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New to brushless, Could use some help picking the right battery

Old 09-28-2006, 01:09 PM
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packyj
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Default New to brushless, Could use some help picking the right battery

Sorry for the ignorance here but I really could use some help. I've downloaded motocalc but as of yet cannot get it to work. I've pieced together a very very cheap setup at www.peakmodels.com. Thought that with the prices their showing me it would be well worth it to try.

So I've pulled up a 330 fuse at:

http://www.peakmodel.com/index.php?m...roducts_id=176

They recommended to me the following brushless/esc:

Motor:
http://www.peakmodel.com/index.php?m...products_id=92

Esc:
http://www.peakmodel.com/index.php?m...products_id=12

From rough calculations in my crazy monkey math I come up with a measily 5-6 minutes with a 2000mah 3 cell lipo... did i do the math wrong or is there some finer learnings i've yet to come across when building a brushless setup?

Any help is appreciated
patrick
Old 09-28-2006, 08:33 PM
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Matt Kirsch
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Default RE: New to brushless, Could use some help picking the right battery

Capacity / Average Current = Length of Flight

6 minute flight = .1 hours = 2200mAh / Your Expected Average Current

Your Expected Average Current = 22 Amps

Sound about right? Your math is okay, but you're assuming that you'll be flying around at full throttle for the entire flight. It's a pretty safe bet that you won't be flying like that. Back off on the throttle and your flights will stretch out to 10 minutes or more. It'll also be much easier on the equipment.
Old 09-28-2006, 10:36 PM
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packyj
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Default RE: New to brushless, Could use some help picking the right battery

Thank you for the input matt, I was pretty sure I calculated the way I was supposed to but a little affirmation goes a very long way when trying to convince your significant other you're not just wasting money ... just ordered a 2100 20c 11.1..... should be just fine I'm guessing

Patrick
Old 10-04-2006, 08:44 AM
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Jim B
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Default RE: New to brushless, Could use some help picking the right battery

patrick,
2100mAh 3-cell should be perfect, skyshark sells a nice battery for economy, the new EVO battery is unbelievable, the amperage they are capable of delivering is awesome. my son and i use these with our e-flite 480's in our fliton edge and extra. you get at LEAST a 10-12 min flight. Make sure you have adequate air around your speed control. we now mount our ESC's up front in the cowl. up there they rarely get hot.
Jim B.
Old 10-04-2006, 12:49 PM
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packyj
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Default RE: New to brushless, Could use some help picking the right battery

Thanks for the tip Jim,

I'll probably have plenty of time to plan out the electronics once I get the plane considering, from New Zealand, it will probably be windy and winter before she's built at this rate. I'm guessing that at partial throttle... if not half throttle, I'll have more than enough time in the first 2 or 3 flights to work the bugs out... at 15 minutes per flight or so I'm guessing. This will be my first balsa plane so the nerves are really starting to become a factor, trying not to get in too much of a hurry.
Old 10-16-2006, 09:23 AM
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Dr Kiwi
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Default RE: New to brushless, Could use some help picking the right battery

ORIGINAL: packyj

Sorry for the ignorance here but I really could use some help. I've downloaded motocalc but as of yet cannot get it to work. I've pieced together a very very cheap setup at www.peakmodels.com. Thought that with the prices their showing me it would be well worth it to try.

So I've pulled up a 330 fuse at:

http://www.peakmodel.com/index.php?m...roducts_id=176

They recommended to me the following brushless/esc:

Motor:
http://www.peakmodel.com/index.php?m...products_id=92

Esc:
http://www.peakmodel.com/index.php?m...products_id=12

From rough calculations in my crazy monkey math I come up with a measily 5-6 minutes with a 2000mah 3 cell lipo... did i do the math wrong or is there some finer learnings i've yet to come across when building a brushless setup?

Any help is appreciated
patrick
[

Not sure you want the peakmodels link! peakmodel is more on topic!
Old 10-16-2006, 10:11 AM
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packyj
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Default RE: New to brushless, Could use some help picking the right battery

lol hadn't noticed that before... now the misses is going to wonder why i got into this hobby after all
Old 10-22-2006, 10:22 PM
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himeros
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Default RE: New to brushless, Could use some help picking the right battery

It would do well to remember that most all battery makers over estimate the C rating of their batteries. If it is rated at 20c, then you would be safe at running at 10 to 12c. Others may have different experence, but from my bench testing if you run them at the marked C rating they will overheat quickly.

Himeros

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