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Oscar_P's avatar
Oscar_P
Explorer
Apr 05, 2018

Solar assistance

I have a solar panel that is rated at 315w@9a. My converter in the camper is a BW Model 6406, which apparently means it will allow me to run off of batteries for my electrical needs, but will not charge the batteries. I'm trying to set up a solar system, but am over my head with the information I've been gathering and I know I will run out of time before I get it all narrowed down and installed, so could y'all lend a little assistance?

I'm trying to figure out a decent set of batteries to run and which inverter to get to charge the batteries. My electrical needs are not huge, 3 lights that will have LED bulbs soon and one furnace fan. Electrical will not be used during the day, lights will only be used for about 1-2 hours max and furnace ran as long through the night as possible. I'll be boon-dock camping in the Colorado mountains, so no option of shore power for recharge and wanting to fight off the sub 32* nights.

Can anyone help guide me to the proper size batteries and inverter needed to be a close to self sustaining system working with what I already have? I'm not asking for anyone to do the shopping for me, just getting confused on the exact specs I need for this.
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  • work2much's avatar
    work2much
    Explorer
    Apr 05, 2018
    2oldman wrote:
    I'd suggest you start by reading this: 12v side of life.

    work2much wrote:
    As far as inverters you need to calculate your max draw and size. 1000 Watts should be more than enough for your battery capacity..
    I didn't see anything in his post indicating he needs an inverter. I think he's mixing up terminology.


    After rereading again I think you are correct.
  • kerrlakeRoo's avatar
    kerrlakeRoo
    Explorer
    Apr 05, 2018
    OP, as others have said, Go with the 6volt if possible, Fitznj also mentioned winter camping in a pop up and listed the buddy heater, if you are trying to heat a pop up as was listed in your earlier post, thats an almost continious user of heat. The Buddy heater will be more efficient use and wont deplete your battery like the furnace, and the Wave heaters may well be even better for your usage. Olympian 3 unit will be able to run at a very low heat level 3000 btuh on high and about 1600 btuh on low. with the small space your looking at, the tiny heater like this would greatly extend your battery time since it would not utilize electricity at all. You will also see very low consumption of propane vs a furnace type of heat production.
  • 2oldman's avatar
    2oldman
    Explorer II
    Apr 05, 2018
    I'd suggest you start by reading this: 12v side of life.

    work2much wrote:
    As far as inverters you need to calculate your max draw and size. 1000 Watts should be more than enough for your battery capacity..
    I didn't see anything in his post indicating he needs an inverter. I think he's mixing up terminology.
  • work2much's avatar
    work2much
    Explorer
    Apr 05, 2018
    Aside from fuses and cables you need 4 basic components. Panels, batteries, solar charge controller and inverter to make your 120v power. Your solar charge controller will need to be an mppt type to deal with the high voltage panel you have. For cheap units many like the epever. For a quality unit I like Victron.

    As far as batteries I would go with a pair of 6v true deep cycle like Trojans if they fit your compartment. I also recommend a shunt based battery monitor. Again Victron makes a good one.

    As far as inverters you need to calculate your max draw and size. 1000 Watts should be more than enough for your battery capacity.

    Keep cable lengths from battery to inverter as short as possible. Use a voltage drop calculator to determine correct gauge of cable.
  • fitznj's avatar
    fitznj
    Explorer
    Apr 05, 2018
    I have the following:

    2 x 12V Walmart (group 26?) batteries
    2 x ~130W Solar panels
    1 MPPT controller

    I camp at state/ferderal parks with no hookups and have only once run
    out of electricity (when we had 3-4 days of clouds); I have all LED lights and use a Buddy Heater to warm up the camper - I am careful to minimize my use of the furnace.

    I do carry generator during the winter months when electrical loads are higher.
  • mkirsch's avatar
    mkirsch
    Nomad II
    Apr 05, 2018
    An inverter is used to take 12V DC from a battery and turn it into 120V AC power to power devices that are not available as 12V DC devices. That is not what you need to charge the batteries.
  • donn0128's avatar
    donn0128
    Explorer II
    Apr 05, 2018
    You need to match battery capacity to panel capacity. Basically a 125 watt panel should be OK for two 12VDC batteries. 250 watts of panels will give you a bit of margin on cloudy rainy days. Be sure to include a good charge controller to your system. You will wire the solar directly to the batteries. The batyeries then will power your house systems.
  • Oscar_P's avatar
    Oscar_P
    Explorer
    Apr 05, 2018
    I'm thinking I have room for two batteries in the system, but not sure if they should be 12v or 6v for my application.

    6v seems to have the greater Ah ratings, but there has to be an advantage to running the 12v since that seems to be standard for most people's setups.

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