oran

hallo all,

i just bought an axi 2808/24 , 3s lipo , 10/7 prop and jeti 18amp.
will i need to replace my esc ?
thanks

INeedHelp

My Feedback: (1)

I think the 18 amp is ok with that combination but I will run it through Motocalc later for you.

jooNorway

No, it is too much load, propably close to 25A. Try a 8x6 or 9x5 APC(E) prop.

INeedHelp

My Feedback: (1)

Per Motocalc that combination will draw about 17.6 amps static and drop to about 14.7 amps at full speed in the air.

Please keep in mind that these numbers are a referance only and if you have access to a watt meter that is the way to go.

jooNorway

Sorry to say this INeedHelp, but both datasheets from AXI and practical testing shows me other numbers than you get from Motorcalc... I have long time ago stopped to use Motorcalc since the numbers it gives often are wrong in a lot of the tests I have done myself and read. I only thrust ampere-meters and wattmeters, and use both to double-check.
But the motor would work fine on 9x5, only remember not to run it static for more than a few seconds.

INeedHelp

My Feedback: (1)

jooNorway, I agree with the Motocalc numbers not always being accurate but it will give you some idea. I have found that the amp draw is usually higher than Motocalc says it is but it has been accurate at times for me. I add a statement similar to the above when I give the numbers out of Motocalc so people know that a wattmeter would be more accurate. I place absolutely no faith in the performance numbers at all I get out of this program or anyother for that matter since actual performance is all that matters anyway. I have done alot of testing with different motor/prop combinations and Motocalc was the most "accurate" of the programs I have use but it is still usually 1 or 2 amps low on average.

jooNorway

I agree INeedHelp, Motorcalc works Ok several times, but sometimes the difference from practical tests are large. And of course Motorcalc depends on numbers from the producers, and slightly wrong numbers will cause wrong results. Nothing works perfect everytime, and something that makes these thing so interesting is just the ability we have to doublecheck and try to figure out why and how and so on