Automotive power supply

I’m hoping I can get some opinions on a power supply for my next project. I am installing 4 rings of 41 neopixels as well as four strips of 15 RGBs into my car. Automotive voltage varies quite a bit, I’ve taken readings between 10.5v-14.5v at the battery so I need something to regulate it to a stable 12v. To do this I was thinking of just going to use a dc to dc step down transformer but I was thinking that since the voltage difference is so small, that there might be a better way of doing this.

Then I was going to add a relay and a 3s 25 amp lipo board after that so the lights, sensors, and Arduino don’t run on the car battery when the car is off and possibly drain it and leave me stranded. I was going to use two separate step down power supplies, one for the lights and one for the electronics to get my 5v. then make a small circuit board with capacitors for the neopixels and a resistor for the data lines.

What do you guys think? is there an easier way to go about this?

How are you planning to step DOWN from 11 volts to 12 volts?

Caution: Some automotive electrical systems have brief excursions to almost 50 volts that will not show up in a casual measurement but can destroy electronics.

What car (manufacturer, model, year, engine, other details), and how did you make the measurement?

I don't know that I can be of much help but perhaps others will help.

vaj4088:
How are you planning to step DOWN from 11 volts to 12 volts?

Caution: Some automotive electrical systems have brief excursions to almost 50 volts that will not show up in a casual measurement but can destroy electronics.

What car (manufacturer, model, year, engine, other details), and how did you make the measurement?

I don't know that I can be of much help but perhaps others will help.

I was trying to keep my post brief because I tend to write long posts. The car is a 2002 BMW 325i. I just used a standard multimeter and took a reading when the engine was off, during start-up, and when on. I do know about the spikes and if the alternator goes bad, it could stay at a high voltage too. I don't need it to step down less than 12v since I will have a lipo battery pack to keep it going when the car is off.

Converting voltage when there is less than about a volt and a half difference between the input voltage and the output voltage can be challenging, although there are designs such as buck-boost converters that can achieve this.

For you, consider some options.
You can convert the voltage up, then down to 12 volts.
You can convert the voltage down, then up to 12 volts.
You can convert the voltage down to 3.3 volts.
You can convert the voltage down to 5 volts. You probably have a local store that sells a device that plugs into a cigarette lighter for automotive power (and has the protections you should have) and provides a USB connection for 5 volts.

Of course, you may have to also re-think the rechargeable battery.