YDL 3.7V 5000mAh 905090 Rechargeable Lithium Polymer Battery

Better than advertised !

When I received 3 of these units, I fully charged them, and then put 2 of them in my discharge instrument to measure the capacity (a 24 hour test for each device). To my surprise, they both exceeded the 5Ahr advertised capacity (getting 5.2Ahr = 110% of capacity) This was a surprise because I've bought 3 different brands of the 18650 cells, and all of them yielded between 10-20% of the advertised capacity. Also, they cam in at $1.86 per Ahr, which is a very good value. I highly recommend these. (I've designed an ESP32 based LoRa measurement system for the field, and battery capacity is of utmost importance)

Not the correct battery

I bought a battery, it was not correct. They were nice about helping me get another battery that would be correct. I of course had to pay again and they didn't want the first incorrect one back. After sending several photos they assured me the battery they had was correct. I ordered 3. Now I have 4 batteries that won't work. Their answer was for me to cut the connectors and splice the wires from the old battery and the new one