emax 2815/09 3s or 4s

[david 7]

Hi, just receivied a emax 2815/09 for my dave boddingtons 30 year old ic conversion, when i checked the spec for the motor i wanted it to run on 4s lipos .

when i checked the internet for information some sites say it runs on 3slipos and other sites say it can run on 3/4 lipos, i found a couple of people running 4s lipos on the same motor.

Not to sure now if its ok to run on 4s now, is any one running this motor on 4slipos, the same motor is on the brc web site and they have tested it on 4s lipos ant advise would be welcomed.

Dave.

[Tim Mackey]

Its all about the prop size.

[Tim Mackey]

To elaborate a bit.... almost any motor can run on almost any battery you want, it doesnt really care.

What it does care about more is the total current being passed through its windings!

As you increase the battery volts ( 3s = 11V and 4s = 14.5V approx ) the current increases. Thats the law, ohms law.

To reduce this current, you reduce the workload of the motor...by fitting a smaller prop.

A Wattmeter will tell you exactly how much current is being consumed as it spins the prop, and as long as the current doesnt exceed the maximum allowed for the motor ( as per the specs ) yure fine.

Of course, whether that small fast revving prop will now be suited to the type of model / flying that you intend to do with it is another matter

[david 7]

Thanks tim, my real concern or my lack of knowledge is the 3 and 4 cell lipos have 2 diffrent volatage, is this what could cause damage to the motor, or is it if i am drawing to many watts for the motor ie i have fitted the wrong prop and am drawing to many amps for the spec of the motor, if i was to run the motor to its spec with the correct prop esc and test it with my watt meter and was in the spec does it matter if i run it on 4s lipos is realy what iam trying to say in my own words.

Dave

[david 7]

sorry tim did not see your 2nd post, think you must of read my mind

Dave