General Battery Question

[Flaflyer]

hi guys ,,I bought a used foamie and it has a RC Smart 1084kv,, outrunner Brushless motor ,,it says its 1084RPM/V ,,continuous current 20A,,,Max 25A input voltage 6-20 ,,i bought a new ESP for it ,,a 30amp,,35 max ,,,any idea what size battery for it ? im thinking a 3 cell maybe 1000mah or1200mah???but not sure??thanks

 

[Tony]

The mah of the battery will depend on how big the plane is. If it's meant to have a small battery, I would stay under 1000mah. the best way to figure this out is to find the stock CoG of the plane, and add weight until you get the correct CoG. Take the amount of weight you had to add, and match that to the weight of a 3s battery. this will get you as close to the correct weight you will need on a battery.

Obviously the best way is to find the owners manual (if it had one) and use the battery they suggest. Is this a foamboard plane? Or like beer cooler foam?

 

[Flaflyer]

Hi tony ,, it shows 3 different setups for power in the manual ,, but the motor in the plane isent any of the 3 listed ,,,,,but the batterys are listed as a 1320mah 3 cell,, to,, a 860 mah 3cell depending on the motor ,,,,,,,it is a flat board foamie 37 inch wing span

 

[Tony]

Okay cool, we can work with that. What motor battery combo in the manual best matches the motor you have on the plane?

 

[Flaflyer]

motor 1080=900mah 3cell

 

[RandyDSok]

I found the specs for the motor with a simple Google search...

Rotational Speed : 1084 RPM/V
Continuous Current : 20A
Max. Current : 25A
Input Voltage : 6 - 20V
Max. Efficiency : 98%
No Load Current : 0.7A
Internal Resistance 62mΩ
Motor Dimensions (Diameter x Length): 28mm x 28.7mm
Shaft Dimensions (Diameter x Length): 2.95mm x 12mm (Front & Back)

The specs are a bit suspect but it isn't anything I haven't seen before on a cheap motor listing... no motor that I know of is 98% efficient.

 

[Tony]

cool, i would keep it to about 1000mah then. 3s, 30c, 1000mah should work great on that plane. And you should still have room to move the battery around to adjust to the perfect CoG.