Simple solar setup?

Discussion in 'Power - Site Power/Batteries/Generators/Solar' started by NaterPotaiter, Nov 20, 2020.

  1. NaterPotaiter

    NaterPotaiter New Member

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    Hi, I am wanting to add a simple setup to just keep the trailer batteries charged so I can run the furnace at night this winter. So my power needs aren't much. I'm wondering if you guys have an opinion on just buying the 7 pin adapter and plugging the solar panel into the 7 pin plug. That way it's charging like the pull car is running. My pop up is not wired for solar so I figured it is wired to charge the batteries from 120ac or 12 volts from the car hookup so that would be the easiest charging solution. What are your guy's thoughts. Would there be some obvious downsides to charging that way. Is plugging in a jackery to the ac adapter a good way to charge the trailer batteries?
    Thanks.
     
  2. gladecreekwy

    gladecreekwy Well-Known Member

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    Suitcase solar panel with built in controller directly to your battery
     
  3. gladecreekwy

    gladecreekwy Well-Known Member

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  4. generok

    generok Well-Known Member Gold Supporting Member

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    Well, there's a few things there I need to tackle.

    First, running the furnace solely off the battery all night in winter is probably the most demanding thing you can ask your 12V battery and solar charging rig to do. Your furnace fan is likely the single biggest and most constant draw on your batteries. Of course, if you're in FL and just talking about taking the morning chill off, that's one thing. But if you're in an area where ice forms, you need a lot of amps for a lot of hours.

    It sounds like you're looking at a portable solar setup. So, you could tap the solar charger into the 7-pin, sure, but I think the best you're going to get is 10ga wire there. IIRC, the wire from my solar charger to the batteries is 6ga. You could run 6ga cables to a plug outside your battery box and plug the solar in there too, which might be a better bet.

    No, making 12V into 120V to power a 120V converter to make 12V is not going to be efficient. Charge your batteries off the solar with a quality solar charger directly.

    So, a quick and dirty calculation is 100W of solar capability per 12V battery to charge it fully in one day. The problem is, that calc depends on good sun, all day. In winter, there is less sun overall, so that may not get you where you need to be. You may need to bump that up some to 150W per battery. Also, you can't deplete a battery to less that ~70% charged (depending on the type of battery). So, you may not have enough amp hours in your batteries to run the furnace fan without dipping below the recommended bottom charge state and potentially causing damage to the batteries.

    It sounds simple at first "Add solar, free power forever" and many come to that siren song, but there's some challenges to overcome to make that a reality.
     
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  5. jmkay1

    jmkay1 2004 Fleetwood/Coleman Utah Gold Supporting Member

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    I bought a 100watt solar panel that actually came with almost everything I needed. I only had to buy the cord to connect the controller to the battery which on mine was alligator clips so it was insanely simple to attach and detach when needed. It was pretty close to a plug/ play system as you can get. I lucked out as there was a sale on my setup on Amazon so didn’t spend much. Later I plan to upgrade the controller to something better and easier to read, but it works. The furnace is a huge power draw so even with solar power, conservation will be key. When on battery power I keep my furnace at 55 degrees and only turn it on just before bed. I do sometimes crank it up to 65 when I’m getting ready for bed and knock it down to 55 when I crawl into bed. I sometimes turn it up when I crawl out of bed then turn turn it off during the day. With heat retention measures My solar has had no problem keeping up with this usage at least in the fall and night temps at 30. I don’t camp in the winter so can’t comment on that. I’ve managed to camp for many days although my propane ran out on day 4. I did upgrade my battery to a group 29 so I had more amp hours to play with.
     
  6. NaterPotaiter

    NaterPotaiter New Member

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    Wow, everyone gave me a lot to think about. Sounds like I should adding a good controller to monitor the battery anyway. I bought my a-rame used and it looks like they have 2 6 volts batteries running in series so would it just be as simple as plugging in one wire to the negative on one battery and plugging the other into the positive on the other and running those to a controller that would have the solar panels plugged into? If so, what kind of controller would I be looking for? Thanks again for everyone's help.
     
  7. rsdata

    rsdata Active Member Gold Supporting Member

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    You really need to answer the question asked of you as to just how much power you are going to demand from your batteries. Just give us an idea of what you are thinking of doing with the camper... what time of year and where.

    Yes it is as easy as you mention. Two 6 volt batteries in series gives longer lasting power than one 12V battery.
    You must always use a solar controller between panels and batteries to prevent overcharging and trashing your battery, AND to efficiently charge the battery(s) using whatever solar power is available.

    PWM controllers are cheap and they work, while MPPT controllers are more efficient in low light levels at charging but also more expensive.

    You mentioned Jackery. I have a Jackery 1000 with 2-100 watt Jackery solar panels. The 1000 has the efficient MPPT controller built-in to the solar generator Jackery box. The panels are light weight and easily deployed and re-oriented to the sun angle. THey are thin to store and use the most efficient panel available. using the Jackery 1000 is nice because your power is portable, take it where you need it anywhere and don't need to be in the trailer to enjoy that power usage. You can use the regulated 13.2 VDC output of the Jackery to juice up the camper battery in a pinch, which is more efficient than plugging the trailer into the 110VAC output of the Jackery. Just make a cig plug hookup to maybe 12 Ga wire to a pair of alligator clamps to hook directly to the trailer (series pair) battery. Jackery 12VDC power output is limited to a little over 8 amps so you do not need massive wire gauge like 6. You can use all of the included wiring to recharge the Jackery anywhere near your camp without having to worry about parking the camper in full sun. Search Hobotech on youtube for his in-depth Jackery reviews and links to his discount coupons. Good source of solar knowledge
     
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  8. Anthony Hitchings

    Anthony Hitchings Well-Known Member Silver Supporting Member

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    Yes - but be sure to include a solar charge controller in the setup - which may be included in a "suitcase" type of system. Your idea saves fussing with wiring inside the PUP.

    Be sure to check that the ground side of the circuit is in good shape.
     
  9. SteveP

    SteveP Well-Known Member Platinum Supporting Member

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    Buying a kit is the easiest way to start the solar addiction. They come with an included controller and wiring to connect to your battery. The folding/suitcase kits are pretty much plug and play. A 100 watt kit should be enough supplemental charge to get you through an extended weekend with a little power conservation on your part. If your batteries are in good shape it may be all you'll ever need. But more is always better and 200 watts should be about optimum for your battery bank. The one mod I would make to any kit would be to replace the battery clamps with ring connectors for a more secure connection.

    This is old but a very good 12 volt primer for campers: http://marxrv.com/12volt/12volt.htm
     
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  10. tombiasi

    tombiasi Well-Known Member

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  11. rsdata

    rsdata Active Member Gold Supporting Member

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    Why?

    I generalized that two 6 volt batteries in series has more capacity in amp-hours then most single 12 volt batterys
    A popular 6 volt battery from Trojan T-105 has 225 AH capacity@ 6 VDC with 2 having the same capacity @ 12 VDC. This is about twice the AH of most popular 12 VDC batteries.

    Of course there are exceptions to what I originally posted.
     
    Last edited: Nov 23, 2020
  12. tombiasi

    tombiasi Well-Known Member

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    You are using the amp-hours of the battery. The available AH is that of the lowest rated series battery. Just because you pick a 6 volt battery that has more AH then a 12 volt battery doesn't mean having two 6 volt batteries has anything to do with it. And it doesn't.
     
  13. rsdata

    rsdata Active Member Gold Supporting Member

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    I stand by my two previous posts
     
  14. tombiasi

    tombiasi Well-Known Member

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    You may but you would be incorrect
     
  15. brettstoner

    brettstoner Member

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    2 T-105 batteries
    6v x 2batt x 225ah= 2,700 watts
    124 lbs weight
    Series

    2 Group 31 batteries
    12v x 2batt x 105ah=2,520 watts
    120 lbs weight
    Parallel

    All deep cycle batteries are not designed the same. Read up on it:
    https://marinehowto.com/what-is-a-deep-cycle-battery/

    Cheapest is a single or pair of automotive SLA (sealed lead acid). Then jump up to a true deep cycle like Trojans T-105 or L16 for longer life. Or spend some more and look at Gel or Lithium if you want ultimate performance. Don't forget a good controller to match the battery type.
     
    Last edited: Nov 24, 2020 at 9:18 AM
  16. Michael J

    Michael J New Member

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    6v in series in our experience and those I work with who have campers, or motor home have way better power.
    Yes I am/have been an electrician and understand the AH of a battery no this is not a brag
    This is the reason they use 6- 6v batteries in a man lift for power 36v verses 3-12v batteries for 36 volt
    The AH on 6 volt is way better.
     
  17. rabird

    rabird Howdy!

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    I don't believe anyone is suggesting using 6v lantern batteries [Guitar]
     
  18. Michael J

    Michael J New Member

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    No, lead acid batteries, not lantern :)
     
  19. rabird

    rabird Howdy!

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    I don't believe anyone is considering series connected 6v lead acid like this 7 ah [LOL]

    I use similar 6v lead acid for wild life feeder spinner motors.
     
  20. tombiasi

    tombiasi Well-Known Member

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    We know 6 volt batteries can be obtained that have more AH than some 12 volt batteries. Simply putting 6 volt batteries in series doesn't guarantee you will get more AH than any 12 volt battery battery. specs is what would determine this
     
    Last edited: Nov 24, 2020 at 4:04 PM

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