Posts: 106 Threads: 22 Likes Received: 24 in 20 posts Likes Given: 7 Joined: Jan 2017 Reputation: 0 Ok, how long do you store your lipo at fill charge before you take it back down to storage charge ? And how long (I know this is a loaded question) do you think until the lipo suffers irreversible damage ? Thanks Danny Z • Posts: 2,410 Threads: 136 Likes Received: 1,790 in 1,052 posts Likes Given: 3,302 Joined: Jan 2017 Reputation: 50 All relative to brands on how much abuse a pack can take in my experience. As a general practice if I cant get out and use the lipos within 24hrs Ill discharge to storage. 48 hrs if Im being lazy or hopeful to actually make it out • Posts: 1,590 Threads: 89 Likes Received: 1,283 in 768 posts Likes Given: 1,274 Joined: Jan 2017 Reputation: 31 I'm willing to abuse a little more for now myself... Fully charged lipos are a reason I need to fly soon... If they have to stay charged for 2 or 3 days in hopes of sun... I'll happily ho to a park on a work day morning and show up late to discharge the right way (in the air). I'll suffer the consequences of my actions later if needed... That said.... 4 or 5 days I'd probably get antsy enough to do a discharge... After I've killed a few I'll change my tune... maybe carl.vegas Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein, Slightly modified Vortex 250 Posts: 2,410 Threads: 136 Likes Received: 1,790 in 1,052 posts Likes Given: 3,302 Joined: Jan 2017 Reputation: 50 (11-Apr-2017, 03:31 AM)Carl.Vegas Wrote: I'm willing to abuse a little more for now myself... Fully charged lipos are a reason I need to fly soon... If they have to stay charged for 2 or 3 days in hopes of sun... I'll happily ho to a park on a work day morning and show up late to discharge the right way (in the air). I'll suffer the consequences of my actions later if needed... That said.... 4 or 5 days I'd probably get antsy enough to do a discharge... After I've killed a few I'll change my tune... maybe Most of my lipo experience comes from ground vehicles. The size I use atm are almost $100 batteries and when I run top speeds they are usually used in series so I keep them as even as possible. I agree that quad lipos are more of a "consumable" part though Speaking of which, I almost trashed one the other day from a crash. Even left it inside the fire pit expecting the worst after I aplied some Lipo BandAids (electrical tape ) came out ok, tested well and flew a cycle on it (Tattus 1300s btw) • Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 If I have any fully charged batteries left after a day's flying, I always return them to storage charge at the end of the day. Batteries don't like sitting at full charge. While they are fully charged, a process called electrolyte oxidation is happening at the cathode of the battery (the positive terminal). This is happening all the time while the cells are at 4.10 volts or higher. Oxidation of the electrolyte makes it unable to take part in the chemical processes in the battery any longer and the oxidation is irreversible. Because there's an excess of electrolyte (i.e. more than is actually needed to make the battery work), this process has little effect when the battery is new. However, because the process is irreversible and cumulative, the overall effect over time is non-linear. After a certain point, the battery's capacity will begin to drop dramatically. This is why there's no hard and fast answer to "how long". What can be said is that the longer the battery sits at 4.2 per cell, the shorter its useful life will be. The lower the charge, the longer the battery will last. If you set your charger to stop charging at 4.1 volts instead of 4.2 volts, the batteries will last twice the number of charge/discharge cycles. The longer the cells sit at 4.2 volts, the fewer cycles you will get before the cell capacity is reduced to less than 80%. Many of the 'tricks' with battery chemistry are focussed on mitigating problems with electrolyte oxidation, so how quickly oxidation occurs can vary significantly between one brand of cells to the next, making the question even harder to give a firm answer to. As oxidation is a chemical process and all chemical processes occur more slowly with lowered temperature, you can mitigate electrolyte oxidation to an extent by keeping fully charged batteries in the refrigerator (NOT in the freezer). The problem with cold storage is that you need to allow them to warm up to ambient temperature before you use them as they don't work very well when they are cold as the low temperature also slows down the chemical processes that occur during discharging. tl;dr The less time your batteries sit at full charge, the longer they will last. Posts: 1,590 Threads: 89 Likes Received: 1,283 in 768 posts Likes Given: 1,274 Joined: Jan 2017 Reputation: 31 Interesting info on the oxidation unseen. I haven't read that part before, maybe I'll be a little bit nice to my batteries... There are some times though when I am planning to fly one day, don't get the chance, the next day it's even less possible, but the day after conditions are perfect and begging for me to come out. It's happened a couple of times now and in those cases I usually risk it. As for having packs that are still charged at the end of the flying day... I try not to take more than I have time to fly but the one time that I did I discharged at the end of the day. That scenario is a little different. I see it more like "I already went out with my equipment and used it, now it's time to prepare to put away" rather than "OMG I didn't get to fly yet, I need to find a new time to fly!" lol. Also to DoP, re:the Tattu, I almost started going exclusively to the 95c Tattu R-lines because crown city fpv has them for $32 which isn't much more than my 75c Lumeniers that I've been getting. Then I found out that they're almost 20 extra grams heavier and still have the same burst rating as the Lumeniers (150c). So I am sticking with my first battery (just ordered 5 more). Of course Tattu has an equivalent to my Lumeniers but I figured since I started with one brand, might as well stick with it for now. carl.vegas Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein, Slightly modified Vortex 250 Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 I think that if you don't leave them fully charged for 72 hours too often, you'll probably only pay for it with maybe a 5 - 10% shorter life span. I always parallel balance charge and even if I keep the charge rate to 1C, I can get six batteries charged in the time it takes me to have some breakfast and wake up enough to fly. Posts: 106 Threads: 22 Likes Received: 24 in 20 posts Likes Given: 7 Joined: Jan 2017 Reputation: 0 Thank you unseen for that great explanation, that helps me tremendously, Danny Z Posts: 2,286 Threads: 38 Likes Received: 1,527 in 995 posts Likes Given: 1,881 Joined: Apr 2016 Reputation: 72 (11-Apr-2017, 12:10 PM)DannyZ Wrote: Thank you unseen for that great explanation, that helps me tremendously, Danny Z If my post helped you, please press the 'Like Post' button! Posts: 1,590 Threads: 89 Likes Received: 1,283 in 768 posts Likes Given: 1,274 Joined: Jan 2017 Reputation: 31 (11-Apr-2017, 11:49 AM)unseen Wrote: I think that if you don't leave them fully charged for 72 hours too often, you'll probably only pay for it with maybe a 5 - 10% shorter life span. I always parallel balance charge and even if I keep the charge rate to 1C, I can get six batteries charged in the time it takes me to have some breakfast and wake up enough to fly. Parallel FTW. My world has improved greatly since equipping and learning to parallel charge! carl.vegas Current Quads: Operational: Diatone GT2 200 In need of repair: Bumble Bee, tehStein, Slightly modified Vortex 250 • |