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Pocket Power: ‘Flip 2O’ Test

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Goal Zero is a go-to source for powering your tools in the backcountry. Here we look at the Flip 20 USB charger.

goal zero flip 20 2

As someone who constantly runs my phone to zero power, the Flip 20 has become an everyday-carry item.

About the size of a large pack of chewing gum, it fits in a pocket while plugged into a phone. The $49.99 product is simply a battery bank with USB compatibility.

goal zero flip 20 charging
Two full phone charges inside the little blue box

It plugs into headlamps, GPS units, cameras, and phones. To add power to the Flip’s internal battery you plug it into a laptop or wall outlet to recharge.

For off-the-grid and outdoors use, the Flip serves as a backup power source. In a pocket or backpack it goes unnoticed at just over 4 ounces in weight. (See full specs below.)

Charge Test

I used the Flip 20 for a month and consistently got two full phone charges on my Samsung Galaxy S5. I could get about a charge and a half if I was using the phone during the charging process.

The Flip 20 is designed to be used with Goal Zero’s line of solar panels. It fully charged in about five hours using the Nomad 7 in bright sunlight (see below). At home, for comparison, it took about four hours to charge up on a wall outlet.

goal zero flip 20 solar
Charges via solar, wall outlet, or laptop USB

Power levels for the device can be checked by pressing the USB tip when folded in to illuminate LED lights on the side of the device. They indicate the remaining power.

A nice feature is its “pass-through charging,” which means you can power up a device like a phone while simultaneously charging the Flip power bank. This was especially nice when using it in conjunction with a solar panel where sun and time were limited.


One caveat: Because the charging tip is designed to be used with the USB dongle of the solar panels, it can be a little tricky to charge the Flip off a wall outlet. It hangs awkwardly, and I was worried that after repeated use it might do damage to the USB tip. Just be careful and you’ll be fine.

A micro-USB cable is included, which is becoming the default interface for many gadgets. However, for iPhones and other devices you may need to buy an adapter.

If you’re looking for something that can do double duty in the backcountry and around town, the Flip 20 is a great choice. It has enough power to keep you on the go in a pack-of-gum size object that’s unobtrusive and easy to use.

GOAL ZERO FLIP 20 USB  – $49.99
USB Port (output):   5V, up to 2.1A (10W max), regulated
USB Port (input):   5V, up to 1.5A (7.5W max)
Battery Type:   Li-ion NMC
Battery Size:   18.7Wh (3.6V, 5200mAh)
Cell Type:   2x 18650 by LG chem/Samsung
Lifecycles:   Hundreds of cycles
Shelf-life:   Keep plugged in, or charge every 3-6 months
Fuses:   None
Management system:   Charging and low-battery protection built-in
Weight:   4.6 oz (130 g)
Dimensions:   3.7 x 1.63 x 0.83 in
Operating usage temp:   32-104 F

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