figuring amp draw...
 

whats the easiest/fastest way to figure the amps my nimh battery packs are capable of putting out/...is there a certain meter I need to buy??..thanks...

RE: figuring amp draw...
 

There's no way that I know of to measure the maximum safe discharge rate of a battery, other than through experimentation. This information is usually provided by the battery manufacturer. The maximum safe charge and discharge rates are given as a "C" rating. For example, ThunderPower 2100mAh LiPol batteries have a maximum continuous discharge rate of 10C. That means the battery can be safely discharged continuously at a rate of 10*2100mA = 21 Amps. Most NiMh cells can typically withstand 10C continuous discharge, but they will get hot.

If you want to measure the current draw while the motor is running, then you'll need an ammeter that's capable of handling the Amps. There are a couple of great meters designed specifically for R/C. One of them is made by Astro Flight... http://aeromicro.com/Catalog/astrofl...er_1519029.htm

RE: figuring amp draw...
 

Direwolf..thats kinda what I was guessing..that most consumer packs,,like the raidio shcak 1600 mah nimh..would handle about 10 amps contiuos..I know the industrial grade packs like cbp..can handle 15-20 amps...but wasnt sure about these cheaper packs..and its almost impossible to find specs on them..I need to know becuase I will be runnin a brushless himax 2812-1080 with my off brand nimhs,,I lll just fly..and make sure they get alot of ventialltion..and check theyre heat after each flight...if theyre hot to the touch..I will know theyre being over taxed..

RE: figuring amp draw...
 

Hi guys,
This is a good thread and I hope you are still checking in on it so you might be able to answer my question. If I hook up a 7.2 V, 2400 mah battery to my speed 550 motor and draw near maximum power from said battery pack, how long a flight time might I expect?
Thanks for any and all input, I know there is more art than science to all this. Lee

RE: figuring amp draw...
 

To fiqure this out , we need to know how much current is drawn for this particular motor using 7.2 volts.

This spec is from a 600 motor powered by a 7.2 dc battery.

So if you divide 2.6ma into 2400mAh you would get 0.923076923 hours the batery would last. that is if you only power the motor with the battery which we know you will not. The receiver , esc, and servos current draws are added into the equation to give you a better idea on how long the battery will last.