Question regarding small solar/battery powered system

After a few days of reading about batteries and solar panels I have decided I am totally confused.

My goal is to have maybe one or two deep cycle batteries along with all the inverters/converters/limiters etc... to power/charge a laptop, small tv, small fan, small heater, etc... for at least 20 hours non stop. The tv wouldn't be on for more than one or two hours a day. Laptop most likely would only take one hour to charge. The fan would be on non stop for at least 20 hours, the heater at least 10 hours. All of these things would happen every single day for at least one year.

What type of batteries do I need to do this?

I would also like to get a solar array to charge the two/one battery over the course of the day when I am not using them.

I plan on living in a RV/VAN for a year and would like to have solar power.

The stove will use some form of gas, most likely kerosene, if propane then the tank will be outside the van/RV. The heater will only be used at night when it is cold.

I am tired but I hope you guys get the idea.

Oh, I don't want to use the van's starter battery for anything other than starting the van, well and running the radio etc.. it's normal operations.

I also don't want to use any sort of generator since it would be way to loud.

Think stealth. quite... solar is quite.... (whispering)

Go here at poke around. www.solar-electric.com... There is a forum there. Also go to www.rv.net...

I have a small photovoltaic system on my RV. You will need to "size" your system to fit your needs. You mention wanting to have power for heat. What is your heat source? Propane?

[edit on 4-5-2008 by RKWWWW]

First thing to consider is the amount of power you will be needing, both peak (everything on) and average (for recharging). Based on what you just described:

A small TV will pull about 500 watts when on. When off, it will pull maybe 50-100 to maintain internal voltages.

The laptop will pull about the same, say 400-500 watts.

A fan, depending on size, will pull about 100-150 watts maximum. I am assuming a pretty large fan, such as a window unit, to be conservative.

The heater is a wild card. Since we're talking batteries, I am assuming electric heat. A heater can easily pull 2000-3000 watts, depending on its size.

So all together, we're talking about 4100W peak. That's a HUGE inverter to run these off of a 12V battery system, but they are available. Expect to spend about $300 - $400 dollars for the inverter itself, but the good news is it simply connects to your battery and has plug-ins right on the box.

At peak load, you will be pulling 4100/12, or about 340 amps out of that battery. That's almost what a starter pulls, so you will need multiple batteries. They can simply be wired together, (+) to (+) and (-) to (-). Your wires will need to be large enough to handle the amperage, so figure on using small starter cables.

As far as average, for a day, the TV will be on about an hour, so that's 500W-Hr. 20 hours of the fan is about 20Hr * 150W = 3000 W-Hr. How long will you have the laptop on? The heater? Figure them the same way, time on during one day multiplied by the wattage used. Add all these figures up and that will give you the number of watt-hours used.

Now take that number and divide it by the number of hours each day that you expect to receive solar power (sunshine). That is the number of watts of charging power you need to maintain your battery charge, and will vary some based on your geographic location and time of the year. Take that and divide it by 12 (the voltage) to get the number of amps of power you will need. With that information, you can calculate how many solar panels you will need to install on your rooftop to maintain your batteries. Simply gang the solar panels together in a 13.8V array (charging voltage for a 12V battery) using series connection for the voltage and parallel for the amperage.

Even though I understand you are looking for quiet operation, since you will be in an RV, I would look into a dual-charging system for backup. This is simply a special type of regulator that allows two different batteries to be charged simultaneously from one generator/alternator, while maintaining one battery to be the primary starting system. They are reasonably priced and will allow you to charge your auxiliary batteries while you drive without worrying about the main battery when you are parked using the auxiliaries. It will allow you to use gasoline (or diesel, depending on your RV) as a backup for those days when the sun isn't shining, or when you need to overuse that heater past what you had figured.

If your RV is diesel, you might want to look into a bunk-heater unit. This thing uses a small burner to provide heat directly from the diesel supply without the noise of a motor. From what I understand, they are a bit pricey, but not so much so as to prevent them from being used in semi's to make it cheaper to maintain heat than idling the truck. That will remove your biggest power drain from the battery system and use smaller components and less solar cells.

I hope this helps.

TheRedneck

I use deep cycle marine batteries for backup power for my radio station. I built a generator for the purpose of charging the batteries. Have looked at solar panels and may consider them in future.

Look into self contained LED lighting that will run several weeks off 1 9V battery. Forget the electric heater idea, that's a real alligator on power. Good ideas already mentioned.

I bought a decent sized inverter, for my needs, at Parts America on sale. It will charge everything or run anything needed that doesn't run off 12V DC, that I want to use in the operation.

Problem with TV you probably haven't considered. All TV going digital in USA next Feb. Need another power hungry box to convert old TV to new and improved TV. Small portable B&W battery powered TV will be great radios that get static. Larger TV's are power hungry. Just a heads up...

There are tremendous resources on the internet for what you want to do. One already listed. Just search and you will find all the info you want.

As far as a heater is concerned, I looked on the net a short time ago, looking into the feasibility of burning bio-diesel in a kerosene heater.

One could make enough biodiesel easily enough to fill a tank on one of those heaters.

Let Fabio show you how!
Here is a nice easy to follow website with pics:
www.chemistryland.com...
I am also looking into making bio-diesel to burn in my furnace, but the amounts I need I don't have the equipment for (so far a have a 55 gallon plastic barrel), I also want to make a small solar collector out of a door frame from my house, but I must experiment to find the best design.
This is the year, the cost of fuel to heat my house scares the bejesus out of me!

[edit on 4-5-2008 by Toadmund]

[edit on 4-5-2008 by Toadmund]

[edit on 4-5-2008 by Toadmund]