If you have a voltmeter, you could try checking the battery voltage. These are not actual "BP-5L" standard batteries, so the quality is a bit questionable. Here's a quick guide for the most common lithium-ion chemistry (LiCoO2
), it's a bit over-simplified but should work:Single cell LiCoO2
> 4.3 V = Something is horribly wrong. It's a fire hazard, safely dispose of it.
4.0 - 4.2 V = Fully charged
3.8 - 4.0 V = Mostly charged
3.6 - 3.8 V = Medium charge
3.4 - 3.6 V = Low charge
3.0 - 3.3 V = Empty of useful energy
0 - 2.7V = Something is horribly wrong. It's a fire hazard, safely dispose of it.
Exactly 0V = It's likely the protection circuitry activated. Undervoltage Protection (UVPO) is designed to open-circuit the battery if the voltage drops too low. It usually kicks in at 3.3V - 2.7V, depending on how aggressive the manufacturer tuned it. It might come back to life if you put it back on the charger, but you still might want to do the initial charge outside in a metal box, or at least keep it supervised during charging.https://en.wikipedia.org/wiki/Lithium_cobalt_oxidehttps://batteryuniversity.com/index.php/learn/article/types_of_lithium_ion
Random cheap multimeter: https://www.aliexpress.com/item/32963956708.html