12 volt power from the begining

Discussion in 'Off Grid Living' started by slots, Jan 15, 2008.

  1. slots

    slots Monkey+++

    As I have found out from recent experience, there is a lot more to solar power and electrical systems that your novice (me!) realises.

    If you want to do it yourself and know all about cable sizes, battery sizes, terminals, voltage drops, the law of ohm, etc etc etc, then your wasting your time reading this.

    If however you need things explained to you slowly and clearly from the very begining then take a look at the site below. Click on "technical articles" and then after the disclaimer "Kamper tech" and finally "Electrickery"

  2. fritz_monroe

    fritz_monroe Guest

  3. melbo

    melbo Hunter Gatherer Administrator Founding Member

    Thanks. Nice basic info.
    I think everyone should make at least one small solar project to get their feet wet.
  4. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    OK, I'm getting my feet wet. I just built a small shed and want to put some lights in it, along with some batteries for future use.

    What I was thinking was getting this:
    Northern Industrial Solar-Powered Trickle Charger — 5 Watt

    Getting one or 2 deep cycle 12v batteries and a couple of 12v lights (and a switch in there of course). Primary use now would be to control lights in and possibly outside the shed. Future/SHTF use would be to use an inverter with the batteries to run misc small items in the house. I do have a generator, but since I live in an urban environment, the less I have to run it the better.

    Now, I need a good primer on what lights to get, where to get them and wiring inside the shed.

    I am doing this as a nice primer, as Melbo said, so I can get some limited solar experience.

    Thanks for any help.
  5. melbo

    melbo Hunter Gatherer Administrator Founding Member

    I'd go LEDs or just wire it for 12 automotive lights, (like reverse lights), The Solar to 12V battery to Inverter To 110 AC will kill you with smaller panels. Cut out the AC all together and just go 12V DC
  6. dragonfly

    dragonfly Monkey+++

    I bought 2 large 'amophous' panels, 45 watts, @ $225.00 each (BUT), only 3000 milliamps "current"!
    They weren't cheap, and I got "educated" AFTER I bought them.

    I should have bought the twice as expensive "microcrystalline" panels for $519.99 each, that are ONLY 75 watts, but they are 4.36 'amps'!
    You can see the problem....I'd have to buy a LOT of the el-cheapos to do much good and 'amorphous' panels lose 20% of their capacity in as little as 4 months.
    Live and learn!
    They are ok for charging batteries and running tiny 12 volt stuff, but pretty much worthless for any real 'recharging' of batteries in a solar-110vac system.
  7. monkeyman

    monkeyman Monkey+++ Moderator Emeritus Founding Member

    I would look around and get 12V LED lights. IIRC a lot of RV places carry them. Like Melbo mentioned each step looses some of your power going from panels to DC (batteries) looses some of what the pannels collect then when you go to through the inverter to make it AC you loose a good bit so if you can cut out the AC and keep it DC then your juice goes further. From there its just a matter of keeping the stuff you run as efficient as possible thus LED lights.

    Something I have thought about as a VERY basic tart on some alternative energy is to pick up some of the lawn lights that have the small solar pannels on them to run the lights along a sidewalk or what ever from dusk to dawn. They have AAA rechargable batteries in them that the panel charges so I figure take the bulbs out of a few of them and they could charge batteries for other uses and the others could be brought in at dark and used for light inside if the grid was down.
  8. gunbunny

    gunbunny Never Trust A Bunny

    Another thing I learned about solar panels is that the further north you live, the less energy you get from them. Even if you keep the panels aligned with the sun all day, you will not get as many charging hours as you would if you lived further south.

    I was contemplating building an energy cart, using a 4'x4' trailer and solar panels. I would then add a few batteries to the floor of the cart, charger, and an AC inverter. Then I could move it around as needed. Now I don't know if I see the wisdom in that anymore.

    Even your wiring has to be larger when you deal with 12 volts. Regular 14ga extension chords won't cut it for any distance because the voltage drop.

    If I could find the site again, a gentelman was using a homemade generator powered by his bicycle. That may prove to be more useful, but only in the short term, like to power a radio. How many of us are willing to pedal all day to charge up batteries?

    Multiple ways to charge may be the way to go.
  9. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    For my shed, everything would be 12v, which would be lights only. As far as the inverter goes, I was thinking more along the lines of starting small just to get my feet wet. Having the inverter in case of some local SHTF type thing.

    I found some 15W panels and a 7amp charge controller. I may go with these two items, a deep cycle 12v bat, and some 12v LED camper or car style lights to get some illumination in the shed.

    As I get the pieces in, I'll update here with the process that I'm going through, it might help someone else out.
  10. Elza

    Elza Monkey++

    It wouldn't be that big of a difference. 3,000 mA is 3 amps compared to 4.36 amps. Either one will charge a battery. The 3 amp rate will do it slower but will still get the job done. Depending upon the load, of course.

    <?xml:namespace prefix = o ns = "urn:schemas-microsoft-com<img src=" />It would take 1½ 45 watt panels to equal the 75 watt.
  11. pstevens2

    pstevens2 Monkey+

    I just picked up some books on 12 volt/solar. The Idiot book, the Dummy book and one on 12v RV stuff. That was before I bumped into this site.

    Any recommendations on books for 12v wiring beyond these?

    Tried the kampenwagen thread. didn't seem to work
  12. melbo

    melbo Hunter Gatherer Administrator Founding Member

  13. Nadja

    Nadja RIP 3-11-2013 Forum Leader

    I would tell all of you, I live off the grid and have for about 15 years. Do NOT buy these cheap panels, as they are junk. You are just throwing away your hard earned money. Save up if you have to (I Do) and buy one good 80 watt panel, 12 volt, two trojen 6 volt batteries. You wire the two batteries in parrarell to make them 12 volts. One charge controler, I recommend min size a Xantrex C-60 which will handle about 10 of those panels and a small xantrex invertor like the model 1512. By using 12 volt =yes you end up haveing to use a little larger wire and cable, but it is very easy to learn, easy to instal, and most of all you can add panels as you can afford them. Stick with the multi-crystaline type of panels and they are good to go for about 25 years. As is the warrentee on them if they are good ones. Most of the panels made in Japan such as Kyrocera, Sharp, Mitsibushi and a few others are top of the line. Most of the panels if not all made in China are junk. That includes the ones that are re labeled to make you think are being made elsewhere. There is a lot of fraud when buying panels. That will include such places as northern tool, harbor freight and most of the ones on ebay. Shuco from Germany are quite good, and also right now about the best priced. I have heard from a few friends that a company called "Evergreen" in I believe Wisconsin is making a pretty fair panel also. You buy a good invertor like a xantrex ( used to be called trace) because of the features including a batter charger built in that is better then most of the gas station heavy duty types and also the safeties built in them. They work and work well. As far as wiring, try to determine just how big you need to grow your system before you do the wiring and size accordanly as it will pay off in spades down the road. That is one of the things I had to redo before I figured out that small wire up front will only cost you all over again as you add panels and batteries. Then take a look at the battery cables in your car, as they are small compared to what an invertor really needs. Your car only needs those cables for the starting cycle which is ususally not very long. When your working with solar especially at night the power from the batteries into your invertor is constant, therefore causing a lot of heat. Too small of wire will melt or even catch fire. All dc wiring should be used with "stranded cable" and Ac wiring with solid core wire. Ask anything you want, and if I don't know , I will tell you so.
  14. kckndrgn

    kckndrgn Monkey+++ Moderator Emeritus Founding Member

    Wiring 2 6V batteries will still give you 6V, but will increase your amps. I think you meant wire the 2 6V batteries in series.

    Battery Wiring
  15. Nadja

    Nadja RIP 3-11-2013 Forum Leader

    OK, I am not an electrian, however, I wired my bank of 18 6-volt batteries in both , which creates 9- banks of 12 volt batteries. Two of the batteries are wired neg to pos , which makes 12 volts and then all the interconnected banks are wired pos to pos and neg to neg and so on down the line. If I make a mistake on the Correct termenology, I apoligize ahead of time. I am old, but my solar works well for me and all my neighbors and friends also
  16. dragonfly

    dragonfly Monkey+++

    So far, I have been very "lucky"!
    My el-cheapo panels are working, so I feel good about that part of the fiasco!
    I am still using 2, 12 volt automotive batteries, as I did not have time to do any shopping or searching.
    I have to say that with my 400 watt invertor, it does all I have asked of it from just those batteries.
    ( won't run the fridge even with the 4000 watt invertor though!)
    I am using a lot of those yard lamps also, with 1.5 AA rechargeable batteries, and found that more than one at night in my travel trailer, makes it impossible to sleep! I have painted a few ( 6) with red nail polish for when I want to keep my night vision ( which is terrible anyway) and some ( 4) with green polish for using around the electronics....makes it easier to see in green light than in red!
    I have used these 2 amorphous panels and 2 automotive batteries now for over a year ( 16 months now) and I feel they have at least paid for themselves in that time....
    One of the main concerns was water/rain damage to the panels, so I sealed them around ever possible edge and opening with GE's 50 year, clear silicone!
    So far it has been worth the itme and trouble to do so!
    The "caretaker" has wired up his new mobile home with 6, 12 volt batteries ( marine deep cycle, but will be switching over to the 6 volt golf cart ones soon. He ran everything thru his breaker box, and has 1000-1200 watts of power today without his wind generator ( rated at 400 watts). He has not been able to even dim the lights with everything running, including a 900 watt microwave unit!
    ( he has the blue silicon panels)
    Since I spend limited amounts of time up north, and only use energy very sparingly, I can say I have a good system. Not the best mind you, but for what I needed, it did the job so far.
    For a 21 ft travel trailer they do ok! Not what I'd recommend for anything else though!
    I can watch tv, run a computer, charge my cell phone, and listen to radio, plus have lighting. What else is there?
    More will be added when I relocate to my new land! (Trailer/mobile home is already up there)
  17. Nadja

    Nadja RIP 3-11-2013 Forum Leader

    You should have bought Kyrocera 80 watt panels that are 5.2 amps each and sell retail for around $400.00. If you shop around you may even do better.
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