Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

tns5052tns5052 Registered Users Posts: 3
Hi, I'm a little confused about how to set up a Xantrex SW3000 inverter. So I'm hoping someone can clear it up for me before I buy.
I was told that I take my solar panels and hook them up to my charge controller, then connect that to my battery and finally my batteries to the inverter... right?
So then do I plug my 120v appliances like my mini fridge and microwave directly into the inverter?
Are there outlets on this inverter? if not how do I get 120v outlets connected to the inverter?
What is all this stuff I'm reading about fuses and fuse boxes and what not... Do I need that? Do they connect to the inverter?.. I'm really confused, female, and new to the solar thing. lol

I plan on putting this system into an extended cargo van I bought...
2 Solar panels = 630watts (315 each)
charge controller = Morningstar TS-MPPT-60
Batteries = 6 Trojan T-105RE (making a 12v system @675AH)
And finally, Inverter/Charger = Xantrex Freedom SW 3000
I just need to figure out how to work things from the inverter...

Thanks for any help.

Also, if I do need anything else like wires/cables/fuses/fuse box etc.. what ones should I get?
(links appreciated)
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Requirements: I plan on running my mini fridge 24/7, a waterpump, 1 or 2 lights (3-4hrs), and charging laptop occasionally (2-3hrs per day).
I figure I will need a Honda eu3000 generator for my microwave, electric heater, fans, and other random appliances..
So hopefully this setup will meet my requirements.
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-Tierra S.

I apologize if my main question about inverters has been answered elsewhere. I looked around and couldnt find anything tanswered my questions directly or just plain didnt confuse me.

Comments

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

    Welcome to the forum.

    You've got the gist of it:
    Inverter powers 120 VAC devices, batteries power inverter, panels & controller keep batteries charged.
    Some inverters have built-in outlets, others are meant to be "hardwired".

    Now for what you've got wrong:
    You do not want six batteries. For two reasons; one, three parallel strings cause problems with current sharing, and two, 675 Amp hours @ 12 Volts will not recharge well from 630 Watts of panels. With the MPPT charge controller you will likely get about 40 Amps peak current, which is about right for two parallel strings @ 450 Amp hours @ 12 Volts.

    The good news is that such would give you up to about 2.5 kW hours, more than enough to keep a 'frige going for a day. The panels should be able to supply 1.3 kW hours AC per day (4 hours of good sun) which again is about enough to run it for a day.

    Yes, there are parts of the system that will need fuses or breakers. Naturally there will need to be wires to connect it all, and hardware for mounting.

    If I were you I'd invest in a Kill-A-Watt and get some real world measurements of the power use of everything you want to run. Do this before you spend any money on anything.
  • tns5052tns5052 Registered Users Posts: 3
    Re: Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

    Awesome, thanks!
    So if I do two strings for now with 2 panels, but later decide I need more power I have enough room on my van for one more 315 watt solar panel (each panel is 65x52in, and my van roof is 66x162). Would I need to increase my battery bank if I buy that extra panel? And if more than 2 strings cause problems how do people make a larger battery bank and get around those problems?

    Great recommendation on the Kill-A-Watt, I'll be sure to get one before I make any final purchases.
    And finally, I think the Xantrex freedom sw3000 needs to be hardwired because I don't see any built in outlets in the pics. Do you have any links to teach me how to hardwire the inverter?

    Thanks again!
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

    What you're looking at is the balance between battery capacity and solar charge capacity.
    The basic rule of thumb is that if the array can provide about 10% of the battery capacity in peak charge current and the batteries aren't discharged below 25% it works.

    Example:
    Two parallel strings of the T105 for 450 Amp hours @ 12 Volts. 10% would be a peak charge current of 45 Amps. 45 * 12 = 540 Watts, and after factoring the usually efficiency drop (77%) with an MPPT controller you get (540/0.77) 701 Watt array.

    Your 630 Watts would give you (630 * 0.77 / 12) 40 Amps, which is 8.8% of the battery capacity.

    You can also compare the battery capacity in AC Watt hours to the array's potential:
    450 Amp hours * 0.25 (DOD) = 112 * 12 VDC = 1350 Watt hours * 90% conversion efficiency = 1215 Watt hours.
    And:
    613 Watt array * 4 hours minimum good sun * 0.52 over-all efficiency = 1275 Watt hours.

    See how nicely 25% DOD matches to an array capable of ~10% peak charge rate? :D
  • tns5052tns5052 Registered Users Posts: 3
    Re: Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

    Okay, let me see if I got this right then. Two strings of batteries giving me 450ah /12v with the Two 315wat solar panels is "almost" perfect, and "almost" 10% battery capacity (you said 8.8%)
    So if I would add one more solar panel I would get more than 1.3 kW hours ensuring my fridge stays on all day. This would also make sure that my batteries get a higher charge throughout the day, more than that 8.8%.. Which is better right? Sorry, it's just difficult for me to understand lol, being new to all of this.
    Anyway, if you think the extra solar panel would make things more efficient with the 4 batteries then I'll just go ahead and get 3 of them, max out the space on my van roof, and save on shipping.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Solar noob, Inverter to appliaces, or Inverter to fuse box to outlets to appliaces?

    If you add a third panel you get 945 Watts of array. Typically that would perform as:
    945 * 0.77 / 12 = 60 Amps peak current (maxing out a 60 Amp MPPT controller).
    60 Amps to 450 Amp hours of battery is (60 * 100 /450) 13% charge rate, sort of the upper end of practicality.

    So it will recharge quicker, and it will recharge better on less-than-perfectly-sunny days. It probably will not be a problem for stress on the batteries as most of the time you will not see this maximum current.

    Also there is the matter of "surplus" power; power available from the panels which is not utilized once the batteries are recharged but the sun is still on them. You will have plenty available. This power will, for one thing, run the refrigeration without the system having to draw from the batteries for as long as there is sun enough to support the load. That effectively gives you a bit of "bonus capacity".

    Looking at the 945 Watts using the Icarus Formula:
    945 * 4 hours of good sun * 0.52 over-all efficiency = 1.9 kW hours AC per day
    This assumes all powered stored in batteries, but does not include any "surplus" power as mentioned above, so you can come out ahead. It would also support a larger battery bank, but you probably won't need it; as it is you've got about as much storage capacity as I have to run the whole cabin (450 * 12 = 5400 Watt hours total, I've got 232 * 24 =5568 Watt hours total). And you don't really want to parallel more than two battery strings (be sure you connect them right also: do not "ladder" the two strings; take the negative from one and the positive from the other).

    Keep in mind that with three panels in parallel you need to put a fuse on each one to protect things in the event of a short in one of them.

    How are we doing so far?
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