Batteries for the HK450 heli

2200maH 25C 3Cell 11.1Volt Lipo Batteries are the best choice for the HK450

Why?
Well here is the reasoning behind this.
2200maH is 2.2AH which simply means the lipo battery can deliver for 1 Hour 2.2 Amps continuous.
ma is Thousandths of an Amp, so 1000mA is simply 1.0A
The H simply stands for Hour
The C Rating of the battery is the Multiplier for constant current without damage
For example if a batter is 1000maH and is 10c then the resulting output is 1A x 10c = 10Amps
In requesting this supply from the battery you need to consider the following, if the battery is rated at 1000maH 10c then we require 10A to be supplied then the amount of time it can supply that for is 6minuites, because you must divide the hour by the same amount.
i.e.: 10A is 10 times the maH rating so therefore it will be 10 times less supply time.
In the same fashion if it was a 20C battery and we requested the full 20Amps supply then the time it can supply this power is 3 minutes.
Ahhh I see an understanding now.
So let’s take for example the recommended batteries I stated above.
We know from actual measured results that a HK450 will hover from 12Amps to 18Amps depending on mainly the weight of the bird for example a 760gm bird 15A to hover and a 800gm bird 18A to hover so that 40 grams makes a difference, also the efficiency and many factors, but let’s take the midpoint of 15Amps to do our calculations
Firstly, work out how long the battery can supply this amount.
2200maH x 25c = 55Amps Maximum Constant Supply
and we know that 2200maH is 2.2Amps for 1 Hour
Now we know we need to divide 15Amps by 2.2Amps to figure out the hourly divider.
15/2.2 = 6.818 so we take this magic number and calculate the time like this
1 Hour being 60 Minutes divided by 6.818 = 8.8 Mins (this is for 15Amps)
1 Hour being 60 Minutes divided by 5.45 = 11 Mins (this is for 12 Amps)
1 Hour being 60 Minutes divided by 8.18 - 7.3 Mins (this is for 18Amps)
So as you can see the heavier your heli is the more amps it needs to fly and the shorter the flight times are. Just remember that a bigger battery costs in weight and amps, so there is a balance, smaller batteries less supply bog down motors etc larger batteries less flight time too heavy, so keep it around 170 grams 25c 2200maH. Remembering 70grams is 10% of the heli’s weight.
Keep in mind that this is not the only governing factor for flight times.
There is Motor Efficiency
There is AUW of the Heli
There is Timing of the ESC
And as always your flying style, Hard 3D flights are shorter than Sports Flying, and normal flight and then hovering…  For Hard 3D you can draw up to 55Amps with some setups. The key is to have the heli as efficient as possible
A Battery for the HK450 should weigh less than 200 grams, the lighter the better, but not at the expense of no reserve power so in saying that 150 grams to 200 grams is what you should aim for.
I found that the 2200maH 25C FlightMax Batteries are 171Grams, that’s about half way in the weight mentioned above.
There is also the Burst Current that should be considered.
If you do pop ups you will find that the HK450 will draw anywhere from 25Amps to 45Amps depending on the configuration. I like to have a battery that can supply the maximum of 45Amps because as I get better at 3D flying I require more amps to do stunts. So again the 2200mah 25C batteries are able to deliver 55Amps Maximum so I am safe with this level and feel assured that I won’t over stress the batteries.

Regards
Elias Gourvelos (EatAtJoes)