Difference between pages "Main Page" and "Volts and Amps"

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<strong>E-bike Wiki is an online collaborative encyclopedia focused on selecting or building an E-bike, repair and related information.</strong>
Volts, Amp, Amp hours, watts and watt hours, what do they mean for an e-bike?


  [[File:Wiki Cover.jpg|center|800x800px]]
These are the units of measurements for batteries, controllers and motors. Lets dive into what each means in detail:


We hope to answer all the questions you have about electric bikes from where and what parts to buy all the way to riding them for the maximum range. This wiki is maintained by the E-Bikes discord. If you wish to chat in real time with us, come join us on [https://discord.gg/PZ2y4gv Discord] and please support us financially via [https://www.patreon.com/Ebikes Patreon] so we can continue to bring you e-bike information!
==Volts==
==Beginners start here==
Volts is directly related to max RPM for a given motor. For a given battery voltage will slowly decrease as it discharges (See https://cdn.discordapp.com/attachments/734563841228275763/787404431360000001/unknown.png for chart).


* [[Safety Tips]], Safety first. Don't skip this section!
==Current==
Current (measured in amps) is directly related to the torque of your motor. You will often see a controller specify its 'battery amps' and 'phase amps'. Phase amps are your peak torque at lower RPM, where the controller can exchange voltage for amps to give you extra torque at low speed. Battery amps are what will be drawn from the battery. You absolutely must have a battery rated for the same or more amps then your controller is rated to use or you will damage your battery when the controller draws too much.
==Watts==
Voltage * battery Amps = Watts. Watts are your power. In fact it takes 745.7watts to make one horsepower. While voltage determins your absolute max RPM, without more watts you won't go any faster unless you where limited by the motor reaching its max RPM before you ran out of watts.
==Amp Hours==
Amp hours are how many amps your battery can give for one hour. For example if it was 10 amp hours, it could give 10amps for one hour, or 20 amps for 30 minutes, or 5amps for 2 hours. You might be mistaken into thinking that amp hours are equal to range, but that is only true for a given voltage as watt hours are the true unit of energy storage.
==Watt Hours==
Watt hours are Amp hours * Voltage. They tell you the true power capacity of a battery. In fact you will often find electric vehicles energy efficency expressed in watt hours per KM or mile. (wh/km or wh/mi). For a very rough idea, you can assume about 10wh/km for very slow riding at 25kph or below on flat ground, 20wh/km for fast riding up to 45kph or on slightly hilly ground, and up to 40wh/km for very fast riding at up to 60kph or on very hilly ground.  Exact figures vary greatly but this gives you a rough idea.
==C Rating==
Cells have what is known as a C rating, this is basically how quickly they can be discharged, with 1C being the current needed to fully discharge the cell in exactly 1 hour. You can calculate the peak discharge current by multiplying the AH rating and C rating hence for a 3.3Ah cell, 1C would be 3.3A and take 1 hour to discharge at that current. For a 2.5Ah cell, 1C would be 2.5A and also take one hour to discharge. a 2.5AH cell at 2C would fully discharge the cell in 30 minutes and at 5A current, 4C is the rate that would fully discharge the cell in 15 minutes at 10A for a 2.5AH cell, and so forth.


*[[Premade or DIY]], what one is right for you?
Note that the C rating is only the maximum you can safely draw from the cell, if you only draw at a lower current the cell will take as long to discharge as a lower C rated cell of the same Ah value
 
*[[Volts and Amps]], amp hours, watts and watt hours, what do they mean for an e-bike?
 
* [[Hub or Mid drive]], what one is best for you?
 
*[[Pedal Assist (PAS) or torque sensor]], Methods to control your e-bike
 
*[[Prebuilt]] Prebuilt bicycles, just order and drive!
 
*[[Motor Controller]] Learn what your motor controller is and does
 
==Do It Yourself! ==
 
*[[Buy a bike]] to convert.
 
*[[Batteries]], where to buy and what to look for.
 
*[[Motor]], where to buy and how to pick.
 
* [[Tools needed]] to convert a bike to an e-bike.
 
*[[Parallel Batteries]] for more capacity.
 
*[[Connectors]] to use and ones to avoid.
 
==Accessories for your e-bike==
 
*[[LED Lighting]], Information about all the LED lights on the market and how to buy the right ones for you.
 
*[[Racks and Panniers]], Storage for your e-bike! put it to work getting your groceries.
 
*[[Tires]] Where the rubber meets the road! Learn to buy tires won't leave you on the side of the road with a flat.
 
==Other websites of interest==
 
*[https://www.ebikes.ca/tools/simulator.html E-bike Simulator] Very accurate and useful e-bike Simulator. Has many motors modeled by actual testing including wind tunnel testing for cooling values. Often accurate within 10% or better to real world for top speed.
 
*[https://www.ebikes.ca/product-info/torque-arms.html Grin Torque Arm info] Super critical to read information about torque arms. Never use a V1 style torque arm they are well known to fail. Always use a V2/V3/V4 style if you are using a hub motor or your hub motor may destroy itself.
 
*[https://www.mpoweruk.com/ Electropaedia] a website about battery types and energy production.

Latest revision as of 04:21, 29 July 2022

Volts, Amp, Amp hours, watts and watt hours, what do they mean for an e-bike?

These are the units of measurements for batteries, controllers and motors. Lets dive into what each means in detail:

Volts

Volts is directly related to max RPM for a given motor. For a given battery voltage will slowly decrease as it discharges (See https://cdn.discordapp.com/attachments/734563841228275763/787404431360000001/unknown.png for chart).

Current

Current (measured in amps) is directly related to the torque of your motor. You will often see a controller specify its 'battery amps' and 'phase amps'. Phase amps are your peak torque at lower RPM, where the controller can exchange voltage for amps to give you extra torque at low speed. Battery amps are what will be drawn from the battery. You absolutely must have a battery rated for the same or more amps then your controller is rated to use or you will damage your battery when the controller draws too much.

Watts

Voltage * battery Amps = Watts. Watts are your power. In fact it takes 745.7watts to make one horsepower. While voltage determins your absolute max RPM, without more watts you won't go any faster unless you where limited by the motor reaching its max RPM before you ran out of watts.

Amp Hours

Amp hours are how many amps your battery can give for one hour. For example if it was 10 amp hours, it could give 10amps for one hour, or 20 amps for 30 minutes, or 5amps for 2 hours. You might be mistaken into thinking that amp hours are equal to range, but that is only true for a given voltage as watt hours are the true unit of energy storage.

Watt Hours

Watt hours are Amp hours * Voltage. They tell you the true power capacity of a battery. In fact you will often find electric vehicles energy efficency expressed in watt hours per KM or mile. (wh/km or wh/mi). For a very rough idea, you can assume about 10wh/km for very slow riding at 25kph or below on flat ground, 20wh/km for fast riding up to 45kph or on slightly hilly ground, and up to 40wh/km for very fast riding at up to 60kph or on very hilly ground. Exact figures vary greatly but this gives you a rough idea.

C Rating

Cells have what is known as a C rating, this is basically how quickly they can be discharged, with 1C being the current needed to fully discharge the cell in exactly 1 hour. You can calculate the peak discharge current by multiplying the AH rating and C rating hence for a 3.3Ah cell, 1C would be 3.3A and take 1 hour to discharge at that current. For a 2.5Ah cell, 1C would be 2.5A and also take one hour to discharge. a 2.5AH cell at 2C would fully discharge the cell in 30 minutes and at 5A current, 4C is the rate that would fully discharge the cell in 15 minutes at 10A for a 2.5AH cell, and so forth.

Note that the C rating is only the maximum you can safely draw from the cell, if you only draw at a lower current the cell will take as long to discharge as a lower C rated cell of the same Ah value