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

  • Context: Undergrad 
  • Thread starter Thread starter just.karl
  • Start date Start date
  • Tags Tags
    Amp
Click For Summary

Discussion Overview

The discussion revolves around the feasibility of using capacitors instead of lead-acid batteries for powering an E-bike, specifically exploring the relationship between capacitance (in Farads) and energy storage (in Amp hours) at a voltage of 12V.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions the possibility of using capacitors for an E-bike and asks how many Farads would equal 1 Amp hour at 12V.
  • Another participant provides a calculation indicating that 1 Ah is equivalent to 300 Farads at 12V, but suggests that more capacitance is needed due to voltage drop during discharge, proposing around 600 Farads with additional electronics to maintain voltage.
  • A third participant introduces energy storage equations for capacitors and batteries, suggesting a comparison of energy stored in both systems.
  • A later reply expresses realization that using capacitors may be more impractical than initially thought, reflecting on the responses received.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the practicality of using capacitors for this application, with some calculations and considerations presented but no definitive agreement on the feasibility.

Contextual Notes

Limitations include assumptions about voltage stability during discharge and the specific energy requirements for the E-bike, which are not fully resolved in the discussion.

just.karl
Messages
64
Reaction score
0
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!
 
Physics news on Phys.org
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.
 

Similar threads

  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 10 ·
Replies
10
Views
50K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 36 ·
2
Replies
36
Views
6K
  • · Replies 19 ·
Replies
19
Views
4K
  • · Replies 16 ·
Replies
16
Views
4K
  • · Replies 1 ·
Replies
1
Views
3K