# How to choose a battery for a copter

Hello

I am building a Y6 configuration drone.

How do I chose a battery?
Is there a website or some guidelines I can input my parameters in to figure out what kind of battery I need?

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Purchase a subscription to eCalc. Plug in the components and weight of the craft. Add the battery weight until the Motor @ Hover Throttle Linear value is between 45 and 50% and then buy the battery that weighs ~ that amount.

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That’s awesome. Thanks a lot!

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If you are building a vehicle from scratch, look at section 1 of How to methodically tune (almost) any multicopter using ArduCopter 4.4.x you’ll learn a thing or two. And reduce the number or iterations required to get it right.

Very interesting. Will check it right away

Started working my way into the calculations on eCalc website.

I am wondering if it is normal that they don’t have Matek flight controller in the list?

I would be surprised if eCalc (Xcopter Calc) knew any flight controllers. It is used to simulate calculate the propulsion system and the FC isn’t part of that, the FC is part of the control system.

However there is the “Accessories” part where you can enter current draw and weight for non-propulsion-system components (i.e. FC, GPS module(s) and other sensors, powered payloads like gimbals, cameras, etc)

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The thing is it is asking me questions such as continuous and maximum Amperage.
I found a few Amps figures on the specs page and am not sure which one to use:

This has nothing to do with the Flight Controller. If you are looking at the Controller section that’s the ESC. Just pick any one of sufficient current, or more, and leave the default values where they are.

Pick a weight “incl drive”
Pick a frame size
PIck a battery configuration (3S, 4S, etc) and a capacity.
Pick an ESC (controller), say 40A to start.
Select a motor
Enter the prop configuration, size and pitch.
Hit Calculate.
What does the Motor@Hover>Throttle (linear) say? It better be <= 50%