Last year we discussed power banks in my column titled More Power Part 2 (https://go.ttot.link/TGMorePower-2).

This time we’ll discuss them in a bit more detail. Why? Well, there’s a lot more to know that can help you make a sound purchase decision. So, let’s get to it, shall we?

First, just to review a little, what are power banks? In the context of phones, tablets and laptops, they’re small, portable batteries that you can use to recharge your devices. You plug them in to a power outlet to charge the power banks then you can carry them around and use them to recharge your device when you’re on the go or even recharge your devices in the case of a power outage.

Next, all of your power banks, indeed, all of your electrical devices, should bear either an Underwriters Laboratories (UL) or Conformité Européenne (CE) certification mark. UL is the American standard and CE is the European standard and they are pretty much equivalent so if your device bears a CE mark but not a UL mark, don’t be concerned. Both UL and CE require the power bank, in fact, all electrical devices who bear their mark, to undergo testing to show that the marked device is safe and manufactured properly. Read more about UL and how its mark is shown on devices at https://go.ttot.link/UL-Mark and CE at https://go.ttot.link/CE-Mark.

There are many different types of batteries used in power banks. Very old ones used nickel cadmium (NiCd) batteries but they didn’t hold a charge very well and had a “memory effect” wherein, after a period of time, the battery would indicate it held more of a charge than it really did. What’s the end result? Your power bank would run out of power long before it was supposed to. Nowadays, power banks tend to use other technologies for their batteries, typically Lithium Ion (known as Li-Ion) or Lithium Polymer (Li-Po, which is a newer technology). They have no memory effects to speak of and can store quite a bit of power in a small, light package but, and this is important, they can catch fire or explode if they get hot.

Have you read about those electric scooters catching fire when they’re being charged? They used poorly manufactured Lithium batteries. So, it’s important to make sure your power bank has an UL or a CE certification mark. Batteries that bear that mark should not catch fire or explode when charging. Note that they’re still susceptible to heat so you shouldn’t store them in a hot car or truck.

Even newer than Li-Po and Li-Ion is Gallium Nitride (GaN). It makes for a lighter battery and can store even more power in a smaller package but, of course, it comes at a higher price. GaN power banks will often display more information about how full the battery is, how fast it’s charging any attached devices or how fast the power bank itself is being charged if it’s plugged in to replenish its power.

Power banks come in all sizes, from small ones that weigh a few ounces to larger ones that weigh a pound or more. Weight translates directly to how much power they can store, which is indicated in milliamp-hours (mAh). A battery with a larger mAh rating will be larger and weigh more than one with a smaller rating, and weight and size can be important if you plan to carry it with you all the time vs packing it in, for example, a backpack. How much power the power bank can store is indicated by the “ma” or millamps part, how long it can deliver that power is indicated by the “h” or hours part. I know, that doesn’t really tell you much so let me explain a bit more.

Your phone’s battery can store a certain amount of power — the Apple iPhone 14 Pro Max, for instance, contains a battery with a capacity of 4,323 mAh. In order to completely recharge an iPhone 14 Pro Max whose battery is completely empty, you’ll need a power bank that has at least 4,323 mAh. How quickly will your power bank recharge it? It depends on the charging technology that your phone, power bank, and (yes) your cable uses. Most power banks can be taken on an airplane but some of the larger ones require a permit or are prohibited altogether. Read https://go.ttot.link/TSAOnPwr for more details. And if you want a lot more information about power banks in general, go to https://go.ttot.link/LotsOnPwrBanks.

My go-to when it comes to power banks is Anker (https://www.anker.com/) and they have a good set of frequently asked questions about power banks at https://go.ttot.link/AnkerPwrBanks. They have a good selection of power banks of various capacities, battery technologies, connectivity options and recharge speeds. All of the ones I’ve looked at or owned have either a UL or a CE mark (or both). And, as I said earlier (and I cannot stress this enough) make sure all your electrical devices bear such a mark.

That’s all for this week’s column. I hope this helps you have a better understanding of power banks, their capacities and what to look for and consider when buying one. Don’t hesitate to write to me if you have questions!

As always, my intent with these columns is to spark your curiosity, give you enough information to get started, and arm you with the necessary keywords (or buzzwords) so you’ll understand the basics and are equipped to search for more detailed information.

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Tony Sumrall, a Hillsboro native whose parents ran the former Highland Lanes bowling alley, is a maker with both leadership and technical skills. He’s been in the computing arena since his graduation from Miami University with a bachelor’s degree in systems analysis, working for and with companies ranging in size from five to hundreds of thousands of employees. He holds five patents and lives and thrives in Silicon Valley which feeds his love for all things tech.