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Old Aug 10, 2012, 08:31 AM
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bdelapen's Avatar
Miramar, FL
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Let me add to my post as I left out the most important comment. From what you are seeing in your voltages, yes, your packs are older but they are not yet at their end of life, the voltage variances are still pretty small and the packs will probably give a very useful life for a while still.

I measure pack life in the 100's of cycles now a days, 200 for a decent battery up to 400 for a good battery. I remember the batteries that we used for the Solar Car back in 1993, they chemistry was silver zinc and the expected deep discharge cycle life was about 20 - 25 cycles

- Birger
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Old Aug 10, 2012, 02:12 PM
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seeingeyegod's Avatar
United States, OR, Portland
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How do you guys even know how many cycles are on your batteries, do you keep a spreadsheet and update it every time, write it on the battery with a pencil, have a charger that recognizes the individual battery somehow and keeps track?
Or are you just guestimating? I also wonder this about people who says "I have 125 flights on this plane". I just can't force myself to be that detail oriented. Recorded the first two "flight reports" of my Pete n Poke when I finished it in the back of the manual, then got lazy and have flown it like 10 times since and haven't kept track
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Old Aug 10, 2012, 02:31 PM
I fly, therefore, I crash!!!
SteveT.'s Avatar
San Jose, CA
Joined Jan 2008
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Originally Posted by seeingeyegod View Post
How do you guys even know how many cycles are on your batteries, do you keep a spreadsheet and update it every time, write it on the battery with a pencil, have a charger that recognizes the individual battery somehow and keeps track?
Or are you just guestimating? I also wonder this about people who says "I have 125 flights on this plane". I just can't force myself to be that detail oriented. Recorded the first two "flight reports" of my Pete n Poke when I finished it in the back of the manual, then got lazy and have flown it like 10 times since and haven't kept track
Many people do keep a log of each flight. It is normally, simply writing every thing down in a small spiral notebook. I have one friend that has a notebook for each plane. Another method if you have an iPhone, is to purchase the RC Logbook by "CleverTangerine" or one of the other iPhone apps...

SteveT
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Old Aug 10, 2012, 03:15 PM
So I'M meant to be in control?
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Ilkley, West Yorkshire, UK
Joined Nov 2008
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Originally Posted by seeingeyegod View Post
....do you keep a spreadsheet and update it every time....
I'm sorry to say yes, exactly. Sad I know, but it comes with the territory. Aeromodelling is a very engineering based pastime; many who partake are either engineers of some sort or have an engineering interest. And many engineers (like me) are sad enough to see beauty in data........
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Old Aug 10, 2012, 03:20 PM
Fly it like you STOL it!
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USA, VA, Spotsylvania
Joined Jan 2011
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I love seeing the numbers in things...unfortunately i tend to forget to keep track of things like that, so it happens on and off for me. my logs are intermittent
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Old Aug 10, 2012, 05:49 PM
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Joined Jun 2009
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Originally Posted by dag214 View Post
There are never stupid questions EVER

And feel free to ask anything........

Rock ON!

DAG
Dag, are you going to sell this plane at some time in the future (after you got tired of it, maybe) ?
Also, have you ever sold one of your scratch built giant scale planes ?
I'm not planning on buying it, I'm just curious ...
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Old Aug 10, 2012, 07:01 PM
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United States, GA, Jonesboro
Joined Nov 2010
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Originally Posted by dag214 View Post
There are never stupid questions EVER

In the past I have covered planes with everything. I have even sheeted and then monokoted and then painted the monokote.

This plane will be planked, sheeted, glasses, filler, primed, and painted

And feel free to ask anything........

Rock ON!

DAG
thats right dag, ive always said " the only stupid questions there are, are questions that arent asked" people should'nt ever feel ashamed to ask anything. awesome work.
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Old Aug 10, 2012, 08:21 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Quote:
Originally Posted by seeingeyegod View Post
How do you guys even know how many cycles are on your batteries, do you keep a spreadsheet and update it every time, write it on the battery with a pencil, have a charger that recognizes the individual battery somehow and keeps track?
Or are you just guestimating? I also wonder this about people who says "I have 125 flights on this plane". I just can't force myself to be that detail oriented. Recorded the first two "flight reports" of my Pete n Poke when I finished it in the back of the manual, then got lazy and have flown it like 10 times since and haven't kept track
Guess it depends on the type of plane and your investment in batteries.

Most of my big planes (over 55) per the AMA I need to keep a long book on. I actually buy a log book for a full scale plane for each of my big Rc planes.

I have over 3-4k in lipos, each of my big ones (over 3000 mAh 5S) I have numbered and try to keep a log of cycles, but since I have a flight log on the Emmaselle and I only have 2 sets of the 4 packs it take to fly her it is easy to track cycles.... It is easier to track a problem when you know what you have done to a lipo...

Thanks!!!

DAG
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Old Aug 10, 2012, 08:22 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Originally Posted by Colonel Blink View Post
I'm sorry to say yes, exactly. Sad I know, but it comes with the territory. Aeromodelling is a very engineering based pastime; many who partake are either engineers of some sort or have an engineering interest. And many engineers (like me) are sad enough to see beauty in data........
Science and data never lies.....

I LUV me data.........

DAG
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Old Aug 10, 2012, 08:29 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Originally Posted by flylowfast View Post
Dag, are you going to sell this plane at some time in the future (after you got tired of it, maybe) ?
Also, have you ever sold one of your scratch built giant scale planes ?
I'm not planning on buying it, I'm just curious ...
I joked earlier in the thread that I was going to make BNF versions of the 36. Unpainted is $105,000.00, Painted is $105,055.00.

I had a big (50%) Pitts that is hanging somewhere in the US in a lodge, and I have a 178" B-29 with about 30 flights hanging in a bar somewhere....

I have sold a few planes in the past. Not sure how I would ever sell the B-36. I may one day donate it to the AMA or WPAFB, but that would be after 3-4 years of flying. It would make me nervous to sell such a complicated and maintenance hog plane to someone who does not understand all the systems, and what it would take to fly her safely. If someone was going to put it on display maybe.... Just not sure how I would feel with it being operated safely.

Keep in mind after my 10-15 tests flights if she makes me nervous to fly, then she off to being donated somewhere. She has to be safe and fun...........

Sorry for being so wordy......

DAG
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Old Aug 10, 2012, 08:32 PM
It only takes one good idea
dag214's Avatar
Fishers, Indiana
Joined Oct 2004
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Well if anyone is going to be close to Ft Wayne Ind. tomorrow I am taking the Emmaselle to the Ft Wayne Flying Circuits Monster Mash....

http://www.flyingcircuits.org/26th%2...ter%20Mash.pdf

Rock ON!!!!

Damon
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Old Aug 10, 2012, 11:54 PM
Mosquito 6
Joined Jun 2012
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OMG .. the Peacemaker lives ...

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Originally Posted by dag214 View Post
Here.....

Thanks, DAG
A flight of three of these beauties flew right over my grade school to land at Moffett Field .. obviously, unforgettable. Awesome build .. thanks for sharing DAG
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Old Aug 11, 2012, 01:53 AM
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The Netherlands, NB, Tilburg
Joined Feb 2007
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Originally Posted by bdelapen View Post
(...)

So what is an abused pack, well in general there are 3 things to consider: first and foremost, over-discharge (take the cells to a very low voltage, the lower the voltage the worse the effect); hard discharge, the more Cs for longer time the worse for the pack; finally, and this is more relevant with the higher C rated batteries, is storage voltage, you want to store your batteries around 3.8V per cell for better life, it is bad to keep them at a lower voltage but it is worse to keep them at a higher voltage (fully charged).

(..)
Great build DAG, superb! And thanks for your vision on Lipo's. I like actual statistics and measurements above stories and believes. In extend, I have two questions about the above paragrah Birger:
  • What qualifies as 'storage'? Would that be storing the battery for a month or longer? Or does the advised voltage also apply between two flying sessions about a week and a half apart?
  • Would it be a problem already if you flew a battery almost empty by accident once or twice (to about 3%)? Or is this only considered bad if you would do this often?

Thanks!
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Old Aug 11, 2012, 05:07 AM
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bdelapen's Avatar
Miramar, FL
Joined Aug 2008
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Originally Posted by roberthabraken View Post
Great build DAG, superb! And thanks for your vision on Lipo's. I like actual statistics and measurements above stories and believes. In extend, I have two questions about the above paragrah Birger:
  • What qualifies as 'storage'? Would that be storing the battery for a month or longer? Or does the advised voltage also apply between two flying sessions about a week and a half apart?
  • Would it be a problem already if you flew a battery almost empty by accident once or twice (to about 3%)? Or is this only considered bad if you would do this often?

Thanks!
Hi,

Like everything in life, there are no black and whites, just shades of gray but here goes some of my "experience"
  • Storage is to some extent a function of C rating but in almost all cases storing a pack for more than a few days will have a negative effect. The longer the storage time the worse the negative effect. The higher the C rating the more the cells are affected by being stored fully charged, on my high C rated batteries (45C - 65C) I don't even store them overnight any more. This has had a big effect on how I fly, I used to charge all my batteries the evening before I went out and I would charge a lot of batteries. Many times I wouldn't even fly all the batteries I charged and I would then leave them. I now try to charge less batteries the evening before and discharge everything I charge within 24 hours and my high rated C batteries I charge at the field and fly within an hour of charging. I have found much less puffing of my packs and consequently better performance over a larger number of flights. Not that there is no electricity at my field so I have to carry my own charging capacity so this has been a large effort.
  • This is like everyting in life. I would recommend never taking more than 80% out of your batteries. If you do it, it will not kill them immediately, it will just shorted their lifespan. I have had EDF plane batteries down to 2.7V per cell back to 3.5V after they rest and they haven't died, I did probably slightly shorten their lifespan. My goal now a days is to never have my packs under 3.7v per cell after a flight is done but I will still accept 3.6v. Anything below that and I start considering a timer adjustment. Again, the more you do it the more it will affect the packs.
As with everything, this also varies by the quality of batteries, without inciting a brand war (so I won't state brands) I must say that I have some batteries that are over 4 years old that have been over discharged several times and have been kept in storage fully charged for over 6 months and they are not puffed and going extremely strong. I also have other batteries (same equivalent capacity, C rating and usage) that have lasted me less than 20 cycles being treated exactly the same, they are completely puffed and flight performance (when I still dare to use them) is vastly inferior to when they were new.

One final unrelated comment, I have also found that "breaking in" new packs has a huge performance and longevity effect. If your first 5 to 10 cycles (the more the better) are controlled where the packes are charged at 1C or less, immediately discharged at 10C or less and discharged to about (but no lower than) 80% the packs will have a much better life. I now do this, using my chargers (which can only discharge at about 0.5C on my largest packs), with all my new packs for any of my larger applications. On the smaller packs I don't care as much any more as I consider 2200 4S or 3000 3S or smaller mostly disposable and not worth the effort now a days with the cheaper prices available.

Everything is relative and every little bit helps. Using us as an example, it's good to eat healthy and it's good to exercise regularly but it's better to eat healthy and exercise regulartly (neither of which I do for those that know me ) .

Regards,

- Birger
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Old Aug 11, 2012, 06:09 AM
We shall serve the Lord
kingsflyer's Avatar
United States, TX, Kingsland
Joined Sep 2005
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Quote:
Originally Posted by bdelapen View Post
Like everything in life, there are no black and whites, just shades of gray but here goes some of my "experience"

Storage is to some extent a function of C rating but in almost all cases storing a pack for more than a few days will have a negative effect. The longer the storage time the worse the negative effect. - Birger
I think you meant that storing the batteries in a fully charged state for more than a few days ...... is a bad thing.

I agree with you 100%, its just that I read one of the previous posts with a question about storage charging and I didn't want anyone to think that "storage charging" and leaving them for a few days was a bad thing.

I also like your practice of breaking in your packs when you first get them. I started doing this with my EF-1 racing batteries and it makes a huge difference.

McD
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