How long can you leave your lipos fully charged without damaging them?
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- čas přidán 31. 10. 2021
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From what I've read, the lithium dendrite growth over time that cause the reduction in capacity. Overcharge and over discharge seems to quicken this effect and when the dendrites reach from one side to the other, you get a short and a fire. The mechanism that govern the rate of growth of this stuff seems like a hot topic in Li-ion battery research for improving performance. Very cool stuff.
Awesome Video...I've been thinking a lot about this lately. Good information JB!
I swear this is the big question that's been on my mind here lately. You rock!
Good info Joshua. DJI has even developed a self discharge on there smart packs now. It’s cool that they go into auto discharge after a few short days. Certainly saves me from having to worry about it. I often charge up the night before and wake up to rain or unpredictable circumstances leaving me leaving my drone in its flight bag for a few days.
Great job at voicing that way of thinking about it.
Really great topic to discuss, I had to click. Sometimes I leave my lipos charged for three or four days but I worry more about how volatile they are in that time. Not how fast they degrade from that time, holding full charge. Thanks again for the great content and everything you do for the fpv community 🙂
That is what I worry about most. Is there a higher risk they could explode/ignite being fully charged and sitting. Especially cause I use a bag with several batteries in them. If I fly once or twice a week.. and recycle is 300 times.. I got a good few years at least out of them. That's a pretty long time in my opinion. As Josh said.. likely to see them die from flying and crashing than aged out of recharge cycles.
Kemosabe, thanks for addressing this fact on Lipo batteries as U & I touched on this several weeks ago as my kawd flight schedule is frequently interrupted due to my on-call business vs free-time. Again, excellent food for thought for many.
It’s like you read my mind, I was just wondering about this recently, thanks J.B.
You guys are amazing with everything you guys do and still take care of your kids I know how hard it is with my one and three year old boys.
ok, that was an unexpected comment out of the blue 😃
I love your knowledge on these batteries I just subscribed and hit the bell.
Keep up the good work
Keith
I think you answered a really on topic question here! Great video!
Thanks for the information man. I do the same thing for my crawler. Lipos last SOOOO MUCH LONGER than the NiCads I grew up with in RC. 3hrs run time, I run outa stuff to climb. 2 packs are 3 years old and balance charged for great performance.
I think they might degrade 5% when left 30 days charged the first time, but if you leave them the second time charged for 30 days they don't degrade another 5%. Maybe another 2% or so. Im a professional charged battery procrastinator, for many years now. I have packs that are 4 years old and have been left charged for 2 weeks (thats my max) for at least 5-6 times and they are still "fine". I mean they don't feel like new but i get a meaningful flight from them still.
What if I just leave my phone charging for just 5 hours? Is it unhealthy for my battery or just fine? I'm just over protective for my phone
@@ronaldgamer6430 controller will stop charging it once the battery is full
Yea I have left some fully charged for awhile. They degrade some but I didn't find them dead. But my drone isn't amp hungry. My batteries are over kill for my drone
I have 9 years old 16s 2p lipo pack in ebike. Made around 80000-100000km on them and they still work perfectly fine. I usually charge to 4-4.1V per cell. Its only few % capacity less, no big deal. I think its worth to take care about batteries, they will serve veeeeery long time.
@@bobikbobikowy5458 you have Li-ion not Li-po. I'm not sure what the difference is but Li-ion can handle a lot more abuse than LI-PO. I have recycled many 18650 Lion cells from cordless Drill, Saw, etc packs and some have lasted for years. Lipo, not so much.
Thanks Bardwell for ur opinion 👍im so glad i learned a lot about lipos and liions before starting Fpv :D
Thank you Bardwell.
I'd say I agree with your theory and time lines 👍 nice work jb
Very good points! I am very "relaxed" about how long I leave my batteries at full charge (I like to have them ready to rip) and I am unable to tell any difference in performance. That doesn't mean there isn't a performance degradation, just that I'm not bothered by it. 👍
Was just discharging batteries when this popped up. Very insightful, thank you!
Very helpful and makes sense! And cute little kid there!!
Great info. Thanks, Joshua.
Loved this video, thank you!
I never leave my batteries fully charged for more than a day and I have used some lipos for 4 years which performed just fine. I don't fly bandos though. Nice side effect: You can always parallel charge your lipos before going to fly because they are all at 3.8V.
Exactly how i charge my packs 👌
How frequently do u fly?
@@Lucas-eq1ul Admittedly not too often, about once a week in spring/summer.
@@Lucas-eq1ul I was about to ask the same question. I never had a battery last more than 12 months. I always kill them during flight.
@@bassohollic you’re definitely abusing your packs if they’re dying after a year. That shouldn’t happen
Joshua, Good info on the batteries. I recently did a test with my phones lipo, which took 2+ years to complete.
I read that, like you mentioned, a lipo's ability to hold a charge was reduced to the 70% arena after 300-400 charge cycles. BUT, just modifying two parameters would increase that life to 1700 - 2000 charge cycles. Now, to be fair, a charge cycle is defined as charging back 100% of the battery's capacity. ie , a 4S 1550 would need 1550ma of power charged back in to be considered 1 charge cycle.. Two 775ma charge sessions would be considered only 1 charge cycle, as well.
The two parameters I mentioned are 1) Limiting the cell voltage to 4.00v/cell (or 80% of the battery's capacity) and 2) limiting the amount put back into the pack, at any one time, to 20% of it's capacity. The second would require multiple charge sessions to get back to the 80% mark. Funny, it's the 80/20 rule that we see in business all the time. 80% charge cap, and a max of 20% at any one time.
You might ask "What do these two things accomplish?"
1 - The 80% rule addresses the phenomenon of the battery chemistry crystalizing in the cell at anything greater than 4.00v. Well, it actually occurs at all voltages but what experts have learned is that it accelerates at voltages above 4.00v.
2 - Limiting charge amount, only adding 20% at a time, addresses the second killer of lipo's, and that's heat. When you charge back >20% the battery naturally starts producing heat internally, which also accelerates the crystalizing phenomenon spoken of earlier.
So, back to my phone test. I bought a new Samsung Note 9 in Sept 2018. I installed an app called AccuBattery, which tracks your battery's health in terms of capacity, and will let you know what its capacity at any point during its life. It will also alarm when it reaches the maximum capacity that you set it to. Mine was set to 80%. By changing the way I charged, limiting it to 80% capacity (the Notes have a 4000ma pack so I wasn't really limited at being at 80%) and by "bump-charging" on a wireless charging pad several times a day, I was able to trade in that phone at the 2 1/2 year mark....and AccuBattery said that my batteries capacity was still at 87%. The second owner of that phone got a bargain, if you ask me, because used phones typically have batteries that have been "rode hard and hung up wet", and you never know what their life is. Kind of like a used car. Getting a phones battery replaced can be expensive.
Conclusion: I'm glad we don't fly phones!! We can toss a mini quad lipo and replace it once we feel the sag coming on sooner, knowing the pack has seen better days.
Thanks for the video, as I've often wondered about how long I can store before I start crystalizing the chemistry.
Thank you!! The best question answered!!
Thanks! This was just the video I needed as I have 8 fairly pricey Cinelifter batteries and was just about to buy some of the smart lipo battery dis-chargers since I may only film a job once a week, and was debating how long to let them go before I discharged
I am also a firm believer that the better the cell the less keeping them changed is a problem.. I have one single 3s Lipo (2600mah) that I have had for 10 years for an airplane.. and yes it is low C compaired to drone batteries now a days.. but that thing sat chaged for 5 years at 4.2v and I recently cycled it a few times in that same plane and it was perfect..
A 4.2v lipo bomb has more damage potential than a 3.8v lipo bomb. Probably also worth noting
I wanted to mention it too! Thanks and like
Completely agree, a cell at 4.2V is way more unstable than one at 3.8V. Personally, I never keep them at full charge more than a few hours.
czcams.com/video/Y9qCovQiTQs/video.html
Yes, I cannot sleep well away from home, if I left my overcharged lipos at-home over night.
I'm already quite concerned about the lipos will burn down my place eventually
@@jacktheripper1784 99.999% of lipo fires occur during charging/discharging. A fully charged lipo is just as safe as one at storage if the battery is in good condition
very useful for newbies and veterans
Beautifully explained, thank you sir O7
My thoughts exactly. Great info!
Great topic! , wondered about that alot my self 👍
lookin buttery smooth professor!
I tend to agree with your cumulative hypothesis for full charge degradation. And I'm confident I do the most damage to my batteries when I accidentally overdischarge them or smashing them, not waiting a few days between charge to discharge.
Great video man very helpful
The question becomes: What is the relative impact on battery life of a charge/discharge cycle vs. being left charged for 24hrs (or some multiple thereof). Knowing that would help to guide the question of whether to leave charged until use or storage (dis)charge them until next charge & use.
This was a small video that gave us a few answers but left some perhaps even bigger questions. Your stated conclusions do tend to mirror my own, thanks for the confirming/supporting opinion.
J.P.
I agree. This video has little fact and lots of supposition, but JB raises some good points, especially about the concept that a battery has a lifetime based on its time at full charge and the impact of leaving a battery at full charge vs discharge/recharge. I just hope these questions will now be answered by people with some real data. JB have you any ideas or contacts who can get some such data?
I would imagine that how you discharge matters too. Normally when I discharge, it's using one of those store safe things which is way under 1c, so the impact of discharging it is much less harmful than when I actually use it flying. Thus, I don't feel it is wasting a full cycle.
@@dogatech5763 I don't think it matters if you discharge it under 1C, you are performing a discharge cycle anyway.
Slow discharge is really not that harmful to them, and wouldn't be any worse than discharging them through flight (at least 2x as kind), but realistically most batteries aren't getting electrically worn out anyway unless you're trying to pull triple digit amperges out of them, then landing gently.
To conclude this we should really deep into the chemistry, the quality variable and testing batteries a ton of times
Helpful vids man even for us car guys 👍👊
Thanks for this great info Joshua.
I just pulled my quads out of the closet last night, after two years, and remembered I hadn’t discharged my batteries to storage level before they got boxed up when we moved.
Two of my Tattu R-Line 850 4s batteries were completely dead, and two of my Ovonic 1550 4s batteries each had a single cell below 0.5 volts.
The rest seem to be fine, and have discharged down to 3.6-3.8v per cell on their own.
I was able to resurrect both Tattu batteries using the NiCd direct-charge trick to 13v, then balance charging the rest on LiPo. They’ve both held charge across all cells overnight so far. Fingers crossed.
I was also able to resurrect the single cells in both Ovonic batteries by charging them through the balance lead using NiCd to 3.5v, and then LiPo 1s to top them off.
Now I’ll just have to see if performance has degraded much. The batteries didn’t have a whole lot of usage before being stored so I’m hoping for the best.
This sounds like playing with fire, like... literally 😅
Thank you for this!
Small addition for batteries that are brand new: These still contain a certain chemistry that protects the batteries before they are charged for the first or second time. The fact that these arrive at 3.8V per cell is no proof that they can therefore be stored for ages later, I think.
I was once told by a GensAce employee that correct and slow charging should be much more important at the beginning. But in the end it's all about having fun and batteries usually only last one season for me anyway. 🤣
I still have my fist 5 lipos from a Walkera heli... my batteries last a long time but that's likely due to the Polly effect;-)
Did you go to China to talk to them? 🤔🤔
at the beginning of exploitation or at the beginning of each charging?
Great basic info. Worth noting that the level of degradation between full and storage voltage is not linear. Reducing the voltage from 100% to 90% or 80% can greatly decrease rate of degradation, without having to do a full round trip to storage voltage and then back up to takeoff voltage.
Not mentioned is the speed (or amps used) to charge and discharge cells. The higher the more degradation occurs. With drones, discharging almost always occurs at hight amps. Being bit more gentle at end of a charge, and recharging can reduce some stress on the cells. Degree of voltage sage is a general indicator of how much cells are being stressed.
The other important factor is heat. Heat is bad for cells, particularly when are fully charged, as it amplifies all the bad chemical reaction in a cell that causes it to degrade. Simple tips, is try not to leave charged cells in warm car, or sun. Letting cells cool before charging.
A good reference to learn is "battery university". It covers both basic stuff, but also gets into hardcore details should anyone want a deep dive into chemistry and physics.
100% agree, as example my Mavic Batteries do auto discharge after 3 Days, BUT they are very likely never to be broken in a crash, in fact, the oldest one is rocking 472 cycles and i still can fly 14 minutes with it. but for the freestyle Lipo's if i go out with the gang and somethings some along the way .. i just leave them and use them up over the span of the week flying them to the storage voltage (ish) so the charger just need minutes to finalize the storage. i repeat this until 4 packs are left (always have 4 fully charged)
Exactly what I was needing perfect 👌
great info, thanks.
Thanks for your explanation 👍
I am so jealous that you still have Tshirt weather
Really appreciated the point that putting them back to storage is a cycle that comes with it's own wear and tear. Definitely something to keep in mind
Thanks for this..good to know!
Thanks buddy,,, very helpful
I recently purchased an ISDT discharger because I'm not good about discharging my fully charged batteries when I have them. Now it is so easy.
I was just going back and forth with my flying buddy about this yesterday! He left his fully stored for a few months when we got rained out, I said they would be weak all day but he couldn’t tell a difference. I never realized charging and storing also wears out the lipo
Thanks Joshua... very helpful video. I been trying to find someone (anyone) who can give me an "honest" answer to the question of how long batteries can be left fully charged and this is the closest I have ever gotten to that answer
The ugu gaga worked, I subscribed. yay!
Thanks!
Awesome, Joshua! Thanks a lot! 😊
I wonder the same about lithium ion batteries... Like the 18650s. They seem to be able to hold power for much longer, but... Other than that it's a mystery to me.
Anyway, stay safe there with your family! 🖖😊
Pretty sure it's different with liions , e bikes have them and those are usually stored at 100% , however they will smart discharge after 2 months of no usage to 60-80%
I charge - discharge/recycle my lipos to my 4S3P 21700 "Powerbank". This is quick and the Lion pack didn't notice this little amount of energy.
I have 7-8 years old lipos and they are still fine after hundreds of cycles.
That's an excellent idea!
I too have 4S 1800 mAh flight batteries from 2016. Not suitable for flying anymore, but works fine for googles or radio charging.
Yup same, I have a big 18650-based field pack that I usually discharge into, then use those to store any batteries I need to, then top it off to storage if it gets pretty low.
Best advice I've seen today! Love it. This convinced me to use a car battery as a power bank.
@@yannickg6904 Thx. Car battery's are so unhandy. Grab a spot welder and some cheap 18650. DIY packs are a lot of fun. 😉
We have some Turnigy Nanotech lipos that I believe were purchased around 2015-2016. They haven't been used all that much and are stored at around 38%. Seem to be perfectly fine
Storage voltage is important. Landing the quad early is good if you dont go home and charge when done flying.
I left my lipo 1.3 4s at storage for over 2 years...i thought i lost them in a move. And this christmas i was going through bins for decorations and found it, they are still at 3.8 and im charging them now. Im so excited.
I have Lipos from 2017 (yes, 4 years old). I have religiously “storage charged” them 10 minutes after each flight and they have only been fully charged for a maximum of 2 hours (I fly at my house) during their lifetime. Their capacity is around 80% of what they were when I bought them but they are still going strong and I still use them. If you keep your batteries in storage charge for most of their “sitting around time” then they will last.
I have some 3s lipos from 2007 (yes 14 years). Still usable
I can second that but you need to buy high quality batteries in the first place for that.
Not worth for me personally since I tend to crash my 5 inch quite a bit and sometimes the battery takes a hit so most of the time they "break" before performance is an issue. This is very impressive though
I agree with you, I think it’s a cumulative effect. My goal is always to keep my batteries charged as short a time as possible, and keep them at 3.8v as long as possible. I think following that rule will extend the life of the battery.
Same here. 1 or 2 days are not a big deal. But after 3 days of bad weather and not flying i always put them back in storage.
Your the Best! 🤘🏽
There's also temperature.
I had a PDA that I kept fully charged in a hot environment and the battery wouldn't charge in less than 6 months.
The worst thing is to over discharge, next is to keep too full at high temperatures.
Totally agree, its a chemical process that happens while in a high charge state, even if you only have the pack fully charged for an hour it still happens.
It’s nice the spectrums g2 batteries have an automatic discharge built in and you set the for 72 hours Down to 12 kinda of a cool function
This came at an awesome time as I have 1 battery I forgot I had charged and can't really discharge since my drone is awaiting repairs. I'll probably retire it since 2 cells literally won't budge from 4.2v while the other 2 are at 4.05. Will also buy a proper battery charger (that can also discharge)
Been in that situation alot of times charge the night before only to wake up to rain(gotta start checking the weather forecast). But the most time I leave my battery's charged is 3 days after that ill charge them back to storage charge. Joshua you should do a review on the bigdaddy battery's and the zees. They are cheap but hold up well.
ThankU 😊👍
In re smashing your batteries:
That's why I switched to Floureon batteries. They have little plates in them.
They're heavier, but after chopping one battery in my props and bashing a Tattu into the ground until it broke, I got the "armored" Floureons. They perform decently too, but my charger doesn't think they hold balance well at all.
Better than those cheap pair that one just decided to go up sitting on my table. Left a burn spot. The other one has a lame cell, but interestingly my charger has no issue with its balancing.
I use those cool LiPoSuction things that discharge the battery to storage super slow. very convenient. I have a set of batteries almost 3 yrs old and still going strong. My previous set of batteries that i left at full charge for a couple days each week only lasted about 9 months. So I am now under the impression that cycling the battery is better than leaving it at full charge. Just my one opinion though.
Hi Joshua!
There's an opinion, that's it's better to store lipos in fridge. This is because the batteries lost their capacity cause of chemical reaction, and when low temperature the reaction goes slower. That would be great if you test that. Because for me its easier to drop my batteries in fridge instead of discharging them if for example i want to store them one week before next weekend. Thank you!
Great video thank JB. some times i charge all the lipos then when i get back home I really dont do nothing to them just put them in the amo box then a few weeks later I storage them I dont fly every weekend its just been lazy
So - leaving em fully charged reduces the capacity to hold charge - vs packs with bad Internal Resistance (IR) which have reduced capacity to deliver the charge they have. I've been storing some packs fully charged for too long now - and I note that some cannot be fully charged any more - they instead peak out during charge at 4.10v for instance, rather than at 4.20v. But some still have low IR. Learned something new today. You can reduce the capacity to hold charge (leave em fully charged all the time), and you can reduce the capacity to deliver charge (run em down to 3.0v a few times - I think that will do that)
For those of us that don't churn through batteries (especially me with RC crawlers) keeping them as healthy as possible can save money over the life of the battery. Especially when I have 2-3 batteries for each crawler and one battery gets through several hours of crawling.
thanks
Just switched to 6s, brand new batteries , so , great timing sir! AND he’s a dad , who knew. Lol. Future fpv’r?
useful topic 👍👍
When at storage charge also store at 5degC. I have batteries from 2007 which are still over 80% rated capacity thanks to living in a beer fridge.
I would say it’s all about your own comfort zone on how long you keep your batteries fully charged.I my self won’t go more than a week.and have never noticed a difference.I would also say that it depends on the quality of battery you are using..there are certain name batteries I’ve used that wear out a lot quicker than others.in the end as long as your comfortable with the way you take care of your batteries…..
I know this, but I didn't used to.... I left 3 batteries of the same type, Turnergy Graphene Panther ones, for over a year... 2 are still good and one is a bit pants... But one was always a bit pants. I have heard from other RC nutts that it doesn't matter, but personal experience tells me it matters a bit. I still use the Turnergy batteries today and only seem a little off their best.
I usually store my lipos on 3.95v.(70%) it's pretty nice because you are ready to fly much quicker.
I do the same. I am so sad that there are no charging modules out there that stop at 4.0V
For some applications i dont need 3000mAh but i need 2000mAh for 6 years and like the convinience to 4.0V charge every few month and not need to measure the voltage every 30min
Thanks for saving my new batteries. Totally forgot to discharge them last week.
The same 'useful life budget' concept applies to discharging them at or above the 55C effective discharge rate - LiPos are incredibly impressive (the LiHV chemistries too), but realistically you have about an hour of useful life at the higher discharge rate, but in reality that's actually pretty excellent because it's a whole lot kinder to be at anything other than wide open throttle.
This is why a two-year old battery with about 80 cycles that has spent probably a touch over month charged up gets transitioned to the practice bin, because it's about halfway through its total useful life but no longer has the edge to be a racing pack or the one to use when a shot really matters... but it can push a lot deeper.
On the rare chance my packs to live to the 150 cycle (4+ year) point without mechanical destruction, then they get to be ground station power sources off BECs, because if I kill those I won't really be sad about it.
Agree with the information you shared here. Minus one point.
Taking a charged battery to storage voltage is not one cycle!
One cycle is full capacity from full to empty, and back to full again.
Considering storage voltage is approximately 50% capacity.
And assuming you discharge to this 50% point, then later recharge back to 100% for use. That would technically only be half a cycle. Which IMO is still less detrimental than leaving the battery at 100% for any period of time.
I am running a 6S6P Li-ion field pack, a couple of M6D chargers, and I usually take 4-5 flight lipos to the field. All of that fits comfortably in a Torvol lipo safe bag.
Makes life very easy; 3-4 packs on the charger, one on the quad, and you can keep on flying.
Battery at 3.95V/cell after a crash? No messing around with partially depleted batteries which are empty when you are right in the flow, just swap for a fully charged one and put the 3.95V one on the charger.
Day coming to an end? You know when that is going to happen. Already start bringing flightpacks to storage , go home, throw bag in closet, recharge the Li-ion pack to 4V/cell whenever that suits you, done.
You get that 'lets do a quick fly, NOW' call? Pick up the bag, put 4 batteries on the chargers in the field with one at 3-5C, prepare your stuff, take the first one off that charger, fly, and let the rest reach full charge.
Need a bit of extra juice? Make sure field packs are charged, find a car or wall socket, charge the Li+ pack at 18 Amps, and once you start with the last flight pack there is a lot of juice in the Li+ pack again.
And so on. It really beats bringing 20 packs to the field in convenience, and your precious flightpacks spend as little time at 4.2V or below 3.5V as possible.
If you are frequently killing your batteries in a crash, consider mounting a TPU 'landing pad' that also protects the edges. Works for topmounted batteries too. I can emty a pack in 2-3 minutes, I do crash at speed, I break arms, props, motors, midplates, etc., but I seldom destroy a battery. Please do whatever you can to avoid burning down batteries at the flying spots. That's a serious fire hazard, it smells awful for a long time, and it seriously bends public opinion the wrong way.
The way I usually explain it is that basically everything causes wear on batteries, just some things cause more. Storage voltage at 20C/70F wears the least, and full charge, full discharge, high current and so on wear them more. Same thing with fast charging, even if a pack says it's rated to 2-3C charge, that will wear it faster than 1C or .5C, same with discharge. All those factors are much more important with batteries and systems that are likely to actually physically survive more than a few months, however 😅
Great video. Question: how do they define "performance"? Voltage sag? Overall flight time? All of the above?
flight time and cells seem to become harder to balance
@@KonstantinFPV Voltage sag is more related to cell chemistry, and how fast new ions are formed. Resistance does come into play a bit, but is relatively constant across cell types (at least for new cells. Less true as cells age and internal resistance increases) This partially why voltage will sag more in cold weather (as chemical reactions are slower to react).
One way of looking at it using the available information... but over a decade testing lets me say temperature during storage just above freezing almost stops the clock... and GNB says to maintain capacity to store their HV Lipos just above their wet charge state (somewhere just above 3.0v) and NOT at 3.85v as most people say repeating what they have been told.
I keep mine stored in a way that if one did catch fire, it wouldn't affect anything. No burning house, minimal loss of other batteries. Because of this, I have stored them wherever they end up at the end of the day. Full, 3/4, wherever. I've never had a noticeable deterioration, and never had a fire. I've been treating them this way since lipos became consumer grade.
Wait, you think a lipo at 3.8v is incapable of causing a fire if damaged? Also, who do you know that had a fire with a fully charged battery that is stored?
@@nofluxgiven1949 I didn't say either of those things, but OK.
What about HV charged batteries I wonder? My guess is that performance degrades much faster. HV whoop batteries don't last all that long, but there are other factors that degrade their performance (like overheating) so it's hard to say without more data.
The more C-Rating, lesser capacity and HV they degrade much faster than non HV multiple cell packs when fully charged.
From what I have found regarding leaving a lipo fully charged for a week an then fly them. Ovonic lipos will keep there ability to be useful over time. Now cnhl lipos really don't an begin to degrade after a few days of being left charged. I have also found that the high mAh of a lipo seems to degrade the lipo fast than a lower mAh lipo...2200mah -850mah, My Rdq lipos seem to do this. However, my pyrodrone graphene lipos seem to do alright which surprised me. Being a resident of Washington state, rainy days with the wind an cold, I try to charge my lipos two days before planning a flight.
I tend to find higher performance /higher C rated batteries are also the less tolerant of any "neglect". I run my batteries down to around 10%, storage change them back up once they cool down, and then finish charging the day before. And run them down two days later if they don't get used (when I remember to!). Had a "race-grade" go from perfect to absolutely useless after leaving it fully charged for 3-4 months. :-/
Usually if it's been 3-4 days at full charge I ask myself if I'm gonna fly them in the next 2 days by looking at weather forecasts and how much free time I have etc. If not, I usually discharge them to around 3.9 volts/cell since doing even that saves quite a bit of time over 4-7 batteries. Also most of the broken batteries I had have broken from a cell that is too low or doesn't read, or excessive physical damage, which makes me not feel safe charging it. Only a couple of them have bad enough performance or high IR, usually caused by overdischarge anyway. Basically if you don't fly cinematic or long range I wouldn't stress about it, just don't make a habit of leaving them for over a week often.
I would love to see some hard test data on the subject. Most chemical/molecular reactions are exponential. Meaning they start slow and build over time. Think of the school volcano experiment. It starts slow and builds versus exploding off the bat. Or boiling water, which is molecular but so is chemical really, it starts a bubble here and there before it turns to a full boil. Or a spreading fire from a spark. I've always assumed batteries were the same when outside of storage voltage.
Reliable test data is hard to find. However, I have experienced that fully charged LiPo's die after being stored for a prolonged time (>2yrs). Empty batteries seemed to survive better. Therefor I try to adhere to the 50% storage level that many manufacturers advise for longer storage periods.
I currently don't have any quads (I've wanted to get into fpv for a looonnngggg time which is why I'm here) though I do play airsoft and I do fly highwings and midwings. Ive had lipos last anywhere between a year to two. The airsoft lipos last way longer ( I would assume it has to do with the draw rate) though my plane lipos do last for quite a large number of flights. With that being said I am a little conservative as far as charging goes. I estimate how much I'll want to fly/have time for and I'll only fly that amount of packs. Then I charge to store when I'm done. With that being said, that doesn't mean I don't want a portable charging station to fly all day
Also, charging the batteries at high currents wears them out faster than gently charge them at 1C. Same for discharging, although that's hard to influence. So it's not necessary the best to wait until the last second and then charge at 4C just to minimize the time they are full.
Lipobench once did a test that found the opposite. That charging at 5C was better for the battery than 1C. The hypothesis was that the higher charge rate heated the battery up more which reduces IR and means it takes charge easier. But it's only one test, and charging at higher C rate absolutely does increase the chance of a fire if the battery is damaged.
@@JoshuaBardwell I've seen numerous tests stating that the higher charge rate reduced the life cycles
Smart batteries have internal preservation discharge circuit.
Then would it make sense to not charge your battery right after flying but to wait until you're ready to fly again?
So here's a question re the DJI FPV drone: DJI has no provision for charging or manually discharging to storage voltage. So, after I fly, is it better to leave the battery discharged or let it cool then charge it and let it discharge as per DJI's inbuilt discharge?
Great response to a perennial question jb! Now can you answer the same question on the opposite end of 3.8 volts? That is, how long can I leave my battery Undercharged under 3.8 volts?!
its same as keepin them fully charged has same effect
I believe it will be basically the same. The root cause for the damage is the pressure put on the separator, which is basically "pushed" when the battery is full charged, and "pulled" when it is flat, which is why you leave the battery at storage - it is basically neutral pressure. This is also why they can rapidly deteriorate as once the separator starts getting punctured it rapidly gets worse.
@@pfeerick what exactly is the "separator?"
I think its important that people understand that batteries start to degrade as soon as the cells are assembled. They degrade at the slowest rate at storage voltage. This normally only comes until play when someone stores a pack at storage voltage for a year and wonders what happened.
Even storage charge isn't guaranteed to maintain your lipos. I recently came back from a 6 month break from FPV (all lipos charged to storage level), and about 1/2 of my packs had dead cells that I couldn't recover. I went as far as trying to brute force some charge into them to "wake them up", but no luck.
For now on, I'm putting all packs I don't use on storage charge at least every couple months, even if they were already charged to storage levels. LiPo's just don't hold up well.
For reference, I mainly use Tattu R-Lines and a Venom Duo Pro charger that has storage charge capabilities.