LED Hand lamps

[toad a caravan]

For what reason do LED lamps that have a yellow led strip turn off without prior warning whilst led lamps with rows of stand alone Led lamps loose their brightness gradually? Just curious

 

[ProfJohnL]

For what reason do LED lamps that have a yellow led strip turn off without prior warning whilst led lamps with rows of stand alone Led lamps loose their brightness gradually? Just curious

If you have a strip of Leds, the forward voltage voltage combines and may exceed the battery voltage, so to make them work the lamp probably includes a boost regulator, which will provide a very even voltage or current output voltage, but as the voltage of the battery drops, as soon as the regulator can't boost it enough it stops completely.

Even though the lamps may have the same number of LEDS, just wired differently, the boost circuit needs some power so the battery will deplete more quickly. where as if the leds are fed off the battery directly there is nothing to control the discharge and the battery may fall below optimum voltage but it will still continue to deliver some current hence the dimming of the leds and lasting longer.