But itís $300, weighs 1.4 pounds, and has a fan

Battery packs are a dime a dozen these days, and a must for any gadget lover. But while the average Anker on Amazon will let you charge USB-powered gadgets like a smartphone or tablet, they aren't helpful for other types of devices.

Thatís where Omnichargeís battery packs come in. Not only can they charge your phone or tablet a number of times over, they can power anything with a standard three-prong power cord. The larger of the two packs can even wirelessly charge a smartphone placed on top of it.

The Omnicharge comes in two flavors: the Omni 13, which has a 13,400mAh battery and outputs up to 65W, and the Omni 20, which is equipped with a 20,400mAh battery and can push 100W. Both models have one AC outlet, two 5V USB ports, and a barrel port that supports a bunch of laptop plug adapters. The 20 adds the Qi wireless charging option and supports Qualcommís QuickCharge 3.0 on one of its USB ports. It also has an OLED display panel that shows information such as charge remaining and what ports are currently being used.

Neither of these battery packs are cheap: the 13 costs $199 and the 20 commands a jaw-dropping $299. (Omnicharge is still selling both through its Indiegogo campaign for a little less, but they are still undeniably expensive.) You can get USB battery packs with just as much capacity for a fraction of that cost on Amazon, though they wonít have the AC outlet.

Iíve been testing the Omni 20, using it to charge mobile devices as well as laptops and other gadgets, and have found a number of other disappointments with it.

To start, the 20 is a relatively compact square, but itís not light, weighing my bag down by 1.4 pounds. Thatís almost as much as my entire laptop weighs. The 10,000mAh USB battery pack I typically carry around is a fraction of the Omniís size and weight. This is definitely not something I want to lug around every day.

The Omni comes with a bunch of laptop adapters, including one for Microsoft Surfaces and MagSafe 2 for Apple MacBooks. I used the Omni 20 to power my Surface Pro 4 for about three hours before it died, which is sooner than I had expected. Using the AC port to power an HP Spectre x360 15 and its 90-watt power adapter depleted the Omni 20 in just 35 minutes. In that time, the HPís battery went from 18 percent to 55 percent. The Omni 20 may charge your phone a number of times over, but it clearly doesnít last long when its used for more demanding devices.

Further, when the Omni 20 was charging my laptops, its internal fan was racing at full speed, emitting a noise that actually drowned out the HPís already loud fans. Yes, this is a battery pack that has a fan thatís louder than a full-size laptopís fan under load.

Finally, while the Omni 20 does support wireless charging, Iím not sure why youíd ever want to use it for that. The wireless charging spot is rather small, and I had trouble getting a Samsung Galaxy S7 Edge to reliably charge on it. And since this isnít Samsungís fast wireless charging, itís slow, so it just makes more sense to use the QuickCharge 3.0 port the Omni 20 also has to charge a phone.

There are a lot of geeky things to appreciate on the Omni 20, from its OLED display to the variety of devices that it can provide juice to. But Iím struggling with the practicality of it all: itís not large enough to power laptops for any decent stretch of time, and itís far more expensive than comparably sized USB chargers. I have the feeling that if you invested in the Omnicharge hoping it will provide real electricity to you on your next camping trip, youíll be left disappointed before the sun has even gone down.