ElectroClassic EV
Classic Cars Reborn into the Electric Future

Tip the Scales

One question always comes up regarding the weight difference between a gas engine and electric motor with batteries, which prompted me to gather the cursory figures below. Some of the data came from various Porsche websites, and other from my bathroom scale. Once the car is running, I’ll hunt down a truck scale to check the accuracy of my guesstimate, and compare to the factory weight reported on the driver doorpost sticker shown above. I’ll make sure to update this entry when I have that final number (see note at bottom).

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Weight Lost – 532 lbs

  1. Gas engine – 277 lbs
  2. Exhaust manifold and muffler – 30 lbs
  3. Engine fan, hoses, sheet metal – 20 lbs
  4. Starter and solenoid- 13 lbs
  5. Fuel, 16.4 gallons @ 6.3 lbs/gallon – 103 lbs
  6. Gas tank (empty) – 12 lbs
  7. Weight removed from flywheel – 7 lbs
  8. Auto battery, 12 volt – 50 lbs
  9. Bumper tits, 2.5 lbs x 4 – 10 lbs
  10. Trunk lid springs – 10 lbs

Weight Gained – 710 lbs

  1. LiFePO4 battery pack (12.3 lbs x 36) – 444 lbs
  2. AC50 electric drive motor – 122 lbs
  3. Curtis 1238-7601 controller – 16 lbs
  4. Controller cooling plate and circulation system – 20 lbs
  5. Elcon PFC2500 battery charger – 16 lbs
  6. Zivan NG1 DC-DC converter – 7 lbs
  7. CanEV motor adapter and hub – 15lbs
  8. Battery racks: front trunk, fuel bay, and motor bay – 24 lbs
  9. Battery cabling and lugs- 40 lbs
  10. Battery management system – 6 lbs

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The difference between weight lost and gained results in an approximate surplus of 178 lbs, which is excellent compared to earlier EV conversions. Before lithium cell technology became viable, EV enthusiasts powered their cars with regular flooded lead acid auto or marine batteries. Ten or more batteries could add over a half-ton of weight, which required beefing up the suspension of the donor vehicle, reinforcing the body or frame, adding sealed trays to contain possible acid leaks, and installing ventilation fans for hydrogen out-gassing. Lithium batteries are twice as expensive, but are also half to a third the weight, and have greater power density. They also require nearly zero maintenance and last twice as long. If you can stretch, lithium is a better investment in the long run.

** Note: The GVWR reported on the door post sticker is not the vehicle’s curb weight. The exact final curb weight of the car is revealed in the post entitled Sliding Scale.

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3 Responses to “Tip the Scales”

  1. That’s only the weight of an additional passenger. With instant torque, I would guess it will still beat a stock 914 in a quarter-mile!

  2. Wow. That makes my palms sweat!

  3. If you started running instead of dawdling – you could easily loose that
    60 lbs which means your car would only be 106lbs heavier than when it was born, – (just sayin’)
    Fordy


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