DC in AC extensions or lamps.

[Larry Hollenberg]

Hi,

Been a while since I was here last.. I still have an interest in someday having a few solar panels to power my battery I use as back up or as full time as I feel like it..

What I am wondering now since I have little understanding of the load of current DC puts on AC appliance cords and such, is if a new 12 volt florissant bulb which draws much less amps than the old standard bulbs would be safe to operate on a typical home extension cord. I have the cigarette lighter type outlets with converters to regular power plugs. I have used the standard type bulbs with it with no issues, but wondered if I wanted a lamp farther from the plug in than the lamp cord would reach would It be ok to use the extension since these newer bulbs are pulling less power?

While I am on that topic, has anyone finally designed a plug in that is more professional than those ugly cigarette lighter ones? I can't figure why they haven't if not? Surely some other plug in more standard looking could be used and get away from that bulky "in the car" look?

Larry

[Joe Blake]

Larry,

I'd be a little wary of using AC cords for DC purposes. While they generally can handle much higher power than 12 v uses, the concern can be with the plugs and sockets. There is always the possibility of somebody "not in the know" plugging a "12 v" AC cord into a mains socket, which could have fatal consequences.

Further, remember that 12 v DC cannot travel great distances (eg 10 metres or so) without suffering a noticeable voltage drop, without going to very expensive cabling. So adding an ordinary extension cord means you might wind up with non-functioning devices at the far end. This, if my memory serves me correctly, is a function of voltage, and not power.

I think the cigarette lighter plug question is not going to be easily resolved, since in-car cigarette lighters have been around for a LONG time, and the adapter plugs are just using what is there.

My BMW m/cycle has a slightly different, heavy duty power socket, on the dashboard so I can run things like electric vest and/or gloves, as well as trickle charging the battery. (The cigarette lighter socket is for light power use only.)

Unless you go to the extent of hard wiring a fused socket out of sight under the dashboard of your car, I suspect you're going to be stuck with what you can get. (Although I think I've seen mobile phone rechargers with a right-angled plug so they don't stick out too far.)

Joe

PS you might have a read of this link here. It discusses issues pretty close to what you're having.

http://www.greenpowertalk.org/showthread.php?t=5647

J

[Larry Hollenberg]

Thanks Joe,

Yes I have dual sets of plugins. Since I am the only one here to use it I don't have an issue with it so far. However now and then I pour the coffee into the sugar bowl so crazy thing can happen as you age.. I usually have those plastic plug in protectors in the outlets to keep something from being accidently plugged in. They also are chrome outlet plates for the 12V and the regular is painted to match the walls.

I know about the drop in voltage, years ago when Home Power was free, I used to keep the copies, they had an article about the "Bus" method of running a heavy 6 gage wire the length of the house and then using smaller wires to the various items or outlets. I have one fuse in the line near the battery. I never pull much voltage off the lines so far since its mostly a backup and hobby kind of situation. I would like the solar panels however to see how much a couple might provide the battery or batteries.. I had two a one time, but went back to one since I use if so seldom.

Anyway the extension cords would be running like maybe a 2 1/2 amp fan or a light bulb of the florissant type. I would think the wiring would be sufficient to carry that amount of power over a 12' length?

I am wanting to run a test and see if I switch the main power off, how much a full battery will run the lights and small radios I have. Of course if I wanted to run this computer I would have to get a fancy inverter or run a separate generator to make it go..

Larry

[Joe Blake]

Thanks Joe,

Of course if I wanted to run this computer I would have to get a fancy inverter or run a separate generator to make it go..

Larry


Rather than lowering the river, why not raise the drawbridge?

I use one of these computers.

http://www.motium.com.au/products/mpc/mpc435/index.html

They can run directly off a 12 volt battery, and because you can get them with a "M" (mobile) class of processor, they draw much less power. Further, they don't need a fan, so are almost totally inaudible, except when booting up. Just wait till the new Solid State Drives arrive. :D

You can even buy a small monitor which also runs off 12 v DC.

With 128 Watts of solar panels during a sunny winter day (such as today) I was able to run the computer, a 14" monitor, and a 40 litre, 12 volt freezer and still maintain my batteries at peak charge. (Just for simplicity, I run it all off a 500 watt SEA inverter, with the computer and monitor going through a UPS so if the main batteries go flat, I've got a few minutes to transfer everything back to the grid, or vice versa. Using the UPS/Inverter means just unplugging one plug, and I don't even need to power things down. Hot swap.)

Joe