cmoulder

I have a Pletty Advance in my Caelestia which has about 350 flights on it.

A couple of weekends ago I noticed that the battery consumption went WAY up - from 2200 to 2300mAh, up to 3000 to 3200mAh - for flying AMA Advanced. Previously I had gobs of capacity left at the end of the sequence, enough that I could fly the sequence nearly twice. Now, it can barely do the sequence once if I don't very carefully mind the throttle. On the last outside push on the half triangle before the final spin, I am using full throttle and it labors around the corner.

I was using an OS 100-Amp ESC and suspected that might be the problem, however after changing back to the Ice2 80HV I noticed no change in battery consumption - still very high! While I was changing everything out, I took the opportunity to check all the connectors and solder joints, with all checking out fine. I really don't think the problem is the batteries because it exhibits the same high power draw even with the stellar Sky LiPo 4400's which still register astonishingly low IRs - 1.0 -1.7mOhms - even after 70 or so charge cycles.

Upon landing, neither the batteries, ESC nor motor are hot. In fact, the motor and batteries are barely warm, and the ESC is cool.

All of this seems to leave the motor as the only remaining culprit. Has anyone else had this experience? Or should I look elsewhere for the problem?

I will download the Ice2 logs as soon as I get a chance.

can773

My Feedback: (1)

What prop are you using?

cmoulder

Mejzlik 20.5 x 12WE, same as before with low power draw.....

danamania

FWIW, this past Sunday I swapped out my "winter prop," a PT 21x13, for the new Falcon 21x13.5 V2: Got some airspeed back, and while I didn't think to check current draw, did notice that I was back off the throttle stick something noticeable. This I attribute to the warmer, less dense air, now that the chilly practice days have been going away and we are getting back up into the 70s in the afternoon. This might be something to look into (the need for a bit more pitch for the warmer days)?

cmoulder

Dana, it was about 58 degF when I first noticed the problem, and was the same yesterday at 78 degF.

Only thing different was the lack of braking effect on downlines with the CC ESC. The OS was great for that, and I plan to change back to it when I (or someone else) can figure out what the problem might be.

Gonna d/l those logs sooner rather than later.

cmoulder

PS, also the motor itself seems perfect, bearings still silky smooth, no signs/smell of overheating, magnets feel normal when turning by hand, no unusual noises.

danamania

The motor appears normal, is certainly not old, and you ruled out the ESC by evaluating two of them.  While I have not tried the particular prop you are using, it does seem to me like that pitch and diameter would be perfect for the off-season.  Did you fly last season with 12 pitch?  Just a thought.

jgg215

Bob,
I'm running the same motor/esc combination you are with a PT 22X12 prop on a Nuance. My typical consumption is in between your two numbers, about 2750. Less than 3000 although most practice flights end up being 3300-3500 using a timer to limit extra practice. Batteries are genace 5300 although I have used skylipo 4400 as well and have about the same number of flights(300+) on the Advance/OS combo. Regardless, I have plenty of power for extra maneuvers after completing the sequence, just as you used to.
Are you getting the same full throttle rpm as you did before the problem started? Either you have lost the full throttle authority thereby reducing the voltage applied to the motor or?
Since nothing is hot, there is no increase in resistance. Since you were probably not using full throttle in the verticals anyway you may not have noticed that the throttle was further forward throughout the flight. You clearly have enough battery capacity left to perform the half triangle with no problem if the whole flight is taking 3000.
I suggest recalibrating the throttle. Also have you reworked the curve in the TX? Can you confirm that full throttle is somewhere around 6400 rpm?
John

Chris Moon

My Feedback: (8)

We sometimes get reports of odd high consumption and it is often due to the chargers not reading correctly or the batteries not charging to full capacity, never heard of the Advance changing to cause a jump in consumption like that.

can773

My Feedback: (1)

Just for giggles I would try an APC or Falcon and see how you do.

jbudd

My Feedback: (1)

The first step would to be to put a Watt's Up or other type of independent current/mAh recording device in the plane, fly a flight and see how the data it records compares. If the readings are approximately the same then I'd try systematically swapping out other power system components (including the motor) until you isolate the problem. If the readings are different, but on the order of what you're seeing now, I'd put the recording device in another plane just to verify that it's working correctly, and if it is, then I'd try switching chargers.

jarvis johnson

My Feedback: (15)

I had the same problem, back in Oct of 2012, I switched out the OS esc, and replaced it with a HV 85. Still the same problem. it turned out to be the Sky Lipo 4400, i checked the batteries and they
charged up just fine with low IR. 4 packs, and they were all 4400 40c, those packs just stop work, I could only get like 5 to 6 min. I also have a Sky Lipo 20c pack that i'm still using. I got that pack
back in 2010. So try a different set of batteries, the problem should go away.

cmoulder

Thank you very much, gentlemen! You have given me some more avenues to pursue.

I have been using a variety of batteries and mentioned the Sky LiPos only because they are such good-performing packs. However, I am flying 2 sets of Skys, 2 sets of Turnigy Nano 4500 and also a Zippy compact 4500 (with about 10 cycles on it) and the issue is observed with all of them.

John G, I didn't do anything to the throttle curve when it started happening "out of the blue", but I will give that a check anyway.

Chris M, same with the charger, but I have been charging at 8A with the Cellpro 10XP's and will switch to 1C w/accurate charge to see if that has any effect.

Jerry, the weather today is dreary and wet (but we need the rain!) so it is a good time to download the CC logs.

lopflyers

My Feedback: (12)

350 flights, you have flown the living days out of that bird!!!

cmoulder

Believe me, for a Pattern model that is not much at all, especially an electric one. My 62" Osiris (electric) has 358 flights on it.

I would hazard a guess that Dave Lockhart has more than 5,000 flights on his #1 Wistmodel Bravo. Dave keeps meticulous records... unlike me.[]

cmoulder

Speaking of records, I downloaded the CC logs but they appear to be from some earlier flights. I thought I had reset the logger by powering up with throttle stick up, but after reading the CC instruction sheet I now see that I didn't do it correctly.

In any event, I cleared the log with the CC Link so the data I get tomorrow will be good. Weather forecast for tomorrow is spectacular.

pvogel

I'm betting that clearing the log solves your problem. The CC ICE speed controls are known to have issues when their logs fill up.

Peter+

cmoulder

Peter, I hope that's the case, but the issue first appeared with the OS controller....[]

pvogel

If it's not the ICE, check the timing settings you have. I can say that the OS 100 + my Hacker Q60 28 pole motor caused a huge increase in current consumption without an increase in power. But the ICE did fine and a Jeti Mezon behaves as well as (actually a little better than) the ICE. Is it possible some firmware timing setting reverted on you?

Peter+

cmoulder

Early on I had a problem with the latest ICE firmware update but it worked fine after replacing it with an earlier version. Never had an issue with the OS.

I am very curious to see the actual logs. One would suspect high amp draw, however there should be some increase in heat production somewhere in the system, which I'm not seeing.

danamania

Hi Bob, just re-read your opening post and Chad's.  My money is on the prop.  While I may lose this little bet with myself, what will make me even more sad is if it's the motor.  The advance is a newer design and I have not heard one bad thing about it.  Please prove yourself wrong and tell me it's not the motor or I will be very sad indeed.  A 22x12 on a Nuance is one thing; a 20.5x12 on your slicker airframe is quite another, given your flying style.  If that 12 pitch is just not moving enough air now that the air is warmer and less dense, it stands to reason that more RPMs would needed than before to realize the same performance, only at a cost of decreased efficiency and increased battery drain.  What other props can you test, if I may be so bold to ask?  Or is there something else we need to know about the Advance now that a few hundred flights are accumulating?  I really hope not; and I hope you find out what ails your ride tomorrow, in any case, good luck my friend.  Dana

Silent-AV8R

I'm still leaning towards old batteries. People have fixated on IR as the be all - end all about the packs. I've got some SkyLipo 4400 packs with low IR but they can barely get out of their own way. FWIW I use the same OS esc with an Advance. Try newer packs.

woodie

There are 2 aspects of Lipo packs that determine performance.

First is IR which basically is the packs ability to maintain voltage under load. IR typically climbs with age.

Second is capacity. One of the things we forget about lipos is they also loose capacity with age.

I got caught by this a couple years ago when I noticed I was getting lower and lower ending voltage for my packs after flying the same sequences in basically the same wind conditions. I tried everything, props, checking for motor problems, esc settings, made sure all connections were good/clean. Then, reading a thread on RCG, there was a discussion about lipo aging and the decreased capacity over time. Just because the label may say 4400mah, that was on day one. Who knows what it is on day 300 after 150 cycles or so. What I discovered after testing my packs was I had lost over 20% of the capacity and was in fact draining the packs more and more as time went by but was not pushing them any harder nor flying different sequences. I had 2 set of Hyperion 5000mah 25C packs that got retired due to capacity (not IR) issues. The IR values began to climb very slowly after about 150 cycles but the packs got to the point where I could not complete a sequence without stressing the packs due to being overdischarged.

Woodie

cmoulder

I am grateful for the continuing responses and plan to check different things tomorrow.

If it is the packs, I will have a good control to check against, in the form of a brand new set of Sky 4400's. I'm not going to push them hard, but if that is the problem it should provide some contrast between an older and a new pack given the same treatment with some easy break-in flights.

Dana, I too really-really-REALLY hope it isn't (and am becoming more convinced it isn't) the motor because it is such a technological jewel. NASA-level tolerances. Gotta love that.

The thing that spooks me is that it happened with all the packs, all at once.

Well I should know a bit more after tomorrow.

jgg215

Bob,
I assume you are checking all cell voltages after charging to insure you are getting a full charge. What charger are you using?
I suggest tomorrow you record voltages before the flight and after with both the new battery and an old one. Put in a flight with an old battery first just to make sure the problem did not magically disappear.  Also tach full throttle. If you have an ammeter, see what the full throttle current is as well.
Recharge both batteries and record the mah put back in.
Then post all the results for us.
John