We have a house with an outdoor staircase lit by warm white LED strip lights. However, the lights are "too bright" and we want to lower the intensity of the LED lights. On another loop of the garden lights, the same LED strip lights are lower in intensity because there are more LED lights on the same loop. So, I was wondering what resistor (or other device) would be the smartest to use? A dimmer normally works with 110 V but that is not possible here to use. It has to be something on the low voltage loop so therefore I was thinking adding a resistor or similar to that specific loop. The loop it is currently on is a 5 V loop with 8 LED lights pulling 6 W each (=48 W). Anyone with experience/suggestions?
The best and most economical way is to reduce the voltage of the supply with the small orange screw near the terminals. Outdoor hermetically sealed supply don't have this adjustable screw (potentiometer). In this case replacing the supply may be necessary. It can be cheaper or not more expensive than buying a PWM dimmer. PWM dimmer consume more electricity but are better fit for accessible, user friendly, regularly adjustment. For a one time adjustment, setting a lower voltage is better and more climate friendly (LOL). The change in voltage has to be of the order of 10%. If you replace the supply by a supply with 30% less voltage, it will be too much. You can reduce voltage safely. But you can't increase it.
Using a resistor won't be the smartest thing to do here. It will dissipate a lot of heat depending upon the dimming requirements.
I suggest using a PWM to dim the LEDs. Something like this:
You can make one yourself if you are patient enough. Alternatively buy it online. Make sure your PWM dimmer works at 5 V.
If you are making one yourself, there are two ways to do it - Using a microcontroller like arduino or plain hardware based using 555 timer.
TIP: If you happen to be laying long cables to run multiple LEDs (or a long LED strip) from a single power supply source, consider using 24 V LEDs. It will give you lesser voltage drop in the cable and your lighting will look more uniform.
if you can adjust the voltage of the supply to the LEDs that will probably be the simplest fix.
If not, adding a resistor is a good idea, picking the right resistor could be tricky. but if your 48W and 5V figures are accurate about 4.7 ohms 2W sounds like a good start.