Software Development

How and when to charge your tablet battery

Jack Wallen provides some tips for maximizing your tablet battery for a life of extended mobility.

Tablets have taken over the mobile world, because they are the best of all mobile worlds --  smaller and lighter than laptops, and more useable than smartphones. It's also possible to get a better battery life in your tablet than you do with your smartphone or laptop, extending you beyond a full day of work. However, this won't happen if you're careless with your usage and your battery. Believe it or not, there are ways to maximize that battery for a life of extended mobility.

The life of your tablet battery

Much of the change in batteries grew out of the necessity of safety in portable devices. Because mobility means taking a device through severe heat, cold, shock, and vibration, the batteries had to designed for maximum safety and longevity. Although many may doubt this claim, storing energy of several kilowatts can be dangerous, especially when stored in a device that's constantly on the move and often dropped, shaken, and exposed to harsh environments.

Since these batteries are tucked safely away from the user, it's up to the physical and software systems -- the Battery Management System (BMS) -- to care for them. The BMS handles some fairly complex tasks, such as managing the integrity of a battery when cells begin to fail (usually due to the battery lifespan). Unfortunately, the BMS can't do everything. The user of the device still has to take care of the mobile to ensure extended and safe battery life.

Here are three main tips that should easily apply to all batteries in mobile devices:

Temperature: Do not expose your device to extreme temperatures. Cooler temperatures prevent battery corrosion, so it's always best to keep your device from overheating. It happens. Working with a tablet in your lap, you can feel the warmth heating up your legs. That means the battery is also getting hot. Work with your tablet in such a position that heat can easily dissipate. Discharge: It's a myth that modern batteries need a full discharge to retain "memory" (this only applies to a nickel-based battery pack). Every full cycle wears the battery down by a small amount. So, smaller discharges are better. Try not to let your battery go beyond the half-way point before applying a charge. Abuse: This is a no-brainer, but people do get careless, and every drop of that tablet runs the risk of damaging the battery within. This also applies to improper discharges. These types of discharges can happen when a process gets out of control and is allowed to continue on, which quickly runs down the battery. If you see this happening (if the tablet starts responding slowly), find the rogue process and kill it or restart the tablet.

Let's look at some more tips on how and when to charge your tablet battery.

First charge: When you first unbox your tablet, you should approach the first charge differently, depending upon the type of battery the tablet has:
  • Lead acid: The battery should be fully charge. Apply a top-off charge before using.
  • Nickel-based: Charge the battery 14-16 hours before the first use.
  • Lithium Ion: Apply a top-off charge before the first use.
Full vs. partial charge: Some batteries actually do poorly if you only give it a partial charge.
  • Lead acid: You must always give this battery a full charge, as a partial charge can create sulfation.
  • Nickel-base: A partial charge is good.
  • Lithium Ion:  A partial charge is actually better than full charge.
Full discharge: There are types of batteries that actually prefer a complete discharge now and then.
  • Lead acid: A deep discharge can damage the battery.
  • Nickel-base: Apply scheduled discharges only to prevent the battery from retaining memory.
  • Lithium Ion: A deep discharge can damage the battery.
Battery calibration: Some batteries do not need calibration. Here are the details:
  • Lead acid: Not applicable.
  • Nickel-base: Apply a discharge/charge when the fuel gauge becomes inaccurate. Repeat every 1-3 months.
  • Lithium Ion: Apply a discharge/charge when the fuel gauge becomes inaccurate. Repeat every 1-3 months.
Use while charging: Is it okay to have your device on while charging it?
  • Lead acid: It's okay to have device on when charging.
  • Nickel-base: It's always best to turn the device off during a charge, since a parasitic load can either alter full-charge detection, overcharge the battery, and/or cause mini-cycles.
  • Lithium Ion: It's always best to turn the device off during a charge, since a parasitic load can either alter full-charge detection, overcharge the battery, and/or cause mini-cycles.
Unplugging when charged: Is it necessary to unplug your device once the charge is complete?
  • Lead acid: This depends on the charger. If the charger has correct float voltage, then it's fine.
  • Nickel-base: Always remove your device after a few days in the charger.
  • Lithium Ion:  This is unnecessary, because the charger turns off.
Temperature: How does temperature effect charging?
  • Lead acid: It creates a slow charge from 32-113 degrees Fahrenheit / fast charge from 41-113 degrees Fahrenheit / the threshold is lowered above 77 degrees Fahrenheit.
  • Nickel-base: It creates a slow charge from 32-113 degrees Fahrenheit / fast charge from 41-113 degrees Fahrenheit / the battery will not fully charge when it's hot.
  • Lithium Ion:  Do not charge below freezing. Do not charge when above 122 degrees Fahrenheit.

Of course, this doesn't take into consideration the effects of various types of software or networks (such as 4G, which will quickly drain a battery). Ultimately, if you use your battery with intelligence, it will reward you with a long life.

About

Jack Wallen is an award-winning writer for TechRepublic and Linux.com. He’s an avid promoter of open source and the voice of The Android Expert. For more news about Jack Wallen, visit his website getjackd.net.

20 comments
SchultzyBeckett
SchultzyBeckett

As you may already know, the crankshaft is what converts the engine's power into rotational movement, eventually turning the wheels of the car.But consider for a second the forces that are acting on the crankshaft  they're tremendous. Each time a cylinder fires, a force acts upon the crankshaft, causing it to twist.

Schultty  https://www.yourmechanic.com/

good hope
good hope

At last a complete article about this issue which causes many headaches and is so information hermetic! Excellent article, thanks!

MissGYD
MissGYD

I have an Azpen A700 that seemed to run out of a charge literally a couple of hours after a full charge.  Now it won't charge at all, no matter what charger I use.  Am I gonna have to give up on it now, or replace it?  And if so, how do I get all my apps out of it?

cincy2014
cincy2014

I have an Asus Vivo Tab RT and what I was wondering is what happens when it's battery no longer holds a charge, is there a way to replace the battery myself or will I have to send it in, like Ipad users?

Adelejukerberg
Adelejukerberg

You write really good. I really appreciate that. But please write about data recovery from TAB through various methods.

danekan
danekan

I've heard it's actually bad to keep a lithium ion permanently plugged in. The battery actually needs occasional charge and discharge. I have seen evidence this is true based off of laptop batteries when it comes to recycling time... I have 2 users who have laptops but couldn't tell you how to undock them without a call to support. (OK actually they both just retired in the last two months). When it came time to recycling our Dell D620s and D630s, without fail every person whose laptop was always on the dock had a non-functional battery. Every single one. Those who used it as a normal notebook system had functional batteries, for the most part. Out of say a sampling of 50 or so I'm talking here, so not huge but still noticeable. Also, I've also heard operating a battery operated device that normally works on battery without a battery in it will potentially cause issue on "some" systems. The issue here is the battery itself acts as a capacitor. Power variances are absorbed into the battery, not the device. I don't know if the operating system of some devices would recover a quick or minor hardware issue better than others, so this may or may not be noticeable to the end user. But even so, you may still have things happening in the back end. I've heard this specifically w/ wireless Crestron panels which is just a small tablet w/ WinXP embedded in it when it comes down to it.

NigelJR
NigelJR

Hi I've had a generic android tablet (Chinese build) for just over a week. Works perfectly. However, after following the manual instruction to first fully charge for 6 hours and discharge (twice), followed by 4-hour charge thereafter ... all with tablet switched off ... the tablet only indicated 90% charge... and started to lose it quite quickly. BUT ... at that point (after reaching about 90% charge, as described above) ... I now leave the tablet switched ON, but IDLE, reconnect the charger, and after about 1 hour or less the tablet shows 100% charge .. and retains the charge quite well (2-5 hours, according to use). Have I discovered the way to fully charge the lithium poylmer battery? Or am I mistaken?

avengine
avengine

I have the Samsung galaxy tab p1000, the battery indicator show 18% all night after charge and when I charge it to 60% then it jump to 99% in few minute. Something just do not make any sense. 2 questions, what might be the error? and what is the sign that I should replace the battery? my tablet is about 1.5 yrs old, and so far I have to charge every day. thanks.

aroc
aroc

Most tablet battery specs I have seen are in the 3-4 Amp hour (provide that amperage for 1 hour before voltage drops below usable rating - around 3-3.7 volts) range - they usually specify them as milli-Ampere hours so 3000-4000 mAh. (http://www.batteriesplus.com/t-faq2.aspx#10) So at max charge with 3.7 volts times 4 amps, that would be 14.8 Watts - hardly anywhere near 1000 (1 kilo) watts (as I recall my basic electronics/physics classes...). I believe the main danger of concern is from the potentially explosive chemical reaction to excess heat with Lithium-based batteries.

clankfu
clankfu

What do you mean by applying a "top-off charge"? Great guide btw.

chris-b
chris-b

That last bit about the effect of temp on charging made absolutely no sense to me - the slow and fast times (32-113 and 42-113) overlap by 81 degrees, and I thought I was supposed to keep my battery from getting that hot. Am I misreading, or is the author mis-writing?

ddalley
ddalley

I've been waiting a long time for charging info for lithium-ion batteries!

Barc777
Barc777

"Of course this doesn't apply to Apple gadgets because you can't remove the battery." I'm not really sure how to even begin removing the batteries from my tablets, sealed devices that they appear to be. I do hope that the batteries can be replaced, and will be really disapponted if I eventually lose the TouchPad due to the battery's eventual demise.

Barc777
Barc777

Nickel is the element; nickle is the 5-cent piece.

Gisabun
Gisabun

If your device will be mostly stationary [i.e. it stays on a desk most of it's time and you rarely take it on the road or to the washroom or on the balcony], rem ove the battery and use the charger only. Only nregative issue could be a power failure. Of course this doesn't apply to Apple gadgets because you can't remove the battery.

jmahr1127
jmahr1127

Which one of those three types of battery is found inside a tablet/ If they all are, could you do me a favor and tell me which kind of battery is found inside the HP Touchpad/ thanks

Contradiction
Contradiction

Maybe someone can keep up with the info above for a while. But after some time you just don???t care anymore. You just plug it in, charge it and use it. In a couple of years I will probably replace my iPad, so I don???t really care about its battery. Plus, LiPo (Lithium Ion) is considered one of the best batteries today. Good info though.

rmerchberger
rmerchberger

Nickel is both the element and the coin; Nickle is the programming language and the last name of several prominent Canadians.

nwallette
nwallette

Either way, the care and feeding is the same. NiMH hasn't been used in years for consumer electronics because the power-to-weight ratio isn't up to par with Li-Ion and LiPo. (NiMH is still common in cordless phones, and rechargeable cells like AA batteries, but not in a cell phone, laptop, or tablet.) NiCd was out of style when NiMH showed up, so it's all but extinct now. (Again, some cordless phones and old rechargeable cells still use this chemistry.) Lead-Acid is what's in your car, UPS, and other large-scale, low-maintenance, low-duty cycle battery applications. It's not something you'll ever find in a portable device. Lead is heavy, can leak, is not meant to be used until depletion, and exhausts explosive gases during charging. I'm not really sure why it's even mentioned in this article except for completeness sake, because it's not relevant.

aroc
aroc

Never mind the following - I missed your parenthetical part to the same effect. Sorry about that. It is used in about any cordless phones for landlines I have had for the 20 years or so - just got a Panasonic Answering System package (base and 3 handsets) today that uses that battery type. Also seems common in outdoor solar lights.

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