# Solar set-up system check, could someone smart confirm this?



## Noahchardy (Jun 22, 2014)

My wife and I are building our house completely off grid. We are to the point where we would like to start living in the house, but I have installed the solar yet. Well, I may purchase the equipment this week and I was hoping some nice folks on here could give some final input on whether my set up is on the right track.

I am hoping to run:
6 Avancis 115w panels
1 Sunriser 30amp mppt charge controller
8 Trojan T105 6v's wired series/parallel to 24v
1 Magnum 1500w inverter/charger

I want this setup to power a dorm sized fridge and a chest freezer primarily. I also would like to get some DC LED's to brighten the place up at night and simple cellphone charging. If it turns out I have enough extra to charge the laptop the great.

I don't have anyone here that knows solar well enough to bounce this off of, so I was hoping for some help. Thanks!
Also, we are in Michigan. Should hope for 3 hrs average sun at the darkest part of the year.


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## TnAndy (Sep 15, 2005)

3 comments:

1. I'd put in a larger amp charge controller, like an Outback FX60, so if you find you do need more power, you're already set up for it controller wise....you'd just add more panels rather than later have to add bigger CC.

2. I assume you're gonna plan on running a generator some

3. You might closely check the power use of that 'dorm' fridge. Lot of them are real power hogs, their size not meaning low power use. You might be better off to get another small chest freezer of equal,or even slightly larger, cubic foot, and run an external thermostat to make it into a fridge. I'd almost bet you could cut your power use significantly....a 5-7cuft chest freezer will consume only 100-150 watt hours of power a day !

http://www.kegman.net/9025-freezer-temperature-controler-freezer-tamer-9025/


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## Noahchardy (Jun 22, 2014)

First, THANK YOU! and in response to your comments...

1. that is some good info... are charge controllers something that wear out, or if i decided to upgrade would I just have an extra charge controller lying around? Maybe I could just upgrade panels when it comes time for a new controller?

2. I plan to run the generator every other day for an hour or so, maybe more. We have some big loads that don't make sense right now to size for solar. Like vacuum, wash machine, well pump.

3. I have shopped the fridges pretty extensively and narrowed to the most efficient small fridge I can find. It was a happy compromise between the wife and I. While no where near the 150 watts, the one we found was around 600 daily. I'm hoping to meet/beat that as we have already been practicing more efficient refrigeration techniques.


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## wy_white_wolf (Oct 14, 2004)

Noahchardy said:


> ...I want this setup to power a dorm sized fridge and a chest freezer primarily. I also would like to get some DC LED's to brighten the place up at night and simple cellphone charging. If it turns out I have enough extra to charge the laptop the great.
> 
> I don't have anyone here that knows solar well enough to bounce this off of, so I was hoping for some help. Thanks!
> Also, we are in Michigan. Should hope for 3 hrs average sun at the darkest part of the year.


 You're dreaming on the 3 hours of insolation. From what I've seen no place in Michigan has over 2 hours in December or January with most running 1.2 to 1.5 hours a day. http://www.gaisma.com/en/dir/us-mi-country.html 

You've done a poor job of defining you loads so there is little we can do to determine if the system is sized properly. Define the total usage in KWH per day and we might be able to help.

It would be best to forget about the 115W panels. You can get 250W+ grid tie panels for less and use an MPPT charge controller to bring the voltage down. With the low insolation you'll need the MPPT to make the system as efficient as possible.

Also with the low insolation pay attention to the battery to array size. FLA batteries need to have a charge rate between C/8 and C/12 to properly charge. C/10 is usually ideal. Going straight by the load numbers gets you to high of charge rates in low insolation areas.

WWW


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## Steve_S (Feb 25, 2015)

Take some time and do some careful shopping. The 100-200 Watt panels will cost you far more per Watt than 250-350 Watt panels which can be had for less than $1 a watt. You'd be far better off buying 4x 250 Watt panels... Price Compare and Consider it.

The Triststar MPPT 45 & 60 Charge controllers as most other decent controllers will handle the higher voltage / amperage panels and can handle more panels down the road if needed / wanted. These are reasonably priced and feature rich as compared to Outback or Midnite without extra add-ons. 

Charge Controllers do not wear out as such... Their firmware can be updated if need be. Many do have cooling fans which can fail over time but these are not a big deal to replace.

*The Inverter / Charger *converts your battery power to AC 120/240. It's extra to get one that does 240 volts and as that isn't necessary for you keep that in mind. IF POSSIBLE, get an Inverter/Charger Combo unit which will do the charging of your batteries as well for you, these usually have 45 to 70 Amp chargers designed specifically for Deep Cycle batteries... Otherwise you'll have to buy another separate charger like an IOTA which while good, not as efficient for the task. NB: There are "Combi" units which even have a Generator Auto-Start mode to kick the gen-set on when batt's get low and will bypass to the cabin while charging the batteries... Here is a link to a Inverter/Charger Combo similar to what I have (Mine is 3Kw for a 24V battery bank) ZODORE-Frequency-Inverter-Charger-Converter *NOTE ! * Make sure the Inverter makes *PURE Sinewave not Modified Sinewave* There are many brands like AIMS, AnyPowerCorp which offer good units... *[TIP:] *RV & MARINE Suppliers usually carry these as they are not intended for conventional residential use but serve off-grid / cabin / homesteading quite well.

Power Efficient Fridge:
Have a close look at "Danby" brand "Apartment sized" fridges. They have 10 cubic foot units that use less than 300 Kwh per year ! I have just such a unit and it's amazingly efficient and works very well. They offer models with freezer & without. Optimally a complete fridge unit and a separate freezer is the most efficient as neither has to compromise for dual use making them more efficient (power frugal). danby.com Apartment Size Refrigeration


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## manolito (Apr 7, 2013)

Are you going to use propane for cooking in the house? If so look at propane refrigerators. The information given is the best about size of panels. Where is the water coming from? Solar well pump? Wind gravity etc. 

Remember panels start out with a igh number but their efficiency decreases as time goes by. 

Are you going to rotate or track the panels with the sun? As said a lot of unanswered questions. 

Good Luck and just for fun figure the value of product in the average chest freezer you might be surprised how much money can sit in the freezer for winter use.


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## Noahchardy (Jun 22, 2014)

Awesome, thanks everyone for the info. To answer some of the questions; I primarily want the solar system to run a fridge(small) at 620 watts daily, and a chest freezer at 910 watts daily. Anything more than that is gravy on top. 

I do plan to change the panel angles 4x per year.

I have a generator to get me through the lean times and to run some of the loads that are to big for me to consider solar with now, like well pump, washer, vacuum.

So if I buy grid tie panels, I can just use an Mppt controller and its ok?


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## Noahchardy (Jun 22, 2014)

Also the reason I want to get the Avancis panels, is because the guy is selling them to me at $75 each.


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## TnAndy (Sep 15, 2005)

Noahchardy said:


> So if I buy grid tie panels, I can just use an Mppt controller and its ok?


The controller doesn't care what kind of panels you use, as long as you stay within the max voltage limits (plus de-ating for cold temps). For example, the Outback FX60 (only because I'm familiar with them, not trying to sell you one) has a voltage in limit of 150v.....say 120v for your climate (as temp goes down, panel voltage goes up)....and a total wattage limit of 1600w @ 24v output. (800 for 12v, 3200 for 48v, etc)

SO, you can wire however many panels you want as long as you don't exceed those two limits. Say you buy 250w panels, and they are 36v max....you could connect 3 of them in series, putting you at 108v input, and only 750w.

OR you could wire two pair in parallel, each pair in series, and give you 72v input, and 1000w

OR you could wire three pair in parallel, each pair in series, give you the same 72v, and 1500w.....that would about max out the charge controller on the wattage allowed.

You can do all kinds of different combinations, depending on the panel specs (voltage and wattage), but DO NOT mix panels....do all of one type....you can't run 100v on say 3 panels, and 72v on 2 more....controller not designed to handle that.

So, it's a matter of which controller you go with and which panels you go with, as to how you can mix up the way they are wired and get the maximum use out of a controller.

For example: My initial arrays were 8-- 175w panels (33v) on an FX60. 1400watts. I decided to "test" the limits of the controller, and I put another pair, for a total of 10 on the controller....1750w on a 1600w limit (24v). Guess what....I've never on the coldest day here (sub zero) seen it go much over 1600w....and that was with a bright sun on snow covered ground (lots of reflection)....so I'm comfortable with fudging that much. Not advising anyone else do it, but I do.


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## wy_white_wolf (Oct 14, 2004)

Noahchardy said:


> ...I primarily want the solar system to run a fridge(small) at 620 watts daily, and a chest freezer at 910 watts daily...


So 1530 Watthours total daily.

With an MPPT controller so your efficiency would be about 80% and at most 1.5 hours insolation in the winter.

1530*1.2/1.5 = 1224 watts minimum your array needs to be.

6*115 = 690 watts is about half of what you need. Hope you have a good genny to run at least every other day.

For the battery bank. You should never use more than 20% in 1 day. This will also give you 2.5 days atonomy before you hit the 50% level that you should never go below.

1530W/24V*5 = 318 amphours. The 8 T-105s should be about 450 so you're a little oversized there but OK.

for balance between the array and bank.

1224W/28.8V (charging voltage) = 42.5A just under C/10 so you good there if you get the proper size array. That also tells you the minimum charge controller size you need.

Your 690W array would put you at about C/20. Your batteries would exist under a chronic state of undercharge and sulfate to an early death as the charge rate is to low to keep the acid mixed up.

WWW


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## Noahchardy (Jun 22, 2014)

Thanks for sticking with me here everyone! I appreciate all the inputs from everybody. It sounds like I'm going to need more for the winter...

Would I be better off going for more solar? or diversifying to wind?


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## wy_white_wolf (Oct 14, 2004)

Noahchardy said:


> Thanks for sticking with me here everyone! I appreciate all the inputs from everybody. It sounds like I'm going to need more for the winter...
> 
> Would I be better off going for more solar? or diversifying to wind?


 Solar is for people that want to be passive in there electrical generation. that is there's very little to no maintenance required for the solar panels. 

Wind is for a person that is willing to be active in there electrical generation. With all the moving parts you need to pay attention to what's happening and do the required maintenance. The little air 403s are a good example. While they show no to little maintenance required I haven't seem one of them yet that didn't throw a blade or 2 in high winds. Don't get it shut down right away and the imbalance tears the thing to shreds.

So do you want to be an active or passive person when it comes to power generation?

Next question is do you have the wind? Unless you have daily problems in the winter with standing up straight and keep your hat on you don't.

WWW


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