looking for feedback on plan for small solar setup

[burnt]

Hello! I'm new to the forum and new to solar. I've got a strong carpentry background and have done a lot of residential AC wiring and some DC boat wiring, but am definitely on a learning curve with the solar.

I'm planning and building a small solar power system for my family's off-grid cabin in northern Minnesota. We're planning to limit it to DC only - basically running a DC fridge-freezer, a few lights, and charging capability for phones, a CPAP battery, etc. We use the cabin May-October. I've drawn up a plan and it occurred to me that it would be useful to run it by you all in this forum, if any of you are interested and wiling to give me some feedback.

Some general points:
1) For our DC loads I'm planning to use a Blue Sea marine 12V circuit breaker panel that is rated for only 45A, so that's why I have specified a 40A breaker between the battery and the panel.

2) The panels are Hyundai HiD-S300RG(BK) 300W panels.

3) We've decided to go with the Classic 150 for a charge controller even though it is a bit of overkill. I really like the ground fault and arc fault protection, the overall quality, the user community, etc. Also if we expand the system later we won't have to upgrade the controller.

4) The drawing isn't 100% complete; for example I didn't draw in the wiring for the surge protector (Midnite MNSPD-300-DC). Also the labeling is probably a bit cryptic and I'm not much of an artist!

Anyways, thanks in advance for any feedback you might have and for the info I've already gleaned from this forum.

-OAO

[ClassicCrazy]

If you want to make your wiring easier and neater , get a Midnite MNDC box . You can mount the Classic on top of it and the holes line up. It also has an inverter breaker built in - for the future if you don't want one now you will be ready. It has place for 5 DC Din rail breakers so one for PV in , one for Bat out  and then you have three other spots for DC breakers so you could maybe not have to get the other DC breaker box. Otherwise another option is to use Midnite combiner box for a DC breaker distribution - they have them different sizes.

I would use the maximum size wire for  your PV in and use the max breaker for that wire - so if you expand in the future you are all set up and using larger wire is less voltage drop. So 60 or 63 amp 6 gauge on PV in and then 60 amp out to batteries. If in the future you max out the Classic  you might want to change the battery out to 100 amp breaker and that uses 4 gauge wire but you would have to use different stud mount breakers and then only three of those fit in MNDC box.

The nice thing about the MNDC box is that the schematic is right there  ( ignore the arc fault part of it drawn in ) .
take a look at the manual to see the schematic and compare your wiring
http://www.midnitesolar.com/products.php?menuItem=products&productCat_ID=8&productCatName=Mini%20%20DC%20Disconnect

Your are wise to get the Classic now since not only room to expand but you will get the very best monitoring capabilities - lots of options there with Midnite monitoring or other open source software options. You can't do that with the Kid model.

Oh make sure you don't get the Classic SL model -  you probably know that already but just in case - it is missing features of regular Classic.

Getting one of the inexpensive hydraulic crimpers from Harbor Freight or elsewhere makes putting terminals on big wire easy and quality connection.

I didn't look at your drawing too close  yet . Vic may weigh in - he is the pro at critiquing and installing systems ( as are others ) .

Larry

[Vic]

Hi burnt,

Classic Crazy Larry,   has given some very good advice  --  using the MidNite MNDC box,  and MN breakers,   and choosing  the Standard Classic.

He linked to the manual,   the following link to a reseller will give you some info,   and an idea of the selling price,  if you have not already looked for that:
https://www.solar-electric.com/search/?q=mndc+125

The MNDC ### Plus  would be preferred  (probably),  as this model includes that bracket that allows the use up to five of the MNEPV DIN-rail breakers,  or the use of fewer Panel Mount breakers,   as Larry noted.

Blue Sea makes some good products,   but starting with MidNite boxes/panels,  circuit breakers,  etc,   gets you into the Industry Standard designs that meet,  and are tested to ETL (and other Safety agency)  specifications.   The MN breakers are switch-rated,   and are speced to very high DC interrupting currents for many thousands of cycles,   which is very important on the battery side of the system.

EDIT:  Will add this brief comment   â€¦   appears that you have not returned for five days,   and may not do so   â€¦     but,   would suggest that you pay careful attention to the power consumption of that refer/freezer.   Choose one which is Energy Star rated,   and you have enough battery capacity to run it in the environment where it is located.<

Please let us know how your design is proceeding.   Thanks,   Vic