How to keep a smartphone's battery charged when not in use

ultrarunner2015

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Hi;
I just bought a new LG Fiesta 2 TracFone to replace a 1yr old LG Fiesta, also TracFone. I purchased the new phone solely because it was the least expensive way to purchase a new airtime/service plan.
so now I have a backup phone. that's great, but how do I keep the battery in the old - unused phone charged so that it doesn't lose its capacity while in storage.
I do not want to remove the battery from the phone. That would pretty much negate the advantage of having a back-up phone.
So I'm trying to set up a schedule to recharge the battery, and periodically cycle it down (to 10-20% I think is the value I was told) to keep it fresh.

At this point I have no idea of how fast the battery will drain when the phone is not turned on, so I set up my Google calendar - which is synched to my phone - to remind me to check the battery every Friday. Once I determine how fast the battery is draining, I can set up a schedule to recharge and periodically cycle the battery down then recharge to full.

Any advice?

Thanks

FW
 

FRITZHID

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I've tried a ton of variations on this, facts are, you can't. You CAN try and manually keep it at the optimum 70-75% charge but it's going to fail.... Eventually.
I got a max of one year on a new batt, 24h charging. About 1.5 yrs on a new batt with various "holding charge" methods and less then 1 year recharging when it need it.
Without a proper maintenance charger, it's ALWAYS up to the phn and it's internal charger programming. If you're lucky, you can plug the charger in and then remove the batt and it might stay functional, saving the batt any abuse.
 

ultrarunner2015

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I hear you. The phone is never really 'off'. My Nikon D200 has the same issue. The battery was always running down, even when I didn't use the camera for a while. So I got into the habit of removing the battery, and now it holds its charge very well. On my older (non-smart) phones the battery was removable by simply detaching it from the back.
so I guess I'll just keep the schedule for every Friday until I find that I don't need to check it that often.

I am using an older, lower current charger to charge my LG Fiesta. I didn't like the fact that the supplied charger - intended for a fast recharge without consideration to battery life - made the battery pretty warm during charge. This older charger, which I believe is from an old iPhone, has a lower capacity, but will still charge the battery to 100%. It just takes longer.
I use a timer on the charger, so that if I leave it overnight, the phone won't be sitting there on the charger for the whole night. If I set the timer right, I can limit the recharge to whatever I want - something less than 100%, but sometimes I just don't have the patience to do that. In any case, I try to keep the phone somewhere between 75 & 85%, but will charge to 100% when I'm going out for a long run (20+ miles) and wouldn't want the battery to die on me.

Back when I had a Huawi phone (cheap model from TF) I needed to carry a Li-Ion battery pack with me on long runs, as the battery in that phone wouldn't last for the duration of some longer runs. But starting with the Moto e, I haven't had to use the pack much.

It's too bad about battery life. It seems that phone manufacturers are only interested in giving users the fastest recharge that is safely possible. I guess that's fine if you're not going to keep your phone longer than 2 years. And now that I have found it is less expensive to buy a new phone with airtime and service on TracFone than it is to buy just the new airtime & service plan, I probably won't be using my phone longer than 1yr either. That's too bad. There are too many still-working electronic gadgets going to the landfills. I suppose that some parts are reclaimed by recycling plans, but I doubt that many people bother with that.
 

iamlucky13

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Is this a phone designed to prevent the user from easily accessing the battery? Otherwise, I'm not clear why you don't want to remove it.

Your basic plan of checking the phone periodically to determine how fast it drains is the right idea.

You don't need to cycle lithium-ion batteries to refresh them like nickel-based batteries, however. Just give it a partial charge, and then when the state of charged has dropped to your cutoff level (I think 10-20% is probably fine), charge it back up to that partial level.

If you want to absolutely maximize battery shelf-life, partial charging to about 50% is a good goal. Not many people keep their phones more than 3-4 years though, so unless that's your plan, I'd go ahead and charge to 75-80% so you don't have to recharge as often.

It sounds like you're also concerned about charge rate. If your phone normally takes more than 2 hours to fully charge, I wouldn't worry about it. Between 1-2 hours, if I remember right, there's usually a small to moderate hit to battery life, and faster than 1 hour, the effect on battery life can be significant.
 

StarHalo

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In my experience, the Target-shelf phones usually end up with completely ruined displays long before the battery shows age. I have Kyocera and Motorola Android models from only a few years ago, the Motorola's display looks like swiss cheese with dime sized holes all over it, the Kyocera has maybe 30% of the screen still functioning. They charge/start/run fine otherwise.
 

ultrarunner2015

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I have read that it is a good idea to allow a Li-Ion battery to discharge to about 20% before recharging, every few months.
On the same note, I read that when you get a new phone, you should charge the battery full, then allow it to discharge to about 20% before recharging for the first time.
Is this info still applicable? I understand that battery technology is changing all the time, so what worked 2 years ago may not apply today.
Reason I am asking about new phone battery is that I want to get the longest life out of the battery in this phone. When I talk about longest life, I'm not necessarily saying that I plan to keep the phone more than 2 years, but that I want the battery to have the full capacity for as long as possible.

As for removing the battery - it is not 'user removable', but it can be removed by opening the back and unplugging it. I will have a look at that.
 

StarHalo

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As for removing the battery - it is not 'user removable', but it can be removed by opening the back and unplugging it. I will have a look at that.

That's the smartphone version of user removable, it's assumed you will pop off the rear panel to service the battery or get the sim card.

Li-ions don't generally care how/when you charge them, which is especially true if you're not concerned about battery life after a couple years. Charge it full then remove it.

Be aware that a battery-replaceable phone means you can buy another battery.
 

iamlucky13

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I have read that it is a good idea to allow a Li-Ion battery to discharge to about 20% before recharging, every few months.
On the same note, I read that when you get a new phone, you should charge the battery full, then allow it to discharge to about 20% before recharging for the first time.
Is this info still applicable?

This is typically for the sake of calibrating the battery meter. Lithium-ion voltage isn't a super reliable method of knowing partial state of charge very precisely. Battery meters in devices like this often estimate state of charge by knowing what the capacity is and monitoring how much energy has been used. Doing a full cycle helps the battery management algorithm figure out the current capacity and account for errors that can accumulate over multiple partial charges.
 

ultrarunner2015

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This is typically for the sake of calibrating the battery meter. Lithium-ion voltage isn't a super reliable method of knowing partial state of charge very precisely. Battery meters in devices like this often estimate state of charge by knowing what the capacity is and monitoring how much energy has been used. Doing a full cycle helps the battery management algorithm figure out the current capacity and account for errors that can accumulate over multiple partial charges.
So I guess that cycling the battery on a bran-new phone isn't necessary, as the meter's calibration should pretty much match the battery. I only wish there was an app that could actually stop the battery from charging past 80%. But so far as I know, there is no method for software to control the charging process - that's all in the firmware.
I have used Ampere in the past, but I seem to have gotten into the habit of checking the charge status several times per day.
 

Gauss163

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[...] Li-ions don't generally care how/when you charge them, which is especially true if you're not concerned about battery life after a couple years. Charge it full then remove it.

In fact they do care, e.g. it is possible to greatly extend their life if you avoid extreme voltages and temperatures.
 

Gauss163

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[...] Lithium-ion voltage isn't a super reliable method of knowing partial state of charge very precisely..

Actually resting voltage is a fairly accurate method of estimating Li-ion SOC (typically accurate to a few percent) because Li-ion chemistries typically have low voltage hysteresis and not very-flat discharge curves (unlike NiMh where the opposite holds). But this simple fuel gauge method is not applicable to phones because the battery is rarely completely at rest, so one needs to use more sophisticated methods to estimate SOC (e.g. look up TI's impedance-tracking algorithm).
 

WalkIntoTheLight

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I only wish there was an app that could actually stop the battery from charging past 80%. But so far as I know, there is no method for software to control the charging process - that's all in the firmware.
I have used Ampere in the past, but I seem to have gotten into the habit of checking the charge status several times per day.

They design smart phones to be thrown away after a couple of years, which is probably why they're not concerned about optimal battery health. Charging to 100% isn't the best thing for your battery, but it's good enough that it will last at least a couple of years.

I like to keep old smartphones, to use as GPS devices (with google maps), or remote controls (with netflix and a chromecast device). Battery health does become an issue after 3 or 4 years. I don't think the lipo packs they use in smartphones are as robust as good 18650 cells.
 

bykfixer

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I keep a couple of small power packs with me.

The ones a bit larger than an 18650 will charge my iPhone 5s twice from 30%. Having 2 means 4 charges or a source of electricity while using a discharged phone in an emergency and 2 more charges with the backup.

If you know how long it takes to recharge to a given point just plug your cord into a time'd wall outlet that will start and stop at 30 minute points you set it to. Say you start at 30% and it takes 2 hours to reach 100%, set your timer to run 1.5 hours. My wife uses one to start and stop items for her chameleon hut. Works great.

I remove the battery from my SLR cameras and as long as a year later typically have 60-75% remaining power. Not less than 50%.
 
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Gauss163

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[...] If you know how long it takes to recharge to a given point just plug your cord into a time'd wall outlet that will start and stop at 30 minute points you set it to. Say you start at 30% and it takes 2 hours to reach 100%, set your timer to run 1.5 hours. My wife uses one to start and stop items for her chameleon hut. Works great

It's not that simple because the charge current is not constant after it reaches CV stage. so then there is no longer a linear relation between time and %charge. Further newer fast charge algorithms may vary the current during the CV phase which also destroys linearity. Further, the point that it enters CV phase will vary as the cell ages and IR increases.

This really needs to be done in software - like laptop battery saver software - but don't hold your breath for that since phone manufacturers are more interested in maximizing profit than phone/battery life. Some - like Apple - are esp. evil in such regards and do everything possible to prevent you from doing repairs that extend lifetime. Better to support consumer right-to-repair laws and not evil companies.
 
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eh4

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If it's a backup phone, why not keep it off until you need it as a backup?
To truly minimize the battery wear, you could discharge the phone to 60% or so, turn it off, take one of those silica gel packs from some packaged food, stick it in with the phone in a Ziploc bag, and put it in the fridge.
If the battery is removable, get a spare or two and put the spares in the bag in fridge instead.
Also, depending upon the OS that LG added over the basic Android OS, there should be a battery saving mode, Samsung has a moderate as well as an extreme battery saving mode.

Another idea is to get one of those programmable outlet timers that'll let you do multiple day programming. You could set it to charge the phone for a half hour per day, or whatever worked out to keep it charged within the min and max that you require.
 
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