A log of the trials, tribulations, and general boring stuff involved in owning an electric car... an EV conversion... a battery-only electric car... Plankton the electric 1976 BMW 2002.
Plankton's current specs
Plankton's Current Specs:
Motor: 9" Series DC, refurbished by Jim Husted in Redmond, OR.
Controller: Synkromotive
Batteries: 35 CALB LiFePo4 cells (115.5V nominal pack voltage)
Charger: Elcon PFC1500, so far only charging from house mains 110-120 AC.
Pedal: Ford Ranger TPS
-No clutch
-12V Pb-Acid auxiliary battery for car electrical (blinkers, lights, etc.)
-Generic (??) vacuum pump for brake assist (no power steering)
Monday, February 2, 2009
Cool! My aluminum just showed up on 1/30/09. (I'm catching up to real-time in my blog... almost). The plate on the left was water-jet cut to my CAD dimensions by the metals place (IRC Aluminum and Stainless in St. Johns), the other hunk of aluminum will be put on a machining center which will mill it down to the dimensions of my CAD design.
Here is a shot of the CAD design of how I'll mate the motor to the transmission. The motor is hanging out to the left, the big flange thing is the adapter plate, and the shaft couple is in the center (half of it's colored blue).
And here is a cross-section in case anybody would like to peruse it. The motor is in black. This is a little reversed from the photo of the CAD. Oops.
And here is a cross-section in case anybody would like to peruse it. The motor is in black. This is a little reversed from the photo of the CAD. Oops.
I needed a way to connect the two shafts- one from the electric motor and one from the existing BMW transmission. The problem is, they weren't made to go together. The shaft from the motor is a smooth shaft with a keyway, and the shaft from the transmission is splined (the old clutch disk is splined and slid onto the splines of the tranny... well at least it used to, but I won't have a clutch). So here is the first thing I got, a Lovejoy coupling. It is basically two metal collars that slide together, with a urethane spacer in between them. The urethane allows a little bit of give if there is minor misalignment. I thought it sounded good to allow for a little misalignment. The picture shows the coupling (assembled) on the left, there is a key (for the keyway) in the center, and a collar is shown on the right. The collar, plus another, will keep this whole assembly from moving fore and aft on the two shafts. It'll be trapped.
The shaft of the motor fits right onto this thing, but I need to mod the other half to accept the splined center of the old clutch disk. I'll have a shot of that later, it's not done yet.
The shaft of the motor fits right onto this thing, but I need to mod the other half to accept the splined center of the old clutch disk. I'll have a shot of that later, it's not done yet.
Transmission digitizing
Next step was to start figuring out how to connect the motor to the existing transmission. I decided to do without a clutch... rumor has it that 2nd gear is good for around town, maybe 3rd gear for the freeway. So, there will be a bit of a learning curve on shifting without a clutch, we'll see how it goes.
The tranny was already out with the motor, so I hauled it to work and digitized the bolt-hole positions on our CMM (coordinate measurement machine).
The tranny was already out with the motor, so I hauled it to work and digitized the bolt-hole positions on our CMM (coordinate measurement machine).
Motor arrival
I think it was Sept 16th 2008 or so, when my motor showed up! I ordered it from Jim Husted in Redmond, OR. He's a pro at rebuilding them evidently. I think this was an old forklift motor. Eventually we'll see how it works! Here's a comparison shot of the two tire-screechin' ground-poundin' mills side-by-side.
The beginning
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