3.7V 40mAh 301020 Lipo Battery Rechargeable Lithium Polymer ion Battery Pack with PH2.0mm JST Connector

Works great. We’ve used it several times. Small and compact. Exactly as described.

I used the battery to replace a defective one in a rechargeable headlamp. The headlamp didn't have a connector, but it was easy to remove the old battery and solder in the new one. The new battery was a little bit thicker than the original, but it still fit in, although a bit tight. The battery had a partial charge when delivered, and charged fully within a hour.

The battery works well and provides the expected 3.7 Volts output, but you definitely need a BMS (battery management system) to safely charge and recharge it. Once set up properly, it’s a solid LiPo pack for electronics projects and good value for the money.

I bought this battery for my son's walkie talkie. However, the connection did not fit. My husband had to cut the connection from the old battery and remove the connection from the new battery and place the old battery's connection onto it. It worked perfectly afterwards. It was the right size and it functions well. It keeps good charge.

This was a random purchase but it ended up working! My mom had an old electronic magnifier that used this model battery and she was sad when it stopped holding a charge. I opened it up, ordered this battery, and one spicy pillow swapped out later, it must have been a perfect match for voltage, capacity, and type because her device works again and holds a nice long charge.

This battery does not hold a charge very well. I am regretting this purchase.

I'm an experienced Electronic Technician. I was rebuilding a Bluetooth Smart speaker. I knew the battery was bad. I found this replacement and installed it without checking the polarity but who checks this on a simple remove and replacement. You assume the product was quality checked prior to shipping. I installed the battery and turned it on. The unit didn't work so I knew it was a defective battery. I saw it unit powered up but just didn't function properly. I removed the battery and compared it with the old battery. See attached picture. The leads were reversed. I simply reversed the leads and the speaker powered up just fine. I'm guessing a person performing a battery replacement at this level must have a little experience with an understanding of polarity. For me this is not a big issue. Overall the price is right and I love the Prime shipping speed.

Worked great I just had to put my DeWalt Lazer measure end on the battery.

Me sirvió a ir perfección para reparar mis audífonos

Works perfect as the replacement battery. Packaged very well.

I ended up having to replace the battery inside of my Dash cam. Since it's a fairly expensive dash cam I decided to go this route as my old battery swelled. And it would no longer hold time or settings in the dash cam itself. I couldn't find the original 240mah battery. Took a chance as this is about 2 mm larger in every dimension then the original. But it fits perfectly in the case and the dash cam stays on for longer when the vehicle is turned off. which is great. Would recommend the battery seems to work good.

Remplace une batterie pour un laser

My small Bluetooth cube speaker battery had long given up the ghost so a full charge only lasted about 15 minutes. The old battery was rated at 450mAH and this one is supposed to be 500mAH in the same package size but I have no idea if that's real or just inflated specs. In any case the speaker is back to holding a charge for several hours and I'm happy. I thought I was going to have to transfer over the old BMS (battery management system) PCB but this new one came with one already attached.