First commute with LiFePo4 batteries!!

Alot of changes I haven't posted about:

- Synkromotive controller installed

- 35 CALB LiFePo4 cells installed

Today was my first day commuting with the CALB cells. Granted, it's only a 14-mile round-trip commute, but I was still pretty excited about doing it! And- it was uneventful. The car kept up with traffic no problem (old Pb-Acid cells were lethargic), I had plenty of reserve range to make it to work, and it rained (this is July in Oregon... yay).

I set my Elcon charger to charge to approximately 3.54 V/cell and it worked great, finished the charge. I had balanced the cells the previous weekend so that was as expected. I plan to balance again this weekend just to make sure things are leveled out. My cells were not equal as-delivered. But CALB was great to work with other than that, answered all my questions promptly and delivered promptly too. I had to wire transfer in order to save a CC surcharge, but that was fine with me.

The Synkromotive has been just awesome so far. One problem I have though, is that the CAT5 communications with it seem to drop out when I accelerate the car. This is probably due to some issues with EMF, there is no way to avoid going past some HV cables with the CAT5. Still trying to iron that out with ferrite filters and such.

That's all for now. Stay posted for more boring commute logs. Feel free to ask questions!!

-Todd

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.

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.

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).

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.

Here's a shot of the motor being pulled out. He didn't want to give it up easy, but it finally came.