# Help with Project...I'm New Here!

#### electric_shock

Joined Jun 25, 2008
11
Hey guys, I hope you all can help me out I am trying to work on what seems to be a simple project, but need some help.

I'll go step by step and try to make it real short:

1) My source of current will come from a car 12V battery or motorcycle battery. The battery will be out of the car or motorcycle, so I can attach the +/- terminal to get power from there.

2) I want it to go into a step up transformer to bring it up to regulate between 50V to 120V (estimated, but doesn't have to be, at least 100V).

3) I want a knob to be attach to it, where I can reduce or increase the the voltage on the output end. (not sure what this part is called).

4) I also want a Multi-meter tied into it so I can see the actual voltage coming out and use the knob in #3 to regulate it.

5) The catnode and anode will be connect to different thing such as light bulb, etc... I can work with the output end, just #1, 2, 3, and 4 I'm worried about.

I mostly will be using this at camping, if anyone is wondering and trying to come up with a different idea and want to build something on my own with the help of you guys here.

Thanks
Mike

#### beenthere

Joined Apr 20, 2004
15,808
The device you are looking for is called an inverter. The variable output is interesting, but not too practical. An inverter uses a circuit to chop the 12 volts from the battery and simulate an AC voltage to drive a step up transformer.

Since the inverter uses a transformer, you can't control the voltage out. If it's improtant, a triac dimmer might be able to do that.

Here is a link to an outfit that sells inverters for camping uses - http://www.4lots.com/power_inverter/camping.htm. Using "camping inverter" with google brings up lots of hits.

#### electric_shock

Joined Jun 25, 2008
11
Sorry for the confusion guys.

I want to keep this as direct current, so it will come off of a regular 12V car battery, (battery will be removed from the car). Then I want it to go into a step up transformer, to up the voltage, and if there's any way to monitor the voltage coming out, I'll like to do that as well.

Pardon my n0ob-nest, but you can put a set up transformer on a 12 DC battery?

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#### beenthere

Joined Apr 20, 2004
15,808
No, but you can use a DC-DC converter (essentially an inverter) to up the voltage. Or simply rectify the AC out of the inverter and use a FET or transistor to control power to a load.

One important thing is to know the size of the load in watts - the inverter or DC-DC converter selection comes from the power it has to produce.

#### electric_shock

Joined Jun 25, 2008
11
Hey beenthere,

Thanks for constant checking on my thread, I appreciate it, as I am trying to figure out what to do, you've been a great help so far believe it or not.

I decided to go with the first suggestion with the inverter, but here's the thing.

Can I cut off the part the plug into the car charger and connect it directly to the battery? Will I still get the 150W output on the inverter?

Now after the inverter puts out it's 115V; Is there a device to regulate the voltage? (lower/higher voltage).

For example, The batter send 12V to the inverter, the inverter puts out 115V and have a voltage regulator (if there's such thing) connect to the inverter to lower the voltage is necessary, I don't mind having the end wire peel, I can deal with that into a different piece. So I'm not worried about that part.

PS: I'm not looking to built my own piece, just purchase pieces already built and put together what I need.

Thanks again

It should look something like this.

And the output will be whatever I want to connect there. But I'm not sure about the Adjuster Unit (is there such a thing to connect to the inverter output to regulate the voltage coming out lower or higher before reaching the last output that will be open.

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#### SgtWookie

Joined Jul 17, 2007
22,201
Well, if you want to build a flyback DC-DC converter, here's a great page:
http://www.dos4ever.com/flyback/flyback.html

It's not "for dummies", Ronald just has a great sense of humor.

If you are considering powering an incandescent lamp or lamps, I suggest that you should instead consider super-bright LED's. Otherwise, you will quickly wind up in the dark with a dead battery in the middle of noplace and no way to start your vehicle.

Also, motorcycle/auto batteries are not designed to be "deep-cycled"; if their voltage drops below around 12.4, they will begin sulfation; "gook" will form on the plates eventually preventing them from accepting a charge.

LEDs nowadays can put out an amazing amount of light for the small amount of power they consume. That is largely because they do not have to generate heat to produce light, like incandescent bulbs must.

For camping lights, consider building a few Joule Thieves:
http://www.bigclive.com/joule.htm (this is a good one)
Or this Google search: