How to power a circuit of LEDs with maximum 5v
NEVER EVER connect a LED directly to a supply unless it is specifically designed for that. Almost all common LEDs are not.

ALWAYS use a series resistor.

If you make 20 mA flow at 13 V then at 5 V the LED will still work but at a lower brightness. For that 20 mA you need a 500 ohm resistor. 500 ohm resistors are hard to find so get some 560 ohm resistors (that's close enough) and use one resistor in series with one LED. Simple but works flawlessly.