It is only when a real problem shows up, that I go on the war-path. When a leaf spring broke recently on my trailer, weight-reduction became my 'Cause.' The most immediate and large weight-reduction was to downsize the 6-volt (golf cart) batteries from four to two.
One project has been to break the habit of leaving the DC-to-AC inverter "On" 24 hours per day. (I use DVDs as sleeping pills at night.) Although I have an inverter that has a low "idle" power draw, this parasitic draw still totals up to 10 Amp-hours over a 24 hour period. One could argue that this is small compared to the nominal capacity of the battery pair (235 Amp-hours.)
Still, this is my current project, and it is fun. Consider how crazy the voltage situation is, in an RV: every electronic gadget comes with a "power adapter module", that is, a big black brick that weighs as much as the gadget itself. After plugging in two or three of these monstrosities into the usual outlet strip, you are out of plugs.
"Easy," you say. "Just google 12 volt DC gadgets or appliances." Not so fast! That just pulls up specialized, over-priced "12 volt" gadgets and appliances that are sold to truckers. A shrewd consumer prefers to buy mass-produced "AC" gadgets, at the usual big boxes or websites. But if you do that, you have to waste energy with your inverter!, which is what we our trying to get away from.
But wait...all the black power brick does is convert 110 volts AC back into 12 volts DC, or some other DC voltage. This latter voltage is what is coming down the power cord, into your gadget. Therefore an RVer can just cut the power cord, throw the brick away, and wire your gadget directly into the 12 volt DC system of the RV.
|Part of my graveyard of unnecessary power bricks, now that I've become a DC purist.|
Unfortunately not all black power bricks put out 12 Volts DC -- they might put out 19 Volts DC like the laptop I am typing on. I presume that large televisions use more than 12 Volts DC; but why would a serious camper need a large television? My effort here is at helping the redeemable -- not hopeless sybarites, who debauch themselves with 54" diagonal televisions. My 13 inch television uses 12 Volts DC.
Some gadgets such as cameras, cellphones, or MP3 players, use 5 Volts DC. It is supplied through a standard USB cable and connector, and plugged into your laptop. But you can just as easily plug that USB into an adapter that plugs into a standard 12 Volt DC "cigarette socket." (These can be bought everywhere.) Therefore you can charge any of these 5 Volt DC gadgets without running your computer or an energy-wasting inverter.
I was delighted to read the power bricks on my blue-ray player and external computer speakers (for music): they too put out 12 Volts DC to power these gadgets. These gadgets and the television are using the energy that I am prone to wasting at night.
Result: I hardly need to run an inverter, especially at night when it really counts. If you want to give your inverter a rest at night, buy gadgets whose AC black power bricks put out 12 Volts DC. They are always labelled. Snip the brick off, and throw it away.
Notice I have said nothing about gadgets made by Apple. I just assume that with the rest of the industry using 5 or 12 Volts DC, Apple uses 3.87 Volts DC, or something deliberately incompatible with the rest of the industry. But like the commercial says, Apple makes such cooooooool adapters, dude...
Besides all this practical trivia, consider the philosophical appeal of no longer converting your DC battery voltage to AC via the inverter, wasting energy, and then using a black power cube brick to convert the AC back to DC, and wasting more energy.
If this gives you some satisfaction, maybe you have just learned something about one of your past lives: perhaps you were a federal surveyor who laid out the Northwest Territories along regular geometrical Cartesian lines. Or maybe you wangled your way onto the French committee that designed the metric system, during the early days of the Revolution.
Addendum: OK I got my new "laptop DC power adapter" to charge my 19 Volt DC laptop. Sometimes "laptop car charger" might work when doing internet searches. Its input is a cigarette style automotive plug that plugs into the matching female socket, which you can buy at any auto parts store.
Its output is 19 Volts DC, as required by my laptop. And there is the right connector that fits the laptop. The DC power adapter came from LaptopPartsNow.com .
The DC power adapter runs at slightly above room temperature. I don't actually know that it is more efficient than an AC power adapter (black power brick) that plugs into household AC wall outlets.
But the overall efficiency should be better with this DC approach since it allows the DC-AC inverter to be turned off most of the time.
Well, that does it. I have achieved electrical perfection in my camper-trailer.