PDC
05-23-2006, 04:58 PM
Hi!
Made some few calculations, just to give the big overview over what battery will work for an Ion-X.
If we in this example use the NEU 1521-1.5Y motor, which I think is one of the motors there will be a good choice for the Ion-X, and at the same time set the voltage constant under load for a lipo cell to 3,5V, then I think we have a good starting point for some calculations.
It is always very important to focus on optimizing the chain so that you get what you want, at the lowest possible weight, especially in e-heli´s. Therefore the components most be balanced so that there are no weak links and no overkill´s in the chain.
If we chose the NEU 1521-1,5Y motor, we need to be able to use it fully, or it will be a too heavy motor to fly around with.
Lets look at the data for this motor.
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http://www.neumotors.com/motors/neu_neu1500.html
1521
1600-2000 Watts Continuous
3600Watts - 30sec
Max rpm: 60,000
Stator Dia. 1.5"
Magnet/rotor length 2.1"
Shaft: 5mm
Shaft length: .75"
Weight: 480g
Dimensions 3.3"L x 1.56" dia.
Model RPM/Volt Volts Max Amps Efficiency Rm (Ohms) Kt (in-oz/amp) Io
1521/1.5Y 1050 7-50 75* 90+ 0.010 n/a 1.2
*20 sec. at max. voltage. Otherwise, = Watts/your voltage.
-----------------------------------------------
The limits of interest is 1600-2000 Watt cont., 3600 watt 30 sec, 50V and 75A in 20 sec. at max. voltage. Otherwise, = Watts/your voltage. .
This link in the powertrain have a weight of 480gr., so in order to get the most out of this link, I have chosen to go to the voltage limit with 12S = 50,4V fully charged, which gives me the highest rpm = most stored energy in the motor, most HP and torque available and the lowest amps through the chain.
If I have chosen 10S, then to reach the 3600 watt, I need to pull 3600W / 35V = 103 Amp compared to 86 Amp with a 12S setup.
The motor is rated to between 1600-2000W, I believe that one need as high a voltage as possible to get the 2000W cont.
Next, lets look at some calculations on "fuel flow", Amps, C ratings and flight times with different 10S and 12S batteries in order to take out 2KW cont.
10S = 35V x 57,1A = 2KW = fuel flow of 952 Mah / min.
12S = 42V x 47,6A = 2KW = fuel flow of 793 Mah / min.
Flight times and discharge levels in C with 2KW average discharge. All with a battery discharged to 30%.
10S 4000ma = 14,2 C and 3:00 min.
10S 6000ma = 9,5 C and 4:30 min.
10S 8000ma = 7,1 C and 6:00 min.
12S 4000ma = 11,9 C and 3:30 min.
12S 6000ma = 7,9 C and 5:20 min.
12S 8000ma = 6,0 C and 7:10 min.
Right now I use app. 1500-1600 watt in average with mixed 3D and a 12S 6000ma battery, and think this motor is a very balanced link in my chain.
The high C rated battery´s have a higher voltage under load, but at the same time is heavier for the same capacity....anyway, they will always be able to deliver more watt at the same weight as lower C rated battery´s, maybe even more than needed if one also want some flight time.
A lot of other factors like cooling, ambient temperature etc. etc. etc. might change the real life scenario a little, but with the data I have been written down in my logbook, I think this is a good starting point.
Don´t take this as science, only as a way to get the big overview.
- Paul :D
Made some few calculations, just to give the big overview over what battery will work for an Ion-X.
If we in this example use the NEU 1521-1.5Y motor, which I think is one of the motors there will be a good choice for the Ion-X, and at the same time set the voltage constant under load for a lipo cell to 3,5V, then I think we have a good starting point for some calculations.
It is always very important to focus on optimizing the chain so that you get what you want, at the lowest possible weight, especially in e-heli´s. Therefore the components most be balanced so that there are no weak links and no overkill´s in the chain.
If we chose the NEU 1521-1,5Y motor, we need to be able to use it fully, or it will be a too heavy motor to fly around with.
Lets look at the data for this motor.
-----------------------------------------------------------------
http://www.neumotors.com/motors/neu_neu1500.html
1521
1600-2000 Watts Continuous
3600Watts - 30sec
Max rpm: 60,000
Stator Dia. 1.5"
Magnet/rotor length 2.1"
Shaft: 5mm
Shaft length: .75"
Weight: 480g
Dimensions 3.3"L x 1.56" dia.
Model RPM/Volt Volts Max Amps Efficiency Rm (Ohms) Kt (in-oz/amp) Io
1521/1.5Y 1050 7-50 75* 90+ 0.010 n/a 1.2
*20 sec. at max. voltage. Otherwise, = Watts/your voltage.
-----------------------------------------------
The limits of interest is 1600-2000 Watt cont., 3600 watt 30 sec, 50V and 75A in 20 sec. at max. voltage. Otherwise, = Watts/your voltage. .
This link in the powertrain have a weight of 480gr., so in order to get the most out of this link, I have chosen to go to the voltage limit with 12S = 50,4V fully charged, which gives me the highest rpm = most stored energy in the motor, most HP and torque available and the lowest amps through the chain.
If I have chosen 10S, then to reach the 3600 watt, I need to pull 3600W / 35V = 103 Amp compared to 86 Amp with a 12S setup.
The motor is rated to between 1600-2000W, I believe that one need as high a voltage as possible to get the 2000W cont.
Next, lets look at some calculations on "fuel flow", Amps, C ratings and flight times with different 10S and 12S batteries in order to take out 2KW cont.
10S = 35V x 57,1A = 2KW = fuel flow of 952 Mah / min.
12S = 42V x 47,6A = 2KW = fuel flow of 793 Mah / min.
Flight times and discharge levels in C with 2KW average discharge. All with a battery discharged to 30%.
10S 4000ma = 14,2 C and 3:00 min.
10S 6000ma = 9,5 C and 4:30 min.
10S 8000ma = 7,1 C and 6:00 min.
12S 4000ma = 11,9 C and 3:30 min.
12S 6000ma = 7,9 C and 5:20 min.
12S 8000ma = 6,0 C and 7:10 min.
Right now I use app. 1500-1600 watt in average with mixed 3D and a 12S 6000ma battery, and think this motor is a very balanced link in my chain.
The high C rated battery´s have a higher voltage under load, but at the same time is heavier for the same capacity....anyway, they will always be able to deliver more watt at the same weight as lower C rated battery´s, maybe even more than needed if one also want some flight time.
A lot of other factors like cooling, ambient temperature etc. etc. etc. might change the real life scenario a little, but with the data I have been written down in my logbook, I think this is a good starting point.
Don´t take this as science, only as a way to get the big overview.
- Paul :D