Replies to This Discussion

Permalink Reply by Rz_Ten1 on November 11, 2011 at 6:07pm

Actually, in this case both the 3S and the 4S battery have the same capacity (5000mAh).  Increasing the voltage doesn't increase the capacity.  It will mean lower amperage flowing from the battery to achieve the same wattage load, but unless your wires are undersized that should make absolutely 0 difference.  A motor pulling 100W at 12V still pulls 100W at 16V.

If anything (and Davey mentions this) I would guess that you'd lose additional power in the voltage regulation circuity.  A hotter ESC means a less efficient ESC, as energy is being converted to heat instead of RPM.

The only time I would consider replacing a 3S with a 4S would be if you're just not getting enough lift from the engines, and even then it would probably be better trying to shave some weight off somewhere then throwing more voltage at it.  If you can't remove any weight it would likely be best to just get larger engines, anyway. :)

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Permalink Reply by DaveyWaveyBunsenBurner on November 11, 2011 at 7:59pm

Totally agree

Cells= performance
Amps= capacity

Regards

D

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Permalink Reply by Ruben Wijnhoven on November 12, 2011 at 2:56am

I am using 4s3300 and have 20min of flying time. 850kv motors 20 esc 10x4.5 props with 3s 2800 i had 8 mins. for m4s is the way to go.

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Permalink Reply by steve F11music.com on November 12, 2011 at 3:11am

I have had the same experience. To really know, we would have to compare a 4s and a 3s with the same weight. Like a 4s 3000 and 3s 4000 for example. One thing I like about the 4s is the extra rpm in case you need it.

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Permalink Reply by John Campen on December 7, 2011 at 3:37am

how heavy is your rig Ruben? 20 min  is impressive. I have just bought 2x  4s3300 as well so not sure whether to use the  both yet or just one. my rig is about 2kgs and its X8 quad same motors as you are using but with 12x4.5 props

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Permalink Reply by CyberCrash on December 7, 2011 at 4:29am

I would do the following.

Charge a 3000mAh Lipo and then fly for 5minutes. Then recharge to full and read the recharged mAh number on the display.

Then a little bit of math:

5min  =  "your number"mAh

xmin = 1800mAh

_______________________

xmin (flight time with 1800mAh) = (1800 / "your number") * 5

lets say you recharged 2300mAh:

(1800 / 2300) * 5 = 3,91min

So instead of using a 3000mAh Lipo you can use a 1800mAh Lipo and fly 3,91min.

In reality a bit more because the 1800mAh Lipo wouldn't be as heavy as the 3000mAh Lipo.

CyberCrash

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