POW1 - Emergency USB Battery Powered Power Bank Compact Portable uses 4 AA Ideal for Smartphones, Tablets, Mobile, Apple, iPhone, Android/5055751557704

A few written instructions would have been helpful. It takes a long time to charge my phone, but it works fine. Didn't I review this product previously?

I have tried different brands of batteries. I have tried alkaline and lithium, nothing works. It comes on and looks like it’s charging then within 1 minute stops charging. When you press the power button all 4 green lights come on, when you hold it 4 blue lights come. But with no instructions who knows what any of that means. Piece of junk!!!!

I was specifically looking for a product like this which would allow use of 4 rechargeable batteries instead of a built in battery that cannot be removed. It works great for my intended purposes.I use this for running USB lights and not charging a phone or tablet. My tests included AA alkaline, heavy duty as well as rechargeable enerloops and amazon brands. This works well with USB lights using all of the above. That said run time is strictly dependent on the size of the 4 AA batteries the user supplies. The capacity will be much less than other battery banks in any event. I recommend using rechargeable batteries in this device. Nevertheless any charged AA will work to the extent of the battery capacity. Doing the math a 3500ma phone battery will likely need a lot of AA batteries to obtain a full charge since they will vary in size from 1350 ma to 2500 ma.

Worked just fine for my Android phone, although a very slow charge. But it served the purpose during a power outage.Didn't work at all for my Ipad.

If you use normal Alkaline batteries with this, you will be lucky to charge one phone to 25%. Alkaline batteries were never meant to be drained this quickly and they die trying.If you are using this for long term storage in your car for emergencies, use Energizer Lithium batteries. they have a 20 year shelf life and are rated for high temperatures. It's $8 in batteries, but it's for an emergency.If you want to use this every day, use Eneloop Nimh rechargeable batteries. But seriously, if you want to use this as a daily battery get your self an Anker rechargeable battery, not this.I ran a test on this today using 4x Energizer Lithium batteries (don't buy them on amazon there are a lot of fakes) and it charged one iPhone 6S Plus from dead-a-month-ago to 70% and another from dead to 45% (It's what I had for testing). It charges at 1Amp (I had a meter on it), so it took 2hrs to charge the one phone to 70%.

Saving for emergencies to come.

I purchased this product to work as a portable 5V USB voltage source for a small Bluetooth receiver. It is made by Mercury, model number USB-B108. When tuned on, it works for about 30 seconds before shutting off automatically. I found the device, however, works fine when used as a 5V USB power source for charging a smartphone. With some testing, done by applying various current loads using 1Watt resistors, I discovered that the USB-B108 must source a minimum load of at least 107 mAmps to keep the device from turning off automatically. It will not stay on if it does not sense a sufficient load. This feature is apparently intended to shut the device off when the load is disconnected. My Bluetooth receiver only draws 41 mA from the B108, which is not enough to keep the device from shutting off automatically. Mercury did not reply to my email regarding this issue. My solution is to modify the USB cable I use with the B108 and Bluetooth receiver to include a 47 Ohm 1 Watt shunt resistor. This cable will always maintain the minimum current draw required to keep the device on.

Just received the item and it doesn't not work. Put new batteries in and it charges for a second and turns off. After a hour of turning it on my battery has gone down on my phone. DO NOT BY THIS ITEM. WISH I COULD GET MY MONEY BACK.