diymore 1865O Battery Holder Double Li-ion V8 Battery Shield Micro USB 5V/3A 3V/1A Power Bank Battery Charging Module for Raspberry Pi and Arduino...

When connected to a small 5v DC fan (less then 300ma) It would flash the leds 5 times and turn off. If it was connected to a power source via USB-C, it would power the fan just fan. Removing the usb power and the device would turn off, with no power being supplied to the fan. Verified the 5v USB output and 5v on board output are both at 5.14V without load. Tried multiple batteries, fresh from charger.

Look, these are pretty cool little units. However, like many people I assume, I looked at the stringent warnings about battery polarity and thought, "well I'll never accidentally put the battery in backwards like a n00b!" and went about my business. Then, sure enough, because the holder really only works well with flat top cells, it wasn't so visually obvious which was positive and negative, and I put the battery in backwards. Within seconds, the magic spirits came out and floated around the room, and then it didn't work (and I was holding a severe fire hazard). Diodes - even high current diodes - are small and cheap. Why on EARTH would they not put one in there? At least on the battery load/discharge side (obviously you need to be able to both charge and discharge, but why couldn't the component that goes up in a poof of smoke be protected?? That could hardly cost more than a few cents and would make this product a lot more valuable. Anyway, WARNING: DON'T REVERSE BATTERY POLARITY OR THERE WILL BE FIRE. Just as foretold in the prophecies.

This is a nice, compact and functional device that I am finding useful in a number of small robotics projects. I like that several 0.1 in spaced pads are available to solder connectors of my choosing for both the 3.3 V and 5.0 V outputs. The device supplies stable and accurate power. A couple of suggestions: As others note, a protection diode would be nice. Also, adding a pair of solder pads connected to the raw battery terminals would be useful. For my projects I like being able to sense the battery voltage in order to predict and display remaining charge. With the current product I have to solder wires to the tabs connected to the battery holder and hot-glue a connector to the board. It works, but it would be great if such a connection point were part of the PCB.

New info: I like these well enough to order more, but now both unit three and it's replacement unit 4 have been damaged upon arrival,.. I'm returning again for replacement hoping third time is the charm... This last one both sides of the 5v USB output socket where completely crushed/scraped to death. No way this got past QC On a brighter side Iv found quite a few uses for these regurdless of their shortcomings. Original review: As others have mentioned the 90ma requirement to stay in always on mode is not ideal.. but also note this can't be used as an uninterruptible 5v psu either as there is a full 4 to 5 second power output delivery gap from the point the charging circuit losses power to the point the 5v battery power cycles up on the 5v output. In addition it's not a very good charging other devices circuit either only able to charge dumb devices, any thing that requires a handshake won't charge off of it at a decent rate, (aka most modern cell phones) All that together limits what this circuit can do more than I expected when I purchased it, although still has potential... Oh, and I did blow one up,.. I'm not sure if I made a connection mistake while tinkering, or it fried on its own.. I double checked everything after it went out ... I'm about 75% i didn't make a mistake... If only it was uninterruptible.

If you're looking for a reliable and versatile battery holder for your electronics projects, the diymore 18650 Battery Holder Double Li-ion V8 Battery Shield Micro USB is an excellent choice. Upon receiving the product, I was impressed with its sturdy construction and easy-to-use design. The holder is compatible with two 18650 batteries and features a micro USB port for convenient charging. The V8 battery shield also ensures that the batteries are protected from overcharging and short-circuiting. One of the standout features of the diymore 18650 Battery Holder is its versatility. It can be used with a variety of electronics projects, including the Raspberry Pi, Arduino, and other microcontrollers. The holder's compact size also makes it ideal for portable projects that require reliable and long-lasting power. In addition to its versatility, the holder also boasts excellent battery life. When fully charged, the 18650 batteries can provide hours of uninterrupted power, making it an ideal choice for projects that require consistent and reliable power. One potential downside is that the holder may not be compatible with all battery types, so be sure to check the specifications before purchasing. Additionally, the holder may not be suitable for high-current applications, as the batteries may not be able to provide enough power. Overall, I would highly recommend the diymore 18650 Battery Holder Double Li-ion V8 Battery Shield Micro USB to anyone in need of a reliable and versatile battery holder for their electronics projects. Its sturdy construction, easy-to-use design, and excellent battery life make it a top-performing and reliable choice for a variety of applications.