Originally Posted by Sandero
Why NOT use 12v and NOT bother with an inverter?
Originally Posted by Maine Sail
That test was to simulate
what I see on the boats I work on daily. I am on-board hundreds per year and I would estimate 85% +/- are using a large or small inverter to do nothing but charge phones, pads and computers. This is not because they want to, but rather most don't realize the USB 12V inserts exist nor do they realize 12V adapters are available for computers as well.
Sure if you are already running an inverter for other uses by all means the 120V USB chargers work great. If not the USB 12V inserts will be more efficient, charge just as fast, and cost less than a six pack of beer
The only point I was making about inverters is that the efficiency is related directly to the inverter quality itself, not the process of DC-AC-DC conversion. Also, that MSW inverters are horrible things to connect transformers to.
A good inverter will have no practical inefficiencies compared to direct DC. Yes, there will be a theoretical inefficiency, but in practical terms of charging a phone
or tablet, this will be likely <1Ahr/day. If one chooses to make their case using a crap inverter from Big Lots in an unadvisable manner, then one will see awful performance.
One will also see awful performance from a cig lighter socket and pink USB plug
bought from the Dollar Store and wired with 20AWG. But somehow good DC solutions are being compared to awful AC solutions here under the guise of "it's what I see daily".
However, I think some have overlooked the fact that we have and use BOTH types on board, so I'm not pushing one over the other - just providing options, facts, and experiences.
For $15, one can buy an AC outlet that has built in USB outlets. This means that when one is using AC for anything (regardless of one's inverter), one can charge USB devices without taking up any of the AC outlets for wall warts. The DC conversion on these ports
is efficient. In addition, there is usually an AC socket in every compartment on a boat and exchanging the existing outlets for USB combo outlets can be handy when guests are onboard.
Note that I am NOT advocating running wall warts off inverters regardless of the inverter. My goal is to get rid of wall warts completely - they really irritate me.
For another $15, one can buy a DC USB outlet and directly wire that into the DC system. Or place them all around the boat for convenience.
I personally don't like cigarette lighter sockets and plugs as DC solutions. I have seen few that are acceptable to me, and certainly wouldn't be drilling big holes in several places around our boat to install them just to plug stuff into to avoid using an inverter.
So I do advocate against the cig lighter and cheap auto USB plug solution.