Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Nov 04, 2012, 08:20 AM
Registered User
Joined Nov 2012
37 Posts
Discussion
Mini CP 2min gentle flight time

Hi,

Something is happening to my mini CP and I need some help debugging the problem.

New I got a good 4 mins of hovering time out of it (I'm a beginner). Now I get 2 mins 15s out of my best battery before it lands out of lack of power. I'm not talking hard 3D but mooving around a room. My worst batteries (I have 7 stock batteries) are lasting approximately 30s.

From the very beginning of a flight I can feel there's not much juice i.e. it's not lifting as vigorously as before.

The voltage after charge is 4.18V. I'm using the stock usb chargers. There's no vertical play (more a milimeter or so). I've measured resistance from connector to curcuit-board and from circuit board to main motor - it is approx 0.7 ohms.

Some help is badly needed here.

Thanks
Johan
johan_alps is offline Find More Posts by johan_alps
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 04, 2012, 09:58 AM
Cranky old fart
Balr14's Avatar
Germantown, WI.
Joined Oct 2007
21,413 Posts
Those motors do not last long, a few hours is all. The brushes start to wear out almost immediately. A brushless upgrade is very common to this model.
Balr14 is offline Find More Posts by Balr14
Reply With Quote
Old Nov 04, 2012, 01:25 PM
Smoke em' if you got em'
ifly504's Avatar
United States, LA, New Orleans
Joined Jun 2011
29 Posts
Check your gear mesh (motor pinion and main gear). Make sure its not to tight. Or too loose.
ifly504 is offline Find More Posts by ifly504
Reply With Quote
Old Nov 05, 2012, 05:52 PM
Registered User
Joined Nov 2012
37 Posts
They're good, atleast as far as I can see, main gear turns freely, no looseness and well the main motor it is hard to say because it is so hard to turn around anyway. It did work correctly from the start so I suppose it didn't tighten itself up
johan_alps is offline Find More Posts by johan_alps
Reply With Quote
Old Nov 05, 2012, 05:55 PM
Registered User
Joined Nov 2012
37 Posts
Quote:
Originally Posted by Balr14 View Post
Those motors do not last long, a few hours is all. The brushes start to wear out almost immediately. A brushless upgrade is very common to this model.
Wow really? The brushes wear out to a point where it consumes almost 2 times more energy?

I was a bit worried about my batteries, any way I could rule out that they're not to blame?
johan_alps is offline Find More Posts by johan_alps
Reply With Quote
Old Nov 09, 2012, 10:01 AM
Registered User
Tucson, Az
Joined Feb 2007
6,808 Posts
Another possible cause is to much pitch and working motor to hard and excessive hovering. Hobbykings nano-tech 260ma batteries work better than stock Walkrea's. Not a great advanyage but it sure helps.
dankar04 is online now Find More Posts by dankar04
Reply With Quote
Old Nov 09, 2012, 10:38 AM
Cranky old fart
Balr14's Avatar
Germantown, WI.
Joined Oct 2007
21,413 Posts
Quote:
Originally Posted by johan_alps View Post
Wow really? The brushes wear out to a point where it consumes almost 2 times more energy?

I was a bit worried about my batteries, any way I could rule out that they're not to blame?
Walkera brushed motors have been poor for years, especially their micro sized motors. They will get to a point where they won't last 5 seconds. As dankar04 pointed out, Walkera batteries are not the best either. But, I'd sure bet on the motor. Try a Walkera Genius motor. For some reason, those things last. But, don't expect miracles for flight time without a brushless upgrade.
Balr14 is offline Find More Posts by Balr14
Reply With Quote
Old Nov 09, 2012, 12:18 PM
Finding Creative Ways To Crash
RCCrashTestDummy's Avatar
Joined Jun 2012
448 Posts
Johan,

I have no idea if your problem is being caused by the stock motors being worn-out, but I found a brushless upgrade kit for your Mini CP. Hope this helps.

http://www.wowhobbies.com/turboace41...43g-3-1-1.aspx

-Pat
RCCrashTestDummy is offline Find More Posts by RCCrashTestDummy
Reply With Quote
Old Nov 09, 2012, 01:32 PM
Registered User
Joined Nov 2011
771 Posts
Quote:
Originally Posted by johan_alps View Post
Hi,

Something is happening to my mini CP and I need some help debugging the problem.

New I got a good 4 mins of hovering time out of it (I'm a beginner). Now I get 2 mins 15s out of my best battery before it lands out of lack of power. I'm not talking hard 3D but mooving around a room. My worst batteries (I have 7 stock batteries) are lasting approximately 30s.

From the very beginning of a flight I can feel there's not much juice i.e. it's not lifting as vigorously as before.

The voltage after charge is 4.18V. I'm using the stock usb chargers. There's no vertical play (more a milimeter or so). I've measured resistance from connector to curcuit-board and from circuit board to main motor - it is approx 0.7 ohms.

Some help is badly needed here.

Thanks
Johan
I notice that you say you're landing because you're out of power... Out of curiosity have you been running your batteries till they start to drop off the whole time? Lipos like to be kept in that 4.2 - 3.7 volt range, running them much below 3.7 will cause the cells to degrade. If you have a charger that checks IR then you could verify if your packs were getting damaged. Are any of them puffy?
TucsonFlyer is online now Find More Posts by TucsonFlyer
Reply With Quote
Old Nov 09, 2012, 03:30 PM
Registered User
Joined Oct 2010
1,201 Posts
Quote:
Originally Posted by TucsonFlyer View Post
I notice that you say you're landing because you're out of power... Out of curiosity have you been running your batteries till they start to drop off the whole time? Lipos like to be kept in that 4.2 - 3.7 volt range, running them much below 3.7 will cause the cells to degrade. If you have a charger that checks IR then you could verify if your packs were getting damaged. Are any of them puffy?
the lvc in the rcvr would prevent this unless he were to be running it even when it no longer can take off.
pmerritt is offline Find More Posts by pmerritt
Reply With Quote
Old Nov 09, 2012, 03:47 PM
Registered User
Joined Nov 2012
37 Posts
I have been flying until the batteries drop off the whole time indeed. Sometimes going until it lands out of power. So perhaps that was my mistake.

By "IR", do you mean voltage?
johan_alps is offline Find More Posts by johan_alps
Reply With Quote
Old Nov 09, 2012, 10:35 PM
Registered User
Joined Oct 2010
1,201 Posts
Quote:
Originally Posted by johan_alps View Post
I have been flying until the batteries drop off the whole time indeed. Sometimes going until it lands out of power. So perhaps that was my mistake.

By "IR", do you mean voltage?
Internal Resistance of the battery
pmerritt is offline Find More Posts by pmerritt
Reply With Quote
Old Nov 10, 2012, 03:24 PM
Registered User
Joined Nov 2012
37 Posts
Dont know how I should go about measuring the internale resistance. As I understand I need to connect some sort of load (which can hardly be the helicopter). More appropriate would be a standard resistance if I can find any. Perhaps you guys know of something in a normal household that would do?

If I understand this link correctly : http://www.mpoweruk.com/testing.htm I should
- first measure voltage (ok easy 4.18V)
- then connect my multimeter in serial with a constant load to measure Amps)?
- then I measure voltage over that same load?
- then I can simply apply ohms law.

Are steps two and three correct?
johan_alps is offline Find More Posts by johan_alps
Last edited by johan_alps; Nov 10, 2012 at 04:01 PM. Reason: Naively tried to measure IR by measuring ohms over the battery connectors
Reply With Quote
Old Nov 10, 2012, 06:46 PM
Heli collector
livonia bob's Avatar
United States, MI, Livonia
Joined Apr 2009
16,522 Posts
Quote:
Originally Posted by johan_alps View Post
Dont know how I should go about measuring the internale resistance. As I understand I need to connect some sort of load (which can hardly be the helicopter). More appropriate would be a standard resistance if I can find any. Perhaps you guys know of something in a normal household that would do?

If I understand this link correctly : http://www.mpoweruk.com/testing.htm I should
- first measure voltage (ok easy 4.18V)
- then connect my multimeter in serial with a constant load to measure Amps)?
- then I measure voltage over that same load?
- then I can simply apply ohms law.

Are steps two and three correct?
For years the first thing we all used to have do was change the stock Walkera plugs out to Micro Deans as the wires were breaking at the battery connector on the heli's side causing a lost of power and flight time.. You might want to check the wires.
livonia bob is offline Find More Posts by livonia bob
Reply With Quote
Old Nov 10, 2012, 07:45 PM
Registered User
Joined Nov 2012
37 Posts
Quote:
Originally Posted by livonia bob View Post
For years the first thing we all used to have do was change the stock Walkera plugs out to Micro Deans as the wires were breaking at the battery connector on the heli's side causing a lost of power and flight time.. You might want to check the wires.
When you say check you mean change them and test the flight time?

Doing that means I'l have to change the connectors of all my batteries as well right? I would love to have missed something here
johan_alps is offline Find More Posts by johan_alps
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Mini-Review Walkera Mini CP Review - Pictures, Video, Flight Times, Head Speed, Brushless Upgrade Tom Z Micro Helis 701 Aug 17, 2014 11:54 AM
Mini-Review Walkera Master CP Review - Pictures, Videos, Flight Time, and Head Speed Tom Z Micro Helis 368 Aug 11, 2014 01:09 AM
Help! New mini cp started acting funny after 6-7 flights (video included) waveOmatic Micro Helis 18 Sep 25, 2012 06:10 PM
Discussion Mini CP / Mcpx Night flight Xermalk Micro Helis 0 Sep 14, 2012 06:49 AM