ExFokkerFlyer

My Feedback: (4)

Just curious as to what kind of longevity you guys are seeing with your batteries, and what brands and configs they are.

As of today I have 126 cycles on one set, and 118 on the other. Running TP 5s3p 6000 in 10s config with an AXI, and a Jeti ESC.

depo

I'm also really interested about this topic. I'm planing to convert my pattern planes (#1 Fantasy and #1 Eclipse CA Model) from glow to EP, but i need same reliable information about the longevity of a 10s LiPo pack (Thunder Power, Kokam, E-Flight ... )

I'm planning to use an Axi 5330/F3A, TP 10s3p 6000 (Fantasy) and a Plettenberg 30/10 TP 10s4p 5300 (Eclipse), both with Jeti O-90.

Best regards,

depo

Adamg-RCU

You don't need a 90A ESC for a pattern plane.

depo

Yes Adamg-RCU,

you are true, but I just think it's safer rather than a Jeti 77 or than an Hacker Master 77 (or any similar 70 Amps ESC)...

Kolsso12

Do not forget that LiPo batteries are ageing. OK for competition the first year and is OK for practice the second. Because of this reason I try to reduce number of variants I have. Remember that one battery for each plane will give you long waiting time between each flight. I try to have 3 batteries and 2 chargers, 2 batteries and 2 chargers are OK.

I am also building a CA Model Eclipse. I will also have a Plettenberg XTRA 30-10 and will probably tray Xcell 4300 mAh (it has 4400 mAh). It is a single cell which I like and it is very cheap. If I need more mAh I will by a TP 5300 for competition. I do not manage TP 6000 and XTRA 30-10, it will be too heavy.

Link to test of Xcell: [link]http://www.elektromodellflug.de/akku-test/xcell.htm[/link]

depo

Thanks Kolsso12,

you gave me a great tip about the XCell ( i didn't know them). This battery packs looks goog, light, powerfull and cheep enough. I think there will be less problem to balance a 10s1p pack than a 10s4p pack, maybe they can hold an higher number of cycles: "less cells, less failures"

I wish to excange with you our EP-Eclipse's experience as soon as possible.

best regards

can773

My Feedback: (1)

Depo

So far (about 75 ish cycles) my 10s4p's are in perfect balance. They typically stay about 0.002-0.007V maximum difference in voltage between the cells. I do use balancers but not every charge and when I dont use them the balance is just as good as when I do use them.

Certainly less cells in parallel is better, but so far the TP 5300's seem to be very good at keeping balanced. I would not let their large xP count stop you from using them!

depo

Thanks Chad, you are always impeccable in you explanation. I won't forghet your pieces of advice about the TP5300. A frind of mine from Denmark thinks the same like you....

Greg Covey

We have been looking at the effects of temperature and current stress on Lithium packs for over a year now and have greatly increased the longevity of LiPo packs in F3A pattern flying to over 400 cycles.

Please read my article on [link=http://www.fmadirect.com/new_applications/LithiumPowerSolutions/index.htm]Lithium Power Solutions[/link] for a brief top-level description of the latest technology.

can773

My Feedback: (1)

Greg

Your link outlines the Kokam 3200 cell....a fellow in pattern land (I wont use his name) ran these cells in F3A with the discharge protection modules and cycle life was around 30 if I remember right....a far cry from 400.

There was much discussion about this on the pattern list some months back, the conclusion was that 10s 3200 Kokam cells were not suitable (I am sure a 2p version would be).

ExFokkerFlyer

My Feedback: (4)

I guess 'longevity' is the wrong term... how many cycles are we seeing out there. Manufacturers boast the potential of hundreds of cycles, has anybody done it though?

Greg Covey

Chad,

You are correct. We gained valuable information from several pattern flyers during the beta development phase of Skyvolt last Fall and have not deployed new product to them as we await new packs from Kokam using 4800mAh cells that can deliver 100amps of current. The wait should only be a few weeks now. A 2p configuration of 3200 cells would work but is too heavy and costly for most users.

What we learned from our pattern test flyers is that the real world usage of Lithium packs cannot easily be duplicated in the lab. For example, just before production release of the BalancePro HD (formerly Skyvolt) line, we removed the air gap between the cells as it drastically reduced the cycle life due to warping from the spacers. The real world handling of these packs revealed the effect of capacity loss from our measurements. The difference in internal cell temperature was only 10 degrees F so it wasn't as effective as we originally hoped for. We had a chuckle as the PolyQuest packs soon came out with air gaps shortly afterwords as we had been advertising our packs this way as a feature.

We have improved the Discharge Protection Module (DPM) software and the 6s charger software (both products are re-programmable) in areas that affect both cycle life of the packs, usage, and speed of charging. A 20 minute full charge is now seen instead of only 90%. We lowered the full charge voltage by 0.05v and disable the low voltage cutoff for the first 30 seconds of flight.

The 3200mAh cell just didn't cut it in the F3A world. Most top pilots including QuiQue use a 5AH capacity. Unlike the ThunderPower 5AH packs, the new Kokam 4.8AH packs using the BalancePro HD charger and DPM will stand up to the current demand. What we found is that top sponsored pilots didn't care about pack longevity as they got their equipment for free. This was not the case for the majority competition pattern flyer and they often could not afford the expense of replacing Lithium packs several times a season.

The two areas of pack longevity that the user must still control are temperature and discharge current. For temperature, we provide an indicator on the pack that helps you determine if your air flow is sufficient. Since Kokam cells produce less heat during discharge, this helps the performance. The 3200 cells could only deliver 64amps which was just shy of the pattern planes power demands. The new 4800 cells are the same width but longer and thicker and they can deliver 100amps and stay under the 140 degree F threshold of damage. The new Cell Rating Specs show the true operating current for maximum longevity so the advanced user can seperate reality from advertising hype...at least on packs from FMA.

I'll be off at the GP E-Fest until Tuesday and check back then...

Kolsso12

In Europe we are already able to by Kokam 4800.

Test on the new cell: [link]http://www.elektromodellflug.de/akku-test/kokam-parade.htm[/link]


The Xcell 4300 mAh get 15 degrees hotter and has 200 to 300 mAh less capacity compare to Kokam 4800. Xcell 4300 hold high current under longer time and is 40 % cheaper.

Test on Xcell 4300: [link]http://www.elektromodellflug.de/akku-test/xcell.htm[/link]

Adamg-RCU

I've been informally keeping score, and I haven't heard a single report of a Thunder Power Pro Lite 5s4p5300 or 5s3p6000 failure when used in a pattern application. Previous generations? Absolutely, lots. Pro Lites? Not a one.

To be accurate, there is no published evidence that a comparable Kokam cell produces less heat than the Thunder Power cell. The only data available shows the obvious: add mass to a heat-producing body and the temperature won't climb as fast.

-Adam

Fred Marks

To the contrary: Lots of evidence in the following threads. All these come from independent testers and modelers, not from Kokam or TP. The attached is a plot of the temperature data from the battery test data taken by a massive set of modelers who did tests with the CBA. The KOK 3200has performance superior to any RC cell as seen in the data from Wattflyer. The internal resistance is so much lower that RC Tester plots show the KOK 3200 delivering 64 amps continuously with temperature just slightly exceeding 140 deg F.

http://www.wattflyer.com/forums/showthread.php?t=3628

http://www.rcgroups.com/forums/showt...ghlight=TESTER

http://www.rcgroups.com/forums/forumdisplay.php?f=336

http://www.rcgroups.com/forums/showthread.php?t=473158

http://www.wattflyer.com/forums/showthread.php?t=1661

www.trextuning.com

FLYERSG

It's my personel view that FMA won't be successful selling LiPo packs to C50 Hacker pattern flyers until attention is paid to battery pack weight. A Hacker C50 spinning a 22 x 12 APC on a windy day can pull in the area of 4400 ma from a pack. The only current Kokam pack with sufficient capacity to meet that kind of a need is the 5S2p 6400 pack, two of which (in series) weigh nearly 4 lbs.! The next lower size pack is the 5S2P 4000 which, while it weighs only 38.4 oz, does not have sufficient capacity. The 5S1P 3200 is not even a player. I have not seen the weight of a 4800 10S pack; however, a 2S1P 4800 pack weighs 115 grams. From that, I would estimate that the 4800 cell used in a 10S string would be close in weight to the TP5300. But....why would I buy a Kokam 4800 if I could get a 5300 mah TP pack at the same weight. In addition the TP 5300 has been establishing a very good performance record. Weight Mr. Marks....I can't buy your LiPos for use in my pattern C50 powered pattern aircraft until I can obtain something that will provide sufficient capacity to make it through upper class patterns with sufficient reserve to support a margin of safety and good battery longevity, while keeping my aircraft under the competition weight limit.

can773

My Feedback: (1)

Fred

Quite frankly CBA and other testing is not remotely close to results myself and others see while running TP packs in F3A applications.

You can quote all the static air testing you want where those performing the tests let the temps soar to rediculously high values....its not realistic in an F3A application. Our packs see a huge amount of forced air cooling through the entire flight...I have rarely ever seen one of my packs go above 50C (122F) post flight. Testing a pack and letting it run at 180F and having a failure is not representative of real world.

Fact is the Prolites are great cells in real world applications, which is where it matters.

To the original posting at hand...my highest cycle pack is sitting about 75 cycles (TP 5300) perfect balance and the same V under load that it had as new....not noticable degredation that I can tell. I have "heard" of others running well over 100 cycles, but ExFokkerFlyer is the only one that I trust has valid #'s I think a lot of people guess at their cycles! and are way off!

If you have 4 packs of Prolites and claim 200 cycles each you would have needed to flown 800 flights since about June of 2005!

depo

I agree 100% with FLYERSG's consideration about Kokam 4800 and TP 5300 in pattern planes. Between this 2 packs, i would choose TP 5300.

Now I would consider the new LongGo lightpack 10s2p 5000,

http://www.rc-electronic.com/html/en...go_flight.html

Here we have a 5000 Lipo pack, able to deliver 50A continuous, and 100A burst. Those light packs are more than enough for F3A application.
Does anyone have any experience with this pack?
I know the LongGo 4000 use Kokam cells, but i'm not sure if it is the same for the LongGo 5000. The price it's really lower than the Kokam 4800 or TP 5300, so I wouldn't be sure to choose TP 5300 between Tp5300, Kok4800 and LongGo5000, becuse the price is the half!

Best regards,

Bruno

Adamg-RCU

That longgo 10s5000 pack is a good sign. Light and cheap (2xTP5s4p5300 is 460Euro from the cheapest place, plus shipping). That's pretty much what we need in electric pattern. That and a non-customer to test the pack and show it holds up to pattern.

depo

460 Euros? Where??? I'd like to know witch is the cheapest place :-) Bye

Adamg-RCU

PM sent...

BrunoCH

Hey Adam, can you tell me about this place? That´s a pretty good price...

Greg Covey

The posts seen in this thread are a good example of the misconceptions often seen in Lithium technology. Some posts are the result of not reading all the previous posts before it and others are simply the results of good marketing.

It is ok to have an opinion. Seperating opinion, rumor, and hearsay can only be done with testing data from third party sources. We are providing that data for those that wish to read it.

The issue of cell weight is directly related to current delivery, temperature under discharge, and pack longevity. There is no free lunch, reguardless of rumor. Lithium is lithium and only the size of the internal plates determine differences in weight and current delivery capability. A 1p pack solution will be superior to a 4p solution as each cell can be monitored. The test results prove this to be fact over marketing hype.

As the industry learns more about the proper use of Lithium technology, I feel that product lines like the BalancePro HD and Cellpro line of balancing chargers and discharge protection modules will become the new norm by providing a safe and long lasting solution.

The glow and gas engine paradigm of paying for fuel as you go has given rise to paying less for a Lithium pack up front without any reguard to how many cycles the pack will actually provide. In the long run, the lower expense is seen on packs that last for 400 cycles or more.

ExFokkerFlyer

My Feedback: (4)

Greg, I am not disagreeing with your explanation of the technology of the lithiums. Nor am i disagreeing that your product's safety features could be the wave of the future. The problem is, the Kokams or rather the BalancePro batteries are either too small in capacity, or too heavy. A 3200 mah, assuming you don't want to go over 80% capacity in discharge is just too small. And in my set up, I mean just... I can do a Masters pattern flight for less than that, but there is no margin for error or extra manuvers. And that is with an AXI which seems, not scientific at this point, to use less battery for a given flight... at least in my examples. A 2 x 5s2p 6400 would have enough capacity, but it's 25 ounces over the TP 5s4p set up, way too heavy. As it is it's hard to make weight... a pack set up over 44 ounces is almost unusable in most pattern applications.

I like the features that FMA's lithiums offer, they are just not the right size.

As far as the original topic of this thread, do people not keep track of cycles? I know Chad probably keeps the most meticulous records, and I'm somewhat less so... but I'm curious as to why more people have not come forward with results. Is it because of lack of a record, or that it's not an issue of importance and I should just shut up about it?

patternrules

My Feedback: (6)

RM has some results in this forum, the biggest problem is lots of us are in the winter season, you sunshine guys get to fly all year round LOL. I have talked to a couple of people up here that have 90-100 cycles on packs either TP 5s3p 6000 or 5s4p 5300, and there still only about 2% lose of capacity, now stored for the winter.
Steve Maxwell