I am doing research on best practices for my lithium batteries and lifepo4 powerstation. There’s some conflicting opinions and variation for cycle numbers.
Will leaving my things plugged in at 100% hurt it more than constantly unplugging at 80% and replugging at 20%?
None of the information you find here or on the internet in general will be correct, because most of information is either older nicad or nickle metal hydride, or when talking about lithiums people are talking LiPoly which is not your Lithium Iron Phosphate.
Your best bet is to ask the LiFeP04 manufacturer
LiFePO4 batteries like being charged up high, so you’re probably fine keeping them plugged in.
You’re right about not going under 20% often, but you’ll want to charge to 100% at least periodically to allow the cells to balance.
Edit: Please make sure you’re looking up information on Lithium Iron Phosphate batteries specifically, they behave differently from standard lithium batteries and a lot of the advice shared here won’t apply.
Another anecdote:
My girlfriend and I bought our phones (different makes and models, sadly) at the same time, about a year ago. I have been doing 80/20 religiously while she dgaf and does what she likes. I have not noticed any change in how much charge mine holds while she has started to complain that hers needs charging more often. Her phone cost twice as much as mine.
Similar situation here, except I do 90/30 and my charge speed is limited to 1.8W (I usually boost it to ~10W when I’m in a hurry)
My phone battery still holds its capacity like new, whilst my partner is practically tethered to a charger all the time, with a device newer than mine
My understanding is that it depends on the device, and most modern devices take care of what’s best by themselves
That’s not true.
Lithium batteries have a longer useful life if not allowed to drop too low or charged too high. 20% and 80% are typical values. Ideally they would be at 50% SOC and that’s why most batteries in new devices will arrive charged to around 3.6-3.8v.
This creates a problem for device manufacturers because if they force the device to treat the battery well, users won’t get as long between charges. They will sometimes give you options (most laptops will have a setting to stop it charging beyond 60% or 80%, some phones will have a setting to stop it charging to full) but they’ll advertise the full battery runtime they can squeeze out while damaging the battery and that will be the default setting.
Convenience dictates that you may need to charge above, or discharge below, the recommended levels. Which would be much less of an issue if batteries were easily replaceable. But increasingly, they’re not.
tldr; manufacturers have zero incentive to make sure their devices treat the batteries well
manufacturers have zero incentive to make sure their devices treat the batteries well
as long as they survive the warranty period
iPhones figure out when you usually take your phone off the charger (e.g. based on your wake up alarm setting, but I think it also does some machine learning) and when you charge your phone it only charges it to 80%. Then, just before you are expected to take it off the charger in the morning it charges it to full. That way the battery spends less time above 80% charged.
My android pixel does the same.
They don’t outside of not doing things that cause acute damage to the battery. They can’t because “best” is situational.
If I have a phone with an empty battery and I’m going out all day starting in an hour, best is to charge as fast as possible to 100%. That’s the most wear I could put on the battery out of any charge cycle, but going easy on the battery isn’t my first priority in that scenario.
On the other hand, if I have all night to charge and won’t be away from charging for more than a few hours the next day, best is to spend most of the night charging to 60% and stop there. It’s an order of magnitude less wear than the above, maybe more.
For best service life, avoid fully discharging[1] the battery, charging it above 60%, storing it long-term charged over 60%, getting it hot, or charging it in less than several hours. In most devices, you don’t have the ability to control any of that so the best you can do is plug it in at 20% and unplug it at 60% (or 80% if you need the extra runtime - it’s still better than 100%). I’d like to see consumer devices get an “eco mode” or some such to select battery-preserving behavior manually, but that’s not in the interests of device manufacturers who want you to buy something new when the battery wears out.
[1] An actual full discharge to zero volts causes acute damage to Li-ion batteries and most devices won’t let you do it
If it does battery pass through (supplying power directly from the outlet instead of using the battery as a middleman), leaving them plugged in should be fine. If it doesn’t the battery will repeatedly charge and discharge and and depending on the charge level limit that can be very degrading.
Charging the battery to 100% does do more damage than if you practice 20-80. However doing so limits the battery to 60% of its original capacity. Unless the battery is low quality or over stressed by default, it might take thousands of cycles until the gains from lower degradation outpace the losses.
I think the comfort factor is the most important tho. If you need to manually keep track of the battery and unplug it once it reaches 80% (and risk forgetting to plug it back once it gets low), just replacing the battery when it degrades might be the better option. If you can control it automatically, doing so would only be beneficial.
Afait reducing the amount of cycles is the best - my reasoning is that every cycle just slightly damages the membrane between anode/cathode.
Also I have heard that for long storage 80% is the best but it’s just something I have heard/read.
About 10 years ago, the norm was to, from time to time, drain lithium batteries to minimum and so do a full cycle, this is something my father told me but I actually don’t know the reasoning.
bout 10 years ago, the norm was to, from time to time, drain lithium batteries to minimum and so do a full cycle, this is something my father told me but I actually don’t know the reasoning.
Early rechargeable batteries such as nickel-cadmium and nickel-metal-hydride would develop “memory”. For example if you made a habit of always recharging the batteries once they hit 50%, the battery would think “I guess they don’t need the rest of the capacity, I’ll throw it in the trash” and you ended up with a battery with half it’s original capacity. So it became good practice to occasionally discharge them completely before recharging. Sort of a ‘use it or lose it’ scenario. Now lithium batteries do not have this issue but it took people a long time to break the habit.
I believe it’s because software managing batteries needs to calibrate voltages to understand how charged a battery is. Fully power cycling allows, for example, your phone to understand what 100, 0 and everything in-between.
Title says plugged in and body says plugged in at 100%; these can be separate concepts if one has fine control over the charging voltage.
Will leaving my things plugged in at 100% hurt it more than constantly unplugging at 80% and replugging at 20%?
Plenty of academic research out there showing that pegging Li to 100% SoC reduces cycle counts to EOL (by electrolyte degradation and other processes), especially at higher voltages/temps. You didn’t mention capacity reduction associated with charging at freezing temps so I assume that is a non-issue in your use case.
It seems to me that if leaving it plugged in is an option you have shore/mains/grid power. So I’d
- charge to middling SoC and unplug the powerstation (according to the manual); and
- run the loads off the wall socket
Am I missing something here?
offgrid with LiFePO4
I live offgrid with Li on a very limited budget, so performance and maximal cycle life is a practical matter for me. Based on my own reading and experimentation I charge my 4S LiFePO4 to 13.8v (3.45Vpc) until Absorption falls to 0.10C then quasi-float at 13.31v (3.3275Vpc). I warm them to 50F and charge at ≤0.4C.
Hi there! Looks like you linked to a Lemmy community using a URL instead of its name, which doesn’t work well for people on different instances. Try fixing it like this: [email protected]
Every charging cycle ages the battery but worrying about it really isn’t worth the hassle.
If this is an Android phone, go install Accubattery and do what that says. It’s designed for many different phone batteries and associated tech (e.g. overcharge circuitry).
There are so many different models and variations in the electrochemistry, general advice is usually a miss.
If you insist on generalizing lithium tech, keep it between 30-80% charge for good longevity. The extremes of full and empty are rougher on it.
If this is an Android phone, go install Accubattery
Too bad that app has 7 trackers embedded and access to the ad ID :/
The permissions look fairly reasonable to me considering it needs to run at startup and monitor other apps, and the Pro upgrade is an embedded option that would need connectivity.
I just firewall it anyway, but that requires root.
IIRC you can change your ad ID any time but that’s kinda outside the scope here.
I’m not sure if the general advice for lithium ion batteries will apply to lithium iron phosphate batteries.
For lithium ion batteries, I like to charge them during the day rather than leaving them plugged through the night, but that’s because I don’t know if I can trust the BMS (my father would keep his phones plugged whenever he was home and every single smartphone he owned eventually had inflated battery syndrome, even though I warned him many times, I don’t know if he still does that or not, but his current phone shows no sign of inflating yet).
My previous phone was a Sony phone, and their smart battery management tool allowed the phone to charge to 80% (or 90%, I don’t quite remember), stop, and only start charging so it would be full by the time I usually wake up, which I thought was rather smart. I often charge to 90% rather than to 100% when I know I won’t need the full 100%, but if I know I might not have an opportunity to charge or going to need to spend a lot of battery on something, I’ll charge it fully.
I don’t know much about lithium iron phosphate batteries other than that they typically have longer lifespans and better fire safety compared to lithium ion batteries, but it doesn’t mean they should be abused beyond the specs recommended. Are you doing a solar & battery installation? If you’re DIYing it, make sure to do a lot of research about getting a good BMS and installing everything correctly so you don’t burn your house down by accident.
Thank you for the reply. Yes I am off griding running off solar just got a bluetti eb3a to manage panel power since I’ve never done any solar before and didn’t want to mess things up. it seems pretty smart.
I just googled it, it seems like it is an all in one system. I assumed you were talking about buying battery cells and designing your own system, but since you have a self contained system (which already obviously has a BMS), you can ignore the last paragraph I wrote previously.
Hope it serves you well.
I am off griding running off solar
This would have been useful to mention in the original post.
just got a bluetti eb3a to manage panel power since
We have very little control over what the solar does with “power stations”. I’d just leave the panels plugged in.
I’ve never done any solar before
Copied from a different comment of mine:
well, you see batteries should not sit at 100% at all and if so, only if you start discharging immediately. So just getting them discharged and charging them again to 100% where they will sit at for 20h a day won’t help much against degrading the batteries.
"Choi 2002 shows that the constant voltage part is the most harmful to a battery, charging to 4.2V itself using constant current at 1C doesn't degrade it too badly, but by holding the battery at that voltage for an additional time causes most of the damage to the cell., [Source] (https://accubattery.zendesk.com/hc/en-us/articles/210224725-Charging-research-and-methodology)I use a an App called Al Dente where I can set the maximum charge: https://github.com/davidwernhart/AlDente-Charge-Limiter
And there is also this: Basmati: https://github.com/aykevl/basmati
You can get it for windows too (googled that for you) https://www.thewindowsclub.com/battery-limiter-software-for-windows-10
For Linux my quick search found this: https://www.linuxuprising.com/2021/02/how-to-limit-battery-charging-set.html
Absolute best is keeping the battery plugged at 60%
Some phones have “store mode” that caps battery charge at this level and its used primarly by stores to keep one phone always plugged and turned on for display.
If you cant do that then 80 to 20 is second best thing. Keeping it at 100% is the worst.
This is about lithium ion batteries, no idea what best practices are for lifepo4
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This is the dilema since we use lithium batteries. And if it was truth we would be certain of it.
I believe that there is a difference, but I think it is in the range of few percents of capacity lost per year, which means you will be using 60% of the capacity. That’s capacity you get after 10+ years of use.
We all know batteries don’t last that long anyway.
All that said I do keep laptop on 80% ¯_(ツ)_/¯
since I rarely use it on battery.Lithium chargers completely stop charging when the battery is full. Even if the charger remains plugged in, the battery will not be receiving power
That said, letting a lithium battery sit at 100% indefinitely is not good for it. If you can, reprogram the charger to fill the lithium to 80% instead, otherwise just let the battery sit at 100% as usual and just replace it after a few years when the runtime no longer is long enough for your application
I believe things are different for Lifepo4 which IIRC is more accepting of a float charge when full, although not ideal.
