T-REX 700e: 10 or 12S for AP?

[erbrou]

I have asked this question elswhere but did not get a response. Maybe you guys who do not do AP might have a comment for me on the following.

Would you go on 10 or 12S with a T-rex 700 that will be used for AP (710 mm blades)? It looks like it is possible to fly 200g lighter on 10S for the same mAh capacity... Will an higher voltage be really a big advantage on an AP set-up?

Thank you

[mapleleafs]

10S less power but more flight time....

[jetpilot]

must be joking right!

[erbrou]

:thinking ...joking?

[mapleleafs]

must be joking right!

Does AP not stand for Aerial Photography? I guess if the machine is going to be very heavy go 12S.....

[erbrou]

Does AP not stand for Aerial Photography? I guess if the machine is going to be very heavy go 12S..... Yes, Aerial Photography. Do you think the power on 10S at least equivalent to the 700N?

Thank for your input

Eric

[mapleleafs]

10S is equivalent to a Trex 700N (power by an OS 91 SZ-H), hence my friend has one running on a 5000 10S battery, and we feel both have similar power....

However, i also know AP equipped heli is very very heavy(another guy at club converted his 600) and might be to to much strain for 10S set-up, so something like a 12S would be better suited.

[LITHIUMSTATIC]

12s, less strain on the packs

[erbrou]

:confused:

I will meditate on that, I still do not no what set-up to choose...

[jetpilot]

Je te jure 12S.....tu prens 2x6S 5000 MAH en serie




Luc

[mapleleafs]

12S= expensive,more power, shorter flight times, cooler electronics, heavier, and less strain on equipment all around.....

10S=longer flight times, cheaper, warm/hot electronics, more strain, lighter.....

hope this helps, it really isnt a big issue......

[jetpilot]

sorry sir!


Are you saying you will get more flight time with a 10S then a 12S?

[HeliDaddy]

Are you saying you will get more flight time with a 10S then a 12S?


Yea I am going to have to call BS on that one.:clappp

Mike

[LITHIUMSTATIC]

sorry sir!


Are you saying you will get more flight time with a 10S then a 12S?

You will not get more flight time out of either one because it's all based on the capacity of the pack and the efficiency of the setup. With that being said, a 12s setup will be more efficient because it will run cooler do to lower amp draw thus making better use of the capacity available.

Take for example the Outrage G5. It's designed to run 6s 1300 Lipos on a 450 size heli. Everything runs very cool because it has a lot less amp draw than a 3s setup. Flight times are increased, and the level of power the heli makes is near the same from the beginning of the flight until the end of the flight. Little to no thermal slow down over 3s system that has a radical change with the heli feeling weaker towards the end of a hard flight.

Basically, higher amp draw = shorter flight times with degraded performance. This will vary a little or a lot, depending on equipment used and flying style.:thumbup:

I would PM MrMel, he has a lot of knowledge on 700 electrics.

[HeliDaddy]

Yea what Lithiumstatic said.

Mike

[mapleleafs]

Yea I am going to have to call BS on that one.:clappp

Mike

this is where a tiny bit of my plank history shows.....sorry guys, go a bit confused.

[HeliDaddy]

No problem man, we are here for you.:YeaBaby:

Mike

[viperhawk]

I just finished a 700 electric conversion for my AP business, www.louisianahelicam.com. I decided to go 12S.

[teshreve]

It sure is flat in Louisiana!!!

[martiol]

Just for future reference: I'm using 5000mah as an example

12*3,7 = 44,4 V
44,4 V * 5000mAh = 222Wh

10*3,7 = 37 V
37 V * 5000mAh = 185Wh

To achieve the same flight time on 10s you need 6000mAh
222000mWh / 37 = 6000mAh

Flight time depends on Wh. (P(w) = U(v) * I (a))


If your motor at a given time outputs 1000W on 12S (44,4V) the current drawn is I = P / U; 1000 / 44,4 = 22,5A
Change to 10S: 1000 / 37 = 27A
So, lover voltage means higher voltage to achieve the same power. Nothing more!

The current limit of your ESC is one constant as well as max voltage. The wanted effect is another and so is weight. But within these limits many of the variables can be changed to your liking.

Maybe i should make a heli power / current calculator someday?