HomeAppleTau Energy Financial institution evaluate: a helpful energy supply in your keyring

Tau Energy Financial institution evaluate: a helpful energy supply in your keyring

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Tau helps encourage you to maintain your energy financial institution modified by simply clipping to your keys, and it prices with a novel magnetic charging base.

We have all been there — you are nearly prepared to finish your day, and while you examine your telephone, you notice you are minutes away from a useless battery. Generally this is not an enormous deal, however it’s a large drawback if you happen to anticipate a vital telephone name or textual content, or must hail an Uber to get house.

Rolling Sq. has tried to resolve this drawback with Tau, a keyring-sized energy financial institution that hooks onto your keys, guaranteeing that you’ve got at all times acquired energy wherever you go.


Tau is a small energy financial institution, a little bit bigger than a key fob, that attaches to your keys. The thought is that you will at all times have a backup battery wherever you go, because it’s linked to an merchandise you are going to carry round anyway.

The battery portion recharges through a magnetic charging base, one designed to hold in your wall through an adhesive strip or screws. Whereas Tau supplies a chunk of nanosuction adhesive that you need to use, we opted for a 3M strip out of an abundance of warning, as sure sorts of paints might be vulnerable to pulling up with nanosuction adhesives.

Tau's charger can be removed and taken with you if need be, thanks to the sliding back cover

That is particularly good, because it offers you a devoted spot to recharge Tau and cling your keys. The design is nice as a result of it solves each our problems with shedding our keys and routinely forgetting to cost an influence financial institution earlier than leaving for the day.

Nonetheless, there’s a little bit of a draw back to the design, as Tau solely recharges through the magnetic dock. There is no solution to manually recharge the battery by different means.

Must you wish to recharge the battery whereas out, you are out of luck.

Nonetheless, if you wish to take Tau’s dock with you, we respect that the charging base might be slid off of the again cowl. This characteristic permits you to take Tau — and its charger — on the street.


Tau weighs just a bit over 1.4 ounces and might maintain as much as 12 ounces. By itself, we did not suppose the battery was too giant whereas connected to a set of keys, however if you happen to’ve acquired a key fob and an AirTag, you would possibly discover it a little bit cumbersome.

The battery is 1,400mAh, which ought to recharge an iPhone 13 from 0% to 45%. Positive, it isn’t going to recharge your telephone completely, however it will undoubtedly be greater than sufficient to maintain your telephone functioning whilst you wait in your rideshare of selection to choose you up.

Tau can charge USB-C, microUSB, and Lightning-compatible devices

Tau can cost USB-C, microUSB, and Lightning-compatible gadgets

To cost your telephone — or another rechargeable electronics you may have — Tau comes outfitted with a USB-C charger together with a Lightning and micro USB twin charger.


Tau is just not designed to be a charger to maintain heavy telephone customers up and lively all day, however it’s a unbelievable resolution for individuals who fear about their telephone dying earlier than their day is up.

It is an ideal backup for emergencies, and its budget-friendly value makes it a great gift for anybody.

  • Charging dock offers customers a handy place to cost Tau, cling keys
  • Small dimension is simple to take anyplace
  • Can cost USB-C, microUSB, and Lightning gadgets
  • Could also be too giant to suit comfortably on keys with present key fobs
  • Battery life is comparatively low in comparison with different powerbanks available on the market

Ranking: 4 out of 5

The place to purchase

If you would like to choose up a Tau of your personal, they’re out there in charcoal black, pure white, and agave inexperienced. You possibly can decide one up from Rolling Sq. for $29.



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