How Many Farads Equal 1 Amp Hour at 12V for an E-Bike?

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SUMMARY

The discussion centers on the feasibility of using capacitors instead of lead-acid batteries for powering an E-bike. It establishes that to equal 1 Amp hour at 12V, approximately 300 Farads are required, but due to voltage drop during discharge, a total of 600 Farads is recommended. This translates to needing 160 capacitors rated at 3V and 60F each. The conversation highlights the impracticality of this approach compared to traditional batteries, emphasizing the need for additional electronics to maintain voltage stability.

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just.karl
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I was just curious if it would be possible to make my E-bike run on capacitors instead of Lead acid batteries even if the range was much shorter. So how many Farads would equal 1 Amp hour? At 12v let's say for now. Thanks!
 
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1 Farad is 1 Ampere second per Volt. 1 F = 1 As/V.
1 Ah = 3600 As
3600 As / 12V = 300 As/V = 300F
But you need more then that because the voltage will drop as the capacitor discharges. Half the charge means half the voltage.
With a lead acid battery that's different. A battery that is half empty still has nearly the same voltage as it had at the start.
Maybe 600F and some electronics to automatically step up the voltage so it stays at 12V.
So you'd need to buy 160 capacitors with 3V and 60F each.
 
You will want to calculate each in terms of energy stored:

E = 1/2 C V^2 for a capacitor

E = P * time for a battery (P = V * I)


EDIT -- DrZ was too fast for me!
 
O... yeah so running it off capacitors was even more impractical than i thought. Thanks for the quick responses! This puts everything into perspective better for me.
 

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