Difference between pages "Main Page" and "DIY-battery"

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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>
'''Intent:''' This page is created as a guideline whether if assembling/designing your own battery pack is a viable option compared to buying a pre-made battery.
Prerequisite software/knowledge (before building a pack)


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.  
Ability to draw 2D schematics/diagrams. - you need to do this if you are trying to make a pack with a certain dimension constraint. use of CAD is encouraged.


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 support us via [https://www.patreon.com/Ebikes Patreon]
You know how to use the [https://ebikewiki.com/index.php/Simulator|Grin simulator] - You need to know how much current your battery will be drawing.


[[File:Wiki_Cover.jpg|link=https://www.patreon.com/Ebikes|Support us on Patreon|frame]]
Ohm's law. Since we are not going into AC power, complex number/angle is not needed.  


==Beginners start here==
Ability to read battery cell datasheet. - As the wiki page becomes older, more cell info will be added to the page; but for cells that are not on this wiki/internet in a simplified format, reading datasheet will be necessary. [https://www.batteryspace.com/prod-specs/11514.pdf LG M50LT datasheet, from batteryspace], [https://www.batemo.de/products/batemo-cell-library/lg-energy-solution-inr21700-m50lt/ Simplified datasheet of M50LT, courtesy of Batemo.de]


*[[Safety Tips]], Safety first. Don't skip this section!
You will most likely see terminologies that you've never encountered before, this will be explained along the article.


*[[Premade or DIY]], what one is right for you?


*[[Volts and Amps]], amp hours, watts and watt hours, what do they mean for an e-bike?
==Safety==
Batteries become explosives if they are uncontrollably discharged. Therefore, at all times, you must respect the cell and equipment that you are using and know how to operate them. This would mean:


*[[Hub or Mid drive]], what one is best for you?
*Do not solder directly onto cells, unless you know what you're doing. you are thermally stressing the cell. In practical term, this would be putting soldering iron onto cell junction for extended period of times. The industry uses spot welders or screw-on terminals to reduce thermal stress on cells.


*[[Pedal Assist (PAS) or torque sensor]], Methods to control your e-bike
*Do not leave individual cells outside packaging unkept. Store them in a container, if possible.


*[[Prebuilt]] Prebuilt bicycles, just order and drive!
*Do not use used cells, if possible. Used cells are not recommended because they will have different internal resistance (IR) and it will be harder for BMS to balance packs with different IR and increase chance of cell failure.


*[[Motor Controller]] Learn what your motor controller is and does
*Do not make a battery pack without a BMS. Always use BMS from reputable sellers with appropriate discharge rating. For example, 30A battery should have at most, 30A BMS, preferably slightly lower for safety margin)


==Do It Yourself!==
*Do not place/use conductive objects when making battery, if possible. This is generally unavoidable when using spot welders. In this case, cover the areas that you are not working on to reduce likelihood of shorts.


*[[Buy a bike]] to convert.
*In case of actual fire, do not try to put out the fire, Li-ion fires are uncontrollable and specialized fire extinguishers are needed. [https://www.youtube.com/watch?v=HQFff-KQ7EY Even this is not enough for large li-ion fire]


*[[Batteries]], where to buy and what to look for.
If this is your first electronics project, stop what you're doing. You're most likely to screw something up and burn your house down. If you don't know how to use a soldering iron and doesn't know how to use a multimeter, consider doing some other electronics project (learn from makerspace) then try again later.


*[[Motor]], where to buy and how to pick.


*[[Tools needed]] to convert a bike to an e-bike.
==Equipment requirement==


*[[Parallel Batteries]] for more capacity.
===Soldering iron===
depending on design, you may not even have to solder anything, but you most likely will for balance wires. Balance wires are used by the Battery Management System (Hereinafter BMS) to read a pack's voltage for charge/discharge/storage.
Pinecil will work for balance wires, but a higher power soldering iron will be necessary if you are soldering bus wire/plates.


*[[Connectors]] to use and ones to avoid.
===Battery case===
The shape/volume of the case determines how much cell you can fit in the case. You can 3D Print a battery case, and this will be explained further. In general, injection-molded/hardcase plastic battery case (if designed/manufactured well) will be almost always superior to a 3D printed/handmade case. Therefore, the latter cases are for more experimental purpose that market does not provide i.e. very large in dimension, custom mounting/hole for heatsinking, etc.


== Accessories for your e-bike ==
===Spot welder===
Spot welder of your choice, and something that won't fail after using it for an hour. They are either battery-powered, or supercap-powered. [https://www.nasa.gov/sites/default/files/atoms/files/prc-0009_current.pdf NASA's guideline on spot welding.]
Most li-po based spot welders on ecommerce site doesn't seem to last long. Expect anything under $100 be a "lottery", more or less.


*[[LED Lighting]], Information about all the LED lights on the market and how to buy the right ones for you.
===Multimeter===
used for troubleshooting. Red probe goes on V+, Negative probe goes on V-. '''Do not mix these up.'''
Cheap, reliable multimeter will do. we're not measuring high voltage here. Something like fluke 101 works.


*[[Racks and Panniers]], Storage for your e-bike! put it to work getting your groceries.
===2D/3D CAD software===  
 
To your preference - there are hobbyist/entry level software that usually has limited/featureset comapred to hobbyist-level and professional (career)-level software, but for this purpose, as long as you can do 2D sketch and do 3D model using sketch, it will work. Example: [https://www.tinkercad.com/ Tinkercad] [https://www.autodesk.com/products/fusion-360/free-trial Fusion 360]
*[[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.

Revision as of 13:10, 13 September 2023

Intent: This page is created as a guideline whether if assembling/designing your own battery pack is a viable option compared to buying a pre-made battery. Prerequisite software/knowledge (before building a pack)

Ability to draw 2D schematics/diagrams. - you need to do this if you are trying to make a pack with a certain dimension constraint. use of CAD is encouraged.

You know how to use the simulator - You need to know how much current your battery will be drawing.

Ohm's law. Since we are not going into AC power, complex number/angle is not needed.

Ability to read battery cell datasheet. - As the wiki page becomes older, more cell info will be added to the page; but for cells that are not on this wiki/internet in a simplified format, reading datasheet will be necessary. LG M50LT datasheet, from batteryspace, Simplified datasheet of M50LT, courtesy of Batemo.de

You will most likely see terminologies that you've never encountered before, this will be explained along the article.


Safety

Batteries become explosives if they are uncontrollably discharged. Therefore, at all times, you must respect the cell and equipment that you are using and know how to operate them. This would mean:

  • Do not solder directly onto cells, unless you know what you're doing. you are thermally stressing the cell. In practical term, this would be putting soldering iron onto cell junction for extended period of times. The industry uses spot welders or screw-on terminals to reduce thermal stress on cells.
  • Do not leave individual cells outside packaging unkept. Store them in a container, if possible.
  • Do not use used cells, if possible. Used cells are not recommended because they will have different internal resistance (IR) and it will be harder for BMS to balance packs with different IR and increase chance of cell failure.
  • Do not make a battery pack without a BMS. Always use BMS from reputable sellers with appropriate discharge rating. For example, 30A battery should have at most, 30A BMS, preferably slightly lower for safety margin)
  • Do not place/use conductive objects when making battery, if possible. This is generally unavoidable when using spot welders. In this case, cover the areas that you are not working on to reduce likelihood of shorts.

If this is your first electronics project, stop what you're doing. You're most likely to screw something up and burn your house down. If you don't know how to use a soldering iron and doesn't know how to use a multimeter, consider doing some other electronics project (learn from makerspace) then try again later.


Equipment requirement

Soldering iron

depending on design, you may not even have to solder anything, but you most likely will for balance wires. Balance wires are used by the Battery Management System (Hereinafter BMS) to read a pack's voltage for charge/discharge/storage. Pinecil will work for balance wires, but a higher power soldering iron will be necessary if you are soldering bus wire/plates.

Battery case

The shape/volume of the case determines how much cell you can fit in the case. You can 3D Print a battery case, and this will be explained further. In general, injection-molded/hardcase plastic battery case (if designed/manufactured well) will be almost always superior to a 3D printed/handmade case. Therefore, the latter cases are for more experimental purpose that market does not provide i.e. very large in dimension, custom mounting/hole for heatsinking, etc.

Spot welder

Spot welder of your choice, and something that won't fail after using it for an hour. They are either battery-powered, or supercap-powered. NASA's guideline on spot welding. Most li-po based spot welders on ecommerce site doesn't seem to last long. Expect anything under $100 be a "lottery", more or less.

Multimeter

used for troubleshooting. Red probe goes on V+, Negative probe goes on V-. Do not mix these up. Cheap, reliable multimeter will do. we're not measuring high voltage here. Something like fluke 101 works.

2D/3D CAD software

To your preference - there are hobbyist/entry level software that usually has limited/featureset comapred to hobbyist-level and professional (career)-level software, but for this purpose, as long as you can do 2D sketch and do 3D model using sketch, it will work. Example: Tinkercad Fusion 360