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Discussion Starter · #1 · (Edited)
Hi, I am new here reading a couple of EV data which looks very interesting and motivating.

Can anybody suggest me the detaisl on my below requirement.

If i wanted to convert a VW beetle to an electric car .

Desired top speed is = 150mph
Desired power is = 170hp
Desired range is = 100 miles.
Battery desired is lifepo4 batteries.

what would be the total voltage (V) and current(ah) that i should be considering for the battery pack.?
 

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Hi Invent
Not sure if 170 hp is enough for 150 mph

You want 100 miles range - I assume that is at highway speed

So you need about 40 Kwhrs for your range

170 Hp is 127 Kw - a 40 Kwhr battery should be capable of delivering that for a short period

Why do you want lifepo4 batteries?? - they will be much more expensive and not as good as using Tesla or Leaf or Volt batteries

The voltage required depends on the motor/controller that you have

The cheapest way of meeting your requirements would be get a complete scrapped Nissan Leaf and transferring the bits across + a new controller brain board
 

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So you need about 40 Kwhrs for your range

170 Hp is 127 Kw - a 40 Kwhr battery should be capable of delivering that for a short period
Key point Duncan is making here 40Kwhr will be great for your range at moderate speeds 50-60mph. If you want your range at 150mph then you probably will need that 300Kwhr pack. I think the ideal target is somewhere in between. But 40Kwh is a common target, usually due to budget, weight and availability constraints.

The maximum voltage and current can't be answered in isolation.
It depends on the direction you choose. What motor and what controller. Then you specify your battery pack to target the upper limits of those two components.

Keep in mind the voltage and current limits of the battery are not necessarily the same as the volatage and current at the motor.


  1. Once you have the desired voltage of the battery pack you divide it by the maximum voltage of the type of chemistry to know how many cells in series.
  2. Then multiply the number of cells in series by their capacity (amphours) to get capacity of a single 'sting" in series.
  3. Then divide your target capacity by the capacity of the single string in series to understand how many 'strings' of cells will be required in parrallel.
I hope that makes sense.

At a rough guess I think you should start looking at maybe 300v, 1000amps at the battery and more like 60Kwh to give you a buffer. I think 60Kwh is a better bet because to achieve the performance you are targetting you will end up with a heavier vehicle and VWs aren't the most aerodynamic cars.
I think your motor/s will need to handle around 2000amps for short periods to acheive that sort of speed....but I wouldn't be trying to hold those speeds for long. 2000amps for lets say 2minutes to get you to 150mph would mean motor system that handle around 1000amps continuous.
 

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I can't add much to the guidance already provided, but I have to ask...

  • A real Beetle (hopeless antique that should never go 150 mh), or a New Beetle (generic modern compact with retro body)?
  • Why the Beetle (either way)?
  • Do you understand that the 150 mph speed is exceptionally high, for either an electric vehicle or for any variety of Beetle?
 

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If the zombie 222 can almost hit 200 a beetle can go 150.
Even aside from the fact that the original Mustang was designed three decades after the original Beetle, they have nothing in common, and the Mustang is fundamentally much more sound for high-speed operation.

Still, even a old Beetle chassis could go 150 mph with an adequate degree of stability, with a bunch of work. After all, an old Porsche is nothing but a slightly rebodied Beetle.

I'm just curious, not judging. :)
 

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Even aside from the fact that the original Mustang was designed three decades after the original Beetle, they have nothing in common, and the Mustang is fundamentally much more sound for high-speed operation.

Still, even a old Beetle chassis could go 150 mph with an adequate degree of stability, with a bunch of work. After all, an old Porsche is nothing but a slightly rebodied Beetle.

I'm just curious, not judging. :)
True. And true.

Sent from my SM-N910V using Tapatalk
 
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