Thanks in advance for anyone who can help me with my specific question!
I have many 18v Li-on battery packs (1.5Ah-4Ah) due to the other tools that use this voltage, and I am making a lamp using a specific 12v 36W filament. The spec sheet for the filament states colour temp up to 14.5v input so I know it can take this voltage no problem.
Using P=VA, I know the filament will draw 2.91A and so the resistance of the filament is 4.12 ohms. Hopefully I am correct so far!
I want to reduce the voltage from the battery to 14.5 volts, and have adjustment due to the slight variation of voltage from the battery as it depletes (20v-16v), to enable the colour temp of the filament to stay constant.
What is the best way to do this? Can I use a simple adjustable voltage divider such as a potentiometer, and if so, what rating do I need, 10k, 50k? It's this part that I cannot work out, confused!! Many thanks.