Batteries

[Donovan Mahoney]

I just recently got into the hobby and I was wondering how to tell what size battery to put in my plane because I know with rc cars if you get a battery that has too high watts it will burn out the components and was wondering If it is the same with planes and if so how can I tell what specs to get?

 

[Bricks]

It`s not Watts it`s voltage, easiest is look at the ESC and what the motor will take for voltage each will have voltage ( S rating ).

 

[Foamforce]

I just recently got into the hobby and I was wondering how to tell what size battery to put in my plane because I know with rc cars if you get a battery that has too high watts it will burn out the components and was wondering If it is the same with planes and if so how can I tell what specs to get?

There are a few factors.

• Connector type. There are a bunch, but Flite Test generally uses XT30 for smaller models and XT60 for larger. You could use the larger XT60 for everything, it would just be more weight and take more space.
• Voltage (Like Bricks said). Most Lipo batteries that are used on foam planes are 2s, 3s, or 4s. That means 2, 3, or 4 lipo cells hooked in series. Each lipo cell is generally 3.7v (nominal), so 2s is 7.4v, 3s is 11.1, and 4s is 14.8. 3s is the most common and most motors will accept that, but check the specs on the motor if you’re unsure. 4s is less common, so fewer motors will accept that. Higher voltage means the motor spins faster. A plane that is a beast with 3s will be pretty tame on 2s.
• (Milli)amp Hours. The basically means the runtime. A smallish plane will be around 500mah. A bigger plane will be about 3000mah. You can put as big of a battery as you want in a plane and it won’t hurt the electronics, but it will add weight. If you put a big battery into a little plane you will have to fly very fast to keep it in the air, otherwise it will stall.
• C rating. This is basically how much power you can get out of a battery under full throttle. Generally for our foam planes, as long as you get the recommend capacity battery, you probably don’t need to be concerned with this. The exception is that you shouldn’t put a very small battery (e.g., 500mah) in a big plane that normally takes a 3000mah.

All of the flight test plans have a recommended battery on the printout. Just go with that, plus or minus 20% for the capacity. Go smaller for easier handling and larger for longer runtime.

 

[quorneng]

Donovan
As has been pointed out it is voltage that determines how many amps the motor will take. Note it is the motor that draws the amps out of the battery not the battery that forces the amps in.
If the motor load (the prop) and the rest of the electrics are designed to work on a 3s battery voltage then the battery can be as big as you like, as long as it is a 3s voltage, the motor will not draw any more amps but the weight of a big battery will likely mean the plane will not fly!
So you have to arrange that the load on the motor does not cause it to draw too many amps and over heat. Similarly you have to ensure the electronic speed controller (ESC) can handle both battery voltage and the max amps the motor will draw. Then finally you have to ensure the battery has the capability to deliver the max amps without damaging itself and all for a weight that allows the plane to fly with using the motor power available.
There is no single right solution it is always a compromise to best suit your objectives.
You can make an electric plane that can fly for hours or one that can take off vertically but not (yet!) do both at the same time!

 

[Donovan Mahoney]

Wow thank you so much I wasn't expecting to get such an extensive reply but going off of what you were saying with how on the plans it says what battery to use what about the master series planes? I've never bought one before so I don't know what comes with it.. So is there a spot that I can look to find that out?

 

[Foamforce]

Oh yeah, no plans for us Master Series. Then look on the store instead. They have a couple batteries listed with each airplane. Those will be the recommended sizes.