General question about the VIN/DC barrel jack.

So I know about the specs and usage, even advice not to use it. NOT what Im asking but more of inputs on using my benchtop ADC regulated power supply. Im using this model in particular: Radio Shack 22-504 Regulated Power Supply 3 AMP 13.8 VDC, I have three SMD LED strip, appx 12 SMD LED per strip, power draw fine, added another line to power Arduino Uno, its just fine so far also. Arduino has LED x6 and LCD I2C x1 buzzer x1 attached.

Question: is any long term damage or running off the barrel jack? Short life span? Not enough or too much?

Reasoning for use/question: if I use 5V 2amp on barrel jack LCD won't work but lights up. But all (of course) works on USB 5V? But Im tired of leaving it plugged to computer and computer staying on, even with powered USB hub comp has to be on. I can use my SATA Shield with 5V in and one 5V out molex for devices, but don't want that either because I hate leaving it powered on it and HDD's spinning with no computer needs for it.

So...built barrel jack adaptor and plugged into benchtop regulated power supply then arduino..

Sorry second post ever, and second post EVER on internet, so if I ask for help wrong...sorry. Figured I come out observer mode to start contributing if I can.

The Arduino power jack needs 7 to 9VDC.

Any more voltage may damage the onboard Arduino voltage regulator if you draw too much current from it.

And indeed, the advice is - just forget the "Barrel Jack" or "Vin" on the older Arduino boards. The newer ones have proper switchmode regulators.

Use a "Phone charger" with a USB output. Plug in to the USB port - you have 500 mA (or maybe slightly less) available to run your devices. If you need more, a proper 5 V regulated supply to power them and feed the 5 V into the "5V" pin.

There is a diode between the barrel jam and the Vin pin, so you will get 0.7V less at the Vin than you put into the jack.
That diode will also restrict the current you can get out of Vin pin to less than 800mA or so.

What sort of led strip do you have? What voltage does it need and what current does it take. How are you controlling it from the Arduino’s output pins.