Oct 10, 2012, 04:52 PM
Australia, VIC, Melbourne
Joined Nov 2006
There is a problem with these 'test figures'.....
They don't tell you much at all.
It is not a lot of use knowing Vm... Volts Minimum. Or Ap... Amps Peak....
Or Wp... Watts peak.....
And even the 1.1Kg is no real use.....
1) Vm could occur at many time points.... it depends on how long you ran the motor. And at what power level - constant? Varied at any point?
Most likely Vm was at the end of the run..... however long that run was. Run it longer and Vm would have been lower. Don't go to WOT later and Vm would have gone lower if you had. THAT battery could give a fairly different Vm than another battery - even one of the same type.
So knowig Vm alone is useless really.
2) Ap will pretty surely occur right at the initial test start up. It will be a lot higher than you see for the rest of the motor run. It will alter according to how good a battery was used.
So knowing Ap alone is useless really.
3) Wp is again highly likely to be the initial start up point in time. And Watts will drop off a lot after that, due to Volts and thus Amps dropping off a fair amount right from that time point onwards.
So knowing Ap alone is useless.
4) 1.1Kg... when?? Maximum? For 3 seconds? Or ongoing (hopefully)?
Oh dear.... now all four are useless numbers..... LOL
For any info to be of real use to someone wanting to know how a motor/fan/battery combo goes it needs a LOT more info.
Those first 3 ARE useful, for certain reasons they can be good to know (not overly good use ever though), but all the other missing ones are far more useful.
1) What battery - ALL its specs
2) Ongoing Amps and Watts.... they actually decline all of the run, but generally somewhat stabilise after 30secs, so if you are going to use 'fixed' numbers to list, wait and list those ones. Best is to list peaks AND ongoings. But ongpoings are the most useful.
3) Thrust... again, annotate peak, but then after stabilsied decline (30secs or whatever you chose)
4) TIMES.... that you recorded those values at
All that those numbers above tell me are:
1) 330W is very low and it is PEAK, so it would drop to 250W most likely.
Fine if you only need that much power/thrust but maybe you do....
Maybe it was a poor battery, so if I use a better one it might run X amount more powerfully.
2) Ap of 33Amps, so will give you a guide as to what ESC rating you will base that choice off.
That is all..... and that is not enough to be of any use to work out what will truly happen when you use it.
And far far better..... VIDEO the entire test, with the camera recording all the meters. Including the throttle point can't hurt either.
That will catch the entire process, as well as the meters 'min/max' readouts.
And then you can look back later and ferret out all of the USEFUL numbers to post.
I am not actually picking on Anlucas... he helps out a LOT with things all over RCgroups!! But it is more useful help (in this case) to list numbers that are actually of use to guide users to the meaningul results of a test.