Power banks are extremely useful but they can be cumbersome, especially when you also have to carry assorted cables to transfer that power from the bank to your phone. Flux Card is the opposite of those power banks, slim, portable and with no extra cables required – for iPhone or Android. Also see: Best power banks 2016.
Flux Card review: UK price and availability
The Flux Card is sold direct from fluxchargers.com in the US, where it costs $25. Shipping within the US is free, but to the UK it will cost you $8.50 and take six or seven days to arrive. We should also point out that we were charged an £11.50 Customs fee by Royal Mail before we were able to receive the power bank, which would take the total cost up to around £35 ($33.50 + £11.50).
The Flux Card offers great value when purchased within the US. Shipped to the UK it’s relatively expensive and much cheaper power banks are available, but it’s not unreasonable if the cable-free design particularly appeals to you.
For every Flux Card purchased $1 goes to Flux’s charity of the month (currently YouCaring.com).
Flux Card review: Performance, features and design
We’ve seen compact power banks with built-in Micro-USB or Lightning connectors before, such as PNY’s M3000 and DCM2200, but you are always required to choose between Android or iPhone before making your purchase (which is a real pain if you later change platform or use both). The Flux Card differs in that it can cater to both Android and iPhone. Also see: Best MiFi 2016.
On the side of the Flux Card is a Micro-USB input for refilling its battery, while a Micro-USB output is attached to the bottom of the device via a light blue rubber cable that clips into place. Underneath this is what looks like another Micro-USB; it’s actually a Lightning adaptor. Pull it out and you can charge an iPhone instead.
On our review sample the Lightning adaptor didn’t sit particularly tight to the Micro-USB connector, but it worked just fine in charging an attached iPhone 6s Plus. It’s MFI-certified as well, so it won’t stop working following an iOS update. Also see: How to charge your phone’s battery faster.
With a white matt plastic housing the Flux Card has a minimalistic yet sturdy design. It’s incredibly small and light, a credit-card-sized 6.6mm-thick power bank that weighs just 60g. Yet it contains 2,500mAh of power, which is easily enough to fully charge an iPhone once.
Flux doesn’t specify the efficiency rating, but the industry standard is around 65- to 70 percent (energy is lost through heat generated and voltage conversion). This means it’s unlikely to fully charge most Android phones, but it will certainly offer enough power to get you through to the end of the day. Also see: How to improve smartphone battery life.
With a 2A (10W) output the Flux Card is quick to charge your phone, but not so quick to charge itself with only a 1A (5W) input – it should be fully charged in around an hour and a half. Its relatively low capacity means recharging is less of a chore, but we would like to have seen support for passthrough charging (the ability to charge itself and a phone at once).
There’s no buttons on the device, so to charge your phone you simply plug it in for automatic charging to begin. If charging completes before the Flux Card’s battery runs dry you’ll need to remember to unplug your phone to prevent wasted power. Also see: What is Quick Charge 3.0
A single LED on the rear of the device glows a constant blue when charging a phone, and flashes when its own battery is being charged. There’s no way of telling how much power remains in the bank, but it should be fairly easy to remember that if you’ve charged your phone using the Flux Card then it needs a recharge.
There’s not a huge amount in the way of advanced or extra features here, but the Flux Card isn’t that type of power bank. It’s a small and light emergency charger that you can slip into a bag and forget about until you find yourself stuck away from mains power with a fading phone battery. And it does that job very well.
Read next: Best desktop chargers 2016.