Proposed Off Grid Solar Panel System

[oudin_coil]

I am putting the parts together for a mid-sized off grid system that I would like to assemble in early spring. Attached below is a quick schematic I put together so that I have a plan in place for assembly. Does it look right or am I missing something important?

Thanks

 

[Craig]

The 6 awg wire may be a bit small for 80 feet of distance from SCC. If your panels are 3s going in to combiner pox you will need 20Amp breakers

 

[oudin_coil]

The 6 awg wire may be a bit small for 80 feet of distance from SCC. If your panels are 3s going in to combiner pox you will need 20Amp breakers

Just to clarify, this combiner box has four pairs of inputs. I figured I could use three sets of inputs, string three panels in series into each pair.

I thought the series configuration would be additive for the voltage but not the current.

 

[Craig]

Ok my misunderstanding I see what you are doing now. yes he 10Amp breakers should be fine.

 

[MichaelK]

What's the specified charging rate of your BYD batteries? Looking at their spec sheets I didn't find anything pertaining to that. With only 9 panels, I'd expect you to only get about 35amps of charging current at noon, and significantly less the rest of the day. Will the panels be mounted on fixed frames or will they rotate and be seasonally adjustable. I've seen my output go up by about 50% per day rotating my panels more or less to face the sun. Here's a pic of frames designed to hold three panels. It's made out of welded unistruts, schedule 40 pipe, and rebar. I don't recognize that brand of inverter. Is it designed to be used with a power center? A power center would hold the DC breaker designed to cut power from the battery to the invert, so fusing would not be required.I would also up the diameter of wire leading to the inverter to reduce voltage drop. I'm using 0000 diameter wire to connect my inverter.

 

[Solar addict]

hi, i found the following info that you might find useful about the battery

 

[Steve_S]

Hmmm, I have 8x CS260P (260W Canadian Solar Poly's.) 4 per string, 2 strings. BY noon I'm seeing 1800W 70-75A coming from the Midnite Classic 200 Solar Controller. From Panels to Powerhouse (DC) I am running AWG-8 for 45' and zero issues. Of course it all hinges in the SCC and it's capabilities, I don't know the MPP product line but they appear to have reasonably respectable specs, so it's a matter of finding the "sweet spot" for the configuration relative to locality.

I thought I read in a post that MPP has a Panel Configuration tool maybe it was another company. Victron, Midnite have that tool on the websites for their products.

@oudin_coil you have all the right bits & pieces shown in your logical diagram. The BATT fuse I see is for the "pair" correct ? I would suggest a MRBF fuse on each "pack" to protect them individually, as one could drop out while the one is live. I've really come to like the MRBF's and use them only now for the batteries.

Fuse Block kit wit 150A fuse = $25 ea.

Bay Marine – Marine Rated Battery Fuse and MRBF Single Fuse Holder Kit – 30-300A | eBay

Choice of Fuse Sizes Available: 30A, 40A, 50A, 60A, 75A, 80A, 90A, 100A, 125A, 150A, 175A, 200A, 225A, 250A, 300A. Fuse Size List Ignition Protected – Safe for installation aboard gasoline powered boats.

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