Got my Little Starter Off-Grid 2.5+Kw System about where I want it

[Matrix]

Got my Little Starter Off-Grid 2.5+Kw System About Where I want It

This 2.5kw starter system stared in my mind as a "what if" 2 days into power loss from hurrican Irma and I was enjoying the little Harbor Freight 100watt system I threw together at the last minute to get us thru that storm. So this is my first venture into DIY solar and I wanted it to be safe so I spent the extra money to get all components that were certified UL 1741.

Basic System was purchased from Webo Solar who I believe gave me a very fair price on all the components.
- 9 REC TwinPeak 2 Poly 285w modules connected 3S 3P (2,565 watts / 95.7 vmp / 89.1 charging amps)
- WEEBs for the racking system and 10 awg solar wire
- MidNite Solar MNPV3 Combiner Box
- MidNite Solar Classic 150 Charge Controller
- MidNite Solar E-Panel. Which is the Electric service panel for the whole system and made install and connection to the Inverter a snap
- Conext SW 4024 Inverter and Control panel
- All appropriate size breakers for the electrical
- 4 Trojan L16H-AC 435ah batteries in series 24v (purchased from a local battery supplier so I did not have to pay freight)

All other components like racking system, and electrical supplies came form local vendors like Home Depot, Lowes and Electrical Supply companies.

So far after a month the system has exceed my expectations powering most of my home's daily needs including well pump, fridge, lights, fans, propane gas stove starters, internet, tvs and computers ... all while never discharging past 35%. We have been running the system 24 / 7 since Oct 16 (I will now turn the fridge back to line side and run it on grid as it seems to be the biggest daily draw at 2.7 Kw hours per day. I want to try to make the batteries last as long as possible and doing so will only discharge the batteries about 20% each day)

The install went like this ... A big truck full with a pallet of Panels showed up at my house about 10 days after I placed my order for the REC TwinPeak 2 panels from Webo Solar.
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Supports for Unistrut Lagged to Roof like this

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The Unistrut Looked like this

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And it went up like this

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Into a MidNite Solar Combiner box just under the Array thru the Soffit in the Attic via 10 awg Solar wire

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This all ran down to the garage in conduit with #8 awg THHN to the E-Panel and the Midnight Solar Classic 150

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[Matrix]

Most of my ideas for the Hot Water heater Dump load came from this web site ... and Pete's PDF. Both of these helped me visualize just how totally easy it would be to heat water with solar panels, and with a few tweaks to their ideas, and Connecting the system to my AC side using L1 out of my inverter ... the set up was pretty much a no brainer. It is doing everything I want it to do. We have been off-grid with the hot water heater for 10 days now ... and have only had to use line power to heat the top twice. All other days it was free solar heated hot water.

Here are the links to the info I found most helpful Again thanks to Pete, as he has been very helpful in emailing me and actually looking at my set up and walking me thru the process.

Midnite Solar SSR Discussion (you can go back and read it all if you like)

Converting an AC water heater to DC (or splitting it AC line and DC solar)

How to Harvest Surplus Energy

Pete's PDF on the Subject
- he has been very helpful to me personally

[Matrix]

The Midnite Solar E-Panel made for a very straight forward load panel connection to the Inverter. #8 was used to connect the PV to the CC and #4 was used to connect the CC to the battery breakers for charging. 4/0 then ran to the batteries from the inverter thru a 250 amp DC breaker. AC in to the inverter and AC out from the inverter was run wiht #8-3 NMB with ground. IMG_20171014_192958517_HDR.jpg



And it all came out pretty clean IMG_20171015_223110157_HDR.jpg



Happy Stash of Brand New Trojan L16H-AC 435ah batteries IMG_20171011_093557030.jpg



So I closed up the Wall and Built a Nice battery box outside the shop in a carport using 10' 4/0 battery cable to get the batteries and gassing effect away from the system IMG_20171114_094036469_HDR.jpg
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Locked the box And secured it with a Wireless Alarm Sensor Door Contactor Connected to my monitored alarm system IMG_20171114_094241300_HDR.jpg



I was happy so Far .... The system was performing as Expected... Except ...

[Matrix]

Well Except it became very apparent I was not Fully utilizing the potential of the Array. What to do? What to do? I was dumping excess power in the Sand every day. So More research ... and I came up with the idea of a dump load using the Midnite solar Aux 1 Waste Not feature. I connected an AC 120v 40amp SSR controlled by the low volt signal of the Classic 150s Aux 1 port ... and presto, with my water heater, now split into 2 parts: 240v upper element connected to grid ... the lower element running at 120v now only draws 1140 watts. Perfect dump load. The element is a bit too large unless I have full sun, so I am changing it out to be 750watts tomorrow. And I am still tweaking the settings in Aux 1 of the Classic 50, but it working as expected, taking my daily power generation with full sun from 4.5Kw previously with out dump diversion to now 10.2 Kw per day on a good day. Perfect. Wast Not Want Not.

Crydom D1240 DC control / AC Load SSR is mounted on a Heat Sink with thermal paste. It is connected to the L1 side of the inverter ... which has more than enough extra power to power the 1140watt load as the inverter was way over sized for my load and needs. Although I am dropping the element size to 750 watts to get better performance and dump on less than perfect days. With 1140 watts, if the sun is not out fully the Aux 1 turns the element on and off every 15 seconds because there is just not enough power to charge batteries and power an element that large. Eventually I may get a larger array.

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Mounted inside the extra space of the E-Panel ... and doing its job flawlessly.

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So now excess power problem solved. Just need to do some tweaking, Change from teh 1140w to 750w and the system should be pretty much dialed in. Been very happy with the end results. Thanks for all the help you folks on this forum have given me.

[Matrix]

As an extra layer of control, I installed this Reliance Controls 306 CRK 6 circuit generator transfer switch. Using it as a Solar / AC line transfer switch, the 306 CRK lets me switch out up to 6 connected circuits from solar to Line load electric depending on my conservation. All from inside the house in the closet where the main load panel is located.

I then took the Generator Connector and back fed it into my main load panel, and using a generator safety switch, now I can power off of Solar / AC Line / Or Generator, which ever is available. My inverter charger can also be powered with either AC line or generator so I can charge the batteries with or without sun and with or without AC Line Power if the grid goes down.

I ran #8-3 NMB with Ground between my Inverter's L1 and L2 and the 306CRK breaker busbar replacing the smaller wire that was on the bus bar from Reliance. So rather than a Generator Transfer switch, the 306CRK functions as a Solar transfer switch.

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[Matrix]

Here is a link to the Reliance Controls 306 CRK

http://reliancecontrols.com/ProductDetail.aspx?306CRK

[Mike90250]

Bummer about punching bolt holes through the metal roof. There are special clamps (structural) to mount racking to standing seam roofs without having to drill holes. Otherwise, it looks nice, and if you have excess power for water heating, why not run the fridge off the array instead of a water heater ?

[papitohead]

Awesome. You have done a very good jop. Thanks for sharing.

[Syberdog]

Very Impressive and nice job.
I noticed the flex cable coming off the roof- didn't see any securing clamps etc, might want to check that against movement under wind.

[PNPmacnab]

Good to see you are heating water with excess. Our gas water heater failed just before a trip. Picked up an electric water heater I had in storage on the way back. I ran that on 120V AC or 700W for a couple years till I attached an external heat pump to the tank. We are low use, but we had no shortage with the power that low

[Matrix]

Bummer about punching bolt holes through the metal roof. There are special clamps (structural) to mount racking to standing seam roofs without having to drill holes. Otherwise, it looks nice, and if you have excess power for water heating, why not run the fridge off the array instead of a water heater ?

Thanks for the compliment. As the the Fridge, Already running the Fridge and still coming up "short" as the case may be. Have been running the fridge the past month. My typical KW per day was about 5-6kw. Once I threw the hot water heater in it with an 1140w element, my power generation jumped to 10.2kw with the fridge.

I could run the fridge in ideal conditions, but now that i know it works I prefer to save the batteries not discharging so much.

Doing the Water heater gave me just one more off grid option, that would not have to be Gen powered if a black out. So having the ability to heat water thru the solar is just one more convenience in case of the worst.

[Matrix]

Awesome. You have done a very good jop. Thanks for sharing.

I hope this helps if and when you start your project. Let me know If I can help you further.

[Matrix]

Very Impressive and nice job.
I noticed the flex cable coming off the roof- didn't see any securing clamps etc, might want to check that against movement under wind.

Thanks. the Flex on the roof is clamped at the rack, then it makes the 18" run to the edge, makes the 180* turn where under the eve there is another clamp. It is just not showing in the pic.

[Matrix]

Good to see you are heating water with excess. Our gas water heater failed just before a trip. Picked up an electric water heater I had in storage on the way back. I ran that on 120V AC or 700W for a couple years till I attached an external heat pump to the tank. We are low use, but we had no shortage with the power that low

Just did a complete cleaning of the Hot Water tank today and bleached it out and the lines too. Once done I removed the lower 4500w 240v (that was running at 1140w 120v) element and installed a 3000w 240v / 720w 120v element today running at 720w off the inverter. 1140w was just too much of a dump load. It was not staying on enough and fighting too much with the charge side of things. I think the 720w is going to work really well because the load will not be so much (1140w) that it keeps pulling the battery/system volts down and kicks off ... but it should just match up nicely so it runs all day. I have the stat set to 160* so as it will shut off if needed, but won't unless very hi temps are met.

I also just swapped out my lower stat today with a second upper stat. This way the 240v supply has a rest button ... and the lower 120v stat has a reset button too. The way it was before, the upper stat was the rest for both upper and lower as they were tied together, but now that they are on separate circuits, I thought it might be best for each to have its own reset button.

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[NEOW]

Matrix, thanks for sharing, you have done almost exactly what I want to do. I'm sure I'll have PM's for you at some point.

Question, why did you go with the MidNite Solar Classic 150 Charge Controller over say the Conext^TM MPPT 60 150 or a Morningstar MPPT 60?

Can the Midnight controller talk to the SW 4024 via Xanbus?

Although I have no plans to grid tie I'm torn between the SW-4048 and the XW+5548.