Variable dc power supply from a car battery?

Is this realistic or am I dreaming?

Could you potentially make a variable dc power supply from a 12v battery?

The idea being it seems silly to convert DC to AC just to have an inverter convert it back.

Plus I just love to tinker.

What I’m thinking is a 12v battery along with DC-dc converter to charge batteries and run various DC electronics. I also want to hook up a few USB ports.

I want a portable way to charge a huge variety of things without bringing a ton of charging cables and an inverter.

Put it in a battery enclosure and I have mobile variable power supply I can use for pretty much anything.

This summer we are doing a lot of travel and camping. I’d love to be able charge my li-ions, lipos for RC, USB for phones,camp lighting all from a simple power pack and be inverter free.

Like I said it seems to be a huge waste to do a dc-ac-dc tapdance when a little ingenuity and solder may just work.

I’d love to hear some ideas to make this happen.

There are lots of hobby chargers that run on both Ac and Dc input

most hobby chargers can run on 12v, even the ones with 110 plug, still have DC in jack.

Would I need some kind of voltage regulator between the two? It’s my understanding that car batteries can show a great deal of variance in voltage, especially under load.

A hobby charger would be able to charge 90% of what I need it to.

I don’t understand, there is a cigarette plug in your car, why not use that?

Many battery chargers with 12V input can be used with a car adapter.
For chargers with usb input get a good multiport car usb charger, you can find a few in my tests: index of USB equipment

If you need other voltage, you can get busk and boost converters from ebay for cheap, they just need to be put into a box with some connections.
For ideas check you-tube Julian Ilett, he runs just about all his experiments from car batteries, power banks and a few primary batteries, using buck and boost converter to adapt the voltage.

Most hobby chargers can accept a range of voltages and work. I think my turnigy brand charger (accucel 6) will work down to around 9V. I measured it but I can’t remember now. It might be stated in the user’s manual.

Just get a dc-dc voltage power supply?
There are plenty of cheap buck/boost ones.
Just keep in mind that most batteries should not be charged by just connecting them to a power supply, they require monitoring and regulation, not just constant voltage.

I tried the working voltage range out on the SC608 here… (About 4.5 minutes in)

That little unit is pretty versatile and very compact but reasonably powerful, great for sticking in a glove box.

Thanks for the ideas guys.

Bear in mind this is more of a fun project than practical…

I have to carry a spare battery when I camp anyway for my CPAP, so why not use it to run all my other stuff as well?

I’m liking the idea of using a buck boost converter inside a battery enclosure, throw in some USB ports a nice led display.

I’ve seen lots of plans for power packs using car batteries, just not one that is adjustable.