Hello,
I've been wondering about constructing a portable USB power station using a high capacity 12v car battery. Ideally, I would like to have 30 USB ports available.

Currently, I'm thinking these would be a good way to do the USB side of things: https://www.banggood.com/3Pcs-DC-DC...r-Efficiency-97_5-p-1106577.html?rmmds=search

I assume I could then wire all these back to the battery? The problem I am having is I would like a way to monitor the 12v battery which includes battery voltage, short circuit protection and a low voltage cut off so the USB devices don't over discharge it. Ideally, the system would contain a 12v trickle charger so I can recharge it overnight. Are there any relatively low-cost modules that could do this for me?

Any help would be appreciated and I am open to other ways of doing this!

 

For the cost I am not sure why you don't go with one that is already made. I know you want portable and 12v. I wish I wouldn't have gave a Multi port 110v hub to my Brother. His new store was starting to look over run with employees chargers. So I picked up one of these up for him at this store. Only 1 phone has had an issue on it. Even one person he said has issues with his own charger but worked off that without issue. Just an Idea.

http://www.ebay.com/itm/Multi-12-Po...on-/361336178914?_trksid=p2385738.m2548.l4275

Without thinking about it, I now wish I would have cracked it open to see how it was made. I am sure there is some type of AC to DC going on in side there and maybe it could be converted for your needs. My bother is 2 states away or I would just go take it apart to see. For the cost I could just buy another for my use lol. If it was going to come from China first time took 28 days to get it. I hate to wait lol

 

Thanks for the link - I didn't realise you could get them so cheap! I guess I could use an inverter to run a few of them from a 12v battery.
If I can't get a battery management thing then I might get one of those and see what's inside.
Shipping from China definitely sucks, but the price makes it worth it sometimes!!

 

Thanks for the link - I didn't realise you could get them so cheap! I guess I could use an inverter to run a few of them from a 12v battery.
If I can't get a battery management thing then I might get one of those and see what's inside.
Shipping from China definitely sucks, but the price makes it worth it sometimes!!

You can probably get 12V to 5V buck regulator boards off the shelf and probably not too steep.

It would be convenient to add outputs as and when you need them.

Don't forget a 2A board can supply 4x "spec" USB outputs.