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Post by flydiver on Aug 28, 2013 22:15:49 GMT 1
Light Bulb slow discharge of a Lipo ? never would have thought of that What if one uses their Lipo, in their plane or a bench set motor and have the alarm set on their Tx. to go off when battery reaches that certain volt drop ? Is that possible ? Possible? Yes. Good idea? No. Heat buildup in the ESC and motor from lack of air circulation, plus most ESC have the LVC set well below storage levels. In the Cub the ESC is set @ 8.8-8.9v which is hard on the lipo. I recommend NEVER relying on the Cub LVC. |
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Post by hghost on Aug 29, 2013 1:16:08 GMT 1
Fair enough, just a thought...I have many...most not so brilliant
Thanks Fly
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Post by flydiver on Aug 29, 2013 2:28:09 GMT 1
I did it myself. Luckily that was in the NiMh days, motor was much lower performance, and no damage done. I was surprised when my flying mentor told me that it was not a good idea. The manual actually recommended it to bring the NiMh battery up to speed, something not critical for lipos.
A note on that - another controversy is 'breaking in lipos'. You can find both camps. My personal battery guru (everydayflyer) advocates it, so I do it. Prolonged cold storage also seems to make them 'sluggish' needing a couple easy cycles to wake back up fully. A few easy flying sessions, or a couple storage cycles on the charger seems to be good enough.
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Post by hghost on Aug 29, 2013 17:12:47 GMT 1
I wondered about cold effect on a battery ( as i mentioned before) I was not sure. Of course every battery design is different as we know, but I assume all batteries have the ill effects of Cold and Hot and one extreme to the other . Cold needs warmed up and warm needs cooled down .
I do not understand where so many come up with the "memory affect" in a battery. I guess they fall into a routine and of course their habits are the same and they assume the battery cause of how they use it and recharge it falls into that same routine and must know when it is charged and to what point and or when it is discharged and to what point ? Ill handling of any battery ( of any type) will cause it to either last longer or shorter. If it is Only charged to a certain point that's all you can get and if it as you say, slowly degrades over time and from mis-use and charging mistakes etc etc....it will not work properly, thus shorter run times , whatever.
I know I have a couple NiMh batteries when I use the cheap charger to charge it within 15-20 minutes it shows it fully charged ( green light on charger comes on ) And for the first couple of uses I could not understand why it never lasted more than a few minutes. I thought I had a couple bad batteries. When I bought more batteries and charged them and I saw they took an hour or so to charge I knew something was not right ( did not check battery voltage then) So when this green light comes on and showed full, I unplugged it and sat a minute and re-plugged it up they then charged completely as they should have. Why I wanted a better charger and finally purchased this one, because it charges a host of batteries. But i was worried and intimidated of all the functions and the directions are not clear at all. And as you said the NiMh battery instructions make no sense at all, so i have not used it for them , I have charged with the same cheap charger red light-green light, and those two batteries I know to, unplug it and then plug it back up and they charge full. ( Will Not do that with any Lipo ). But i am learning and getting the hang of how to set it, so hopefully it will work out right. takes me awhile to get it in my head ( reason why I ask so many questions and the same ones over and over at times) Once it gets in there..then I have no more issues and it is one of those "Well Duh " times.
Now that I am getting into the Flight game ...and with Lipo's , I wanted something that would help in securing these batteries and charging and storing them properly .
I charged a few of them with the chargers they came with, but again red light to green light is not my idea of knowing if it is charged correctly.
I am sure when I finally get to using this charger more often, so far not allot, I will have many more questions and those," What is this ? " Moments......
And I will be back as usual asking the same silly questions and having those , " Well Duh ".....times again.
Fly my next picking your brain will probably come when I get my New Tx ( expected in today)....I am sure me trying to program it, I will be asking silly questions about it to....lol
Thanks Fly, don't know what I would do without you and others on this forum.
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Post by flydiver on Aug 29, 2013 19:40:27 GMT 1
I wondered about cold effect on a battery ( as i mentioned before) I was not sure. Of course every battery design is different as we know, but I assume all batteries have the ill effects of Cold and Hot and one extreme to the other . Cold needs warmed up and warm needs cooled down . Cold really degrades lipo performance. In the winter I keep them warm in an insulated container with a warm pack. What I meant by slugging from cold storage is when they are stored cold for several months. Less than a month doesn't seem to make much difference once warmed up and charged. Hot is destructive. Lipos start to fail after 140*F. A lipo too hot to hold is on it's way out. As lipos age the internal resistance goes up. As IR increases they make more heat as they are used. A battery that used to work fine and stay cool that is now lagging in performance and starting to get warm with use is telling to shop for new batteries. There is no way to recover dying lipos. It seems that if men can quote "NiXX has memory effect" they think they actually know something about battery technology, but it generally indicates how little they actually probably do know. For those of you now going, 'WHAT?!' Read this: Dan's Quick Guide to Memory Effect, You Idiots [ www.dansdata.com/gz011.htm] Yep, some chargers are just crap. OTOH, some batteries are crap also. MOST NiMh over 2000mA should be thought of in this light unless PROVEN otherwise. These sites that claim 3000mA+ for a AA are guaranteed crap. That kind of marketing BS is common for the Chinese. Why improve the product when you can simply improve the marketing flyer? Some NiMh can have high internal resistance (which means low performance). This can interfere with the termination program in 'smart' chargers. The negative delta-V termination program in your charger is 'tune-able' but the manual is of little help in HOW to tune it. In a nutshell: lower terminates more easily > less chance of over charge, more chance of under charge. Higher terminates less easily > more chance of over charge, less chance of under charge. FWIW, NiCad in general is more robust than NiMh, has higher output performance, and the termination 'band' is broader making it easier to charge. But capacity is lower, and the Cadmium is toxic making them less desirable as a battery. Ha! I'm still using 72MHz TX. Doubt I can help with anything newer. Again, you are welcome. |
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Post by hghost on Aug 30, 2013 4:29:19 GMT 1
I read an article ( Battery University ) about battery storage they mentioned every battery but the Lipo...Lithium Ion,etc etc but not Lithium Polymer
Here is why I mention it :
Nickel-metal-hydride can be stored for about three years. The capacity drop that occurs during storage can partially be reversed with priming. Nickel-cadmium stores well, even if the terminal voltage falls to zero volts. Field tests done by the US Air Force revealed that NiCd stored for five years still performed well after priming cycles. It is believed that priming becomes necessary if the voltage drops below 1V/cell. Primary alkaline and lithium batteries can be stored for up to 10 years with minimal capacity loss.
And This :
Simple Guidelines for Storing Batteries
Primary batteries store well. Alkaline and primary lithium batteries can be stored for 10 years with moderate loss capacity.
Remove battery from the equipment and store in a dry and cool place.
Avoid freezing. Batteries freeze more easily if in discharged state.
Charge lead acid before storing and monitor the voltage or specific gravity frequently; apply a boost if below 2.10V/cell or an SG below 1.225.
Nickel-based batteries can be stored for five years and longer, even at zero voltage; prime before use.
Lithium-ion must be stored in a charged state, ideally 40 percent. This assures that the battery will not drop below 2.50V/cell with self-discharge and fall asleep.
Discard Li-ion if the voltage has stayed below 2.00/V/cell for more than a week.
I think I mentioned I stored my NiMh batteries charged last year...two gave me a fit charging ( green light on in short time) and they did not perform well and or as long even after I fully charged them , but all the rest of them was fine .
I found old batteries that charged up and worked fine as well. Not sure should not have some charge in them ? Not empty as this article suggested. My Buggies have a cut off ( not sure the level) but they are never ran completely down anyway . They seem to do better the more you use them and the more you charge them. I can get from 10-11 minutes on them and if not running them hard sometimes near 15 minutes, but usually 9-11 running it hard I think is pretty good for a 7.4 v NiMh battery.
These lipo's not sure how long they will last, it varies I know.
Those little tiny batteries for the Champ last a long time. I normally get 15-17 minutes when it is windy and 20+ when it is calm ( very few of those days ) But they have amazed me how long they last ( of course at no time am I running the Champ wide open all the time) most times flying into the wind it is only about 3/4 throttle maybe a bit more at times..most times it is 1/2 or 1/4 throttle the entire time.I let the wind carry it and or if heavy cross winds I stay low to the ground and then back up so the wind can carry it along the other way. ( sure the Cub will be the same way ) I guess if not real windy I will get at least 7-10 minute flights if not more.
Won't at first cause will have to get use to the battery and how long it lasts and it's voltage drop.
these Smaller war Birds well lets say I need to get allot better to keep them in the air...even the Micro T-28 is a pain to fly. Keeps going Inverted and does not want to climb at all. Needs more input on elevator and less on ailerons.Needs adjusted bad. I have played with them, but not to much, do not want to destroy them as I just got them together. Been spending most of my time with the Champ preparing to fly the Cub . Just like I been planning all year to no avail, has rained here again . Holiday weekend coming up , I expect many people at the parks, so looks like it may get put off again till next week. Hopefully the weather will at least clear up enough to fly her , since fall is near , always a nice time here ( hope that stays true)
I use to have an old Tx with 72MHz...use to be that is all one could get. That was what I had for my Balsa Wood Piper J-3 Cub. I searched for it but never found it, i assume it got thrown out at some point.To many storage containers in that old out building...it may still be in there somewhere.
I am accumulating different brands of Transmitters and receivers. wanted just one for all, So i purchased a 6 Channel Tactic TTX650 2.4GHz Tx. Also came with 2 free 6 ch. receivers.( and I bought 3 more as well )
Has 20 model memory and it s designed for the programming of planes and Heli's as well. Has one momentary switch,Two 3 position switches,and four 2 position switches that can be customized.
All channels feature reversing,end point adjustments,and sub trim,dual rates and exponential on ailerons-rudder-elevator channels, and a LCD Screen and a host of other things i can't remember off hand.
Read allot of reviews about it , so far seems to be a very good Tx for the money. no issues I have read at all with it so far. Caught it on sale, decided to get it so i can just get use to one Tx and be able to adjust each plane as needed without having to jump from Tx to Tx or having to adjust and change it every time I fly a different plane.( which i hope to do by next year anyway--my hope any how that is )
Again fly, thank you
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Post by hghost on Sept 1, 2013 2:30:30 GMT 1
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Post by robert on Sept 10, 2013 4:22:01 GMT 1
Hghost, although I'm new to planes, I'm very old to helicopters. I've been flying them on a daily basis, much to the shagrin of my girlfriend, for a few years. All 33 of them use lipos and ive never discharged any ever , and always store them fully charged. I know this is directly in opposition to about 99% of everyones advice. I've got so many helicopters that even if I fly two a day every day, it will be two weeks before I get back to the two I flew today. Guess what...they are all shelved and fully charged right now incase I want to get out of bed and fly for about ten hours straight without recharging anything. only one battery (7.4V 800mah) has shown signs of slightly shorter air time. This battery is actually one of my newest. Many are two years old... possibly by the fact that I have so many, the battery only gets used on a rare occasion. on top of the ridiculous number of choppers in my hangar,many of them have ten or fifteen batteries a piece. So essentially, i may use a battery, immediately recharge it, than months could go by before it gets used again in a chopper.
I'm not downplaying ANYONE who has different thoughts than mine, I'm just illustrating how little (absolutely nothing) I do to prolong life, punch, and safety and have experienced no measurable problems. The one battery that did explode was one day old and aggressively being chewed by my dog. Much to her and my surprise the roadflare in her mouth was instantly spit out on the lawn, and she incurred no injury what so ever. As soon a
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Post by robert on Sept 10, 2013 4:27:28 GMT 1
As soon as we both heard the initial pop, i realized what she had done, and she realized that a battery is not as delicious as advertised. And we both watched it spew out smoke a fire for a surprisingly long time for a 3.4v 180mAh battery. My only precaution now is keep doggy and batteries as far apart from each other.
Again, I'm not advising you to do anything like me, but i am saying that if you're worrying a lot about it, you are worrying far too much.
Just my opinion bro.
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Post by flydiver on Sept 10, 2013 16:34:43 GMT 1
See, told you. You ask, you get lots of opinions, some of them completely opposed to one another.
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Post by hghost on Sept 10, 2013 22:05:22 GMT 1
Robert your right, I am concerned about it, and probably way to much . I just want to be safe and not have to buy to many batteries or get a fire started .
And Fly, you said it, I have read many posts concerning Lipo's ( way to many I admit ) seems almost everyone has a different opinion, i guess it is personal preference .
In honesty I read where most keep them fully charged during the flying season and really only store charge them in the winter months , when they are not able to fly or have no intention to do so. Some I read, as Robert , keep them fully charged all the time cause they fly all year round.
Those opinions and advice come from a array of flyers, from seasoned long time pro's to newbies , From Heli pilots, to Airplane Pilots to even car and racing fanatics.
Again I guess it is personal preference and those who are willing to take a chance one way or the other.
I am not sure how quick a battery discharges on the shelf, but I see many Hobby shops who have them hanging on clips to laying in cases, not sure how often they change their inventory, but I doubt to often .
I "think" what I will do is keep a log on each battery and number them per plane / Heli they fit and then see how they drop and what shape they are in throughout the year and fully charged to storage charged . That should give me an indication of how they discharge either way .
If I get to fly allot I will keep them charged more and if not they will be stored charged more ....seems that in my case will be the best way to handle them.
By keeping a eye on them for awhile should allow me to see how the discharge of the battery works and how they perform both ways.( do not want them to drop to much when not used...some can be along time resting)
Plus gives me something else to do instead of reading about them so much and worrying about it.( which I indeed have )
Thanks Robert , and Plz keep the Pup from the Chew battery.....Sound advice, and btw your not alone in that same routine, there are many who do the same.
And Fly as always, Thank you.
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Post by robert on Sept 11, 2013 1:22:21 GMT 1
hghost,
your method of experimentation is sound. spoken like a true scientist. i recognize your intention as i am a biologist that has left the research field to teach my craft to high school students. not sure if that was the most sound decision i've made, but it's been working for the past 13 years. just thought i'd share.
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Post by hghost on Sept 11, 2013 3:30:14 GMT 1
Robert I know of no better thing one can do than give young people ones wisdom, about what they have experienced and us old ones as well.
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Post by Knackered Sailor on Jan 18, 2014 15:15:57 GMT 1
I came here looking for answers and discovered a wealth of good information, all the questions I had in my mind have been answered. Many thanks.
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Post by hghost on Jan 19, 2014 3:06:22 GMT 1
I came here looking for answers and discovered a wealth of good information, all the questions I had in my mind have been answered. Many thanks. The SC Club has been a Blessing for me with all the info. I am thick headed and sometimes it takes allot to get info sunk in there. I ask allot of questions and ask them multiple times to understand it all It has been invaluable that is for sure. |
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