x88x EV saga, v1.0: Honda E15 Magna

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Originally Posted by Technochicken

That would be 52x the capacity. It's kind of scary to think that those batteries together could discharge about 50 kw continuously...

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Theoretically 75kW, actually. ;) 20-30C. Of course, if I actually took it to 30C there would be a large voltage drop (so wouldn't actually be 75kW) and it would severely shorten the cycle life....and it would completely drain it in 2 minutes...if it didn't burst into flames first.. :whistler:

But yeah, it is kinda crazy to think about the potential. You want crazy though? Once it's complete, the whole pack would theoretically be capable of a burst discharge of up to almost 375kW!

For craziness with lipo though, check out this build. 20kWh of this lipo in a Mazda MX-5 with a 300kW controller/motor combo! :twisted:
http://endless-sphere.com/forums/vie...p?f=34&t=38171

For context for the petrol-heads in the audience, 1HP == 746W, so 300kW ~= 400HP. :twisted: ...in a 2,000lb car....with 400+ ft-lb of torque from 0RPM... :twisted:

Now, let's see how fast, and how far, you can go with this thing....

Yeah, the hard part on an EV with this much power availability is putting the torque to the pavement. Lots of time playing with torque curves for the controller. My brother in law built his son an electric go-kart that is the envy of the neighborhood. Capable of standing itself vertical on takeoff. He dialed the controller way, way down and it's still a widowmaker. Cool stuff.

Heheh, nice, do you know what motor/controller he put in it TLHarrell?

Speaking of motor, I started on the motor mount prototype tonight. I told you I would find something to do with that 1/2" HDPE. ;) That stuff really is a pleasure to work with. Got a first go mocked up.

Lined up pretty well.

Obviously I don't want to wind that motor up on the HDPE mount, but it's plenty strong enough to help me nail down design and dimensions.

Golf cart motor and controller, no idea about the pack he was using. Frame was all hand built from square tube.

Try to keep as much of the weight as low as possible (but you know this).

Been a while since I've been able to update on this; got stuck working 5 days straight of 12 hour shifts....not fun...

So, updates.. Got my Powerlab in; that thing is serious nice...even if it wasn't obvious that it needed to be running off a battery to discharge more than 100W. -_^

I also got the rest of the batteries (for now). 5kWh of yummy, yummy, lipo. :twisted:

Now the fun job of testing all of them. They ship at 50% charge, so I have to charge them up, balancing, and then switch Powerlab profiles and run through two cycles of 40A (8C) discharge, 10A (2C) charge. All told it takes about 80 minutes each. Well, three down, 52 to go... :dead:

My test setup:

Got just about everything else I need for the build coming in the mail; I just need to get the motor brackets sorted out...

Well, it's been a while, but I finally have some exciting updates! :D

I finally finished testing all the battery packs for phase 1 (ie, smaller pack while I wait for them to re-stock the US warehouse)! And a beautiful sight it is too. :D

I ended up being 3 packs short, so I did break down and order 6 from the Hong Kong warehouse...shipping came to almost half what I paid in shipping for each of the 27-cell shipments from the US warehouse! O_O

So, now that I finally know how many I have to work with in this pack, I started working on the battery box. I tweaked my initial design a bit after experimenting with the plastic-only construction...was just too hard to make and not quite strong enough for my liking. So I I went with 1/16"x3/4" aluminum angle for the corners. Bolts go through the alu and thread into the plastic. Seems to be holding together nicely...I do need to get myself a real M4 tap though; the 8-32 I'm using is close, but not quite there. Good enough for a prototype though. :D

I've already found some points I need to address...needs to be about an inch taller to start... Oh well, the materials are relatively cheap, and this is why we make prototypes, neh? :D Does look pretty sweet though, if I do say so myself. :D

Still waiting on the motor adapter and rear sprocket, and still working on finalizing the battery box design, but I got some mockups put together for the battery boxes and got them put in place on the bike.

The Controller will go on top under the tank. The charger will go under the seat...it will require some trimming of the heatsink, but it will fit. And the DC-DC is either going under the seat with the charger or under the tank with the controller...depends where I have space.

I know, I know, 'But how are you going to fit 2.7x that capacity on the frame?' ...well, that's a good question...and that's a bridge I'll cross when I come to it...I am working on that though.

This is an awesome project!

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Originally Posted by x88x

I know, I know, 'But how are you going to fit 2.7x that capacity on the frame?' ...well, that's a good question...and that's a bridge I'll cross when I come to it...I am working on that though.

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Astronaut suit with backpack. You want to look futuristic riding this or what? It's the only way.

Can you turn the two middle packs parallel with the bike and drop them in side by side? Then another two on top of them and then one or two where the top pack currently sits. I'm not sure of the exact dimensions of the packs though, so this might be a wrong estimation.

That's a lot of batteries! 2.7x more?..:think:Trailer?

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Originally Posted by x88x

I know, I know, 'But how are you going to fit 2.7x that capacity on the frame?' ...well, that's a good question...and that's a bridge I'll cross when I come to it...I am working on that though.

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Two words - hardside saddlebags.