Battery maintenance and longevity

What is the best practice to maximise battery capacity and battery life?

My understanding is to basically use the battery the least, but fully discharge and recharge it every few months?

I keep about 100Ah in house to last all devices for a few days for the more major outages.

Are you speaking in terms of years or in terms of how long they last per charge?

No batteries should ever be run flat. You can use them till devices, cars, etc. no longer work but never run them lower than that or you may never be able to re-charge them and if you can they are likely damaged.
I spent 15 years as a power tool mechanic and I have several Nicad and Lithium ion batteries around the house, If I go to use or charge a battery that has not charged in 5-10 years it is likely now garbage even ones that are still brand new.

LiPo Batteries: batteries must not go below a certain percentage or they will not last that is why you should only use them with auto shut off devices installed.

Lithium: Most current Lithium Ion batters have a cut off circuit built in to keep them from going below a set voltage per cell.

AGM batteries: Well that’s another tricky one. When they are new they get water which means they start out at zero and then the water turns into acid when charged. A discharged AGM is approx. 11.9 volts and if you go any lower than that it will damage the battery or if its winter it will just freeze solid

There is probably some new technology that will contradict some of what I have just said but these are my beliefs from what I know and have learned over the years.


I have EDC “every day carry” batteries which cost me in the $10-$20 region, I bought them for all the family, sprinkled around and primarily related to “kids” (which my case = in their 20s) not having flat cellphones. I do not control them, they live whatever life they have.

I then have “home” batteries I maintain, these relate to doomsday type situations of tree falls and wait my turn, earthquake, etc. That is context of my question. The general domestic commodity trend is to USB, I have slowly over the last 5 years moved most power demands to USB (e.g. PC to laptop, to tablet, to cellphone) and so when I add up the phones + torches demand for an assumed worst-case scenario of 10 days of no electricity, I get to about 100Ah.

So I have about 100Ah of batteries, deliberately multiple devices to allow for device failure, deliberately spread around the home to allow for damage from whatever is the root cause (tree fell, etc).

What is the best maintenance strategy for these batteries? They are not aged by frequent reuse? So I should store them in cold? Should I drain and recharge them every few months?

So, best advice on battery maintenance?

I also keep solar, firewood and alcohol stoves, the fuel tends to get used most for BarB’Q and cosey livingroom fires, and camping trips, but I store all this at home deliberarately for the imagined worst case. So live for life but allow for the worst.

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huh, you lost me after “I have” lol… Just use them, store them at room temp and when they don’t work recharge them. you can charge them every so often as there may be some phantom losses but don’t bother purposely running them down first.

I assume your answer to my question is both but I am not sure :stuck_out_tongue_winking_eye: BTW what kind of batteries I assumed Lithium

Dusting off a very old reading session on batteries, I believe if batteries are not in use, so essentially stored for future use, it is recommended to keep batteries in the 30-50% charged range to prevent it becoming a ‘dead’ battery and/or battery exploding from being fully charged. For batteries that get regular use, fully discharge and recharge every 3-4 months.

It’s also often recommended to fully charge at first use to maximize battery life but I have yet to find a device effected by not doing this (laptops anyhow).

As for temperature, check the batteries label or documentation that comes with them, often operating and storage temps are listed.

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@ndalby Funny you were taught the same as me but a lot has changed in even the last 5 years. I used to give that speech to customers regularily. The only point you make that I am not so sold on is the disscharge and recharge, more of a myth or for nicad or older batteries but it can’t hurt them so go ahead and do it.
There is so much conflicting information on batteries and it is very important to know the composition of the battery before determining what is best for storage. I, for discussion will use lithium Ion as I believe all the Anker batteries are Lithium Ion

Here is a link to the literature that comes with a Lithium ion battery.

Here is another short and interesting take on lithium ion longevity and they do mention the 50 % charge when stored as you mentioned

One very important note and just a tip is that if a battery is no good anymore trying to repeatedly charge it can damage your charger as it will keep trying to charge it and overheat the charger and battery unless the charger has more sophisticated electrics to shut down the cycle. We used to have people bring “faulty batteries” Nicad to us in the 1990’s and 50% of the time the fuse in the charger was blown from charging a very cold battery or a dead battery, needless to say those chargers were upgraded a few years later. Good topic though @nigelhealy :smiley:

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Yep, there’s plenty of conflicting info when it comes to batteries and best practices. Another good link;


The advice I give is that, if you want to maximise the life of a LiOn battery, don’t let the charge drop below 30% or charge it past 80% during most usage, but do go to 0% and 100% occasionally. This is based on reading lots of battery university articles and adding a pinch of usability.

In practice though, you will throw most batteries away after two years anyway so it doesn’t really matter. A good battery (such as an Anker) will have management firmware that keeps you far enough away from the margins that fully charging and discharging won’t massively shorten the life, unless maybe you leave it at 0% for months.


Thanks, that is a long but excellent read.

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According to some tear-downs, the electronics in Anker don’t let you go down 0%. The actual mah output is than what is stored.

by 0% I just meant ‘no more power is delivered’. I think the battery itself will still be at about 3.7 Volts (or maybe 3.2?), but the low voltage protection would stop any more power being delivered.

I started looking into battery longevity and following the 30-80% rule has done a measurable effect on my phone’s total battery capacity. I use to not care for the first few months, using terrible cheap chargers and always keeping the phone near 100% if I could.

My total capacity dropped 7% in just a few months.

After using only anker chargers and cables and the 30-80% rule it has dropped 3-4% in 11 months.

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What are you using to measure your phone’s capacity? Also out of curiosity what is the total number of cycles on the phone’s battery? Even though you don’t fully charge or fully discharge your phone, you will still be putting “cycles” on the battery.