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A friend just pointed me to this thread. Great stuff and can't wait to see it done. If you don't mind me asking, did you reorganize the Leaf batteries to increase the combined output voltage? Is the discharge rate of the cells comensurate with your target power levels? If there is going to be a bunch of free space in the engine bay area, did you consider mounting a portion of the batteries there?
I have left the inner configuration of each module untouched. The modules themselves are arranged in series for the LEAF and that is how I plan to implement them.
Nissan has made a pretty fantastic claim of 2.5kW/kg for the power density of these cells.
On paper, its apparent that the LEAF isn't even close to pushing the limit, with its paltry 80kW output. Then again, its no suprise that an OEM designed a significant safety margin into its mass produced vehicle.
On paper, its difficult not to be optimistic:
Each module weighs: 3.8kg
3.8kg x 2.5kW/kg = 9.5kW per module
Each module has a nominal voltage of 7.6V
9.5kW/7.6V = 1250A
1250A/66A = 18.93 (calculated peak discharge rate)
I have seen actual load tests of individual cells which suggest a healthy discharge rate is in the neighborhood of 15 or 16C. This absolutely smashes the status quo, as defined by the LiFe prismatic cells primarily used in conversions (which typically have a discharge rate in the neighborhood of 3-8C). Point being, if I discharge a 334V pack at 15C, not only am I within the parameters of the cell as defined by the manufacturer, I should also be making about 440hp which is more than my motor can handle.... for now
Ultimately, placement of the modules in the vehicle will depend on two factors:
1. Weight balance
2. Length of cable to connect modules together. As the length of a conductor increases, so does its resistance. In an effort to maximize the efficiency of the setup, the power cables must have a large diameter: 2/0 or 4/0 AWG and be as short as possible.
I'd at least paint the engine bay a special color while you're in there. You know people will want to see what's under the hood!
You're right. After this thing moves under its own power, I think I might have the rail and apron replaced and the bay sprayed to look nice. However, it needs to be a viable EV before I can justify making it pretty
Dude you have grabbed the attention of everyone on this forum site.. My jaw hit the floor when i read through all of it. This is incredible! Please keep us updated! Hopefully ill get to see this car in person since im not too far from you
I have seen actual load tests of individual cells which suggest a healthy discharge rate is in the neighborhood of 15 or 16C. This absolutely smashes the status quo, as defined by the LiFe prismatic cells primarily used in conversions (which typically have a discharge rate in the neighborhood of 3-8C). Point being, if I discharge a 334V pack at 15C, not only am I within the parameters of the cell as defined by the manufacturer, I should also be making about 440hp which is more than my motor can handle.... for now
...
ok, so OEM was wired entirely in series to give 334 V. Interesting. Would sure seem tempting to go for adding a second set of Leaf batteries.
I wrapped my Evo myself. It's definitely a labor of love.
Here it is, wrapped in Hexis Matte frozen grey just to give you an idea. My evo is also GG and the color difference in the door jams doesn't bother me that much.
ok, so OEM was wired entirely in series to give 334 V. Interesting. Would sure seem tempting to go for adding a second set of Leaf batteries.
The LEAF pack actually comes in at 360V with all 48 modules wired in series. Due to constraints of my 'Zilla' controller, I've had to knock it down to 44 which should net me 334V. The other 4 modules I'll use to power my low current circuits (headlights, instruments, coolant pumps, window motors etc.). You're right though, adding a second string of modules in parallel would dramatically increase my range.
The LEAF pack actually comes in at 360V with all 48 modules wired in series. Due to constraints of my 'Zilla' controller, I've had to knock it down to 44 which should net me 334V. The other 4 modules I'll use to power my low current circuits (headlights, instruments, coolant pumps, window motors etc.). You're right though, adding a second string of modules in parallel would dramatically increase my range.
I was thinking series wiring of additional batteries, but perhaps not using the entire 48 modules. I recollect that your current controller can't handle that, so I was thinking of it more as a future endeavor. Maybe there's no controller out there that can handle that kind of voltage? What about motors? Presumably there are motors that can handle more than 360 V but perhaps not 620 V?
If you're willing to pay, the options are almost limitless. There are AC motors out there that will handle more voltage, but ones that make similar torque can cost as much as my entire budget for this build.
Pretty underwhelming I know, but it does mean that I can finally bolt the gearbox to the motor and position it in the motor-bay. Now if I only could find some spare time to do exactly that...
From left to right: spacer, hub for mounting flywheel to motor shaft, bell-housing adapter plate.
Last edited by electron bom; Nov 2, 2015 at 05:40 PM.
One the coolest builds I've ever seen. Is it going to be strictly just electric then? The stock internals on the stock block would be done in your first pull with the kind of torque the electric motor is going to put out at low RPM lol.
The transmission OEM internals should be ok, but you are going to stress test everything more then anyone ever did with all that low end torque the electric build is going to make.
I am a big fan of electric motors. I have another hobby with electric rc cars, which use the little brushless engines.
Just from messing with rc cars, I know how much difference an electric motor is vs gas. That video of the miata was badass. that low ET vs that MPH is a perfect example how much powerband the car has.
I can tell you do something very crazy as a business career which involves serious technology.
...had everything to mate the motor to the gearbox, but I bought the wrong hardware for the motor plates. I was operating off the manufacturer's schematic for the motor and evidently this particular motor was tapped for a different size bolt. Time to revisit the hardware store, hopefully they have a grade 8 offering in the size I need.
One the coolest builds I've ever seen. Is it going to be strictly just electric then? The stock internals on the stock block would be done in your first pull with the kind of torque the electric motor is going to put out at low RPM lol.
The transmission OEM internals should be ok, but you are going to stress test everything more then anyone ever did with all that low end torque the electric build is going to make.
I am a big fan of electric motors. I have another hobby with electric rc cars, which use the little brushless engines.
Just from messing with rc cars, I know how much difference an electric motor is vs gas. That video of the miata was badass. that low ET vs that MPH is a perfect example how much powerband the car has.
I can tell you do something very crazy as a business career which involves serious technology.
Yes it will be electric powered only From what I've read, I expect the transfer case to go first. It will be a balancing act to make this evo fast and yet not tear itself apart. I plan to use a conservative slew rate and will start with a low power tune, slowly increasing motor output as I become more comfortable with the setup.
Oct 27, 2015, 06:31 AM
