New electrical need help

[BB 55 Bubble]

So I want a new converter and lighting. 12 volt lighting throughout is the plan. What confuses the heck out of me is the planning portion of the project. I want to make sure that I have a large enough converter for the lights I plan to use. How do I determine this? I have 2 Very expensive batteries that are like new (less that 12 hours used) that where donated by a family friend to the "trailer cause". I hopping that some one could give me some guidelines on the demands that certain lights have on a system and which direction I should go. I do not want to over do the lighting and kill the batteries and put a strain on what ever new converter I buy.

Can 12 volt household lighting be used in a trailer minus the transformer that is supplied that reduces 110/120 to 12 volt?

Here are some of the lights/converter I was thinking of using:
Vintage Trailer Supply - Vintage travel trailer parts and supplies!
LED Light Fixtures RV Rv'S
Xenon Low Voltage Ultra-Slim Cabinet Lights, Under Cabinet Lighting
Low Voltage Linear Lighting

All I know for sure is that if it is electrical I will shock my self! That is why I plan on kidnapping a local electrician and paying in BEER!

[markdoane]

I've used the Xenon lights wired (through a switch and fuse) directly to the battery. A 20w Xenon bulb seems to put out as much light as a 60w incadescent bulb. A 20w load, even 10 of them, isn't going to bother the Intellipower. 200 watts would consume 17 amps of battery capacity, but thats a lot of light bulbs.

No data, just my subjective opinion. . .

[BB 55 Bubble]

Here is what I learned from a web site that I found this morning!
Hope it helps

Converting Watts to Amps

The conversion of Watts to Amps is governed by the equation Amps = Watts/Volts

For example 12 watts/12 volts = 1 amp
Converting Amps to Watts

The conversion of Amps to Watts is governed by the equation Watts = Amps x Volts

For example 1 amp * 110 volts = 110 watts

Converting Watts to Volts

The conversion of Watts to Volts is governed by the equation Volts = Watts/Amps

For example 100 watts/10 amps = 10 volts

Converting Volts to Watts

The conversion of Volts to Watts is governed by the equation Watts = Amps x Volts

For example 1.5 amps * 12 volts = 18 watts
Converting Volts to Amps at fixed wattage

The conversion of Volts to Amps is governed by the equations Amps = Watts/Volts

For example 120 watts/110 volts = 1.09 amps

Converting Amps to Volts at fixed wattage

The conversion of Amps to Volts is governed by the equation Volts = Watts/Amps

For Example, 48 watts / 12 Amps = 4 Volts

Explanation

Amps are how many electrons flow past a certain point per second. Volts is a measure of how much force that each electron is under. Think of water in a hose. A gallon a minute (think amps) just dribbles out if it is under low pressure (think voltage). But if you restrict the end of the hose, letting the pressure build up, the water can have more power (like watts), even though it is still only one gallon a minute. In fact the power can grow enormous as the pressure builds, to the point that a water knife can cut a sheet of glass. In the same manner as the voltage is increased a small amount of current can turn into a lot of watts.

[BB 55 Bubble]

I know that there are many variables to consider when determining how long a battery can supply a set of lights. I was wondering if any one has seen a chart listing how long a light bulb 12 volt @ 20 watts will last on the average 12 volt RV battery. So thus I can determine just how many lights at what wattage I could use in the RV for the maximum amount of time at night.

[thecatsandi]

You need to know the amp hour capacity of the battery.
12V at 20W will be 20 watt hours.

[markdoane]

You don't want to run the battery below 50% of capacity. If you have a single battery with 100 amp-hour capacity, then you have about 50 amp-hours available.

So in the example I used above, you could expect 50/17= about 3 hours with ten 20w bulbs. Or thirty hours with one bulb. Or 15 hours with two 20w bulbs.

Or six hours with two batteries and 10 bulbs, etc.

[BB 55 Bubble]

I am giddy with anticipation, and my palms are sweaty with the credit card in hand!

[BB 55 Bubble]

If I had found this web page earlier it would have been way easier!
Here is a link to a site that deals with all of the questions I asked and beyond! It is called the 12 volt side of life and has two parts.
Happy Reading!
The 12volt Side of Life (Part 1)

[thecatsandi]

and to get amp hours.....
Power=Voltage * current or Current = Power/Voltage.
20W/12.6V = 1.59 amps
1.59 amps for an hour is 1.59 amp-hours.

[markdoane]

The relationships can be easily remembered with the mnemonic "WAV".

Watts = Amps * Volts

The rest of the equations are just algebraic manipulations.