FOLOMOV A1 Portable Magnetic USB Li-ion Battery Charger with Charging/Discharging Power Bank Funtion Max Current 1000mA

When I received the first one I bought, I plugged it into my computer (regulated 500mA) and got a pop-up on my computer saying a power surge was detected, my computer cut the power to it automatically. I could never get the charge feature to work, but the discharge feature did. The second one I ordered works flawlessly, but I'm scared to plug it into any higher current USB power supplies for fear of it shorting out or something.The discharge capability is what sets this thing apart from the other magnetic 18650 chargers, depending on what end of the USB dongle you plug into, you either take power or store power. So yes, you can turn any 18650 (or any of the other 3.7V such batteries) into a 5V USB power supply.A blue light indicates that you are charging the battery it is hooked up to, a green light indicates you are discharging (pulling power from) the battery.It seems to have an auto power adjustment feature in order to prevent overcharging a battery, I monitored the amperage flow using a USB passthrough multimeter and it started charging at 470mA, then over time ramped down in about 100mA increments until it was eventually only pulling 90mA. I haven't tested the full overcharge protection but I'm fairly certain it will eventually cut off completely when the battery is full.This thing is so light and compact it goes everywhere with my backpack to recharge my flashlights and give me a backup power source.

Overall this device is an ingenious solution for charging up your 3.7 V lithium ion cells of various dimensions, such as the ubiquitous 18650. As a bonus, you can also use it to discharge the battery to power a 5 V USB device, such as your cell phone. My main criticism is the indicator light. It blinks green to indicate charging even if no battery is connected. This makes it difficult to know if the terminals are making good contact with the battery or not, or to guess at whether the battery is done charging.

Works great. It allows a 18650 or similar battery to be used with minimal extra space. I plan to use it to power my Teensys (Arduino compatible).It would be nice if there were a similar solution for 2 batteries and putting out 2 amps instead of 1.

Great construction, great design. Stellar product. I feel like I'm still going to have this, working, on my deathbed.

Outstanding chargers, the only ones that have not broke on me.

This thing is amazing! It both charges batteries and lets the batteries charge and power small devices. A must have tool for tech junkies.

I think it is a great device, I like it a lot. I would recommend this item and this seller.

This things great.