diymore 18650 Battery Holder Double Li-ion V8 Battery Shield Micro USB 5V/3A 3V/1A Power Bank Battery Charging Module(2 Holders)

Works excellent, only 2 things I did not like.It needs pass through charging, and remove the on off switch.if it had pass through charging it would be almost perfect.

This board has some little hang ups. First, you push the button once to turn it on. Twice to turn it off. The switch toggles the auto shut off setting. So if there isn't a load, it will shut off. If you don't want this, turn the switch off.Another BIG problem is these aren't counter oriented. So the positives line up and the negatives line up. Most standard devices are opposite. Look very carefully at the symbols on the board when installing the batteries or you will destroy the board.Last, I used plain old normal, standard 18650 batteries with one flat side and one nubbed side. They fit fine. They both discharged and charged properly. They are a bit of a pain to get in and out, as they fit really snug. But I didn't feel like I was damaging the board or anything taking them out. Its built pretty solid.

I placed in an 18650 battery and it shorted and caught fire.

Here's the good:The DC/DC converters are very efficient, both the 5V and 3.3V - like 94-95% across the whole range of input voltages that a battery is likely to generate. This is WAY better than a lot of DC/DC boost converters you can buy out there.Here's the 'meh':There are a set of LEDs on the bottom. For low current, battery powered devices, this is wasteful and consumes power for no benefit. They are easy enough to remove once you have the device operating properly.The device does not automatically turn when a battery is inserted. You must press the "enable" button once to turn it on.Here's the bad:There is an auto-sense that detects when there is no power being consumed and shuts the unit off. The definition of "no power being consumed" means less than 90mA, which is really quite a lot if you are using this device for a low-power microcontroller design. After about 30 to 35 seconds of "no-load" (<90mA) the unit will shut itself off.They provided a switch to "disable" the auto-sense, but this works by placing a fixed 90mA load on the unit to insure that there is always load above the shutoff threshold. For a long-lived battery device this is unacceptable as 90mA is more than my target design consumes and would drain the battery very quickly. This is a very poor, inefficient solution to the problem and not very good engineering.There is a solution to this, but it is a little hacky and requires cooperation with your target device. I added an external circuit (a single 2N7000 and a control line) to emulate a button press on the "enable" button every 20 seconds or so. When my system is running, I have to make sure that this circuit gets activated (pull the enable pin on the switch low for about a tenth of a second) every 20 seconds. This appears to reset the "no-load" timer and you get another 30-35 seconds. Do this every 20 seconds or so and the unit will run indefinitely at very light loads (my specific design consumes about 2mA nominally).You can't do it too fast as two quick presses of the enable button are what signals the device to shut off.I gave the unit 4 stars because the DC/DC converters are so darned efficient. If I had not been able to do the button-press emulation trick to keep the unit running under light load it would have gotten one star.I hope this helps anyone trying to use this DIYMORE battery shield for very low power designs. It you have the knowledge and provisions to tickle it appropriately it can work well, and be very efficient. If not, then the fixed load, or auto-shutoff might make it tricky to use effectively and efficiently.

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.