I would be careful using a battery charger. Measure the actual voltage with a multimeter. With 12 volts DC you would want 1,000 ohm resistors. The voltage no doubt will be higher with a battery charger.
My inexpensive batter charger measures 12.8 volts DC AND 27.5 volts AC. I did not have a current draw, load, on the charger. Battery chargers are usually unfiltered DC.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
I have an unused 1 amp 6/12 volt trickle charger for car batteries and will that work in powering LED lights for use in my buildings on my layout. My thinking would be to run a power bus line under the layout, then connect the lights and resistors to the power line and the power bus line is hooked up to the charger. From what I have seen is people using chargers for cordless drills or similar type chargers but could not find using a car charger