Is weight the primary objective...?
12-15-2003, 07:50 AM
#1
Thread Starter
Is weight the primary objective...?
Am building several depron ultimates (foamyfactory) and want to go brushless as I can afford it at the moment...and would like good advice on motor/ESC/lipoly combo.
If I get a Typhoon Micro 6 (excellent price in UK) can I run this with an ESC with a high amp rating, e.g. Phoenix 80. Understand downside is weight but is their any other constraint? I want to invest in an ESC I can use later on much bigger models. Should I go no more the 25amp/35amp to save weight.
For this type of model an motor/ESC combo which lipoly would make more sense. I can't get 1200mah in U.K. which is recommended on FoamyFactory. Again, should I think weight but if I go 340mah will I sacrifice performance/duration? My options are...
Kokam 340mah 3s1p (31grams)
Kokam 700mah 3s1p (49 grams)
Kokam 1500mah 3s1p (101 grams)
If someone tells me low weight is way to go then I would go Micro 6/10amp ESC/340mah 3s1p?
Maybe I should stick to I/C SPADS ??? Any help appreciated....!
If I get a Typhoon Micro 6 (excellent price in UK) can I run this with an ESC with a high amp rating, e.g. Phoenix 80. Understand downside is weight but is their any other constraint? I want to invest in an ESC I can use later on much bigger models. Should I go no more the 25amp/35amp to save weight.
For this type of model an motor/ESC combo which lipoly would make more sense. I can't get 1200mah in U.K. which is recommended on FoamyFactory. Again, should I think weight but if I go 340mah will I sacrifice performance/duration? My options are...
Kokam 340mah 3s1p (31grams)
Kokam 700mah 3s1p (49 grams)
Kokam 1500mah 3s1p (101 grams)
If someone tells me low weight is way to go then I would go Micro 6/10amp ESC/340mah 3s1p?
Maybe I should stick to I/C SPADS ??? Any help appreciated....!
12-15-2003, 08:51 AM
#2
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RE: Is weight the primary objective...?
Other than weight, there's no reason the Phoenix 80 would not work.
When choosing LiPoly batteries, you need to take into consideration the anticipated current draw of the motor. LiPolys are very sensitive; draw too much current from one, and you ruin it.
Looking at the statistics for Kokam LiPoly batteries, the 340 is a "20C" cell, and the 1500 is an "8C" cell. C is a relative term, indicating the Capacity of the battery in mA. So, 20C means that a cell can put out a current equaling 20 times the battery's capacity safely. The Kokam 340 can therefore put out 6800mA or 6.8 Amps (20*340mA).
If your motor is going to draw more than 6.8 Amps, you need to move to a larger pack, or connect one or more additional packs in parallel until the total capacity meets or exceeds the current draw of the motor. Let's say you have a motor that draws 18 Amps. We figured out above that each Kokam 340 pack can handle 6.8 Amps. Simple math tells us that we'd need a minimum of three packs in parallel to handle the 18 Amp current of the motor (18/6.8 = 2.64, but you can't have 2.64 packs, so round to 3).
Kokam 340s are a very lightweight (and expensive) way to get lots of current. If your plane can handle larger cells like the Kokam 1500, a single pack of these can handle up to a 12 Amp load, for less money than two Kokam 340 packs.
When choosing LiPoly batteries, you need to take into consideration the anticipated current draw of the motor. LiPolys are very sensitive; draw too much current from one, and you ruin it.
Looking at the statistics for Kokam LiPoly batteries, the 340 is a "20C" cell, and the 1500 is an "8C" cell. C is a relative term, indicating the Capacity of the battery in mA. So, 20C means that a cell can put out a current equaling 20 times the battery's capacity safely. The Kokam 340 can therefore put out 6800mA or 6.8 Amps (20*340mA).
If your motor is going to draw more than 6.8 Amps, you need to move to a larger pack, or connect one or more additional packs in parallel until the total capacity meets or exceeds the current draw of the motor. Let's say you have a motor that draws 18 Amps. We figured out above that each Kokam 340 pack can handle 6.8 Amps. Simple math tells us that we'd need a minimum of three packs in parallel to handle the 18 Amp current of the motor (18/6.8 = 2.64, but you can't have 2.64 packs, so round to 3).
Kokam 340s are a very lightweight (and expensive) way to get lots of current. If your plane can handle larger cells like the Kokam 1500, a single pack of these can handle up to a 12 Amp load, for less money than two Kokam 340 packs.
12-15-2003, 09:36 AM
#3
Thread Starter
RE: Is weight the primary objective...?
Ahhhh....I'm beginning to understand. So of the combinations I have listed and I missed out 1500mah 2s1p there are 2 options for the Micro 6 which draws 12A with 20A surge.
340mah 3s1p (31g weight) which can output 20.4A or,
1500mah 2s1p (68g weight) which can output 24A.
Think I'll go for the first. Thanks for your help Matt. The most helpful post I have read on RCU yet.
340mah 3s1p (31g weight) which can output 20.4A or,
1500mah 2s1p (68g weight) which can output 24A.
Think I'll go for the first. Thanks for your help Matt. The most helpful post I have read on RCU yet.
