Reply To: Changing LED power source from battery to USB powerbank

[blinky465 17029xp 0]

(I’m guessing you don’t have a multimeter or an ammeter you could see what the current draw between BT+ and BT- is?).

Just remembered that these are battery powered – you could *guestimate* the current draw simply by how long they last on batteries? For example, good quality AA batteries have between 1200mAh and 2000mAh capacity (e.g. 1.2A – 2A hour capacity). So if they last, for example, two hours and you know you’re using 2000mAh batteries, you could guess at *very roughly* around 1A current draw (it’d probably be much less than this, since the batteries don’t entirely deplete).

If you’re using cheaper 1200mAh batteries and they last, say, four hours, you’re probably looking at around 300mA current draw (this feels like it’s closer to the actual current draw; a 1A draw off 5V = 5W which is the ~same as a 50W incandecent bulb!).

Personally, I’d allow at least 1A per light so six of them would need a 6A supply just to be sure (this is giving you lots of headroom and room for errror since we’re guessing at a lot of stuff!). A ten-amp supply would probably be good enough and you could still add more lights if you wanted to. But given the cost of a 20A supply compared to a 10A one, I’d probably choose 20 over 10.