Help! Motor Amp draw question

[Zetoyoc]

I have seen people do this test with everything in the plane too. the wattmeter is sticking out the hatch while the plane is held in place. I do prefer to test out of the plane but however you do it just be sure it is held down securely and safely

 

[Wildthing]

I have seen people do this test with everything in the plane too. the wattmeter is sticking out the hatch while the plane is held in place. I do prefer to test out of the plane but however you do it just be sure it is held down securely and safely

I have done quick tests on the planes to but I know with some of these pods there is no access to the battery with the pod locked in. The mount also might be a little safer because you don't have to hang onto the plane plus work the tx and try to watch the gauge.

 

[Bricks]

Along with the watt meter ( to me is a must have ) another handy item is this cell checker, I use mine all the time to check batteries..

https://www.aliexpress.com/item/32811854903.html?spm=a2g0s.8937460.0.0.1dcb2e0eQY6Nel

 

[Wildthing]

Along with the watt meter ( to me is a must have ) another handy item is this cell checker, I use mine all the time to check batteries..

https://www.aliexpress.com/item/32811854903.html?spm=a2g0s.8937460.0.0.1dcb2e0eQY6Nel

Yep, I have a couple of those cheap $2.00 ones plus even the low voltage alarms but with the cell checker I have found why some flights are really short, battery charges ok and all looks good but a minute into the flight power starts dropping. Charge the battery up again, hook up the cell checker to the balance plug and run the motor , sure enough there is a single cell that looses voltage really quick.

 

[The Hangar]

Along with the watt meter ( to me is a must have ) another handy item is this cell checker, I use mine all the time to check batteries..

https://www.aliexpress.com/item/32811854903.html?spm=a2g0s.8937460.0.0.1dcb2e0eQY6Nel

Yeah, those voltage checkers are a must have!

 

[messyhead]

I was thinking about this too. The motors I use are these ones...

https://m.rcmoment.com/p-rm6905.html

It says max amps is 11A, and I have a 20A ESC. So I suppose the ma's is with the 9x5 prop?

I'm planning on using an 8x4 or 9x5 on one plane, and a 6x4 on the other.

 

[Wildthing]

I was thinking about this too. The motors I use are these ones...

https://m.rcmoment.com/p-rm6905.html

It says max amps is 11A, and I have a 20A ESC. So I suppose the ma's is with the 9x5 prop?

I'm planning on using an 8x4 or 9x5 on one plane, and a 6x4 on the other.

Their voltage rating is from a 2S to a 4S battery, recommended props 7.5*3.5 would be the 4S, the 8.4 would be the 3S and 9.5 would be the 2S. Those are the manufacturers recommended specs to keep you around or below that 11A but you should still test each one because different manufacturers props can be the same size and pitch but work the motor different.

 

[messyhead]

Their voltage rating is from a 2S to a 4S battery, recommended props 7.5*3.5 would be the 4S, the 8.4 would be the 3S and 9.5 would be the 2S. Those are the manufacturers recommended specs to keep you around or below that 11A but you should still test each one because different manufacturers props can be the same size and pitch but work the motor different.

Thanks for the info. I'm using a 3s on one plane, so I'll use a 8x4 on that.

The other one is for my son, so I don't want it to be too fast for him. It'll have a 2s,so I suppose I'll need a 9x5 slow fly?

 

[messyhead]

Actually, from what I've just read, a slow fly prop can draw more current than a standard prop, so I'll get a standard one, and a watt meter

 

[Wildthing]

Actually, from what I've just read, a slow fly prop can draw more current than a standard prop, so I'll get a standard one, and a watt meter

That watt meter gauge is a must have.

 

[Sero]

Not all props of the same dimension are the same in amp draw, there can be drastic differences. An amp/watt meter is a very handy tool to have.
Also keep in mind that generally flying max amps is lower than static max amps.

 

[messyhead]

I'd never seen those watt meters, so I'll definitely order one.

 

[TooJung2Die]

I'd never seen those watt meters, so I'll definitely order one.

Since this is all about scratch building, make your own.
$3 Watt Meter
Volts X Amps = Watts
It's good for up to 20A which is enough for most park flyers. I made one for free when Harbor Freight had them "free with any purchase". The resistor value is not critical. I salvaged a 1K resistor in some junk electronics.

Here's the one I made. Just plug it in between the battery and ESC. It measures volts and amps and is very accurate.

Jon

 

[Wildthing]

I would just buy something simple like this, just have to solder on your type of battery connections

https://www.aliexpress.com/item/329...s5jpgSZtEXPsKidRtjgaAkl1EALw_wcB&gclsrc=aw.ds