Whats the criteria for selecting a battery based on motor and controller

[Curiouslearner]

Hello, I am new to Ebiking scenario and want to know that how to pair and select the right battery which would complement the motor and controller as I was planning of getting a entry level ebike and then later add do a dual battery setup or attach an auxiliary battery for my long range commute when need arises. you guys here seem to be really well versed in all such technical and DIY stuff please help me out if you can share some knowledge regarding these.

Points I need clarity on:
Can any battery go on any ebike

What all critics needs to match

Does it depend on controller selection or motor selection

How battery V and AH and motor V should be chosen and approx cost of a standalone battery of 20AH

Please tell me a good battery recommendation for 250w & 500w rear wheel hub motor and what controls usually go along with it and is the process of setting up a auxiliary battery difficult for a complete newbie

 

[Curiouslearner]

Sorry your question is a bit broad.
What do you need to know now? Do you already have an ebike and trying to upgrade it? Are you trying to build your own custom DIY ebike?

No haven't bought anything yet just trying to gain info on how things work as I am confused what would be better buying one or making one

 

[Sierratim]

Points I need clarity on:
Can any battery go on any ebike

Technically yes, but mounting can be hard to easy. Batteries that clip into a rear rack are easy and secure. Batteries that fasten to a down tube can be less secure as a function of the frame inserts and frame material. My first DIY conversion used a rack mounted battery

Does it depend on controller selection or motor selection

How battery V and AH and motor V should be chosem

The battery voltage needs to match the motor rating. The controller voltage rating needs to be the same or higher.

The battery AH rating should be chosen based on the motor power rating ÷ motor voltage rating x 1hr. A 48V 500W motor should be paired with a 48V battery that has an AH rating of at least 500W ÷ 48V x 1hr = 10.4AH. This helps assure that the battery will not be over stressed when driving the motor at max power. A higher AH rating will equate to longer range and extended battery life. The controller current rating should be comfortably higher than the motor's maximum current draw. In this example I'd suggest a minimum 20A rated controller for the 10.4A current the motor will draw.

Approx cost of a standalone battery of 20AH

Please tell me a good battery recommendation for 250w & 500w rear wheel hub motor and what controls usually go along with it and is the process of setting up a auxiliary battery difficult for a complete newbie

Battery quality is determined by the quality of the individual cells and of the assembly. A reputable supplier will address these topics well. I've had good results with Ping Battery;

LiFePO4 Battery - Lithium Iron Phosphate Batteries

LiFePO4 Battery Packs for Electric Bikes, E-Scooters, EVs, Solar Systems, Robotics, Portable and Automated Equipments

www.pingbattery.com

They can cost more than some others but are well worth it, IMHO.

Grin Technologies offers motors, controllers, batteries, and accessories that are worth a look. Their tech support is excellent.

Shop

Grin Technologies

ebikes.ca

 

[Curiouslearner]

Technically yes, but mounting can be hard to easy. Batteries that clip into a rear rack are easy and secure. Batteries that fasten to a down tube can be less secure as a function of the frame inserts and frame material. My first DIY conversion used a rack mounted battery



The battery voltage needs to match the motor rating. The controller voltage rating needs to be the same or higher.

The battery AH rating should be chosen based on the motor power rating ÷ motor voltage rating x 1hr. A 48V 500W motor should be paired with a 48V battery that has an AH rating of at least 500W ÷ 48V x 1hr = 10.4AH. This helps assure that the battery will not be over stressed when driving the motor at max power. A higher AH rating will equate to longer range and extended battery life. The controller current rating should be comfortably higher than the motor's maximum current draw. In this example I'd suggest a minimum 20A rated controller for the 10.4A current the motor will draw.


Battery quality is determined by the quality of the individual cells and of the assembly. A reputable supplier will address these topics well. I've had good results with Ping Battery;

LiFePO4 Battery - Lithium Iron Phosphate Batteries

LiFePO4 Battery Packs for Electric Bikes, E-Scooters, EVs, Solar Systems, Robotics, Portable and Automated Equipments

www.pingbattery.com

They can cost more than some others but are well worth it, IMHO.

Grin Technologies offers motors, controllers, batteries, and accessories that are worth a look. Their tech support is excellent.

Shop

Grin Technologies

ebikes.ca

Thankyou so much sir ,you almost covered all my queries and plus added some extra hot tips I appreciate you sharing your insight on the topic it is now it is a lot more clear to me and I can choose better for myself.
Few more questions is it possible to mount auxiliary battery to any bike if the frame has space or a rear rack is mounted and as long as suitable plug can be found .....?

what I understood by that is as long as I am selecting same V battery as my motor V but with whatever W power the factor affecting my range will b the sum of AM. Asking you for your personal opinion what ymeould you pair with a 36v 250w motor and 36v battery acc to you could possibly be the best battery to get if I want to switch it with a 20AH

And also give a recommendation for the same scenario but this time around48v 500W motor and getting same 20AH out of it

 

[ruffruff]

In terms of an aux. battery it will depend on how you wire it up.
If you wired it in parallel with the existing battery the voltage will stay the same and the Amps will add together.
If you wire it in series with the existing battery the voltage will add up and the Amps will remain the same.
Kirchoff's laws!

If you are just going to swap and only run one battery at time, as long as the V is OK for motor/controller , it's just a matter of matching the connector.