As our dependence on the smartphone has grown, there's been plenty said about the battery life of said devices. Thankfully, external charging solutions provide a way to keep powered up and now there are two that are laying claim to being the quickest of them all. Both the Unu Ultrapack Go and Petalite Flux are pocket-sized portable batteries promising power enough for a day's smartphone use from a 15 minute charge.

First cab off the rank is the Ultrapack Go, which measures 3.95 x 2.05 x 0.68 in (10 x 5.2 x 1.7 cm) and weighs 4.5 oz (127 g). Packing a 3,000 mAh battery, it can be charged to full in 30 minutes, though its developers claim this is more than the typical user will need, with 15 minutes of charging providing 2,000 mAh of power that should be enough juice for a day's use. It comes with a cord to connect to a smartphone or tablet via Micro USB, but is also compatible with other cords, such as an iPhone charge cable. It also features a small screen displaying power and time left to recharge.

The tubular Petalite Flux, on the other hand, weighs in at 3.35 oz (95 g) and measures 3.54 x 1.18 x 1.18 in (90 x 30 x 30 mm). While this smaller size will mean easier transport, it does concede a little ground in battery capacity to the Ultrapack Go. With a capacity of 2,600 mAh, the Petalite reaches a 100 percent charge in 15 minutes and also powers your smartphone or tablet through Micro USB or Apple's Lightning connector.

Instead of a screen, the Petalite also features four LED lights to indicate the level of charge. All four illuminated indicates a whole day's charge for 90 percent of phones on the market, while three lights, or a 75 percent charge, is claimed to be sufficient for a day with an iPhone 5s.

While the Ultrapak uses a standard wall adapter, the Petalite comes with a specialized charging dock. Its developers say this was necessary, as "pushing this amount of amperage through a standard USB port would damage it within seconds."

These lightning-quick external chargers won't be suitable for all, but they could prove handy for those whose busy lifestyles leave them with perpetually drained batteries and little time to charge.

The Ultrapack is priced at US$60 and available for pre-order now via the product page below, with the company hoping to begin shipping on August 25. If the compact Petalite is more to your liking, then you will have to wait a little longer as the company is launching an Indiegogo campaign at the end of the month and is yet to detail pricing.

Sources: Unu, Petalite