Taking Care of Your Gadgets’ Rechargeable Batteries


Taking care of one’s batteries has become increasingly important now that consumer electronics come with sealed batteries that aren’t user replaceable. Proper battery utilization can prolong long-term battery life and prevent unwanted trips to the service center for battery replacements. What follows is a run-through of the battery technology used in personal electronics and how one should use and charge their devices to maximize battery longevity.

Reading Material

This article uses information from in-depth write-ups on lithium-ion batteries published at Battery University; additional articles from Apple, Lifehacker, and Ars Technica were also referenced. Links to the articles are listed below.


Ars Technica

Battery University


Miscellaneous References

Lithium Ion Battery Technology

The major points of confusion with battery usage are related to the battery technology implemented in the gadgets. Today’s laptops, smartphones, and tablets all use rechargeable lithium-ion batteries. All references to “battery” or “rechargeable battery” in this piece of writing will refer to lithium-ion batteries unless otherwise specified. Lithium-ion batteries have the following properties:

Lithium Ion Battery Charging

  1. Lithium-ion batteries are not susceptible to “battery confusion” as they do not have “battery memory” – irregular charging of rechargeable batteries will not prevent the batteries from charging to full when given enough charging time. Hence, they do not need to be fully discharged before they are charged or fully charged before they are unplugged.
  2. The battery-reading circuits in smartphones, laptops, and tablets can get confused by erratic charging cycles. Said devices need to be calibrated on occasion so that battery capacity is properly measured.
  3. The chemicals inside the batteries are stressed when maintained at high internal voltage. Battery capacity is directly related to battery internal voltage, so leaving rechargeable batteries at full or near-full capacity for long periods of time will cause the battery to deteriorate.
  4. Lithium-ion batteries should not be kept at 0% charge. The charging circuit used for rechargeable batteries requires voltage from the battery to operate, and leaving battery charge at zero increases the chances that the charging circuit fails to charge the battery.
  5. Lithium-ion batteries have a maximum safe value of voltage. If rechargeable batteries are charged to above the safe voltage of 4.2 V, they begin to deteriorate and become a safety hazard.
  6. For long-term storage, lithium-ion batteries should be left at 40 – 50% to allow for idle discharge in the battery without placing unneeded stress on its internal chemistry.

Lithium Ion Battery Discharging

  1. Lithium-ion batteries naturally lose capacity over multiple discharge cycles 1.
  2. The long-term degradation of lithium-ion batteries is dependent on the depth of discharge 2 even when consuming the same total amount of energy. A full discharge cycle (using a battery from 100% to 0% without charging) will wear out a battery more than 4 separate discharges of 100% to 75%.
  3. Current draw also affects long-term battery life. A higher current/power draw is more stressful to a battery than idle-state, low-current operation even if the total energy used is equal.
  4. Elevated temperatures accelerate the deterioration of battery capacity.
  5. Using the battery at low voltage/capacity is not ideal for the long-term life of the chemicals inside a rechargeable battery. Delivering power at low remaining voltage places additional strain on the battery and affects its long-term endurance.

How to Use Maximize Your Battery’s Effective Life and Capacity

With the principles of lithium-ion batteries listed above, best-case scenarios for battery usage can now be discussed. I’ll be doing this in question-and-answer form while citing the above principles plus some additional references:

I’ve just received a [insert gadget with rechargeable batteries here], should I drain it to 0% or charge it to full before using it?

The gadgets I’ve bought have had batteries with roughly 40 – 50% charge out of the box, which matches the standard storage procedure for batteries. Apple and Battery University both instruct users to fully charge their new gadgets upon opening. This helps the internal battery determine its full capacity after a long period of idle time.

Should I wait for my battery to reach 0% before charging it?

Draining the battery to 0% before charging provides no benefit to long-term battery life. Rather, draining the battery to critical levels before charging will be more taxing to the battery and reduce its longevity. It is ideal to charge gadgets before they reach their low-charge state.

Can I use my phone/laptop/tablet while it is charging?

It is ideal for batteries to charge when turned off, but using your device while it is charging will not damage the battery. Battery University states that using the device while charging may cause some small errors in device calibration, but the practice will not damage the battery.

Should I always charge my gadgets to 100%? If I can’t charge it fully to 100%, will I damage the battery?

Lithium-ion batteries can be charged at any time and can accept partial charges. Charging a device from 80% to 100% will not damage battery capacity, nor will charging it from 40% – 80%. Hence, people who intermittently charge their devices during the day will not damage their device’s long-term battery life. Regular charges during the day should actually be better for the battery; keeping the battery at a moderate charge level prevents the aforementioned low-charge state that hurts battery longevity.

Can charge my gadget overnight without damaging it?


You’re contradicting yourself, you said that lithium-ion batteries can’t take too high a voltage without breaking. Won’t leaving it overnight cause it to overcharge and fail?

Not to fake people out, but most modern gadgets with lithium-ion batteries also integrate protection circuits in their internal charging systems that prevent the battery voltage and temperature from going too high or too low. These circuits cut off charging supply at 100%, let the battery drain normally, and supply an intermittent topping charge current as needed to maintain battery charge at close to 100% without exceeding safe voltages. Technical details of protection circuitry can be read in miscellaneous references I’ve listed above.

Not every rechargeable electronic device has the appropriate safety measures I’ve described. I’ve personally had a generic portable speaker blow out after leaving it plugged into my computer for too long. Said speaker produced grotesque sound in its death throes, too. Smartphones, tablets, and computers from branded manufacturers can be charged overnight just fine, however. Phone, tablet, and laptop manufacturers mostly source their motherboards and systems-on-a-chip 3 from suppliers like Intel, Qualcomm, or Mediatek, which all provide the needed protection circuity in their designs to prevent overcharging.

It is still ideal for the device and battery to be disconnected from power upon reaching acceptable battery capacity. As mentioned, batteries suffer from strain when held at high voltage, so unplugging the charger upon reaching full capacity can help extend battery longevity.

Does using power banks help extend the long-term working life of my battery?

Phones and tablets don’t accept power directly from the power bank/charger. Even while connected to by power banks or other power inputs, phones and tablets will draw power from its internal battery while the battery is being charged by the connected power supply. Hence, using power banks or keeping a phone or tablet charged all the time won’t result in “free usage” in terms of battery health.

That being said, keeping battery voltage/charge at healthy voltages is better than letting it drain to critical levels. Power banks help extend battery lifetimes by preventing the low-battery-level operation that compounds battery deterioration.

Laptops, on the other hand, can accept AC power directly. Unless you’re expecting a brownout/blackout, keeping a laptop plugged into AC power with the battery physically disconnected will obviously extend battery lifetime. Laptops with integrated batteries don’t enjoy this advantage though.

How should I use my gadgets to prolong my battery’s lifetime?

At this point in the write-up, it is clear that battery deterioration originates from different factors. Batteries are strained by being held at high voltage, by operating at low voltage, by supplying large amounts of current or power at a given time, and by running at elevated temperatures. Battery lifespan can hence be maximized by avoiding these points of battery abuse.

Batteries retain their lifespan better under usage conditions with shorter and low-power loads at lower temperatures. This means that draining 90% of your battery’s capacity when leaving it in a drawer will reduce battery lifespan less than if you drained 90% of your battery playing games. This doesn’t mean that you shouldn’t play games, but keep in mind that regular strenuous usage will shorten battery lifespan.

Batteries also have ideal operating voltages. Battery University clearly presents that keeping batteries at a voltage lower than their maximum 4.2V will prolong their long term health. At the same time, actually using the battery at low voltage will strain the battery more. This means that battery capacity and battery lifespan have to be balanced based on user need.

Ars Technica summarizes frugal battery usage by emphasizing regular and frequent charging, shallow discharges of the battery, and low-current-low-temperature usage of the battery when possible. Going from ~ 90% to 60% regularly with intermittent charges will be better for battery longevity than always draining the battery from full to empty before charging. Gizmodo, Yahoo, Lifehacker,and Battery University all present similar strategies to preserve battery lifespan. Maintaining the battery at an intermediate voltage between 90 and 60 percent reduces the time the battery spends idling at high voltage or draining at low voltage. Additionally, users are encouraged to avoid the high-load and high-temperature condition that significantly affects battery lifespan. This prescribed usage method hence correlates properly with the battery principles that have been discussed.

Let’s repeat the consensus on ideal battery usage: maintain battery charge somewhere between 40% to 80%, go no lower than 20% charge in the worst case, charge frequently, and avoid high-temperature, high-power-draw usage scenarios.

My phone is draining its charge unnaturally. It started at 100% charge in the morning and reached critical charge by noon! Is there something wrong with my battery?

Following the regular charging methods prescribed can lead to the battery reading circuits in gadgets not reading charge properly. A device may read that the battery has been fully drained and shut off even when the battery has charge remaining. It is recommended that you calibrate your battery every 2 months or so by performing a full discharge from 100% to 0% and then charging the device back to full while it is turned off.

A more likely reason for abnormal battery discharge is that Facebook draining your battery in the background. Read this article on how Facebook gobbles up battery even while not active and how you can fix it on iOS. Here’s another article on how Facebook hammers your battery. Android users should install Greenify to force Facebook to go to idle/sleep state or install an alternative Facebook app altogether.

Summary and Quick Points

Modern computing devices have veered away from user-replaceable batteries, which adds importance to properly managing battery usage. The principles behind rechargeable battery operation and the best practices for maintaining its longevity have both been discussed in this write-up. Users are advised to maintain battery voltage between 40% to 80% while going no lower than 20%, to charge their devices frequently, and to avoid high-temperature, high-power-draw usage scenarios when possible. Commonly asked questions regarding battery charging and usage have also been answered. People interested in learning more about lithium-ion battery technology should refer to the links listed above, especially the articles on Battery University.

I’ll finish with some quick points that I didn’t squeeze into the write-up previously:

  • Battery University posts a handy table that summarizes lithium-ion battery usage and charging on this page. If you wanted a tl;dr summary, that table is it.
  • Wireless chargers sound great for keeping gadgets charged all the time, but wireless chargers are actually pretty inefficient and convert a lot of the supplied power into heat. Heat is bad for batteries. I personally recommend buying more USB charger cables and leaving them at the places where you spend your time most.
  • Irresponsibly coded apps will wreak havoc on battery life by keeping gadgets in a power-on state. Modern gadgets get their longevity from rushing their tasks to completion and switching to an low-power idle state. The mentioned app behavior and the ideal OS operation are obviously antithetical. On Android forums, the action of an app to keep a device in its active state instead of switching to idle is called a wake-lock. Greenify on Android helps force apps to sleep and mostly prevents wake-locks from occurring, hence encouraging the low-power idle state desired for extended battery life. On iOS, general procedure is to monitor which apps are accessing data in the background and turn off background data for apps you don’t prioritize. Common culprits on both platforms are Facebook, social networks, social games, and chat apps.
  • It’s nice of Samsung to provide replaceable batteries on the Galaxy S5, but it’s not like anyone actually buys a second battery until they want to replace their old one for good.

  1. A discharge cycle is a unit of measurement for battery utilization. Standard usage of the term “one discharge cycle” refers to one cycle of consumption of a battery’s full capacity. 
  2. The depth of discharge is conventionally defined as the fraction of a battery’s full capacity delivered during one usage cycle without charging. Depth of discharge is the difference the battery’s full capacity and the remaining capacity at the end of the usage cycle before charging, e.g. using a battery from 100% to 73% is measured as 27% depth of discharge. 
  3. A system on a chip, with the acronym SOC, is a single electronics block that includes the processor, sound chip, wifi, telephony/3G chip, and the interfacing technology a phone or tablet needs to function. Its equivalent in desktops and laptops is the motherboard. An easy-to-understand overview for SOCs can be read at Ars Technica

This is What Spotify Plans Will Look Like in 6 Months

Update: The new version of Globe’s GServices app properly shows what Spotify plans will be in a few months. Screenshot below:

Spotify on Globe

It’s interesting that the new plans don’t have a Spotify Basic, 1 GB plan like the current promo does. I wonder whether it’s Globe streamlining its Spotify offerings or Spotify wanting to push ad-free (and paid) Spotify.

Original Post:

I tried and failed horribly to test out streaming Spotify on Globe using their GoSurf plans during the Holy Week. That said, my repeated failures to sign up to the service did turn up something interesting.

The bundled Spotify on GoSurf is likely going away in 6 months, and it will probably be replaced by the PHP 299 for 1 GB streaming plus Spotify Pro package currently supplied to all 30-day GoSurf plans.

(Also, what happened to PHP 999 anti-billshock plans?)

Clarifying Globe’s Spotify Plans

Globe has properly published its GoSurf plans with Spotify online, and they are relatively consistent with the previous press release on the matter. Globe will offer more SKUs of GoSurf than originally released, with plans ranging from PHP 15 to PHP 2499. Spotify Premium still starts at PHP 299 with 700 MB of data. Worth noting is that Globe has placed limits on complementary Spotify use, though all 30-day plans get the maximum allotment of 1 GB free Spotify streaming on top of their mobile data. For perspective, here’s a computation of what 1 GB of Spotify use is in minutes1:

Bit Rate Conversion

The 1 GB cap on Spotify usage is a letdown from the assumed unlimited use in Globe’s original press release, but that was optimistic thinking anyway. Using mobile data to stream just under 24 hours of Spotify on “Normal” isn’t a bad deal for PHP 99 monthly on Spotify Basic or PHP 299+ on Premium. It does mean that Spotify in the office will probably have to come from LAN though.

I paid a visit to the friendly neighborhood Globe store today and heard something interesting: Spotify promos on GoSurf might only last for 6 months. Those interested in Spotify streaming on Globe should subscribe and hope that Spotify plans are popular enough to warrant a permanent spot on the GoSurf basic plans.

Here’s a streaming suggestion: every Eraserheads album2 is on Spotify.

  1. All bitrates are based on mobile use. Desktop use has different equivalent bitrates. 
  2. This doesn’t exclude the Please Transpose EP. 

Spotify is Now Available in the Philippines

Spotify just launched in the Philippines, with premium accounts and everything. Spotify will now provide access to free and premium tiers for Philippine users, with the latter providing ad-free playback and offline listening for PHP 129 a month1. This is a boon for the people who listen to music, if of questionable benefit to musicians. The Pandora’s box of album/song sales was opened long ago though, and I’m more interested to see if music discovery in Spotify will mature with respect to local music. Right now, there’s an OPM radio station available, and that’s it. This means that tide/edit will be followed with Sharon Cuneta, based on my experience using the service today. I’m optimistic that Spotify’s recommendations will improve once their algorithms compile more usage data from Philippine users, but we’ll see.

Spotify has also tied up with Globe for mobile devices, and based on the wording offered on Globe’s announcement, Spotify can be availed on-demand without additional data charges. From the announcement2:

Spotify has also teamed up with Globe Telecom as its exclusive telecommunications partner in the Philippines to offer all 38 million Globe Postpaid, Globe Prepaid and Tattoo-on-the-go Prepaid subscribers free access to Spotify through the telco’s new data plan, GoSURF. GoSURF gives customers mobile internet access together with Spotify for as low as P10 a day. Even better, streaming music on Spotify won’t touch your default data allowance across all GoSurf plans!

Rolling out on April 13, Globe Telecom Prepaid subscribers can register to:

GoSURF 10: PHP 10 for 10 MB of data plus Spotify for 24 hours.

GoSURF 299: PHP 299 for 700MB of data and Spotify Premium, valid for 30 days. (Postpaid only)

GoSURF 999: PHP 999 for 5GB of and Spotify Premium, presumably valid for 30 days. (Postpaid only)

Update (4/13): Globe recently released its GoSurf plan breakdown. Monthly subscribers to GoSurf get 1 GB of free Spotify streaming. 1 GB isn’t unlimited, but it’s roughly 23 hours of streaming on Spotify’s “Normal” quality stream.

The middle tier looks like a great sweet spot, and I’m hopeful Globe and Spotify have arranged a proper back-end to properly link Spotify premium subscriptions to accounts. PHP 170 for 700 MB of data is a good deal too, especially when the current plan is PHP 299 for 300 MB or PHP 499 for 1 GB.

I’ll be looking around Spotify’s library of local music now, thanks.

  1. PHP 129 is a far cry from the ~ PHP 450 that they charge for US users. Spotify using adaptive/prorated pricing for Philippine users is nice. 
  2. Edited for formatting. 

Remembering NwAvGuy

A short profile of NwAvGuy appeared on the front page of Hacker News a week ago, reminding me how impressed I was reading NwAvGuy’s blog. His blog covers personal audio in a data-driven methodology rarely observed in popular audio websites like Head-Fi, with the use of professional-grade testing methods to verify the performance of audio players, amplifiers, and headphones. I originally stumbled upon his website years back while searching for Fiio products I read about on Head-Fi, and I was engrossed by his reviews of cheap but well-engineered audio products that could compete with or exceed the performance of audiophile-branded products twice as expensive.

I recently started rereading NwAvGuy’s blog, and have been intrigued by technical articles I skipped over before. I find the discussion of device impedance, amplification, and subjective versus objective evaluation as real gems for people interested in the science behind their audio gear. Impressively, the comments of each article are also worth reading, as NwAvGuy reliably answered commenter questions that covered the key questions for selecting audio players, external DACs1, headphones, soundcards, and amplifiers2 if needed. People who plan to invest in quality audio equipment will do themselves a favor by reading through the blog3.

I’ll post more links that discuss sound technology, but reading through NwAvGuy’s blog from the start should tide people over nicely until then.

  1. In the context of audio equipment, DACS, or digital-to-analog converters, are what convert a digital audio file into an analog signal that speakers or earphones can process. Phones, tablets, and computers all have internal DACs to process mp3’s and other digital audio files, but there are also dedicated devices that perform the function of a DAC. Examples of dedicated DACs are internal sound cards and USB DACs. Dedicated DACs are useful when the internal DAC or headphone output of an audio player is not up to standard and adds unwanted noise (hiss) and distortion to the audio signal. 
  2. In the context of audio equipment, amplifiers take an analog audio signal and supply it at a higher amplitude/power level. Different headphones and earbuds have different power requirements, and amplifiers are useful for satisfying the power requirements of power-intensive headphones. Amplifiers are also situationally useful in specific combinations of audio players and headphones. A poor match between audio player and headphone due to poor impedance matching will cause undesired distortion in sound, but connecting an appropriate amplifier between the two can improve the signal received by the headphone, leading to better sound. 
  3. Current audiophiles should probably give the blog a look as well, if only to clear up any misconceptions on audio technology they picked up from the usual sources.