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Kelmark GT Solar Series Hybrid

26K views 69 replies 16 participants last post by  Kernel Panic 
#1 · (Edited)
I have been in and out of this forum for about 3 months researching and I thought it was about time that I started my own build thread. Bear with me as this build will be slow. I am a 30 year old mechanic for a pharmaceutical industry also a Navy Reservist. I am a believer in sustainability and using resources efficiently and responsibly. I was a Diesel Mechanic for the Navy Active Duty for 6+ years and modified cars as a teenager.





The project is to make the most efficient car with respectable performance, range, and looks. To do this weight is my enemy. I found a light sporty car now I’ll need to trim the fat even more. This project will not be done until 2013 for many reasons. It is a project, a have a family, and I have a job so balanceing time is important. Also the availability of the 144V AC controller and the price of the batteries push the date out to then.
  • My skill level with auto mechanics and fabrication is above average.
  • The range (75-85miles at 70mph 75%DOD hybrid) (50-60miles at 70mph 75%DOD EV)
  • The level of performance you are hoping to get is <15s 0-60
  • Budget $25,000 + tax breaks + sponsors + friends
The Donor Car

Kelmark GT fiberglass kit car on a 78 VW chassis (Ferrari Dino Replica) This car will be built for local car shows and car audio shows.

I was unable to get the exact curb weight before starting but a stock VW beetle weighs approx 1800lbs and this car is likely 300lbs less so my guess is 1500lbs starting weight. Goal Finished Curb Weight <1600lbs

Drag Coefficiant 0.34
Frontal Area 21.9 sq ft

I see that the stock curb weight of a Kelmark is 1700lbs according to the blueprint. My revised finished weight is to stay at around 1700 lbs which means I need to find additional ways to reduce weight.

Modifications include

Stripped the chassis, replaced floor pans, welded a 3” body lift kit (to increase headroom and add strength to the pan), trimmed any excess metal, changed the head on chassis from ball joint to link pin, and lastly painted.

Purchased
ü Lightweight aluminum beam front beam assembly
ü 4 wheel disc brake kit (still need to machine to reduce weight)
ü All new suspension components
ü New performance transaxle (stock gearing)
ü Racing seats

Looking into;
o Lightweight Flywheel/ and HD Clutch
o Light weight rims and LRR tires
o Lightweight custom interior and stereo
o Reducing weight of fiberglass body
o Race windshield?

The Kit to be used

HPEV AC-50 (Hoping for a 144V controller by the time I am ready)

The Batteries

Dow Kokam SLPB 75106100 (QTY960)
7.5 AH 3.7V 15A Cont
Dimensions; .30 x 4.17 x 3.94 = .34 pounds
40 cells wired in series = 148V Nominal-166V Charged 7.5AH pack 15A cont. = 13.6 pounds
24 packs of 40 is 148V, 180AH, 360A cont 900A peak = 326 pounds

Instrumentation

The Display, stereo, GPS, Cameras, and security: MiMod- www.evinstuments.com


Series Hybrid

This will be a range extender or a way to charge when there is no access to a plug in. “Mainstream produces the world's lightest 2-kW diesel-powered electric generator. The generator is a completely integrated system optimized for size, weight, noise and reliability. This generator is not merely the coupling of a commercial off-the-shelf diesel engine and alternator.” Around 100 lbs and is more efficient and durable than gasoline generators.

Debating on whether to permanently install or have it removable when not needed.
http://www.mainstream-engr.com/products/engines/

Solar

I would like to be able to get a 3 mile per day charge from thin solar cells installed on top of the car. Still in planning phase, need to research more on how to install and which cells will give the best bang per buck. Also need to determine how much my car will use at 35mph for 3miles.
 
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#50 ·
i'm a newbe at this and i have been following your progress. i like the idea of taking your own charger with you just to keep the battery power up. i may want to try that too. be able to take it out to go the the dmv to show all electric and if ever stopped - its a backup power system.
my problem is im used to hot rods - so i want an electric hot rod - 400+ ftlbs to the rear wheels - 1st one off the light, first one to the next, and 80 mph on the freeway. so i am really interrested in how your build turns out.
good luck - well done so far.
 
#51 ·
my problem is im used to hot rods - so i want an electric hot rod - 400+ ftlbs to the rear wheels - 1st one off the light, first one to the next, and 80 mph on the freeway. so i am really interrested in how your build turns out.
good luck - well done so far.
Just look around and read up... in my experience most hot rod lovers make excellent EVs ... Hot Rod lovers know the value of low RPM torque ... and Electric motors have more low RPM Torque than any equal sized ICE ever will... plus hot rod lovers also tend to understand you can't get something for nothing ... just like supping up and ICE into a hot rod costs money so will an EV Hot Rod.

If you haven't seen it yet and you are looking into a EV Hot Rod... I'd recommend looking at the White Zombie... Which launches with 772 Ft/Lbs of torque... he has gone from zero to over 114 MPH in under 12 seconds... and zero to 60 MPH in under 3 seconds... and it is a street legal car for daily commuting too.
 
#52 ·
thank you for the link - i believe i did see that one, but before i understood anything about it.
i think its about time for a change - so this could be it. i do have to learn a new vocabulary but low end torque is that im looking for - not big on 150+ mph on the top end.
i am going to strip out one of my camaro's - no engine or trans and other stuff and im down to 2k lbs. bolting the motor up directly to the rear end and gearing for right rpm for the motor and i could have some real fun on the street.
ok all the controllers and batteries will have to be in the front - but putting the engine over the rear end will make it run like my lotus europa.
what the hell - i wont be wasting gas - i can charge it during the day on solar.
 
#55 ·
It will take another month for me to finish running brake lines and do the fine tuning / alignment of the suspension and then fabricate the racks for the batteries.

After that I will be ready to set the body back on the chassis and take it to be weighed. Then I will have a better idea of what the car will weight when it is done.
 
#62 ·
Hello everyone,

Just wanted to give an update;

I got the body back on the chassis but found that there was a substantial space above the rear tires due to using smaller diameter tires and a 3" body lift kit seen in post#53. Adjusting the spring plates won't be enough so I will have to do some custom fabrication to lower the rear suspension.

The wife says I have to pay off a couple bills before I continue on my project so that has been my focus but hope to be able to start diverting some money back to my project soon.

Also been rethinking the AC motor... I am now considering 11" Kostov with Netgains Warp Drive controller. The efficiencies should be close but potential power is much greater and price is about the same. Any thoughts?
 
#63 ·
I am now considering 11" Kostov with Netgains Warp Drive controller. The efficiencies should be close but potential power is much greater and price is about the same. Any thoughts?
Not from experience, but from calculations... make sure your power is in the rpm range you want it for the voltages you're going to use. I put the 11" WarP motor in my spreadsheet and it really didn't give any better performance, actually worse than what I wanted. Torque was too much on the low end (tires would spin more than a Warp 9) and there wasn't enough power on the higher rpm range to give the top speed I wanted.

If you put enough voltage to the motor, I'm sure you could get the performance you want, but that's more $$$.

P.S. on my spreadsheet if you use it, your car is so light, I wouldn't expect to much more acceleration in G's (~ 32 ft/sec^2) than the what the weight ratio is on the rear wheels, ie if you have .5 on the rear, a little over .5 G's or 16 ft/sec would be about max acceleration with standard tires of the appropriate width. Over that and the tires would probably spin.

Oh, and don't forget to tell your wife how much money you're saving when you buy parts, just like she does when she buys her shoes. ;)
 
#64 ·
Not from experience, but from calculations... make sure your power is in the rpm range you want it for the voltages you're going to use. I put the 11" WarP motor in my spreadsheet and it really didn't give any better performance, actually worse than what I wanted. Torque was too much on the low end (tires would spin more than a Warp 9) and there wasn't enough power on the higher rpm range to give the top speed I wanted.


The reason I started looking at the 11" was because Netgain came out with the HV version. But netgains motor has too much torque and is too heavy so I was reading the history of white zombie and they used the 11" Kostov which has interpoles, less torque, and is lighter.

If you put enough voltage to the motor, I'm sure you could get the performance you want, but that's more $$$.
I would use the highest pack voltage (450?) and would limit motor voltage max rpm 5000. Top speed on this car is going to be limited to 70mph, I am not sure I would feel safe driving the kit car much faster and there isn't really a need, 90% of my driving will be in town.

P.S. on my spreadsheet if you use it, your car is so light, I wouldn't expect to much more acceleration in G's (~ 32 ft/sec^2) than the what the weight ratio is on the rear wheels, ie if you have .5 on the rear, a little over .5 G's or 16 ft/sec would be about max acceleration with standard tires of the appropriate width. Over that and the tires would probably spin.
Thanks I will have to play around with that calculator. The main purpose of going with the 11” kostov was to have “interpoles” which will give me a greater torque band. Also wanted to use a large enough motor that the draw on amps would be less and be more efficient overall.

Oh, and don't forget to tell your wife how much money you're saving when you buy parts, just like she does when she buys her shoes.
LOL
 
#65 ·
I'm just starting my project, but my thoughts on higher voltage, higher voltage = more batteries = more connections = more potential problems.

I could get a longer torque (but lower) band using an Impluse 9" and higher voltage on my project and shift through the gears to get the performance I want, or use a WarP 9" and lower voltage and just start off in 3rd, it calculates about the same as far as acceleration performance on 0-60mph. If you only need to go 70mph, I don't know if you would really need to go real high voltage. I don't know the efficiency difference between 144v vs 300v+ but I think it would be small.

Again, just my thoughts, but if you had a real high power motor and single speed and neeeded to go 10K + rpm, high voltage would make sense, but for 5k rpm and if you plan to keep and use your transmission, someone would really have to explain the benefits to me.

On a different subject, what seats are you using and where did you get them? How much do they weigh?
 
#66 ·
I'm just starting my project, but my thoughts on higher voltage, higher voltage = more batteries = more connections = more potential problems.

On a different subject, what seats are you using and where did you get them? How much do they weigh?
The seats are from JcWhitney, GaragePro I think. I got them for $200 on sale with a discount. They are a bit heavier than I would like at 33 pounds each but I can always upgrade later.

I am planning on using prismatic cells which will have lots of connections no matter what voltage I choose anyway. But I will have the modules assembled professionally and then I will install them.
 
#67 ·
I have been considering another drive for my project that I really think will work well but I thought I would bounce the idea off all of you. Here it is;

Battery Pack

100 Calb 40Ah
320V nominal 360V Charged
Weight- 331 lbs

Drive system

55kW BLDC Motor / Controller. Weight-66.14 lbs

312V nominal 55kW peak power 22kW nominal. 250Nm Maximum Torque (84Nm Nominal) Air-Cooled, with Full Brake Regeneration


The battery pack would be on the small side but I plan on upgrading on my next pack as battery technology improves and prices come down. But as this will be used for local car shows and I live 2 miles from work my actual daily driving will be less than 30 miles.

With this setup I should be able to keep the finished weight of the car under 1700 lbs with pack over and forward of the rear wheels I think this car would have impressive acceleration and handling.

So what do you guys think?
 
#68 · (Edited)
Nice looking motor. Whatabout cost?

I assume since there is a torque curve with it, it's good for a traction motor. A sensorless controller / BLDC motor setup in RC is best for propellers where there is no resistance to starting the propeller. I would just make sure it's a sensored controller / BLDC motor setup or that it actually says it's a traction motor.

55kw / 320 v = 171 amps or over 4 C for the batteries, if you plan on using maxing out the motor. Might shorten the life of those batteries a little. If you're close to the Tesla at highway speeds at ~ 20 to 25kw, thats 1.5 to almost 2 C. Seems I've seen 1 C is good practice for the batteries for extended periods.

Complete speculation on my part, but I'm not of the opinion batteries will get any cheaper, maybe better, but not cheaper. They're already cost competive with oil (if you believe the cycle life claims), and they seem to be gaining popularity, you know that ole supply and demand thing.
 
#69 ·
maxvtol,

This same motor is offered through Current EV Tech as a traction motor for use in EV's just a little less expensive. You bring up a good question on the sensor though I will have to check and see if there is or not.

As for the batteries I have limited my weight to <350Lbs to maximize performance and efficiency. So for this first pack I will limit peak amps to around 145A and I do not think I will be running near 80A continues during normal driving probably closer too 45A or less for <50mph.

The price of Calb are very good just not the weight, my hope is that I can double (80Ah) for the same weight or lighter for less money in 5-8 years than it costs to do now which is $18,000 - $30,000.

Thanks for the feedback!
 
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