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Old 07-07-2011, 01:09 PM   #11
Max
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Re: i need some esc advice please


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Originally Posted by rotormonkey13 View Post
Calculating based on how much the battery takes back is good for figuring out the average load, but won't tell you what the spikes are - and they are important.

For example, you may be only 15amps to hover, but might be pulling a lot more on spool up. Or if you only hover 99% of the time, but one day you decide to punch it a bit. Maybe you crash and don't hit throttle hold right away - that under-rated ESC is going to go up in smoke when the current spikes too much.

jmho.
I agree, Joe. The option I gave for 2 minute hover is all about collecting and analyzing data. That is why the Data-logger or Watts-up would be the better way to go. At this point I was giving an example for 2 minute hover.

Again, this is the poor man's option for someone who doesn't have access to a data-logger or Watts-up device. Once you tried it with a hover and got comfortable results, One could easily repeat the same test by flying 2 minutes of mild 3D and observed the increase in current draw. If the data shows safe with a good safety margin from the ESC's rated Amps, then you could repeat the experiment one more time, upping the the ante with even more aggressive flying for 2 minutes and analyzing the recharge data.

Not the best way to do it, but if its the only option available, it does work.

From personal experience looking at the flight data that I have recorded on my Eagle-tree Data logger, Hover to Max load results in a <%30 rise in power draw (For my heli, cant speak about anyone else's

BTW- flying at 33A for a 2200 mah battery yields 4 minutes. If you fly your heli and you get more than 4 minutes per pack, then you are already below 33W all told.
If you can only fly for 4 minutes and your ESC kicks in to lower our motor output, then yeah, 35A is not going to cut it.
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Old 07-07-2011, 01:45 PM   #12
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Re: i need some esc advice please

Max, yeah I understand what you're saying buddy, but imo it's not a great way to tell whether your ESC is enough to handle the motor you have.

The reason being that it doesn't tell you anything about the peak loads - only the average. And when the ESC is underrated for the motor as it is in this case it's just asking for trouble imo.

It is however a great idea for getting an idea what kind of load your motor is generating overall.

Just thowing this out there - but why use such a hot motor for flying around scale at 2000rpms in the first place?
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