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RE: Battery longevity - 2/15/2006 5:35:26 AM   
ExFokkerFlyer



Posts: 427
Joined: 5/3/2002
From: Fresno, CA,
Status: offline 		I guess we do have it better than others out here in the crazy state as far as flying goes. Sometimes I guess I forget that. Even so, just curious as to how well the batteries fared last season with those who flew electric.

Before I got into electric flying I heard a lot of claims about how long they should last, but I haven't seen much proof yet. It's not that I'm not satisfied with how my batteries are doing, but I am wondering if mine are the exception or the rule.

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RE: Battery longevity - 2/15/2006 1:04:48 PM   
patternrules


 

Posts: 548
Joined: 7/28/2002
From: Nineveh, IN, USA
Status: offline 		Actually this is the main reason some haven't tried to go EP because of the fear of short battery life but from what we're seeing is unjustified. I had heard last year that they only expected to have life cycles of 100-150 for these big batteries, but I feel that was a misleading statement. The biggest problem as I see it was that most flyers last year had so many packs (4-6 sets of 10S) that they didn't put many cycles on each pack, most only having in that season about 90-100 cycles which equaled 400-600 flights, with this many packs it could take 2,3 or even 4 seasons to get any real #'s on battery life. Which would then even put another factor in the mix, being the # years the packs could last (and winter storage). What I expect to see this year is more people using only 2 sets, making less batteries with more cycles per set. We're in a little different situation than most Lipo users, most are using 2sand 3s pack's in smaller foamy's and such, 95% of lipo business. What I've read is that if you keep the temps down, use a standard setup that is proven to work, amps in the right #'s, and short flights (not over 80% capacity, my thought is we could see maybe 400-500 cycles and maybe more. Reason for this is even flyer's that fly alot will be hard pressed to fly more than 600-1000 flights a season.
I'm sure that your reason for asking the question is to compare the price of EP to glow.
So the big question is will the $'s even out or possibly be cheaper in the long run for EP, I think once this is answered we will see most if not all going EP in pattern.
For me break even # would be about 2 seasons with 2 sets of batteries= fuels cost only, not any maintance. I would be very happy with buying 2 sets of batteries every other year.
Sorry for being so long.
Steve Maxwell

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Steve Maxwell

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RE: Battery longevity - 2/15/2006 2:18:16 PM   
Greg Covey



Posts: 4375
Joined: 5/24/2003
From: Rochester, NY, USA
Status: offline 		ExFokkerFlyer,

I agree with you also. I must have interpreted your post wrong since it came after my post #12 where I stated that the 3200mAh cell was not a good solution for pattern flying. Adam from Dragonfly tends to tout ThunderPower solutions without any real data to back up the claims. The truth is that we never had a 5AH pack solution before. The Saehan cells used in the ThunderPower packs are good cells. In fact, we plan to release a new Cellpro Slimline series using these cells because the thin shape will work in places the Kokam or PolyQuest cells cannot fit. The new Slimline series should have been released in January but the U.S. owner of Saehan, Emerging Power, cannot produce the handmade cells in sufficient quantities, and, R/C is not their primary business.

To date, I am only aware of one plane in Europe that was built so light from carbon (as an e-pattern plane) that the 2p 6400mAh (using 3200 cells) pack worked for him. Personally, I don't consider this a mainstream solution and I didn't like the look of the custom-made e-pattern plane. A 5AH capacity seems to be the right choice so I am anxious to get these new packs tested this spring.

In the last post above, Steve seems to state what I believe is the mainstream problem with flying electric pattern planes. Unless you are a sponsored pilot, or have money to burn, the cost of flying electric pattern is far greater than flying a glow-powered plane. We feel that the new Kokam 4800mAh cell combined with the Cellpro or BalancePro systems will change that advantage. Educating users about cell temperature and true cell discharge ratings is also key to increasing pack longevity.


< Message edited by Greg Covey -- 2/15/2006 2:26:36 PM >

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(in reply to patternrules)
       Post #: 28

RE: Battery longevity - 2/18/2006 6:46:35 AM   
patternflyer1



Posts: 1303
Joined: 7/3/2003
From: Tracy, CA, USA
Status: offline 		The cheapest place at this point for the Tp 5300's is www.dynamoelectrics.com
At 287.95 a pack.
As for the Kokam's, I have always found, in the smaller packs, that their ratings are off. They overstate things in my opinion.
Not that they aren't decent packs and don't have potential.
All battery manufacturers state bench tested ratings though and aren't accurate in the real world.
Hope to get more useful info on what this thread is about in the long run, not who think's their packs are better because of ratings.
Great idea for a thread Tom..

Chris

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       Post #: 29

RE: Battery longevity - 2/18/2006 7:41:24 AM   
can773



Posts: 1652
Joined: 1/25/2002
From: Calgary, AB, CANADA
Status: offline
quote:

ORIGINAL: Greg Covey

ExFokkerFlyer,

I agree with you also. I must have interpreted your post wrong since it came after my post #12 where I stated that the 3200mAh cell was not a good solution for pattern flying. Adam from Dragonfly tends to tout ThunderPower solutions without any real data to back up the claims. The truth is that we never had a 5AH pack solution before. The Saehan cells used in the ThunderPower packs are good cells. In fact, we plan to release a new Cellpro Slimline series using these cells because the thin shape will work in places the Kokam or PolyQuest cells cannot fit. The new Slimline series should have been released in January but the U.S. owner of Saehan, Emerging Power, cannot produce the handmade cells in sufficient quantities, and, R/C is not their primary business.

To date, I am only aware of one plane in Europe that was built so light from carbon (as an e-pattern plane) that the 2p 6400mAh (using 3200 cells) pack worked for him. Personally, I don't consider this a mainstream solution and I didn't like the look of the custom-made e-pattern plane. A 5AH capacity seems to be the right choice so I am anxious to get these new packs tested this spring.

In the last post above, Steve seems to state what I believe is the mainstream problem with flying electric pattern planes. Unless you are a sponsored pilot, or have money to burn, the cost of flying electric pattern is far greater than flying a glow-powered plane. We feel that the new Kokam 4800mAh cell combined with the Cellpro or BalancePro systems will change that advantage. Educating users about cell temperature and true cell discharge ratings is also key to increasing pack longevity.



Greg

You obviously missed a few of Adam's posts.....he was was of the first to post CBA plots of cycled packs (6000's Prolite cells) vs new packs back in September. If I remember correctly (I know he is planning on posting them shortly...but he is at my house building new planes....) it was around 3% after 50 cycles or so.....so your comments are a bit off base.

I just finished capacity testing my 5300's vs new packs yesterday and will post the results here shortly as well, but it appears to be about 3-5% loss in 50-70 cycles.

The tests we do are on real packs, use in the Worlds, US Nats and dozens of other events....well travelled well abused packs (I have discharged mine to 90%+ more than once by accident) so its not some hand picked company performed test.

If you have data like we do to back up your claims from people in the field please provide it.

Unless you come up with new tech in cell chemistry the cycle life of current cells is not going to improve much with chargers/balancers......my packs have always remained within 0.010V balance during their life (checked with a calibrated Fluke DVM)....and I have yet to see them reach beyond about 120-130F after a flight. Average 5-6C and burst to maybe 12C.


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Chad Northeast

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RE: Battery longevity - 2/18/2006 4:59:53 PM   
Adamg-RCU



Posts: 722
Joined: 4/22/2003
From: Saskatoon, SK, CANADA
Status: offline 		Greg, now that RCgroups' search function is back, I can educate you. Here is the degradation of the Thunder Power Pro Lite 5s3pV 6000mAh pack used in F3A flights in an F3A airplane in F3A competition (Muncie heat, French wind, Calgary altitude...) - THE most demanding use of a battery. A lot more demanding than a 90-size plane flown in a non-F3A class.

http://www.rcgroups.com/forums/showthread.php?t=404452

Am I biased? I work for Draganfly Innovations, and we are the Canadian distributor of Thunder Power. I am sponsored by Thunder Power. Obviously I'm going to choose Thunder Power packs for my airplanes, and for others'. But I also own a CBA and put cycles on batteries, and brought useful data to help answer the question on every pattern pilot's mind.


Danny Landis is having success with his Tanic batteries: http://www.rcgroups.com/forums/showthread.php?t=479695 (post #16).

Adam Glatt

(in reply to can773)
       Post #: 31

RE: Battery longevity - 2/18/2006 5:12:42 PM   
can773



Posts: 1652
Joined: 1/25/2002
From: Calgary, AB, CANADA
Status: offline 		Greg

As promised here is a CBA plot of my packs, all of them are around 50-60 cycles. The new pack was on its second CBA 1C discharge.



Attachments
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Chad Northeast

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RE: Battery longevity - 2/18/2006 10:56:14 PM   
Greg Covey



Posts: 4375
Joined: 5/24/2003
From: Rochester, NY, USA
Status: offline 		I think we may be talking "apple and oranges" here which is why we have some disagreement.

If you don't stress the pack through high temperature and rated current draw, they will last much longer. When going head-to-head, the ThunderPower cells produce more heat at their rated current delivery, if they can even meet that deliver without bloating. There are some Kokam cells that also do not meet their rated delivery, but they do not bloat. When you parallel enough cells together, you can create a pack that meets (or exceeds) your needs, but the weight advantage of the so-called lighter cell is lost.

Here is a single link to the Wattflyer Battery Vault. Look at not just the discharge currents but also the temperatures and summary comparison links. Soon, cycle life data will be posted here and you may be quite shocked.

Lastly, reguardless of the cell chosen, monitoring each cell on both discharge and charge balancing is the best way to protect the pack. Adapters will soon be available to utilize this technique on ThunderPower and PolyQuest cells. Any one pack or few packs can stay in balance depending upon the use, abuse, handling, and manufacturing lot. The cells all age differently as they are exposed to different criteria like outside handling abuses and inside temperatures. Once this happens, it becomes even more important to safely operate the pack within the limits of the weakest cell.




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RE: Battery longevity - 2/18/2006 11:22:38 PM   
ExFokkerFlyer



Posts: 427
Joined: 5/3/2002
From: Fresno, CA,
Status: offline 		Greg,

One thing to keep in mind is that unlike some of our RC bretheren, most pattern EP set ups require extensive use of throttle management techniques. Max current discharge is generally only reached when testing the system. My last set up was propped at 85 amps WOT, but the only time I ever hit that was testing prior to the first flight with the wattmeter. After that, the most I ever hit in flight was closer to 60-65 amps for short (2-5 seconds) bursts. My TPs 5s3p 6000s are rated in the area of 67 max cont... for level flight I was well under that, only in the verticals did I even approach that number and likely was never close due to the throttle curve.

My point is, batteries bloating at max current draw... which batteries do or don't, is of little importance for our purposes here. I understand what you are saying, touting that FMA's batteries stoutness beats TPs in those tests. But as has been said before, it really matters very little if we can't use your batteries because they are either too small in capacity or to heavy in weight on the other end of the scale. It will be interesting how the 5000's you mentioned will come out. Will they not have the same cells as the TPs?

As far as the TPs giving off more heat, that very well may be true. All I can say about that is during my flights this summer, I never had a pack go over 125 F... and that is in OAT of up to 105 F or so... so again, at least for me, not a problem.

I am looking forward to seeing those adapters you mentioned though. Will there be an airborne unit monitoring the discharge? If so, how much will it weigh?

Thanks for the info.

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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater

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RE: Battery longevity - 2/18/2006 11:34:55 PM   
ExFokkerFlyer



Posts: 427
Joined: 5/3/2002
From: Fresno, CA,
Status: offline 		Oh and one other thing...

I keep reading that only sponsored guys are going electric, and that the costs otherwise are prohibitive for electric pattern. I really take exception to that. It is expensive, I'll grant you that... but have you ever tried to buy, mount, maintain, and feed a big YS 140 or 160? Great motors, don't get me wrong loved most of mine , but they are expensive too! I would put my set up against a new YS set up and when you include the fuel for the year, I'm cheaper... I can't touch a OS 140, I agree... but there are other costs that most people do not take into consideration.

How long do airframes last with vibration? Servos? How much damage can fuel and oil soaking do? I have an Eclipse that has to undergo a rebuild due to vibration after 200 or so flights because of the YS... that won't happen with an electric. Provided no midaires, dumb thumbs, or forgetting to plug in the ailerons (wonder who would do that???)... the things will last forever!

Anyhoo... I just don't agree that all electric set ups are prohibitively expensive or that you have to be a sponsored guy or independently wealthy to afford it. To me, it can pay for itself over a couple of seasons... particularly if the batteries last 2-300 cycles... which was the whole point of this thread anyway.

Sincerely,

Tom

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Any pilot can describe the mechanics of flying. What it can do for the spirit of man is beyond description.- Barry Goldwater

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RE: Battery longevity - 2/18/2006 11:44:08 PM   
patternrules


 

Posts: 548
Joined: 7/28/2002
From: Nineveh, IN, USA
Status: offline 		Tom there is a good discussion on this subject on the NSRCA mailing list right now arckives and joining the list http://www.nsrca.org/discussionA.htm
Steve Maxwell

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RE: Battery longevity - 2/19/2006 2:51:48 PM   
qban_flyer


 

Posts: 43
Joined: 9/17/2003
From: WHEATON, MD, USA
Status: offline 		While I don't fly models that require high current from their power plants, I have three Thunder Power packs that have failed me @ less than 4C discharge rate on take off and less than 3C their rated discharge rate while in flight.

Mind you, these packs have been pampered all throughout their life as my method of charging is to do so @ 70% of 1C and discharge them at less than 50% their stated "safe" discharge rated as specified by its manufacturer. All my Li-Pos have been treated the same way since first purchased almost three years ago.

While Kokams, TPEs, and others are still serving me well, only the ones failing me are the Thunder Powers. I have three of their packs that refuse to take a charge, and three that are following the same path. No bloating has been observed on any of the failed packs or the ones on their way there.

One more thing, one that to me is of paramount importance. The treatment I received from Thunder Power when I e-mailed them to find a solution to this problem was appaling at best. Their reply simply was "Our product is guaranteed for 60 days, if your packs are older than 60 days they are not covered by the warranty". That reply was typed in ALL CAPS, without regards for grammar, punctuation or spelling. It made the reading a rather annoying experience based on that fact alone, the substance of the message just added to my annoyance.

Calling them over the telephone was worse than reading their reply. It got me nowhere. What I demand from a manufacturer that is willing to print claims on their packs regarding continuous as well as burst discharge rate for their Li-Po packs is HONESTY, not hype. I base my decision to buy a battery pack on the needs for the particular aircraft it will be used in. This particular manufacturer chose to print "Made in U.S.A." on their packs knowing full well the cells are made in Asia not the U.S.A. What other things am I being misled about their Li-Po packs?

I trusted what was printed on the label implicitly. I also trusted their C rating as printed on the labels, and based on that information I chose Thunder Power for some of my models. Those models are now being re-fitted with better battery packs. I can assure everyone that I will never purchase a product from a manufacturer that chooses to non chalantly mislead their clients.

I will never patronize Thunder Power products ever again. My experience with that company and its products has left better than 80% of the electric flyers at the two e-clubs I belong to with as bad a taste in their mouths as mine. It's the very reason I have taken the time to post on this particular thread. There are many of us out there that have had the same experience with that company.

I closing I will emphatically state that HYPE won't make a product do what it can't.

(in reply to patternrules)
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RE: Battery longevity - 2/19/2006 4:59:15 PM   
can773



Posts: 1652
Joined: 1/25/2002
From: Calgary, AB, CANADA
Status: offline 		Qban,

Having read the entire thread of your troubles with TP on RC Groups, I dont really think it applies here and doubt you will find many that have had problems with TP Prolites in our application.


quote:

Here is a single link to the Wattflyer Battery Vault. Look at not just the discharge currents but also the temperatures and summary comparison links. Soon, cycle life data will be posted here and you may be quite shocked.


Greg,

CBA plots done by many on RCG and Wattflyer are not all terribly meaningful in this case....first we dont run the pack continuously at 15C...we run it at 5-6C with 10-12C bursts. Second, we dont run them in an enviornment where they will get hot, they are in open airflow in a plane travelling up into 100+ kph. Its a completely unfair test to CBA a pack and allow it to acheive rediculously high temperatures causing failure. All the test indicates is that cooling is going to be required in that case.

Its a well known fact that mass correlates to temperature during discharge, when Kokam releases a 10s 5300 mAh pack that weighs 1000-1100 grams, it will be interesting to compare temps of the cells. My guess is they wont do any better temp wise....not that its a problem in the first place

quote:

Any one pack or few packs can stay in balance depending upon the use, abuse, handling, and manufacturing lot. The cells all age differently as they a