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Batteries Sizing batteries for quad

bigone5500

Well-Known Member
I want to size a battery for a given quadcopter. What's a good rule of thumb or is there a science behind it? FYI: It's for my Micro Alien. I currently use a 650 but I'm sure it needs more.
 

bigone5500

Well-Known Member
Thing is I don't know any specs other than 1407 3500KV. I think I want to try a 4S 1300mAh on it to see if it will be able to handle the weight. I don't know though as it only has 3" props.
 

RandyDSok

Well-Known Member
You have to know the voltage range the motor and ESC are rated for as well as the max amperage... that way you can also then choose the proper C rating to provide the amperage you require. The size of the motor and how many kV it is rated for is of no use when selecting the battery and/or ESC.
 

D.O.G.

Well-Known Member
Goblin 380 Supporter
Thing is I don't know any specs other than 1407 3500KV. I think I want to try a 4S 1300mAh on it to see if it will be able to handle the weight. I don't know though as it only has 3" props.
What size is that quad? 200/210mm? Here's the motors I have on my 3" cinewhoop HGLRC Flame 1407-3600KV 3-4S Drone Motor Purple Blue I'm using 4s 450mah on those motors. Maybe you can get an Idea with those #. At lease a guesstimate.
 

bigone5500

Well-Known Member
What size is that quad? 200/210mm? Here's the motors I have on my 3" cinewhoop HGLRC Flame 1407-3600KV 3-4S Drone Motor Purple Blue I'm using 4s 450mah on those motors. Maybe you can get an Idea with those #. At lease a guesstimate.
This is a 135mm X frame miniaturized clone of the 'Alien' frame. I am using some cheap-o motors I got from amazon. The ESC is part of the HGLRC stack I also purchased from amazon. Here is a better link. The ESC can handle a constant 33A draw.

This quad with the 650 battery installed ready to fly is 263g. I am wondering about not only the current draw from the motors but also the FC, VTX, and DVR. Those things probably use a good bit of current. But I really don't know.
 

D.O.G.

Well-Known Member
Goblin 380 Supporter
I'm using those small mah batteries for the time being. Your correct on the VTX, FC and DVR will eat some power but not crazy like. I don't know of any formula to calculate your flight time. That's for Tony and Randy to chime in. I'm using the TBS 800mw VTX. I'll tell you she eats up some juice now and I'm getting 5 minutes flight time. Most of the time I start off with 3:00m flight time and test the voltage. See what % it's at, then take it from there. With my 5 minute flight time, my battery is down somewhere 14%. Now that's just me. I'm hoping to get around 7:00minutes flight time once I get back to recoding dogs again :). I'm not sure any of this helps but I tried lol :).
 

bigone5500

Well-Known Member
Well now the runcam doesn't work. Just great. I'll not buy another one. Second one to die on me.
 

RandyDSok

Well-Known Member
I never mess with trying to calculate theoretical run times... I always used the practical method that DOG mentioned and run a battery for a certain amount of time and then calculate from real numbers.

When buying a motor, I never purchase one that doesn't have the actual specs available. I assume if they don't list the voltages and amps, it's not worth the money they are asking. I also assume the max amps they list is burst only and not continuous unless it is stated otherwise. Knowing the burst amp draw lets me calc the worst case scenario so I know I won't be over drawing my ESC or battery.
 

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