Forgive me. I'm too noob to even know what words I should be googling.

So, I'm trying to rig a bunch of high amp (2.1A) usb chargers in my jeep. I've come across spec sheets (I think thats what they're called) on how to build one. But, most of them use the LM317 or something that doesn't have sufficient amperage to charge a single 2.1A outlet. I've also come across a few buck converters. Which also seem to lack ideal amperage and are much larger than I'd like.

The closest thing I can find is step down buck converter transformer; or so it is called. However, I'm not entirely sure how to use it without frying stuff.

So the question realistically is if anybody knows or has a spec sheet to make a somewhat small 12 volt to 5 volt usb charger handling up to 4 2.1A charging outlets at the same time safely in my jeep.

The mentioned step down buck converter transformer....
https://www.amazon.com/DROK-Converter-Step-down-Transformer-Waterproof/dp/B00CEP3A0Q?th=1

 

Depends on the type of battery you are trying to charge ?

Different batteries chemistries need specific charge methods to maximize safety
and battery lifetime and capacity.

Regards, Dana.

 

Use 4 x these boards. One for each USB outlet.
https://www.ebay.com.au/itm/New-Min...C-Converter-Input-7V-28V-Output-/282516886062

There are a lot available. These can be had in fixed and variable versions.

 

Depends on the type of battery you are trying to charge ?

Not exactly direct charging batteries. It's more to charge the USB battery packs. Which I assume have their own regulator for charging?

Use 4 x these boards. One for each USB outlet.
https://www.ebay.com.au/itm/New-Min...C-Converter-Input-7V-28V-Output-/282516886062
View attachment 152345

How big are they? Obviously, I'm trying to minimize footprint to fit in my dashboard. Should one be able to just solder usb ports to the output? Don't have to worry about power surges or overvoltage stuff? #Iisnoob

 

22mm x 17mm x 4mm according to the Ebay advert.
And here is a neat little case for it.
https://www.thingiverse.com/thing:1512385
It looks like these boards are rated at 3A max, and 1.5A continuous. Still, they are worth a try I think.