POW1 Portable External Emergency Battery, USB, Portable, 4 AA Batteries, for Smartphones, Tablets, Cellphones, iPhones, iPhones, Android

It is compact; small enough to travel light but big on its actions. Very good.

It's clearly not intended for charging modern smartphones with under 1 amp output but for older devices and powering USB light strips it does the job brilliantly, best thing about it though is you can easily find AA batteries just about anywhere so you don't have to worry about recharging the batteries in the powerbank just slot some fresh/fully charged ones in, very handy for travel if you aren't sure of availability of power.

It works w'ell for charging a small phone, and small camera, on 4 aa batteries, bobolov, whilst hiking in last years, I's also durable, and pretty good weather resistant, I had one and it lasted many many years, and it got wet etc,

Bought this because I'm always lousy at keeping other power banks charged, and it's probably cheaper to replace a set of AA NiMH cells than a power bank every year or so.I have a major gripe with Lithium Ion cells - I just don't like them. They are not readily available (so you can't just go out and buy a set if you have forgotten to charge your power bank); they discharge at quite a high rate, so you can't just throw a power bank in you bag, forget about it, and expect to be able to use it when that once a year occasion happens that you need it; and I just do not like the chemistry - unless you buy top dollar, you can't guarantee that you'll receive a safe cell - when Lithium Ion cells fail, they fail will a big pop!So having something like this has numerous advantages - you can buy AA's anywhere (make sure you get Alkaline cells, Lithium Iron Disulfide, or NiMH rechargeables - anything else is a waste and you'll never get a charge). And AA's will keep for around a decade now. Even decent rechargeable NiMH AA's will keep 90% of their charge after a year.I'm using this with a set of Varta AA NiMH 2100mAh rechargables. I tested it having run my phone to empty (iPhone SE), and this charged it to 100% without issue.I am not sure if the device has a parasitic current drain, due to the IC's or whatnot, as I don't keep the batteries in the device. I figured that it would take too long to test, and I'd rather not risk being in need with the batteries dead. So I used a cheap battery case to hold the AA cells separately.Another thing, I wasn't sure if this would actually be able to use NiMH cells - due to the lower nominal voltage (1.2 x 4 = 4.8V, lower than the 5V output), but I'm surprised to state that this doesn't pose a problem. Likewise, using 4 x 1.5 AA's results in the correct 5V output too. In other words, the built in regulator must be fairly sophisticated at being able to step up and down the source voltage to get the 5V.The device has four LED's to show the charge level of the battery. By default, these LED's are green - set for normal AA Alkaline cells. If you hold the power button in, these LED's will change to blue, and will give a readout reflecting the charge level of a rechargeable battery.For the price, I really can't complain. Brilliant for the money. Lost a star as the packaging and lack of manual (had to google to find out what the blue LED setting meant). Also, it doesn't state whether there is a parasitic current drain - I would much rather leave the cells in it, but don't want to risk them being flat when I need them.Get one, throw this and a pack of AA's into your rucksack, and forget about it. It will be there for when you have been caught out!

AA power banks / phone chargers tend to get middling to poor reviews, with most complaints about slow charge times or poor capacity. This is mainly because AA batteries are no match for the Li-ion or LiPo batteries in smartphones and tablets. So why on earth would anyone want an AA power bank?Well, by far the biggest advantage is that you can buy AA anywhere, from a village post office to a late-night city convenience shop. While a normal power bank will require somehow being recharged once flat, you can just swap out the batteries on an AA bank. That makes them very good for emergencies or as part of a flee bag or car travel kit.Operation with this one is very simple. You insert batteries and press the on switch. Holding the switch will toggle the indicator lights between alkaline (blue) and rechargeable (green) modes. This doesn’t do anything except more accurately tell you how much battery capacity you’ve got left. Batteries are easy to insert and remove, with small clips holding the cover on.The device advertises 800 mA output: that’s a moderately fast charge. I can confirm you’ll get that with fresh alkaline batteries, although at 4.8V: some phones might drop the rate to keep the voltage at dead on 5V. Alkalines being what they are, output rate will get lower as they run down, so the charging will get slower and slower.With rechargeables or less fresh alkalines, the regulator circuit struggles to keep the voltage up at 5V, sinking fast as the load increases. With eneloops I get around 400 mA at 4.8V, quite a slow charge, but consistent until the batteries are flat. I do not recommend lithium AA – it’ll perform well (well over the rated output!) but get quite hot and probably die quickly.From one set of ordinary NiMH or alkaline batteries you may not be able to fully charge a modern smartphone from flat (thought it depends on the phone and the batteries), and certainly not a tablet. Some higher end devices may refuse to charge at all unless the voltage is above 5V, but this is very rare. I can confirm my iPhone 4S has no problem with it, and while not as good as a traditional power bank, it is more than sufficient.There’s no drain on the batteries when the device is off, although in a pocket or bag it may turn it off and on accidentally as the power switch isn’t deeply recessed. There is no torch on this model.While build quality and regulation could be better, I got what I wanted from it. Just be sure before you buy that an AA power bank is what you need or want, or I’d recommend an ordinary rechargeable power bank instead.

Used on my 7 day wild camping TMB in Alps gave me another power option

Just what I needed.Used for a spare iphone that is only there for emergencies and it runs out of power very quickly. Now I can have it recharged if necessary from ordinary batteries that last for years without charging.

I gave this a trial run at home. It charged my iPhone11 20% in about an hour. So although not the fastest charging, it does work. Handy for power cuts.