Off grid proposed system

[Dmoranda]

Thank you. Timer switch saved, I like that one better. Its definitely a much more conscious device.

Ok, If I purchase MPP or Growatt, I'll use watts 24/7, not ebay.

On the AIO side, is there a competing product in growatt or another manufacturer that is a better package in your opinion? Less idle power draw? Even if I run two lower cost hooked up together.

Playing devil's advocate, what would be the 48v inverter you would recommend? I know Michael recommended the Schneider at 3k+. Also the SCC you would recommend as well? It seems you are an advocate for Victron. I'd like to see what this method would cost and compare to the AIO. I realize the AIO is more simple to set up and cost effective, but if I'm limited in expandability or some other blindspot in the future I'd like to know.

The Audit calc is currently telling me 433Ah of batteries for 2 days of storage. If I order the 280AH eve cells from Amy as you did. I would need 16 to build a 48v 280Ah battery correct? What is the rough cost per cell? In a perfect world I would double that to create 560Ah which would give me 2.5 days of storage. Would I need 2 - 48V BMS for the 2 separate packs of 16 or can it be accomplished with one?

My apologies if these are simple questions. Solar and power is a brave new world for me. Thanks again for the help.

 

[snoobler]

Thank you. Timer switch saved, I like that one better. Its definitely a much more conscious device.

Ok, If I purchase MPP or Growatt, I'll use watts 24/7, not ebay.

On the AIO side, is there a competing product in growatt or another manufacturer that is a better package in your opinion? Less idle power draw? Even if I run two lower cost hooked up together.

Not in that price range. AiO are not typically offered in the top tier options. You're paying way less for a inverter+battery monitor+SCC. The compromise is idle power. They do have a low-power mode, but they will NOT provide power during that period. They are searching for loads above X Watts, and if sensed, they will return to normal mode until the load is removed, so if you want any AC power continuously, the lower power mode is not an option.

Playing devil's advocate, what would be the 48v inverter you would recommend? I know Michael recommended the Schneider at 3k+. Also the SCC you would recommend as well? It seems you are an advocate for Victron. I'd like to see what this method would cost and compare to the AIO. I realize the AIO is more simple to set up and cost effective, but if I'm limited in expandability or some other blindspot in the future I'd like to know.

I don't have one beyond a Victron Quattro. They come in 3kW/48V flavors, but they're spendy and you need a lot of extra hardware to build one out that looks like an AiO unit. The Multiplus-II is supposed to be available in 48V/3kW with something like a 17W idle burn, but their release date for 120VAC hasn't been disclosed.

The Audit calc is currently telling me 433Ah of batteries for 2 days of storage. If I order the 280AH eve cells from Amy as you did. I would need 16 to build a 48v 280Ah battery correct? What is the rough cost per cell? In a perfect world I would double that to create 560Ah which would give me 2.5 days of storage. Would I need 2 - 48V BMS for the 2 separate packs of 16 or can it be accomplished with one?

16 is about 14kWh. I'd stick with that. They tend to be around $110 delivered. I round up to $2000 total to allow for BMS.

If you go 560Ah, 2X 16S batteries each with their own BMS is the best way to go.

 

[Dmoranda]

Still waiting on a battery quote from Michael. He’s building drop in 48v which would be nice to not have to build it.

Also working on 8 additional 305 watt panels from the original lot that I purchased from. My cousin purchased them and has not integrated them.

We have had lumber delivered to convert the flat roof into a 36 degree angle shed roof. The total area of the roof will be 16x16 which should accommodate 15 305 watt panels giving us 4575 watts of power for the first string. Hopefully integrating a ground mount as suggested for the 2nd input on the AIO system.

I am now thinking about over sizing the system and going with the Growatt SPF 12000T which has a 100 Amp output giving us more power for the shop and cabins. Any thoughts or reviews of this AIO? I know MPP and growatt are built on a similar platform, but just wanted to check.

The design has changed a bit from having the equipment directly under the shed roof which we were going to waterproof. We have since decided to trench and run the PV cables back to the shop (under A frame) to house the equipment and batteries. The shop has a retained CMU block wall and thick slab which will keep the batteries at a nominal temperature during the hot and cold months. Its probably 200+ feet of distance from the array. What gauge wire should we run for this?

Thanks in advance!

 

[Daddy Tanuki]

my advice... from the sides and giving due respect to those who know much more than me.... over size your panels from the start. you will have charging highs...and lows and anything not used the solar controllers will regulate... and in all honesty at this point and time the panels are the cheapest part of the system overall... you cannot have enough. I have a 900'² cabin and with wife, kids and a 800'² shop i ran 4k panels ragged and am now up building to 8k panels. they are cheaper than batteries, inverters, charge controllers etc. I can overpanel my magnum controllers as far as I want in all reality, 15-30% is the recommended amount on their website with their own calculator.. this means that rainy days or foggy days are not nearly as much an issue as they could be. Just a thought and if done from the start, wiring etc. will not be an issue. you got property in that area, then you have the cash flow to play with it.... don't cheap out it will bite you in the ass afterwards.

 

[Dmoranda]

my advice... from the sides and giving due respect to those who know much more than me.... over size your panels from the start. you will have charging highs...and lows and anything not used the solar controllers will regulate... and in all honesty at this point and time the panels are the cheapest part of the system overall... you cannot have enough. I have a 900'² cabin and with wife, kids and a 800'² shop i ran 4k panels ragged and am now up building to 8k panels. they are cheaper than batteries, inverters, charge controllers etc. I can overpanel my magnum controllers as far as I want in all reality, 15-30% is the recommended amount on their website with their own calculator.. this means that rainy days or foggy days are not nearly as much an issue as they could be. Just a thought and if done from the start, wiring etc. will not be an issue. you got property in that area, then you have the cash flow to play with it.... don't cheap out it will bite you in the ass afterwards.

Thanks for the advice. I totally agree. I’m going to over panel this. Still prepping the roof and getting things ready. I appreciate the input.

 

[Dmoranda]

Well I’ve tabled this system for far too long. Still toiling away in the evenings with research and notes. The ground is softening up with some light rain here in CA. We are going to be doing some trenching soon for our PV lines from the proposed array location to the A frame cabin where the equipment will be installed. I’m in a quandary about some of the equipment used and I’d love some advice. Equipment seems to be coming back in stock and I’d like to procure it before more stocking problems.

After doing some additional planning and thinking I’ve decided to increase power requirements. Going through a another brutally hot summer has motivated me to add mini split a/c units in two structures. Ideally diy Mr. Cool units that are precharged. Also I’d like to plan for EV charging down the line. The equipment I’m looking at allows us to add additional inverter units in parallel for increased power. I will be updating the spreadsheet and calcs for these power loads.

I’m considering two different all in one systems. Two LV6548’s by MPP solar or two SPF 5000 ES by growatt w/ solar edge transformer (110), both for split phase 220 power.

For batteries I’m looking closely at the EG4 48v batteries in a rack configuration with capability to expand later.

Any insights on these two equipment configurations? I will update the power calcs ASAP and post.

Thanks in advance for any advice.

 

[Dmoranda]

Update: Ordered and received (2) MPP LV6548 from watts 24/7 and (2) Jakiper 48V 100AH server rack batteries. Staging and building the system in my garage (will move to off grid shop). Doing my best to get everything in flex conduit for the possibility of rats in the shop. The rest of the components are pretty much spot on recommendations from Will’s videos. 200AMP T-class fuses, current connected bus bars, D line load center with room for expansion if I add more inverters later. Going to be installing the breaker boxes for connections to 3 different arrays. 6x305 watt, 6x305 watt and 4x305 watt. I haven’t sized the breakers yet and could use some help there.

Please let me know if you see anything glaringly wrong with connections. Much appreciated. Really enjoy this community. I’ll continue to update.

 

[Dmoranda]

Progress. I purchased 4/0 cable not knowing the lugs on the Jakiper batteries are 5/16. Looked on the Jakiper website and the company recommends 6 AWG cable. That seems so light. I have some 2/0 cable left over, but I’m conflicted whether to use it. The lugs I bought are 3/8” and are not compatible so I’d need to order some 5/16”. Any thoughts here. Thanks in advance.

 

[Dmoranda]

Alright its been a while, but I have an update. I ordered the 5/16 lugs and filed them down to fit in the Jakiper battery terminals. I was able to use my 4/0 wire that I already purchased (and couldn't return).

I think I'm almost ready to set up a couple of panels and power this up. Can someone take a look at my wiring to see if I have this correct?

Also, at the property we are in the process of finishing our roof framing for the large shed roof that will hold the array. I'll get some photos next time we're down there.

My brother in law has some long lengths of 8/4 SOOW 600volt cable from job sites. The solar array is about 200-225' away from our inverters. We will be trenching after we get some rains, still super dry. My question is this: Can we use this 8/4 SOOW cable for our PV runs back to the inverters? This would save us a ton of money in copper wire. We have (16) 305 Watt panels. It was recommended by 24/7 solar to run a 6S2P configuration with the panels to not exceed

Any input would be greatly appreciated.
Dustin

 

[Dmoranda]

Update: Trenching completed a few weeks ago with PV cable run in conduit back to shop. Inverters mounted to the CMU wall. Finished framing for the solar array. PV mounting hardware arrived and waiting on combiner boxes.

I have a couple of questions for the community.

I’ve been working with Ian from Watts247. He’s recommending a 6SP2 configuration with (12) 305 Watt panels. Connected to (2) MPP LV 6548 with parallel connection for split phase. I have an additional (4) 305 watt panels but I will exceed the 250V input on the inverters.

Is there any device (Solar charge controller or other) that I can purchase as an intermediary between the solar panels and the inverter to govern the voltage to no more than 250V?

I would like to maximize my PV input, especially on overcast days and utilize all of my panels. Ian mentioned that 6S2P would be ample input, but I’m just double checking. I don't mind spending a little more on a device to maximize the inputs.

Here are the specs of my panels:

Solar Panels Model: YL305D-30B
Manufacturer: Yingli Solar
Rated Power: 305.0 Watts
Open Circuit Voltage: 40.00 Volts
Short-Circuit Current: 9.85 Amps
Rated Voltage: 32.90 Volts
Rated Current: 9.28 Amps
Max System Voltage 1000 Volts
Max Series Overcurrent Protection Device Rating: 20 Amps

Here are the recommendations in the LV6548 manual.


I appreciate any help you guys can provide. Thanks

Additional photos attached.

 

[MichaelK]

I’ve been working with Ian from Watts247. He’s recommending a 6SP2 configuration with (12) 305 Watt panels. Connected to (2) MPP LV 6548 with parallel connection for split phase. I have an additional (4) 305 watt panels but I will exceed the 250V input on the inverters.

Is there any device (Solar charge controller or other) that I can purchase as an intermediary between the solar panels and the inverter to govern the voltage to no more than 250V?

I would like to maximize my PV input, especially on overcast days and utilize all of my panels. Ian mentioned that 6S2P would be ample input, but I’m just double checking. I don't mind spending a little more on a device to maximize the inputs.

Please do not try to fool around with some kind of voltage reducer or some other gimmick to get around your voltage limits. Just go ahead and buy two more panels and bring your solar arrays to 6S3P. They don't have to be exactly the same brand, or exactly the same voltage. Just make sure all the strings match voltage within 5%. All the amperages of a single string should also match within 5%, though between strings is not an issue.

If another string exceeds your amp limit, you can get around that with virtual tracking. Assuming that the other two strings are facing South, then have to third (or fourth) array(s) facing either East or West. That way you'll spread out your charging profile over more hours in the day. West works for me because I'm putting a lot of loads on in the kitchen in the late afternoon as I prepare dinner. If you're more off a morning person, then maybe East for early morning power would be better.

 

[Dmoranda]

I have no problem buying more panels. I just don’t want to look back years from now and realize I could have had more PV power. I don’t want to have to do this again.

I can attain 6S3P without exceeding the spec on the inverters?

Would I then get 6-2 combiner boxes to achieve this?

Thanks for your honest input Michael.

 

[MichaelK]

I have no problem buying more panels. I just don’t want to look back years from now and realize I could have had more PV power. I don’t want to have to do this again.

Nobody here has ever complained they have too much solar.

I can attain 6S3P without exceeding the spec on the inverters?

In that case, I'd say go for it.

Would I then get 6-2 combiner boxes to achieve this?

Not sure exactly what you are asking here? What is the controller setup for your AiO. Does it have one MPPT input or two?
Not sure what you mean here by a 6-2 combiner box? For a combiner, your string length is not an issue. Only the number of parallel strings. I have a Midnight 6-bay combiner box, with 7 arrays feeding it. Five of the arrays are on single 12A breakers, and the final two are on a single 15A breaker. Arrays 6 and 7 are ground mounts oriented SE, and due West, so they are never at full output at the same time.

It's OK to put two parallel strings on a single breaker as long as 1) they are the same voltage, and 2) I have a way to independently shut off each array upstream of my combiner breaker, and 3) the combined amperage doesn't exceed the amp rating of the breaker. In the case of array #6, it is actually primarily connected to system #2 for the workshop. But, the combiner for system 2 has a diversion breaker installed, so I can cut its power to system #2 and divert it to system #1 instead. It's great to implement that what 7:30am when I really want to start my wellpump, but don't have enough watts coming out of arrays 1-5. By 8:30am or so, arrays 1-5 are making >2500W, so I divert power coming from array 6 back to system 2.

Here's a pic of one of my ground mounts. If you orient panels in landscape, this frame will hold 6 high-voltage residential panels. Since it can rotate East to West, that might solve your extra production issue. You could rotate it East to make your morning coffee, then rotate it West if you want to run an air-conditioner in the late afternoon. The third array is really going to be important on cloudy days, when production drops down to 10% or so.

 

[Dmoranda]

Just exchanged another email with the vendor. He said I can do 5s2p for one inverter and 5 in series for the other inverter. That’s exactly what the structure will hold so I’m happy with it. He recommended a combiner box at the array for safety and testing should anything go wrong. I just need to see which combiner box spec he recommends.

I will keep the idea of another east/west array option to add later to the 2nd inverter as I think I still have room there. It totally makes sense to add flexibility for mornings and evening. Thanks man!