4 A Convenient Response to an Inconvenient Truth

1957 Porsche 356 Speedster Electric Conversion. Lithium Ion Iron Phosphate Issues.

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• Inconvenient
• Truth

[AlonzoTG]

Your presentation is outstanding save for a minor technical errors. The motor is actually rated for 156 volts (confirmed by correspondence with Netgain). It is not inferior in any way to the Advanced DC motor (a 144 volt motor) it was based on. Why only 72 volt specifications are provided is a mystery for the ages. I'm curious as to why you selected the 90 amp-hour version instead of the 200 amp-hour version.

[marionrickard]

Those are not precisely technical errors Alonzo. The Netgain is a much superior motor to the ADC, in my opinion. And the absolute limit (confirmed with Netgain) is 192 volts.

We originally planned and indeed purchased 180 Ah cells for the vehicle. Unfortunately, the body is mostly curves, and the "granularity" of the size of the cells simply thwarted us in placement. So we wound up with two parallel strings of 90Ah. This gives us the same size pack, but the smaller cell size was better.

[ClematisReiss]

I, as an ev designer, thank you for explaining this in a basic way to all of the people.

[tomaselvis]

Thanks for your answer! :D

[creamyfilling102]

@tomaselvis regenerative braking generaly works better with AC systems. the AC motor controllers have voltage regulating systems that can easily charge from the unconstant motor speed during a slow down. DC systems don't do that, because it requires bulky wiring and a bunch of technical jimmy rig crap and isn't usualy persued.

[tomaselvis]

Do you plan to incorporate recharge from braking power? Instead of just burning the energy away into heat? That would increase the range.

I wonder however if the braking power is to much at once to store.

What do you think?

By the way, beautiful car!!