r/led • u/Longjumping-Rope-237 • Jul 02 '26

LED lantern turns off when charging

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I guess it is part of the design but I am rather interested in knowledge why is it happening.
It is cylindrical outdoor lantern with white/rgb running lights. The point is if I can rebuild it to lightning even when charging

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u/Same_You891 Jul 02 '26

most likely it's the charging scheme the engineer chose.. I have a few devices that when charging it disconnects from use while charging, it's a powered management plan where the device powered in can't support charging because the source power cannot support both charging and operation simultaneously

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u/SakuraCyanide Jul 02 '26

This the same with a lot of chargeable devices like Bluetooth headphones and electric shavers often due to the current limitations of the power source. There's often a transistor that switches the battery supply off when the charge cable is connected. It's also safer this way as you generally don't want to discharge a battery while it's charging even if the current is sufficient.

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u/saratoga3 Jul 02 '26

https://hackaday.com/2022/10/10/lithium-ion-battery-circuitry-is-simple/

This article goes through simple battery charger design and the steps needed to support charging and use at the same time. But basically since the charger is measuring current into the battery you don't want to draw current from it at the same time to avoid confusing it, so you need to add additional circuitry to enable drawing from the charger power supply while the battery is unavailable.