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Hot battery/esc

Old 09-14-2009, 10:46 PM
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rascal35
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Default Hot battery/esc

I have been flying my Multiplex Easy Star for a few months. Recently bought a new one and put my compnents in it: Brushless Quantum motor, 36 amp Castle ESC and am using a 3c Apex 2200 mah 11.1 volt lipo to power it. It is a rocket and the fastest plane with the meanest climb rate I have ever seen, and its in my control, I cant believe it. Anyway, I use to run the same plane, same components but with a Fullymax 7.4 volt 2c 2200mah lipo and it still flew awesome. After a few minutes of flying with the newer battery, (the Apex) not much on full throttle, the battery was hot and all the wires, dean connectors, esc too. I dont know how to figure amps, volts etc... Is my esc too small?? I really want to run this plane with this battery, since it gives me so much power. What is the problem? Thanks for any input.
Old 09-14-2009, 11:07 PM
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Default RE: Hot battery/esc

Okay ... you used to fly on the same set up with a 2S pack if I read you correctly. Now you are flying with a 3S set up. If you maintain the same prop of course it will all heat up. When you increase the number of cells you have to:

i. use a prop with a lighter load (smaller diameter and/or less pitch);
ii. use a motor of a lower KV.

Using a bigger ESC is not the answer. It will still kill the battery or the motor. Get yourself a watt meter, you will never regret puchasing it. You will not use it often but that one time when it tells you things are wrong, that is all you need.
Old 09-15-2009, 01:02 AM
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rascal35
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Default RE: Hot battery/esc

Yes, it was a 2 cell now a three cell, but its a 12 c discharge rate compared to the old batteries 25 c discharge rate. Does this matter? I don't know the specs off hand of my Quantum brushless motor, but its so powerful, today when I flew with this setup. If I continue to fly like this, will there be damage to the planes electronics/battery. All the wires were hot. The battery was feeling like the beginnng of ballooning so I stopped flying. I really liked the power I got out of the whole powerplant. Will using a smaller prop take away from the performance??
Old 09-15-2009, 02:41 AM
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Default RE: Hot battery/esc

The extra cell on the same prop means system is drawing much more amps. That will cause all the heat and eventually kill the system. You see the ballooning with the batteries. Its being over discharged. Drop the prop to a smaller one and you really need the WATT METER. Best set up for the EasyStar is as follows:

Batt - 25C 3S 2,500 (plane needs a heavy pack up front to get the CG spot on and she flies sweeter when slightly nose heavy)
Motor - 28mm x 40 mm motor of no more than 3,000 KV
ESC - 40A
Prop - 4.75 x 4.75, 5x5, 6x4

For me its pointless flying an EasyStar that fast, she is not built for speed, all the power is being wasted. If you want to enjoy speed get the FunJet ... she can cruise about but at least you do not waste all the power. Have fun!
Old 09-15-2009, 11:01 AM
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Default RE: Hot battery/esc

Current wants to go up squared with voltage (keeping everything else the same). So, going from 2 to 3 cells will give an increase in current by factor 2.2! 120% more.


And for a rainy day ...

* Get a current/Watt-meter, it will save you money and will more than pay for itself!
3$ diy Watt-meter:
http://www.rcgroups.com/forums/showthread.php?t=949923

* Presentation: de-mystifying Electric Flight
http://www.rcaircrafters.org/The%20Electric%20Show.pdf

Get a current/Watt-meter

* http://www.ampaviators.com
-> Beginner Guide

Get a current/Watt-meter

* E-book: Everything You Wanted To Know About Electric Powered Flight
http://homepage.mac.com/kmyersefo/ev...ng-e-power.pdf
Corresponding discussion:
http://www.wattflyer.com/forums/showthread.php?t=31071

Get a current/Watt-meter

* Several Wiki's
http://www.wattflyer.com/forums/vbglossar.php

Get a current/Watt-meter

* Battery FAQs
http://www.hangtimes.com/redsbatteryclinic.html
http://www.batteryuniversity.com/


Get a current/Watt-meter

* http://www.ezonemag.com
-> Faq

Get a current/Watt-meter

* System wiring diagrams:
http://scriptasylum.com/rc_speed/_wiring.html
* LiPo pack and balancer cable wiring:
http://scriptasylum.com/rc_speed/_lipo.html

Get a current/Watt-meter

* Monthly Ampeer newsletter, on paper and online available. Excellent articles in the archives by e-flight pioneers Ken Meyers and Keith Shaw a.o.
http://homepage.mac.com/kmyersefo

Get a current/Watt-meter

* Brushless motor animations and simulations. Mostly outrunners but inrunners are just outrunners turned inside out, nothing fancy:
http://www.rcgroups.com/forums/showthread.php?t=216928

Get a current/Watt-meter

* Choosing a power setup
http://www.rcgroups.com/forums/showthread.php?t=739069
http://www.wattflyer.com/forums/showthread.php?t=27019

Get a current/Watt-meter

* About de-rating controllers and motors, starting at 'for everyone else':
http://www.rcgroups.com/forums/showt...0#post11476940

Get a current/Watt-meter

* E-flight calculators, a compilation
http://www.rcgroups.com/forums/showthread.php?t=606703

Get a current/Watt-meter

* Current, voltage, Watt, battery-types and -C-rating explained
http://www.rcgroups.com/forums/showthread.php?t=417868

Get a current/Watt-meter

* About BECs, #servos and battery voltage:
http://www.rcgroups.com/forums/showt...2#post11679182

Get a current/Watt-meter

* 'Dry' testing brushless motors after a mishap:
http://www.wattflyer.com/forums/showthread.php?t=35216
http://www.rcgroups.com/forums/showthread.php?t=240993

Get a current/Watt-meter

* How to repair a brushless motor
http://www.rcgroups.com/forums/showthread.php?t=1079423

Get a current/Watt-meter

* Motor_rewinding_101, about poles, winds, delta, star
http://www.gobrushless.com
-> knowledge base
-> basic overview (1-5)

* And I almost forgot, get a current/Watt-meter



ps: "Get a current/Watt-meter " copyright Cato Maior, 234-149BC



Vriendelijke groeten Ron
Old 09-15-2009, 11:49 AM
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-pkh-
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Default RE: Hot battery/esc

A Wattmeter is one of the best investments you can make if you are getting into electric flight. It lets you change your setup and verify that you aren't going to fry any of your components. They cost about $50, but if it saves you from frying one motor/ESC/battery setup, it will have probably paid for itself!
Old 09-15-2009, 10:23 PM
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rascal35
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Default RE: Hot battery/esc

So I have some more specs on my motor. Its a KMS Quantum brushless 380/10 I/R. Its IO amps is 2.07 and is rated at 4004 KV/RPM Max current continuous is 22A and max current is 39A. I dont know much beyond the numbers of voltage and amps, I just know that Its fast, and is perfect for lugging my canon digi camera up for UAV flights. I don't run the plane at full throttle for more than a few seconds, since I know the Easy Star is not made for speed, but it will climb like a rocket and get to altitude where I kill the motor and soar around for minutes at a time. I don't really see the need for a watt meter, since I still don't understand the lingo that goes with it. I should take the responsibility and learn, but all the planes I have purchased have been RTF kits, so mixing and matching batteries/esc's has never been an issue. So I should just change the prop to something smaller? I am currently using a 6x4 carbon fiber prop, don't know what brand, but it cut my finger last year pretty good, so I learned to respect that part of the plane when the battery is plugged in. I thank you guys again for your help. I love the way this thing flys, and its altitude saoring ability. The funJet sounds and looks like a cool option, but I have an F/A-18 from Nitro Planes I have only flew once, its hanging from my ceiling since I am working on getting more comfortable with 4 channel planes. This Easy Star setup is just awesome, I wish someone could see this thing fly, with this setup. Would it be lame if I were to claim it as the fastest, most powerful Easy Star is San Diego? Thanks again for the help.
Old 09-15-2009, 10:55 PM
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Default RE: Hot battery/esc

Rascal ... 4,000 KV is a little too hot for 3S unless you want to prop it down to like a 4.2x4.1 prop, of which is not suitable for the EasyStar. Get another motor of the same size at about 2,700-3,000 KV if not go back to 2S. A WATT METER is not hard to use, plug it in and see how many amps is being pulled, that's all. You already know how many amps your motor is good for. Its as simple as that.
Old 09-16-2009, 01:26 AM
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rascal35
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Default RE: Hot battery/esc

How is a 3s making it hotter compared to the 2 cell? I dont understand. Obviously, if I go back to the fullymax 2200 mah 7.4 volt 25c lipo, the heat prob should go away, right? I remember months ago flying with that setup and it was slightly warm, which is better than the hot I was getting the other day. do you reccommend something so I dont have to switch out the motor for something smaller?
Old 09-16-2009, 01:45 AM
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Default RE: Hot battery/esc

you should be able to answer your own question in regards to; how is the 3s making it run hotter than the 2 s. how many volts does the 3s lipo have ? how many volts on the 2 s ? also you may want to consider using a larger amp ESC as 35 amps may be ok for a 2 cell but not as safe when running 3 cell lipos. my 450 size heli runs a 55 amp esc on a 3s lipo and my extra 260 also runs 45 amp esc on 3 s lipos.
Old 09-16-2009, 04:28 AM
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Default RE: Hot battery/esc

Rascal ... keep things simple, its not as costly.
Old 09-16-2009, 05:19 AM
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Default RE: Hot battery/esc

ORIGINAL: rascal35

How is a 3s making it hotter compared to the 2 cell? I dont understand. Obviously, if I go back to the fullymax 2200 mah 7.4 volt 25c lipo, the heat prob should go away, right?
Think of voltage as pressure in a hydraulic system. If you increase the pressure too much, the pipes will start bursting. The remedy is to use bigger pipes to handle the flow, or lower the pressure to a level your currently installed pipes can handle.

An electrical system is very similar. Higher voltages (more pressure) cause more electrons to flow against the impedances in the power system resulting in increasing heat, as you have discovered. The remedy is to lower the impedances (increasing wire diameters, ESC capacity) or decreasing the pressure (lowering the voltage, decreasing the load (prop diameter/pitch), or decreasing Kv).

(Edit: corrected increasing Kv to decreasing Kv. Thanks Ron! )
Old 09-16-2009, 05:47 AM
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Default RE: Hot battery/esc

ORIGINAL: rascal35

How is a 3s making it hotter compared to the 2 cell? I dont understand. ...
Motorcurrent wants to go up squared with voltage (keeping everything else the same: battery, controller, timing, motor, prop).

So, going from 2 to 3 cells will give an increase in motorcurrent by factor 2.2! 120% more. And losses in the (any) copperwire go up squared with current. Therefore, copperlosses (=heat produced) increase with voltageā“ (power 4). In your case that would be by a factor (3/2)ā“ = 5! 400% more heat to get rid off!

And that's from copperlosses only. Then there are also the magnetic hysteris losses in the iron, they go up linearly with voltage (voltage = Kv* rpm), and to top it off, the eddy current losses in the iron go up squared with voltage.

If motor gets to hot, (Neodymium) magnets will die, resulting in higher Kv -> higher current -> higher temperature -> deader magnets -> higher Kv -> higher current ... In short: temperature runaway.

Eddy currents explained:
http://en.wikipedia.org/wiki/Eddy_current

Eddy current demos/videos:
http://www.rcgroups.com/forums/showthread.php?t=465019

Vriendelijke groeten Ron
Old 09-16-2009, 05:53 AM
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Default RE: Hot battery/esc


ORIGINAL: whitecrest

... The remedy is to lower the impedances (increasing wire diameters, ESC capacity) or decreasing the pressure (lowering the voltage, decreasing the load (prop diameter/pitch), or increasing Kv).
Typo:
increasing Kv -> decreasing Kv.

Vriendelijke groeten Ron
Old 09-16-2009, 06:44 AM
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Default RE: Hot battery/esc


ORIGINAL: ron_van_sommeren


ORIGINAL: whitecrest

... The remedy is to lower the impedances (increasing wire diameters, ESC capacity) or decreasing the pressure (lowering the voltage, decreasing the load (prop diameter/pitch), or increasing Kv).
Typo:
increasing Kv -> decreasing Kv.

Vriendelijke groeten Ron
Thanks for catching that. Corrected above.
Old 09-16-2009, 07:27 AM
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Default RE: Hot battery/esc

Ron ... I am scared to ask what you do for a living ... heheheheee ...
Old 09-16-2009, 08:12 AM
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Default RE: Hot battery/esc


ORIGINAL: rascal35

How is a 3s making it hotter compared to the 2 cell? I dont understand. Obviously, if I go back to the fullymax 2200 mah 7.4 volt 25c lipo, the heat prob should go away, right? I remember months ago flying with that setup and it was slightly warm, which is better than the hot I was getting the other day. do you reccommend something so I dont have to switch out the motor for something smaller?
Rascal, i'll try to explain it more simply. The motor's kv rating, in your case 4004 kv, means rpm's per volt. So, with that info, your 4004kv motor running on 2S, or 7.4 volts, spins at 29,630 rpm (under ideal conditions. In reality, more like 60-70% of that). That same 4004kv motor on 3S, or 11.1 volt, will try to spin at 44,444 rpm's. The increase in rpm's requires either a smaller diameter prop, or lower pitch prop to keep from drawing excessive current. The increase in rpm puts much more load on the motor to spin the same prop, that's why things are very hot. If you continue to run that setup like that, the motor and/or ESC will certainly fry. A watt meter is a must. Learn to use it, it's not hard. It is much cheaper to invest in a watt meter than to have to replace a motor and ESC.
Old 09-16-2009, 10:05 AM
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Default RE: Hot battery/esc

ORIGINAL: tIANci

Ron ... I am scared to ask what you do for a living ... heheheheee ...
EE by training, thoroughly hated 3-phase and electromechanics classes, turned technical software engineer ( [link=http://www.philips.com]Philips[/link], [link=http://www.ASML.com]ASML[/link], [link=http://www.alsi-international.com]ALSI[/link] ). Right now recovering from a severe burn-out.

I'm also the 'owner' of this diy brushless motor e-mail discsussion group:
www.yahoogroups.com/group/lrk-torquemax
And this D-Calc e-flight calculator discussion group:
www.yahoogroups.com/group/d-calc
Old 09-16-2009, 11:18 PM
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Default RE: Hot battery/esc

Ron ... I should not have wondered! Hahahahaa ... its great to have people like you show us that there is a much bigger picture than what we see.
Old 09-17-2009, 01:47 AM
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Default RE: Hot battery/esc

Problem solved, picked up a Thunder Power RC 2600 mah 2 cell 7.4 volt, for my easy star. That should keep everything back to normal i hope. I am going to use the 3 cell 11.1 v 2200 mah that was the reason for this thread, in the new parkzone F4U Corsair I picked up today. Thanks for your help!!

Joe
Old 09-18-2009, 05:56 AM
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Default RE: Hot battery/esc

ORIGINAL: tIANci

Ron ... I should not have wondered! Hahahahaa ... its great to have people like you show us that there is a much bigger picture than what we see.
I'm thinking of buying [link=http://www.eece.maine.edu/motor/]Brushless Permanent Magnet Motor Design[/link], $165 [sm=omg_smile.gif] Have to have a little chat with she-who-must-be-obeyed.

Prettig weekend Ron


Old 09-18-2009, 06:17 AM
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Default RE: Hot battery/esc

Of course, you need the Finance Minister's permission. If not we men would be bankrupt!

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