slayden an new at this

Slayden
Slayden Registered Users Posts: 2
what can I do with 4 235 watt solor panles an what inverter an how many batteries to make it work correctly

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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: slayden an new at this

    Welcome to the forum.

    Well there's a lot you can do with four 235 Watt solar panels. You could give them to me, for example. :D

    Honestly, you're sort of going about it the wrong way 'round unless someone gave them to you. Normally you determine the power need and then the batteries to supply it and then the solar panels to recharge the batteries.

    But let's see what we can do from the other direction. The panels are probably "GT style" with a Vmp around 30, judging by the Watts. This means they weren't meant for battery systems and can't be used on one without an MPPT controller or a large loss of power.

    Otherwise the array would total 940 Watts. On a 24 Volt system that would supply about 30 Amps peak current, which would be good for around 300 Amp hours of 24 Volt battery. That would give you about 1.8 kW hours to work with at 25% DOD. Or end-to-end about 1.9 (some power coming directly from the panels once the batteries are charged). Respectable.

    You can adjust these numbers to suit the system Voltage and some efficiency may be lost/gained depending on your particular installation.

    Inverter choice is a matter mainly of how many Watts you need to supply at any given time (not to be confused with Watt hours).

    So the real question is: what do you want to achieve?
  • Slayden
    Slayden Registered Users Posts: 2
    Re: slayden an new at this

    sharp nd-f2q235
    nd-f2q230
    we want to run lights an ref frezzer an tv for back up we were given them as payment
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: slayden an new at this
    Slayden wrote: »
    sharp nd-f2q235
    nd-f2q230
    we want to run lights an ref frezzer an tv for back up we were given them as payment

    Well that's easy enough. First thing to do; buy a Kill-A-Watt meter and measure how much power each of these things will draw (Watt hours) in a day. You will probably find the total well within the quantities I mentioned before. I know because I run about that much stuff from 700 Watts of panel.

    Now about back-up power. Usually a generator is cheaper, especially for short and/or infrequent outages. But you already have the panels so there's a $1,000 savings.

    Batteries, on the other hand, aren't cheap and will go bad whether they are used or not. As such it would be a good idea to buy inexpensive ones like 'warehouse' (Costco, Sam's) GC2's. You could put together a minimal battery bank with four of those For about $500.

    The inverter is another issue. You will not need a big one for this. The 'frige will have a high start-up demand but still be under 2kW. Some inverters have built-in chargers, which puts the price up and probably is not necessary for this application. Look at things like 24 Volt Xantrex Prosine if you can find one or the Samlex/Cotek 2kW 24 Volt units. About $800.

    You will need a charge controller that can handle those panels. As I said that means MPPT and about 30 Amps. A very good fit here is the MidNite Kid at $285.

    You will also need wiring and fuses/breakers and such, but that will be worked out once the major components and installation plans are finalized.