These little red boards are everywhere, and they are not all the same. I bought modules from six AliExpress sellers and put each on the bench to check whether charge current, termination voltage, and protection actually match the silkscreen.
| seller | claimed | measured | verdict |
|---|---|---|---|
| Seller A — “1A protected” | 1.00 A | 0.98 A | ok |
| Seller B — “1A fast” | 1.00 A | 1.34 A | runs hot |
| Seller C — bulk ×10 | 4.20 V cut | 4.27 V | overcharges |
| Seller D — “genuine” | 1.00 A | 0.71 A | undersized |