Power up a diving light from an external power supply

[DimitrisV]

Hi All

Is it possible to drive a light from external power supply instead of a battery ?
A friend of mine wants to put a diving light in his store and let it power on for 8-10 hours

The diving light have one 18650 battery and the power consumption is 2 - 2.2A
I tried an external power supply 5V 2A but the the performance was very low
I tried PC power supply 5V 15A but also in very low performance

Last I tried a adjustable power supply 0-30V 3A and it worked in high performance but
after 10sec the led and one resistor ftom the power supply ftied

Any idea why this happend, is it possible to power the light ftom an external power supply

Thanks in Advence
Dimitris

 

[jspeybro]

Hi,

typically, there should not be a problem running a battery powered light from an external power supply.
You don't mention if this is a LED light or something else.
In case of a LED light, it probably uses a driver to set the current through the LED. If the light has modes, you may have swithced it on in a lower mode.
If the light works from a single 18650 cell, you should probably use a power supply that is around 4V. 5V may work if the driver can handle this, but I don't expect much problems here.
A 15A power supply means that this is the maximum it can provide, but if the light doesn't need 15A, it will just take what it needs.
If the light is a HID lamp, you may however need a higher rating than the 2-2.2A that you mention as it needs more current to start the lamp.

Please note that dive lights that use LEDs typpically need the cooling from the water. Using it outside the water may reduce the lifetime of the LED drastically if it is driving the LED hard.

not sure how you managed to blow up your power supply. Are you sure you connected it right and didn't short-circuit something?

Johan

 

[DIWdiver]

+1.

Without knowing more about the light, I would want to make sure any power supply attached to it had a voltage of 3.5-4.2V. Some lights will handle more or less, but that range is very safe for a single LiIon light. Less might not work, more could damage the light.

I don't know about halogen or HID, but any LED light with 800 lm or more is probably not designed to be run out of the water. The larger the metal surface of the light, the more power (roughly proportional to lumens) it will be able to handle out of the water. So a big heavy aluminum light might handle 1200, 1500 lm or more in air, a small pocket light might only handle 500 or less.

This is a temperature problem. LEDs generate heat, but they don't like to be hot. This conundrum is the main reason that LEDs aren't in almost all of our new illumination installations today. Some will say it's about price, but I counter that the price difference is driven by the temperature issue.

Okay, that's enough pontificating for now. The more you can tell us about your friend's light, the more specific advice we'll be able to offer.