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Feb 15, 2011, 04:04 PM
Registered User
Discussion

new to electric surging HELP


Hi Guys
I'm new to electrics and am having a problem with a power combination, it surges at high throttle. Here's what I've got. Turnigy C3536-1300, APC 10X7 electric prop, Sky Wing 60A speed control, Turnigy 3cell 2200 batt. When it is surging it is only drawing 29 Amps. Ideas?
Thanks
Frank
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Feb 15, 2011, 06:53 PM
Registered User
Sounds like a low voltage cut off issue. Do you know what the voltage reads when the motor starts surging?
Feb 15, 2011, 07:05 PM
Registered User
pilotpete2's Avatar
If you're pulling more than 30A, you should consider moving up to at least a 3000mAh pack. Ideally you should not draw much over 10C from a lipo, regardless of the C rating, especially if you want more than a 5 minute flight.
Pete
Feb 15, 2011, 10:05 PM
Registered User
As said above, checking the voltage under load will tell you alot, but could also be a timing issue. If your ESC is programmable, try med timing and see if that helps any.
Feb 16, 2011, 02:21 PM
Registered User
OK so i checked the voltage under load with the motor surging and it's 11.45V
Feb 17, 2011, 07:41 AM
Space Coast USA
hoppy's Avatar
The prop is too big.
Other users reports-
APCE 10x5 = 34A
9 1/2 x 6 gas prop = 35A

APC 9x6sf on 2s lipo= 21amps
APC 10x4.7sf on 2s lipo= 21 amps
APC 7x5e on 3s lipo= 13 amps
Same prop on 2s= 9 amps
APC 8x4e on 3s lipo= 13 amps
Same on 2s = 9 amps

That 10x7 appears to be just too much prop for the motor and pack.
Try a smaller prop.
Feb 17, 2011, 11:50 AM
Registered User
I dropped the prop to a 9X3.8 and no surge and lower readings over but, OK now I'm really confused (or just stupid) Here is the setup and full throtle readings on the park Zone Wildcat that I flew last fall with great results. Most flights around 7 min. medium throttle. Turnigy 3536-1100, Turnigy 3c 2200 APC slowflier 10X7 Mystrey 40A SBEC. the readings are 572.3Wp, 1.6Wh, 51.75Apand 10.62Vm. Battery or ESV never got hot (just warm) Thesr readings are all higher that the ones I getting now and that combination never surges and works fine. I know at full load I'm pushing the 40A ESV and that is why I went to the Sky Wing 60A ....so ???????
Frank
Feb 17, 2011, 02:39 PM
Space Coast USA
hoppy's Avatar
I'm confused also. You're talking about 2 different motors and setups , right? A 35-36/1300 and a 35-36 1100 with APC10x7E and a APC10x7SF prop? Are you also talking about 2 different batteries?

Running the 35-36/1100 on a 10x7SF is again over the top. The motor is rated for 35A for 30sec and you've got it set up for a 51A draw? The APC SF props are notorious amp hogs.
IMO, it should be set up for a 35A draw at full throttle.

In answer to your question, are you talking about the same battery pack? Did you store it over the winter fully charged? In any case, the pack you were using with the Wildcat was in better condition than the one used in post #1. The pack being used with the set-up in post#1 just couldn't provide the power needed with that 10x7 prop.
Feb 17, 2011, 06:02 PM
Registered User
2 different set ups yes. I stored the pack for plane #1 over the winter in the "storage mode according to my charger then full charged it one time before using it on plane #1. The very same battery was used to get the numbers for the Wildcat without any additional charging i.e. did one plane then switched the battery right away to the other and took the readings. If the APC props are amp hogs what do you recommend?
Feb 17, 2011, 07:17 PM
Space Coast USA
hoppy's Avatar
APC-E
GWS-HD or DD

For the level of watts you're talking about, the APC-E props would be my choice. An APC-E 10x7 will draw about 25% less current than an APC-10x7SF.

So, you're saying on the first test the ESC/motor choked on 29A but right afterward, ran another setup at 51A.

That is a puzzler - one explanation - the pack warmed up after the first run which made it able to produce more current. I probably wouldn't bet on that idea but it's a possibility.
Or one ESC has a higher LVC setting than the other.
Last edited by hoppy; Feb 17, 2011 at 10:11 PM.
Feb 18, 2011, 07:24 AM
Registered User
No, the first test was on the new setup I'm trying to figure out (Airplane #1) the second was on the widcat I flew all last year I just used the same battery on each one to eliminate a vairiable. I'm beginning to suspect the speed control (programing?) so I'll do some more test today
Feb 18, 2011, 07:59 AM
Space Coast USA
hoppy's Avatar
Let's see if we can get on the same page.

This is a test you just did, right?
Quote:
Here's what I've got. Turnigy C3536-1300, APC 10X7 electric prop, Sky Wing 60A speed control, Turnigy 3cell 2200 batt. When it is surging it is only drawing 29 Amps. Ideas?
And then you took the battery used for that test and immediately ran this test?
Quote:
Here is the setup and full throtle readings on the park Zone Wildcat that I flew last fall with great results. Most flights around 7 min. medium throttle. Turnigy 3536-1100, Turnigy 3c 2200 APC slowflier 10X7 Mystrey 40A SBEC. the readings are 572.3Wp, 1.6Wh, 51.75Apand 10.62Vm. Battery or ESV never got hot (just warm)
If not, what was the sequence and results?
Feb 19, 2011, 07:06 AM
Registered User
Correct, that was the tests and the sequence.
Feb 19, 2011, 12:13 PM
Space Coast USA
hoppy's Avatar
The results, 29A and 11.45V for Setup #1 may be misleading.
During surging, the LVC is cutting the motor power and the these measurements are at the LVC reduced power level.

Found an interesting chart on your motor. http://www.rcflights.com/fly2air/tdm/C3536-1300.gif

Look at the 9x7.5 APC electric prop data.
Full throttle with a 3s is 26A with a voltage of 9.43V.
Now put a 10x7 APCE prop on there and 2 things will happen.
Amps will increase significantly and voltage will drop. This looks in line with the results you obtained. I would guess that the voltage drop would be well into the LVC range.

The question now is how high would the A go with a pack that could provide the current without dropping voltage so the LVC kicks in. Your test#2 data suggests that it would be above 51A.

In both cases, I would suggest reducing the prop size till the max draw at full throttle is below 35A.

And a chart for the 1100 motor.
http://www.bungymania.com/imageshome...erf1.php?id=79
Last edited by hoppy; Feb 19, 2011 at 12:23 PM.
Feb 19, 2011, 06:35 PM
Dizzying Heights
SargeNZ's Avatar
It could be a timing issue rather than a LVC issue.


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