Would you care for a built-in battery reserve for your smartphone?

Taylor Martin
 from  Concord, NC
| August 12, 2012

It's 2012 and smartphone batteries pretty much suck. It's a fact we all have slowly come to grips with over the years, and there are very few exceptions. You're doing great – better than most – to last an entire day on a single charge. And if you expect much more, you're just greedy, have your expectations set too high or you're just a whiner.

Back in January, I said that 2012 would be the year of battery pack chargers. I argued that, unfortunately, this would not be the year we experience a major battery technology breakthrough and we will instead spend our time discovering countless ways to cope while we (im)patiently wait on manufacturers to uncover the missing link in portable power. Supplementary charges at lunch time or any recharge station (you know, the public USB ports that are popping up all over cities around the world) is becoming the norm. And carrying a spare battery or two in your pocket isn't all that unusual either.

Personally, I've found external battery charging packs and cases that carry juice to be extremely useful – irreplaceable, even. (I shed a single tear for my Incipio offGRID when it would no longer charge.) They're what get me through the day ... every day. On most days, I honestly wouldn't know what to do if I didn't have my Powerbag with me. And making sure I never leave the house with my battery below 100 percent is an absolute must.

Still, with all the portable charging options, a mobile device with a dead battery is inevitable. At some point or another, we all are going to face the dreaded blinking light of a dying phone, or that horrific noise of a low battery tone. Or maybe your phone displays a pop-up notification saying it's time to plug it in. No matter how your phone cries for some extra juice in its final moments, we all face it at some point or another. And there's no worse feeling than getting a notification when there is no immediate way to charge your phone.

It happened to me just the other day. And, of course, it was a day I decided not to carry my Powerbag, since I didn't think I would be gone long and wouldn't need any extra juice. When I left my house, both of my phones were fully charged. About four hours later, the One X hit roughly 60 percent (without ever having left my pocket). And approximately an hour before I returned home, it completely died. Granted, I had another phone to use. But its battery was trickling away pretty quickly, too.

It wasn't the end of the world. (A disconnect from time to time does the mind and body good.) But it's a daunting feeling to know you may miss something important in a world where every second and minute counts, or that you can't make an emergency call if something comes up before you can charge your phone.

Last night, however, I happened upon a rather unique idea by Chris Ziegler in The Verge mobile forums. Ziegler begins by explaining the "reserve tank" technology used in most modern motorcycles:

"When I learned about motorcycles as a kid, I was introduced to the concept of the "reserve tank." I use it in quotes because it is not, in fact, a separate gas tank hidden somewhere on the bike — rather, it's an intake tube that rests lower inside the main (and only) tank than the main intake. Its lower position allows the rider to capture those last few drops of gas that the main intake cannot. A flip of a switch somewhere on the engine selects the reserve, which gives you just enough oomph to reach a gas station or your destination, whichever comes first."

He explains that while the concept may seem "silly", there are two justifications for such a feature: one part practical, one part psychological. Motorcycles don't have gas gauges. Instead of instead of completely and unexpectedly running out of gas in between destinations, however, you can flip to the reserve when your engine starts to sputter. (Reserve has saved me countless times from an empty tank, so I have a deep-down love for the archaic technology.) The psychological factor is that it "imparts you with a sense of urgency," says Ziegler. "It forces you to recognize and acknowledge that you're almost out of gas."

As odd as it may sound, Ziegler sees potential in a similar technology in mobile handsets – not in software, but in hardware. Once your battery gets critically low, you could flip a switch (which Ziegler envisions being beneath the battery door, which would obviously only work with some phones) and keep on trucking for another 45 minutes to an hour.

"Go ahead and cordon off a couple hundred milliamp-hours worth of battery that can only be accessed when I flip that toggle, especially now that stock lithium-ion polymer batteries regularly offer 1,800mAh or more."

As odd and old-fashioned as it may sound, it's not a bad idea. I could actually see this being useful in several ways, and not just for squeezing out another hour of use.

For starters, sure, there are alternatives that already exist: small, ultra portable battery packs that temporarily charge your phone and give it an hour or more of charge. But this method requires you to carry something extra with you when it might not always be possible, practical or convenient. A reserve "tank" would allow you to squeeze out another hour or so without having to carry any additional knickknacks.

"But what good is it if it doesn't actually add any battery life to my phone? It's only partitioning battery life that I would normally have access to without having to flip a switch." True. But ideally, you would forget about it (read: not plan your usage around it) and only use it in dire need, after your phone has already died or is on the verge of dying. And it creates a sense of urgency, unlike an easily dismissed and ignored software message. As Ziegler says:

"… the physical motion of flipping that switch puts it front and center in my mind that I need to focus on finding a charger or be okay with going phoneless for a while."

But there's also a rather handy use that could easily go undetected: swapping batteries. Rather than partitioning a spare battery with the reserve, a reserve in a smartphone could actually be a "reserve tank", a physically separate battery that is built-in to the device itself. If you do carry spare batteries with you, this reserve tank could be switched on while you pop out the dead (or near-dead) battery and pop in a freshly charged one, all without having to skip a beat and power cycle your phone. Minute? Maybe. But very useful.

It may seem like a ridiculous or pointless endeavor. But I can definitely see the usefulness in having battery reserves in a device, even if it's just a couple hundred milliampere-hours. Just as the reserve switch has saved me time and time again on my motorcycle (you would think I would learn how far a tank of gas would take me), I imagine a reserve tank on a smartphone would come in handy more times than one. Then again, just because it seems useful neither makes it practical or probable. Despite being potentially very useful and a lifesaver in certain situatins, the likelihood of a smartphone launching with a "reserve tank" is slim to none.

What say you, folks? Do you like the idea of a "reserve tank" for a smartphone? Or does the current method work just fine for you? Do you think physically flipping a switch for a separate, emergency battery would help you at all?