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Thursday
Dec132012

Video installment 1

Let's begin with the beginning. The Porsche had been sitting, unusable, for some many months and accumulated a coat of dross that truely diminished its beauty. So naturally, we gave it a bath before gutting it.

Frankly, we didn't know what we were in for when it all began. The modest performer had been stuffed to the gills with lead. It frankly was a bit portly. Our intent was to get an official weight before and after, but the tow truck driver was over booked and uncooperative. By spec, we shaved 500 pounds off the car in batteries alone. That doesn't account for the trade-off of steel for aluminum structure holding said batteries. What we can tell you is that the car grew taller by an inch through the whole process.

Hidden fasteners are not unheard of, so we didn't think anything of it when we didn't notice any straps across the tops of the traction batteries. Upon removing the terminal covers, we found that indeed there were no hidden fasteners because there were no fasteners. Of all the batteries, the only one held down was the original 12v left in place from when the car was gasoline powered. This is not acceptable. We still are astonished by the lack of concern for safety that the prior converter displayed.

Beyond a lack of restraint, we discoverd that the battery terminals themselves were not adequately tightened in at least one case. The front of the car had been home to eight 12v batteries with five completely obscured by the other three. Occasional maintenance checks for tension was not an option. Our new batteries feature much more secure connections through the use of Nordlock locking washers; they actually require more force to loosen than was used to initially tighten them.

 

Thursday
Dec132012

Porsche Recap

In writing this, the conversion is nearly complete.  We have deviated from our original intent of just swapping batteries and instead gutted nearly everything and refreshed it all. The only thing we didn't do is remove the mounting bolts on the motor.

  • Reprogram and completely reposition charger
  • Reprogram and improve mounting of motor controller
  • Installed redundent safety disconnects
  • Installed inertia switch
  • Integrated all electric heat into passenger climate controls
  • Integrated motor speet limiting
  • Connected motor RPM to exiting tach guage (had not been done before)
  • Integrated "Check engine" light for motor controller to instrument cluster
  • Integrated Power on confirmation to instrument cluster
  • Eliminated leaky heater system (had previousely damaged charger)
  • Provided full pack voltmeter (previously only displayed portion of pack)
  • Provided Amp-hour meter to track true state of charge
  • Provided for continous power to steering and air conditioning systems
  • Upgraded charger to industry compliant J1772

All in the process of just upgrading some batteries.

Our intent was to publish video and commentary on the process as it was happening. We shot video, but are now publishing it post conversion. Doing it and getting it done were higher priorities than talking about doing it and getting it done.

Friday
Oct122012

Conversion Underway

We have been blessed with the opportunity to resurrect this 1987 Porsche 944 owned and operated here in Des Moines. This is destined to be a real multigenerational EV. It is already in its second generation and with care will certainly continue for some time.

 

The core of our services to the car is replacing the end of life lead batteries with a fresh set of China Aviation Lithium Battery CA100fi Lithium Iron Phosphate cells. These are brutes. In batteries alone we'll have a 500pound reduction in weight. We will also regain some elbow room granted through the better volumetric energy density of these cells. All this while also nearly doubling the expected range.

There is a whole list of other items we will be addressing in future updates.