Does this system look OK (balanced),etc. for my needs?

Rngr275 Solar Expert Posts: 127 ✭✭
12 of these panels:
STC Power Rating 240W
PTC Power Rating 213.4W 1
STC Power per unit of area 13.5W/ft2 (145.5W/m2)
Peak Efficiency 14.55%
Power Tolerances 0%/+5%
Number of Cells 60
Nominal Voltage not applicable
Imp 8.04A
Vmp 29.9V
Isc 8.6A
Voc 37V
NOCT 47.9°C
Temp. Coefficient of Power -0.43%/C
Temp. Coefficient of Voltage -0.122V/C
Series Fuse Rating 15A
Maximum System Voltage 1000V

(1)- Mini Magnum MS4448PAE Power Center (4000w 120/240V), with charger/controller and monitoring
(8)- 6V Surrette S-530 400AH batteries or (8) Trogan L16RE-B 370AH (1-2days)

Charts say 4hr sun average... I am thinking 3 is more like it.... 2 in the winter.

This was proposed from an installer.

Looking to support about 5Kwh a day (maybe a little more)

I can bump up panels to 3.6Kw for ~ $3K installed.... opinions on whether this is worth the cost (might be nice to have a little buffer)

Whet size Generator (min) would I need? I can get a 7.5K for a really good price right now. Is that big enough?

Thanks Gents


  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Does this system look OK (balanced),etc. for my needs?

    although you give details on a proposed system, you fail to go into its applications to even say if you need a larger pv array. assuming it would cover your loads, then fine, all i can say is people are having trouble with surrettes right now so i'd go with the l16re.

    as far as a generator goes, this too depends on how it's to be implemented. if it's just to backup the pvs once in a blue moon then it may only need to cover the loads while solar charges, but if you intend loads as well as charging batteries often then you would need at least those combined. loads are also variable and can be spaced out for if you run everything at once this can severely up the load requirements. to space loads apart may increase runtime on a smaller genny.
  • Rngr275
    Rngr275 Solar Expert Posts: 127 ✭✭
    Re: Does this system look OK (balanced),etc. for my needs?

    My appologizes Niel... This is for my Off grid new to me Amish house. Using a kill-a-watt and figuring in a lot of conservation I am hoping/targeting a daily KwH need of 3-5Kwh. I'm hoping that the generator will be used to help out and charge the batteries as needed and to suppliment the system when I am using some shop equipment if needed. I plan to (we all try) to plan space out loads as much as possible, though this may not always be practical.

    I am very cherry at all this and my family is depending on me to make good choices and decisions. We all realize the huge change that will be needed in how we use electricity. I just want to be able to have a fridge, a few lights and a TV now and then for the X-box (keeps the kids happy). I have done a number of load evaluations now with estimated and actual whr measurements and it always ranges from 2.5-6Kwh per day. So since I am not rich I have been focusing on a medium sized 2.5-3.5Kw PV system. Which I hope to get at least 5Kwh out of on average.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Does this system look OK (balanced),etc. for my needs?

    i am one who thinks the worst case situation would be better to go for, but often it is costs that often lead to a compromise. go with what you can pv-wise and think of expanding on it later for loads only increase. (ask anyone who is off grid and they will tell you that too.) the generator is now a bit more important as i'd want it to be able to charge the batteries as well as handle loads. others here can probably give better specifics and, although inverter/generators are efficient, this may get negated as you might need to run them top out or go with more than one of them so a standard energy hogging high power genny may be needed. this gets into the area of gasoline storage and in general opens up a can of worms in options and opinions on options.

    a higher wattage pv system might seem like an answer, but i know how the weather is and it seems like murphy controls it sometimes and this is worse in the winter when there's less optimal sun to begin with. you will still need the genny to back you up. i'll take a back seat for now and allow some feedback from others as i don't have concrete answers for you and this is something you will need to evaluate. also, see what the installer says and compare to what we say.

    btw, no appologies are necessary.
  • Eric L
    Eric L Solar Expert Posts: 262 ✭✭
    Re: Does this system look OK (balanced),etc. for my needs?
    I can bump up panels to 3.6Kw for ~ $3K installed.... opinions on whether this is worth the cost (might be nice to have a little buffer)

    Is this $3K just for the upgrade from the 2.8 KW system to the 3.6 KW of pv? If so it seems very expensive for only an extra 0.8 KW, but of course I don't know the situation with mounting at your location. If it does cost that much, I would say it's hard to justify at that price.

    One suggestion: you could go with the original proposal, then purchase install extra panels yourself later at significant cost savings. Look into DIY mounts, e.g.

    I have the same Magnum MMP panel and inverter model you're considering. As you'll see, it's easy to wire-in a second charge controller for additional panels later, after you're more familiar with the system. Alternatively, if you buy more of the same or very similar panels yourself, you might even be able to use the controller with the original system (you didn't mention the model).

    For reference, I was able to expand my system with another 1.7 KW of pv for about $1.36/watt (including panels, shipping, fusing, second controller, DIY ground-mounts).

    As I think I've mentioned to you in another thread, I have a similar-sized battery bank and 4.1KW of panels and it can deliver at least 5 KW of power per day with over 95% reliability (only prolonged rainy stretches prevent it), but of course that's at my more southern location (Gulf Coast).