Electric Porsche – Parts revision

With any project parts selection is a difficult process, balancing budget/performance/availability isn’t always easy. After many more calculations it’s very clear that the battery pack will be the limiting factor on the actual power output of my Porsche conversion. So unless I plan to upgrade the battery pack, using the Kostov 11″ motor and Soliton1 are simply overkill which wastes money that could otherwise be put towards the limiting factor which is batteries (I will state that the Soliton1 isn’t a waste of money, it looks like an amazing piece and if the funds are there when it’s time to buy a controller I will choose it over the Warp Drive, however if the funds aren’t there the latter will prevail).

I’ve decided on the Warp 9″ motor, which is common to many many car and truck conversions, it’s reasonably priced, good quality and definitiely proven.

 

The Warp9 should also provide good performance, with the new controller I have chosen I should still be able to get between 237 and 339ftlbs of torque at maximum motor current which will be between 1000A and 1400A this is still quite a bit more than the stock 2.5L motor. Using the 1400A version of the controller the 9″ motor would put out more torque than any of the stock engines of any year the 944 was produced for both the Turbo and NA.

This new controller is also from the Warp family in the form of a Warp Drive 160V 1000A/1200A/1400A beast. The hardware is all the same, and software upgrades unlock the higher current levels ($$$). Higher voltages are also unlockable with software updates with the appropriate exchange of $$$ of course. The nice part is the controller is about $1000 less than the Soliton1 in basic form, with optional but slightly expensive upgrades to allow more power output than even the Soliton1 is capable of. One of the nice parts of this is the controller is designed for it’s maximum power level and scaled back in software to the basic versions, so the controller will not be pushed to it’s limits and should last for many many years.

The controller uses a CAN bus system for expansion and if a few companies get on board there could be a nice selection of extras available in coming years. Since the maximum voltage for the controller is 160V in the form I will be using the battery voltage must be scaled back, I will be using 48 Thundersky cells instead of 90 for the 288V pack, however I will be using larger cells to get a slightly larger pack size than the original design. The new nominal battery voltage will most likely be 153.6V at 200Ah, which is about 15% larger than the previously planned pack. I could also drop down to 160Ah cells which would make a pack just slightly smaller than the previous design, at the cost of continuous current which reduces maximum power.

Peak power (only limited in duration by the amount of heat the motor can dissipate) is 86,400 Watts, the controller and batteries can handle this power on a continuous basis, however the pack would be dead pretty quickly. If I am able to find a source for the CALB 180Ah 4C cells peak power would increase to 103,680 watts. Peak torque is based on the amperage output of the controller, at 1000A being 237ftlbs, 1200A around 288ftlbs and 1400A around 339ftlbs. The RPM range for this torque level will be zero to x rpm where x is the point where current starts to get traded for voltage by the controller based on the current limit of the battery pack. It should be around 2000-2500rpm. The higher current CALB cells would allow maximum torque up to a higher RPM, but either pack will allow full torque at low RPM. To get maximum range the battery current will have to be kept to a reasonable level, so just the same as a gas car, the harder you press the gas the lower your fuel economy gets. With all the upgrades the controller is capable of over 1/2 a megawatt of power or the equivalent of 675 horsepower. However that would require a bigger motor and better batteries than I ever plan on putting in the Porsche.

Right now the car has about 2/3 of a tank of gas, when it’s empty the engine comes out. The gas parts start to go up for sale and the electric motor will get ordered, so I still have a little time to change my mind again on motors.

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