MakerFocus 4pcs 3.7V Lithium Rechargeable Battery JST1.25 Connector 2pin, 952540 3.7V 1000mAh Battery with Protection Board and Insulated Rubber Tape Compatible with ESP32 Development Board

Appropriately sized, used two so far and no issues. Would be nice if the wires were a bit longer, but nothing a little solder and heat shrink can’t fix! Happy with my purchase

I purchased these for my Meshtastic builds. I am using them to power a variety of ESP32-S3 powered devices for Meshtastic. Nearly all are solar charged and with a small 2"x3" 60mw solar panel. The build quality has been excellent and on par with what I see from major hobby RC manufacturers. I have since purchased 3 more sets of different capacities for other projects.

I just ran all four of these through three full charge-discharge cycles and capacity is as claimed, with two of them even testing >1100mah. This was with a 0.5A charge and discharge current, and 3.0V LV cutoff on an iCharger 4010. Keep in mind these are not rated for any high current application and do have a small connector. Longevity remains to be seen but I am happy with them so far.

Works well w/ Heltec Lora32 V3, but pack is 10.8mm thick (not 8.5mm thick as advertised) and will not fit in cases that require a thinner battery such as the muziWORKS H1.

These are great for the meshtastic V3. Keep the devices powered for a hours and seamlessly work after being plugged in. Very happy with this purchase.

Works well for LoRa boards. I put two in parallel with a charging board for 2000mAH in a tiny space.

I planned on using these for leak detectors based on the ESP8266 that I've built. I've programmed them to "phone home" to an FTP server at least once a day even if no leaks and when one doesn't update the file on the FTP server then I would know the battery needs recharging. I've carefully taken current measurements using my Agilent oscilloscope and a 1% resistor so I know the current profile of each of the different modes of operation such as deep sleep, checking sensors, and "phoning home" via WiFi. Under the intended use model I figured I would get at least 10 months between charges using the battery was considered drained at 750mAh. I then ran with a modified profile with less deep sleep that I figured would run for about 3.3 days so I could get an idea of the actual life as well as test the over-discharge protection. Starting with a fully charged battery it ran for 2.87 days which is a bit short of what I think it should have been able to do as that was only delivering about 650mAh by my original current draw measurements but it was only off by a little more than 10% from what I expected. Whatever. It's not that big of a deal. The bigger deal is that the battery is measuring significantly below 2.75V now and when I plugged it in to the charger there was no current draw indicating that it definitely wasn't charging and based upon the voltage of the drained cell I would expect it to be dead. Sorry -- one star since it failed to deliver on its promise of over-discharge protection. As I type this I see that the charger is actually showing about 350mA current draw, which is lower than it should be but maybe it will actually come back to life. If it does, I will update the review but at this point I don't think I can recommend purchasing what I thought was going to be a great find. Update -- Miraculously after about 15 minutes of drawing only negligible current (which could be explained by the charging circuit itself and the charging LED, the charger seemed to actually start delivering current. This is very odd as it normally starts delivering immediately. The charging circuit seems to deliver current for about how long I would expect and the end result is that device is alive and running at this time. I'm running the same test and it has currently been running for about a day and half. Based upon this, it seems that it did deliver on its promise of over-discharge protection. (I plan on recharging every six months anyway so the over-discharge was just an insurance policy so to speak.) I've updated to 4 stars based on this. The price for the batteries is good. I am deducting one star for the capacity. I wasn't naive enough to think I would be able to actually draw 1000mAh but I did expect that I would get at least 750 and probably about 800mAh. Alas I am only seeing about 650mAh in my limited testing which is actually enough for my application but still not what I was expecting. And now we drop it back to one star. All of the batteries provided reasonable life on the first charge/use and they all dropped significantly on their subsequent cycle typically only lasting a little more than 10% of the first cycle. A few of the batteries have completed their third cycle and it was about half of the second cycle. The discharge protection is preventing the batteries from being outright killed but they do seem to be getting damaged. (I bought 8 of these and 6 are in use with all that are in use seeing the same basic issue.)

I've had no problems with these batteries. Right now all four are in use on my various boards. But note that these 3.7 V LIPO batteries plug into Female JST 1.25 mm connectors. Two the the four batteries I purchased I had to cut off the 1.25 mm male JST connectors and replace with 2.0 mm JST connectors so I could use them to power my LilyPad Arduino USB + boards. LilyPad boards have the ability to charge these batteries, and once charged, these batteries can power the LilyPad boards for hours.