Solar setup for camping in a few weeks

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radraymond01
radraymond01 Registered Users Posts: 1
in Solar Beginners Corner #1
Hello guys,

I am planning to go camping in 3 weeks and found out that the campgrounds does not allow gas generators so I decided to look at some alternatives when I stumbled into solar.

I am at the process of gathering the materials for the three days worth but I am a complete newbie when it comes to building things. Point is, I am looking for a beginner setup that can run a laptop for 3 hours (about 90 watts an hour) and maybe some dvd player (30 watts) for the kids at night. I have began to email people/businesses for the materials but I am also on a limited budget.

So far this is what I am about to get:

1 100 watt solar panel that is 24volts
1 EverStart Group Size 24DC Marine Battery from Walmart, which I assume is 12 volts
Cobra 400 power inverter
A 10A PWM charge controller from Ebay


Now my questions are:

I understand that the 24v panel is different from the 12v battery but I can only afford a PWM controller as a MPPT is just way beyond my budget range. Would it be safe to operate and not explode from the different charges? If I stick with a PWM, how much of a watt loss should I expect?

Are you able to run things that uses less wattage while the solar setup is running, for example if you can run a 20 watt item while the system is charging?

How much of a stored power can I expect from a battery mentioned above if it's charged for 6 hours?

Again, I am only going to use this for 3 days while camping. Please let me know what I need to do, thanks so much!
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
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    Re: Solar setup for camping in a few weeks

    Welcome to the forum.

    First of all, the loads are key to everything. Get a Kill-A-Watt meter and really measure what things use. You will probably find your laptop is more like 30 Watts than 90. Over three hours it would be 90 Watt hours. There's the first snag: that battery will have about 540 Watt hours if you're lucky. You'll be surprised how fast that disappears. The DVD player, even with a small screen, is going to chew up power. So you have to be able to replenish it. Will the 100 Watt panel work? No. If you run a 24 Volt panel to a 12 Volt system via a PWM controller basically half of its power is lost; it will produce the current rated, but not the Voltage. So instead of 2.8 Amps @ 35 Volts (100 Watts) you will get 2.8 Amps @ 14 Volts (40 Watts). This is just as an example; not and absolute calculation. You can still get 'real' 12 Volt panels. One example: http://www.solar-electric.com/kykd140wa12v1.html

    Don't count on 6 hours of charging either; as the sun angle changes in respect to the panel so does its power output. Being mobile you would be able to realign it periodically, but this is easy to forget to do.

    Hang on; all is not lost. There will be plenty of others chiming in with suggestions! :D
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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
    #3
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    Re: Solar setup for camping in a few weeks

    Gosh...

    Just 9 years ago I went on a 3 month bike trip, with a laptop and a mp3 player, and no back up, just charged when I could. 4 years before that I spent 9 months cycling with a 10 watt solar panel and a couple small 6 volt, 2Amphour SLA batteries, charged in series and used in parallel, for a radio and a light and even(horror of horror) a 2" TV.

    Before you spend that kind of money on batteries and a solar panel for your once a year vacation, you might rip some dvd's to AVI files and buy them a couple small MP4 players, Craig CMP641f's, they like avi's and cost @$25, 4GB storage expandable with Micro SDHC cards they say 4GB but I've used 16(Adata) and 32GB(sandisk) included software is not windows 7 compatable, but lots of other software converters out there and some movies come with rips now. and a battery back up for these, they run quite a while as mp3 players. I rip library books from CD or you can download library books, check with yor library.

    You could also find a cheap tablet, WalMart is often closing out something, or check "fatwallet" or Slick Deals" web sites for what people are selling cheap.

    If your doing any day trips, you could plug in you laptop to a car adapter and charge. I think even I could make ity 3 days with out a laptop...
    ...maybe...
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
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  • petertearai
    petertearai Solar Expert Posts: 471 ✭✭✭✭
    #4
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    Re: Solar setup for camping in a few weeks

    Leave the laptop at home, and sit around talking and playing cards!!!
    2225 wattts pv . Outback 2kw  fxr pure sine inverter . fm80 charge controller . Mate 3. victron battery monitor . 24 volts  in 2 volt Shoto lead carbon extreme batterys. off grid  holiday home 
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