Electrical upgrades interior - back up battery

so looking to get some kind of battery installed for interior electronics upgrades.

Will likely take it to a shop to do the work -- but anyone know of good threads or info on the topic?

Looking for a backup reserve battery accessible or hardwired to the interior that can provide sockets for Dash Cam, Radio, Nav, 4G signal booster, phone chargers, etc. + any other electronics I want to upgrade to.

1 cigarette lighter AC unit cant be enough for everyone right?

I'd like the back-up battery to charge somehow off the main battery or something - and last for 24 - 48 hours. This will ultimately power the DVR on the dash cams, signal booster, keep the nav updated, etc.

 

https://www.tacomaworld.com/threads...ets-see-them-multiple-batterys-thread.295653/
https://www.tacomaworld.com/threads/off-grid-engineering-dual-battery-system-q-a.468553/

The above two threads should pretty much have the answers to your questions.