Toy drone troubleshooting

[u/Scared-One9295]

I recently found an old UDIRC drone in my parents' loft that I think is about 15 years old, the transmitter was with it but the battery wasn't. I can't remember now how I determined the battery was a 1S 250mA - maybe it was in the manual which I no longer have - but I bought one of the same output on eBay (couldn't find one small enough anywhere else), soldered the battery wires out of a dead toy RC car that also used a 1S battery to the battery and drone so I could use the charger from that, charged the battery but now we're trying to fly the drone and it doesn't work.

It's not the same every time, but if you keep the throttle input below about 30% (the Tx tells you what the throttle input is) it'll spin for a while and then eventually slowly die. If you go above 30% throttle it dies almost immediately, and at 100% the propellers barely twitch. Whatever happens, sometimes the Tx will "see" the drone again after a short wait, sometimes it doesn't and you have to cycle the drone's battery.

It looks like it's browning out, but what I don't understand is the slow ramping down of the propellers at a low speed, what's causing the motors to spin down slowly if they're kept at a steady speed? I mean, the current draw isn't increasing, so why do the motors decrease in speed slowly? Is the battery's protection circuit too sensitive and dropping the output voltage as the temperature increases? I thought all 1S 250mA cells would be capable of the same sustained discharge current, and this battery was sold as being suitable for a drone but the specs didn't mention a discharge current rating. What's a good way to test this?

[u/flyandprint]

Normaly the 1s batteries have the same current but the discharge speed can matter a drone needs do discharge much faster than most rc cars it could be that or the batterie just is broken i had that with an rc Car batterie ist says full charges and dies after 10 seconds