, it's because that key doesn't work the best on my laptop.....


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## electronmonk (Oct 30, 2014)

Another choice I'll have to make at some point is if I build an EV that's only used in warmer weather or take on the challenge of designing in features that will allow it to be used year round.

This is on the front of my mind since the highs have been around or below freezing (32F/0C) all week and it's just the start of winter weather here. The coldest that I usually have to deal with is 0F/-17C.

Now to keep writing ideas and bad drawings in my notebook....


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## electronmonk (Oct 30, 2014)

Working on the roadster design right now and still trying to figure out how to get what's in my head into Inventor Fusion so that I can model it.

Since Thanksgiving is this week, I likely won't get much done, but my design has simplified into a reverse trike layout likely using the front end of a Miata and a single swing arm for the rear similar to a Ducati or Honda Goldwing.

So far I've learned a lot more about how cars go together and that I can't draw curved lines very well.


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## Sethzor (Sep 22, 2014)

If you need help modeling parts or a body let me know I can take your sketch and model it in SolidWorks.


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## Duncan (Dec 8, 2008)

Hi
I had a look at a tadpole trike - but I decided to go for 4 wheels

The single wheel at the back does not save you much at all compared to a std diff and rear end


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## electronmonk (Oct 30, 2014)

Thanks for the offer Sethzor, even if I don't take you up on it, I still will have questions to ask.

I'll take that into consideration Duncan. I've seen the build you have on here and am impressed with how it turned out. I'm still quite a ways out from putting anything together, so it's mostly trying out different ideas on paper right now. With the trike vs 4 wheels, it was more of a style preference than trying to reduce the amount of energy it needs.

Again, thanks for the help and advice!


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## electronmonk (Oct 30, 2014)

It's been a while, and things are settling down around the house. I'm finally able to use my part of the spare bedroom as a workspace/computer room, so I'll be able to work more on the design in SolidWorks (finally was able to get a copy after some convincing of my wife).
I'm currently working out the extra capacity that I'll need for winter driving based on an hour commute both ways, which works out to around 6kWh accounting for losses and whatnot.
Also, while I am still considering a 3-wheel design, I can see the practicality of a 4 wheel, dual motor AWD setup, which is about what I was originally coming up with as a design. Thankfully, none of the work that I've done on paper is a was since I can easily adapt the three wheel to a 4 wheel version (I hadn't gone as far as where to mount the suspension or axles yet). This also means that I wouldn't have to have the motorcycle endorsement on my license to drive it (as required in the states that I looked at).
Now that I have all that done comes thoughts about the motors to use. I have always planned on using an AC motor from HPEV, and am going back and forth between a 96V and a 144V system. I am looking at the continuous ratings of both the motors and associated controllers to pick which one I'll finally go with (opinions/experienced advice is very welcomed). As with many people I've seen on here, I am having the AC-35 vs AC5X debate. If I was running a single motor, it would be either the AC-50 or AC-51 hands down, but I keep going around in my head since both are fairly close in size, and have very similar continuous ratings.

I'll will hopefully be posting more frequently, and have something to show soon.
Thanks for all that's been given already!

David


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## tylerwatts (Feb 9, 2012)

Hi David. I've started a twin drive awd custom EV build myself. Basing it in a proven kitcar chassis. Also going to be digging into the CAD soon, just setting up my laptop gear for it. 
I've got 2 Azure AC24LS drives, but I managed to find a dismantler with a complete body damaged i-MIEV. If I find a second I'll use both, otherwise the battery is worth the price he wants for the entire car. It comes in parts as the shell must be crushed by UK law... I searched for a while and almost all vehicles like this are in the US so dig round as you get everything in one donor then. A leaf or similar wouldn't need awd in a light chassis due to power-weight ratio. 

The other thing is you are going to have a big battery. Can't you partially charge half way, like between commute to and from? That would save alot in weight and budget. I doubt you'll get enough batteries into 3 wheel space otherwise.


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## tylerwatts (Feb 9, 2012)

I see your concept is alot larger than mine. AC 50 to a high ratio diff with smaller wheels would be best. 2 off. Or 51,i forget which is higher torque.


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## electronmonk (Oct 30, 2014)

AC-51 has higher torque, but the 50 has a broader torque band, so somewhat of a trade-off. I'd love for my work to have a charging station, but they aren't thinking of putting them in at all, which is a bummer. I'm trying to keep the weight under 1500 lbs with my wife and myself in it, and I think I'll be able to pull that off. 
I'll search around here for some of those parts, but I've only seen 3 Leafs, 1 Miev, and 1 or 2 Volts. Utah isn't the most EV friendly state outside of Salt Lake City from what I've seen


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## tylerwatts (Feb 9, 2012)

Oh 1500lbs is challenging for my build, and I have half the running gear weight you are proposing. I look forward to seeing some designs.


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## electronmonk (Oct 30, 2014)

My plan is to work in SolidWorks today while my wife is at work, so we will see how far I get. I'm hoping to have some drawings up soon, but that will depend on how quickly I learn


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## electronmonk (Oct 30, 2014)

So far so good in learning Solidworks, it's actually a fun program and I can see why so many companies use it.

Some thoughts/speculations that I could be 100% wrong on:
I've been looking over HPEV's data sheets that they have published for their motors, and I have come to a conclusion concerning the AC-35/AC-51 motors. While both are probably capable of running at a higher voltage (say 192V), I think that the AC-51 would have gains both in peak and continuous power while the AC-35 would see a gain in peak, but a loss in continuous. I'm basing this off how some of their other motors behave as the voltage is increased. I could be completely wrong, but I would like a controller that could run these motors at that voltage.
Anyway, more coming on my design as it begins to come together in my computer.
Happy building (or driving)!


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## Nathan219 (May 18, 2010)

If the motor is like a bell how you ring it is important hit a bell with too little force and it rings very little strike the bell just right and it will ring at its resonate frequency decreasing in amplitude until the energy is imparted to the air. Strike it too hard and the bell breaks and looses its ability to make a nice tone. Hpevs has built their motors to operate with the curtiv controllers ringing them. They have done a very good job delivering a product line able to suit almost any need with a warrantied controller.


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## Tomdb (Jan 28, 2013)

There are next to no controllers out there that will do around the 200v.
You could look into the Sevcon controllers, how ever as mentioned HPEVS gives warranty with the curtis. This also means the curtis controllers come programmed for the motors, any other controller will have to be setup with these controllers.

Mind showing us/me what you got in solidworks so far, im quite interested. 

Two AC50's = 100kg
two AC35's = 80kg

And i am talking bare motors here. How will you fit batteries and passengers in the 1500lb (700kg roughly).

One big side note; where are you finding your traction for two of any of these motors on a 700kg vehicle? 

I would under stand two ac 35's on a vehicle thats meant for hauling goods/cargo. If you want a two seater commuter car that is 680kg a single ac35 will be way plenty. That is if you can fit everything in your car including batteries for such a low weight.

The carbon fibre you mention, do you have any experience? I would steer well clear of this if you do not have any experience because the part can look and feel good but under stress the layers can shear because of trapped air or proper bonding causing really bad results.


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## electronmonk (Oct 30, 2014)

Nathan, I like the description you gave, it's one of the better ways I've heard it explained.

Tom, currently in Solidworks I only have the pressure plate that the first tutorial has you build, so you'd probably be more interested in my notebook, which I will post some pictures from later this week. I'm going to be completing the rest of the tutorials before I start on my design in it. This will take some time since I only have Saturdays to work on it. I'm trying to do this right instead of my usual "dive in to the program and see how it goes".
I'm perfectly happy with the power levels that the HPEVS/Curtis combos provide and was merely making an observation. Also, since I have only seen them sold together, it would be a waste of money to try using a different controller, just saying.
I've always been planning on using a single gear reduction to get power to the wheels, but I'm not sure if that answers your question or not.
Utah recently upped the highway speed limits, so I'll need to be able to do at least 80mph in places. I liked it better when it was only 65. Limiting the upper end of the motor to 7500 RPM, this means that I'll want to run between a 4:1 and 5:1 reduction.
As far as my reasoning for dual motors, it's part because I drive a Subaru currently and like its AWD (even though I wouldn't be able to duplicate it), and part because my commute is far from flat. My commute or even driving around town has me driving up (or down) some fairly large hills (about 500 ft in elevation change from the map). Granted, I keep passing a Leaf on my way here, so a single motor would probably work.
I have a little experience with carbon fiber, and coworkers that have offered their help in that area.

I am continually amazed by the sheer amount of knowledge and experience that is found here, so thanks for taking a moment to give me a sanity check.


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## electronmonk (Oct 30, 2014)

I forgot to mention that I'm basing things off 205/55R16 tires


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## miev 1 (Jan 22, 2015)

You do have ambition if you only have Saturdays.

On the awd, I don't think its needed. Of course, I have only had the miev in 2-3 inches so far. Probably get stuck in 6-8 inches. But for the few times a year, just use another car.

I am not as ambitious, and am in the selecting donor car phase. But plan to model in Sketchup - as I am familiar with that program. It is quicker than the full bore Engineering programs. I am an architect, so that's where it's coming from.

What range you looking for or did I miss that?


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## electronmonk (Oct 30, 2014)

Whatever you want to call it, I'm happy that I have time that I can work on the design.
Thanks for letting me know what the MiEV is capable of, and I may go with RWD and just make sure to bias the weight toward the back and to have a second set of snow tires for the winter (though, I'd probably do that anyway)

I had put the range in the beginning, but I don't mind restating it at all. I have a 70 mile round trip commute with no available charging, so I'll likely want at least 120 miles for sanity's sake.
I am going to be updating this thread with a lot of what I've written down in my notebook tomorrow and working more in learning Solidworks (hopefully)


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## tylerwatts (Feb 9, 2012)

I look forward to seeing some Solidworks modelling soon. Will be doing my own from next week. I'm building a rear drive Porsche 356 replica using a complete i-MIEV donor. Should be a fun toy and commuter.


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## electronmonk (Oct 30, 2014)

Tyler, that's going to look awesome when you're done. Mine won't be near as stylish as that.


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## electronmonk (Oct 30, 2014)

Here are some of the ideas I've had and wrote down in my notebook. The first one the idea that I'm going to try running with.


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## electronmonk (Oct 30, 2014)

I've read on here a few different places about how to estimate how much energy your conversion/build will use by taking the weight in pounds and dividing by ten. I know it's just an estimation, and there are more accurate methods, but I figure it's a good starting point for me to figure how big of a pack I'll need. 

Here are my calculations based on being successful with the 1500 lbs (~700kg) build. 

Capacity needed for 120 mile trip, 150Wh per mile (estimate): 18kWh, 22.5kWh total

153V pack
60Ah: $3168; 62.4 kg; 7.3kWh, 9.2kWh
100Ah: $5280; 163.2 kg; 12.2 kWh, 15.3 kWh
180Ah: $9504; 254.4 kg; 22.1 kWh, 27.6 kWh
200Ah: $10,560; 283.2 kg; 24.5 kWh, 30.7 kWh
300Ah: $15,840; 453.6 kg; 36.8 kWh, 46 kWh

Also, I'm likely going with a 144V build since it'll give me a wider torque band


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## Duncan (Dec 8, 2008)

Hi
I worry about your 150whrs/mile

The Device is light (710Kg) but burns 400whrs/mile at 60mph
(only 200whrs/mile at 30mph)
I know The Device is not very aerodynamic but I think you will be struggling to get 150whrs/mile


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## electronmonk (Oct 30, 2014)

I could be off about it, I need to take the time and sit down with my physics book and actually do some math. 

I did find this thread that was interesting, and I'll try it out as well.
http://www.diyelectriccar.com/forums/showthread.php/yes-another-ev-calculator-45278.html

This is another place that I've seen the weight in pounds/10 formula, there was another that I just lost in my search a moment ago that you had added your numbers too.
http://www.diyelectriccar.com/forums/showthread.php?t=102961&highlight=wh/mi+calculation

Also, though more actual information is needed, I was getting between 150 and 200 wh/mile using this calculator at 75 mph (120 km/h)
http://www.enginuitysystems.com/EVCalculator.htm

There is great truth to the "you're mileage may very" statement. I'll keep your numbers in mind as I continue, so thanks Duncan!


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## PStechPaul (May 1, 2012)

Remember that my EVcalculator is based on what is actually needed for the parameters entered, and does not take efficiency or losses into account. Typical efficiencies might be 95% for drivetrain, 90% for controller, and 85% for the motor. These combine for an overall efficiency of about 72%, so the 200 W-h/m might actually drain 275 W-h/m from the battery pack. 

Also not shown is regeneration, which can improve the numbers, but probably no more than about 10%. Driving style, terrain, and environmental conditions (wind, road surface, etc.) also affect the energy usage. 

BTW, I don't quite understand how a 100 A-h pack can be almost three times the weight of the 60 A-h.



> 60Ah: $3168; 62.4 kg; 7.3kWh, 9.2kWh
> 100Ah: $5280; 163.2 kg; 12.2 kWh, 15.3 kWh


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## electronmonk (Oct 30, 2014)

Thanks, I didn't know if it did or not. That sounds like a much more reasonable number for that speed. I'm keeping it bookmarked so that once I have better data, I can use it as a reference tool to know if I'm in the ballpark. 
I'm a little confused about those 60Ah cells myself. I pulled the numbers from the data sheet for each size. I have the link for the 60Ah ones on the first page of this build thread. They were all packs that were built on paper with no parallel connections. 
If you know more about them in specific, I'm all ears


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## electronmonk (Oct 30, 2014)

Here's the data sheet for the 60Ah cells I had mentioned. I know some of the other "Energetech" cells are Liyaun cells under a different name, so this could also be the case here.


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## electronmonk (Oct 30, 2014)

Two weekends have passed that I haven't been able to work much on the design, other than I'm heavily leaning toward either CALB or Voltronix cells (both available from EV West).

I'll revisit the Wh/mile aspect once I have a lot more on paper, but it's looking like I'll need 30+kWh to get the range I'd like from the numbers that I've been using.

Major thanks to both Duncan and Paul for their help in that.


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## Tomdb (Jan 28, 2013)

how about these?

http://www.evwest.com/catalog/product_info.php?cPath=46&products_id=329&osCsid=77ru60t4g1527mrrnh7usc6k45

Nice packages, and cheap (relatively)


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## electronmonk (Oct 30, 2014)

I'd use them if I had the money to start right now since they're a great building block. The HPEV package that's like 24kWh has also caught my eye


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## electronmonk (Oct 30, 2014)

Glad to hear what he posted was of help to you.


This is something that I've been wondering about and I found this thread helpful:

http://www.diyelectriccar.com/forum...-bottom-balancing-142050.html?highlight=Orion


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## tylerwatts (Feb 9, 2012)

Spambot! Can the moderators do anything about that?


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## electronmonk (Oct 30, 2014)

I was wondering about that.....


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## electronmonk (Oct 30, 2014)

It's been a good weekend, though it did involve me banging my head on my desk for a while. While I haven't started my model in SolidWorks, I did find out that I had been going around leaning it the wrong way. I now know what tools to use for the body/frame, so I will be (finally) starting on that this week.

Also, I'm still having an internal debate on which cells to go with. Since it'll be some time before I actually am able to purchase them, I will be going with a generic battery area in my design, and keeping an eye on what the battery sector is doing.

Also, this is the closest I've been to doing anything with an electric vehicle since I started thinking about building/converting one in 2007.

Thanks all for your input, and to the moderators for keeping the spambots away.


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## electronmonk (Oct 30, 2014)

A question for those of you who have complete or are working on a build: how have you paid for your build? I'm just curious because this is the biggest thing I'm trying to figure out right now.


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