I have a 12 volt source that I need to boost to 19.5 DC to run a laptop and back down again to charge a battery to run a 12V inverter to run a monitor and other things. How would you guys suggest that I proceed?

 

I have a 12 volt source that I need to boost to 19.5 DC to run a laptop and back down again to charge a battery to run a 12V inverter to run a monitor and other things. How would you guys suggest that I proceed?

Buy what you need.

 

I have a 12 volt source that I need to boost to 19.5 DC to run a laptop and back down again to charge a battery to run a 12V inverter to run a monitor and other things. How would you guys suggest that I proceed?

Use a dc-dc boost regulator to get the 19.5Vdc from the 12V source.
Run the 12V source directly to charge the battery (what type), and run the monitor and other things.

It would be inefficient to increase the voltage and then reduce it again.

 

Use a dc-dc boost regulator to get the 19.5Vdc from the 12V source.
Run the 12V source directly to charge the battery (what type), and run the monitor and other things.

It would be inefficient to increase the voltage and then reduce it again.

The battery type is Lithium ion.

The 12V source is a constant voltage source though, and other things run on it. I don't want to battery back up that voltage source. I would rather pipe that voltage source into a setup that can charge a battery, run an inverter, and power my other things without having to battery backup the incoming 12V rail.

 

I don't want to battery back up that voltage source.

I'm confused.
You didn't say anything about backing up the setup, so why do you think you need to backup the voltage source?

 

Ok my bad. Ok, so I have a 12 volt connection that I dont want to permanently attach a battery to. Such as, in the even of a power failure of that circuit, I dont want my system to take on the load.

I would much rather take the power from the 12 volt source to run my own system, which has its own battery. So that in the event of power failure of the 12 volt line, my system retains power on its own rather than doing so while also providing power to the 12V circuit.

 

I would much rather take the power from the 12 volt source to run my own system, which has its own battery.

Still does not make sense.
Now we have two batteries, and a voltage source?

Draw a diagram with everything shown and how you want it connected.

 

Your only solution with those requirements is to boost then buck...how else would you do it?

If you can afford the voltage drop, a diode can isolate your system from the source.