Ampage

[Sqwidge]

So after my blade problems that a few of you helped me get to the bottom of (thanks to all of you) i have another question.

How do you work out Ampage?

I have 3 digital servo's a 401 and a 9257, how would i work out the amps involved to warrant a new esc or to see if my stock 25a esc would take it?

[cap232]

depends on what battery are you using

personally i would put a watt metter on it to findout wahat its pulling from the battery

[xygax]

OK there is a little confusion here .... The amperage total including the motor will be 30+ on a blade in full climb .... Now i think what you require is the worse case current for the servos rx and gyro ... this will be the total load without the motor. and so long as it's less than about 3A it will be OK on a standard ESC with built in BEC. ..... So an RX takes about 0.08A and a 401 somthing similar.
Now an HS65 takes about 0.5A each and a 9257 about 0.4A

so the sums go sumthing like this
HS65 x 3 = 1.5A
9257 x 1 = 0.4A
401 = 0.08A
RX = 0.08A

Total = 2.06A < 3A therefore you dont need a new BEC !!!

Steve

[Sqwidge]

I'm using a 2200mAh 3s 11.1v Li-Po, Xygax, using your maths above does this mean as long as i'm not shooting straight up i could continue to use the stock ESC? I'm only doing basic figure 8's and the odd loop and flip but nothing major.

[Pipistrelli]

You don't have to restrict your flying style. I doubt you will overload the 25A ESC, that rating is current for the main motor, the BEC at 3A is for the radio gear.

In comparison, a Trex 450 takes 11Amps in hover & FF, stick banging from full -ve pitch to full + pitch will probably get close to 25A!

Make sure your battery can provide at least 25A in its discharge rating, or you might damage it!

[Sqwidge]

Says 25c on the battery?

[cap232]

25 amp should surfice

[Holst]

25 amp should surfice

Isnt that 25*2.2 = 55amps ?

(with a 2.2ah battery)

[Sqwidge]

If i was to buy a new esc say a 40a with built in bec, would i have to regulate the power or would it auto run power to my servo at 5.1v? i now understand the amp thing sort of but would hate to cook my servo's due to voltage

[Holst]

If i was to buy a new esc say a 40a with built in bec, would i have to regulate the power or would it auto run power to my servo at 5.1v? i now understand the amp thing sort of but would hate to cook my servo's due to voltage

The BEC voltage should be listed in the ESC specification, if its not listed then I would avoid it.

[Sqwidge]

I'm still so confused lol

[Sqwidge]

Instead of me being confused by all of this, could i not just buy a new 30a/40a esc with a built in bec and run a step down between the esc and the rx?
This would then give me the required voltage (5.1v) but still give me the amp rating needed, well in theory anyway

[machasm]

The BEC (stands for Battery Eliminator Circuit) is the part of the ESC designed to power the radio equipment.
In some ESCs this is programmable and can be changed from 5V to 5,5V or 6V or more.
Others have fixed BEC voltages. You need to make sure that the ESC you buy is
a) Capable of providing enough current to run your motor and
b) Provides the correct voltage (and current) at the BEC for your radio.
Hope this helps to clear things up a little.
Adrian.

[Sqwidge]

Aidrian, i'm with you so far, my stock esc is 25a with a 5v bec but not sure of amp, i was gonna up to around 40a as i have digital gear all round but from my understanding, and correct me if i'm wrong, if it was possible couldnt i keep the 25a for the motor and have a bigger bec? say 5a/5v? i dont know if i can buy this combo or if i would have to solder a bigger bec etc.

[machasm]

Hi Nik.
Why are you going to a 40A ESC? Is it because you need to run a higher specced motor or are you under the impression you can run more power hungry radio gear with it?
If so you are mistaken as most of the BECs in these ESCs are around 2 to 3A.
Have you bought the ESC already?
If you just want to run bigger radio kit but not a bigger motor you can just buy a seperate BEC.
What exactly are you trying to do?
Adrian.