During our 8 days of boondocking in Tucson last month I was monitoring the constant power draws on the batteries. One thing I noticed was the Inverter was drawing a constant 6 amps of power from the battery 24 hours a day. The inverter is what creates 120v AC power from the 12 volts of power the house batteries produce. It has a few amps of overhead and there is also a conversion loss there, not to mention the power conversion loss that also happens at low power devices we have plugged via wall warts. (those little black transformers you plug into wall outlets)
My solution was to find DC-DC power converters that will use the 12v direct from the batteries to change it to the voltage a particular device needs. Some examples are: 8 Port Gigabit Switch It actually runs on 5v so removed the wall wart and used one of these 5.5mm Power Adapter barrel connector coupled with a 5v power supply and also tied in our HDhomerun to that same power supply via another 5.5mm barrel connector.
A note on that power supply, the width around the terminal screws was so small I had to grind down the crimp on connectors. And they were the smallest (Red) connectors I have seen.
I also switched out my 120v POE supply with one of these 12v models: Gig DC-DC POE power supply My WiFi device is passive POE (24v) and this device converts 12v to 24v and injects it into the Gig Ethernet cable to power my Mikrotik Metal CPE The Mikrotik is a CPE WiFi device with an Omni Directional antenna attached that I use to grab WiFi signals when near WiFi Access Points I can logon to. That WiFi signal, once connected to the internet provides a connection to my internal TP-Link AC750 WiFi Access Point via Ethernet cable thru the gig switch. That access point also runs from 5v, but it uses a micro USB cable for power. I power that from one of these 12v to 5v power micro usb output
I tied these all together with this Fuse Box. I also added one of these 3 port 12v power outlet switch box to allow for the Dash-cam and new NUC power supply to connect. I have one left over to power the NVIDIA Shield Android TV device if I ever find a 12v adapter. Is appears that no one makes one yet. And no one makes a decent replacement remote for it either.
In its current form it appears I have reduced the current draw from 6amps to about 2.5amps. A reduction of about 80 amp hours per day from the always on stuff. That’s a lot of amps to replace when not connected to shore power!
Other things I want to change out will be the two TV’s. Until then we will need to run the Inverter only when we use them. Or maybe look into a couple low wattage individual inverters. For now we can just turn on the main inverter to sit in front of the boob tube…