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Old May 08, 2016, 09:53 PM
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Lipo is warm with 5 min of time

I am new to rc planes and lipos. My wife bought me an airfield 1450mm p51 last year for Christmas. I flew it once and realized I need a trainer first. Prior to the flight I charged the lipo it came with. Flew it for a few minutes and stored the plane and the battery. Having not done anything else to the battery. I pulled the plane out the other day, charged the battery and started checking things over. I had the plane in my yard with the tail blocked and spun the motor to full rpm a couple times. Plane was in power for about 3 minutes total. Plane was powered on for about 5. I opened the canopy and immediately felt some heat in the battery/reciever compartment. The battery was warm but not hot. I did not take a temp reading.
Should I be concerned, should I do something different.
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Old May 08, 2016, 10:07 PM
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Captive like that, you didn't get much cooling air through the battery compartment, and the battery generates heat, so will warm with use. BTW, you should get a cell checker to test the battery; it should be stored between flights at about 3.8-3.9V. Higher or lower Voltages, long term, will slowly degrade the battery.
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Old May 10, 2016, 09:59 AM
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Quote:
Originally Posted by Wintr View Post
Captive like that, you didn't get much cooling air through the battery compartment, and the battery generates heat, so will warm with use. BTW, you should get a cell checker to test the battery; it should be stored between flights at about 3.8-3.9V. Higher or lower Voltages, long term, will slowly degrade the battery.
Exactly. You had no airflow moving over the battery, hence the higher temperatures. Also, if you were throttling up the plane full blast for a few minutes, you were asking the battery to produce a lot more power than it does in flight. Most people don't fly full throttle for the entire duration of the flight; throttle management is an important part of electric aviation.
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Old May 10, 2016, 10:54 AM
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What Wintr and Mike mentioned - and to be certain of what is going on, you should buy a wattmeter. If your full throttle current draw is too close to the lipo's capacity x C rating, you're pushing the lipo too hard.
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Old May 10, 2016, 07:39 PM
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Still, for not flying and just being warm to the touch you were okay. Luckily. In general, don't run your motors full throttle for more than a few seconds. Even on systems properly balanced, that can cause red hot stuff to come out of motors and batteries. The red stuff consumes your plane and causes pain when you touch it. Avoid!
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Old May 10, 2016, 07:59 PM
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I've run my motors full throttle for a whole minute while on the ground - nothing happens to them. Motors will only fry if they're overamped.
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Old May 10, 2016, 08:14 PM
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Quote:
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I've run my motors full throttle for a whole minute while on the ground - nothing happens to them. Motors will only fry if they're overamped.
Why would one do this.??
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Old May 10, 2016, 09:06 PM
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Run down my lipos when I wasn't able to fly.
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Old May 13, 2016, 11:02 AM
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Originally Posted by cmdl View Post
I've run my motors full throttle for a whole minute while on the ground - nothing happens to them. Motors will only fry if they're overamped.
Try it with a Radian, where the motor is surrounded by foam. Believe me, you can fry a motor that is not overamped if you don't have the airflow that normally cools it.
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Old May 13, 2016, 11:32 AM
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It won't fry as long as it isn't overamped - the airflow isn't what keeps a motor from getting fried - it helps cool it a bit but that is more useful toward us being able to touch the motors after flying than saving a motor from getting fried.
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Old May 14, 2016, 12:41 AM
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Quote:
Originally Posted by Mike_Then View Post
you were asking the battery to produce a lot more power than it does in flight. Most people don't fly full throttle for the entire duration of the flight;.
And in the situation where it draws the most current. Current draw can vary hugely with airspeed. For example my calmato draws about 50 amps static. Maybe a little more.

But full throttle in level flight it will drop down under 20 amps. Shallow dive can get it down into the 15 amp range.
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Old May 15, 2016, 09:47 PM
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I have several planes that I frequently fly full throttle for the entire flight, it depends on the style of plane.

I would thoroughly test a battery that was stored for a year at an unknown state of charge. LiPos don't appreciate being stored over or under charged.
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