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System Layout Questions Sol Ark 15k and EG4 Batteries

It was a steep learning curve but it’s not rocket science. I got great help from Sol Ark, Practical Preppers, and again Solar. I watched a bunch of YouTube ( follow engineer775). Hired a commercial electrician to do the big wire and conduit. All works better than expected. If you are going off grid I suggest you do DC coupling or a combination of both DC and AC coupling.
 
I was planning on having two cabinets of Eg4 batteries, and having the positive/negative from each cabinet connect to the Sol-Ark.
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But I'm guessing now instead I need a bus bar? Additional fuses just duplicate the 200amp breaker in the Sol-Ark right?
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Your first diagram is fine, the second one introduces extra failure points. How much more protection do you need, each battery has a circuit breaker and the solark does too.
 
Your first diagram is fine, the second one introduces extra failure points. How much more protection do you need, each battery has a circuit breaker and the solark does too.
I don’t completely disagree however the fuses are another safety measure and will really protect just the wire. However I agree it is safe without the fuses
 
@jfpetesn , question since you have 300 amp mega fuses, isn't the 200amp breaker on the Sol-Ark always going to trip before your fuses?
Yes they should and quite frankly the mega fuses may not even be necessary. I went ahead and added them to protect that expense 4/0 cable. Made me feel better anyway. Probably not giving up much safety factor if you did not use them.
 
Yes they should and quite frankly the mega fuses may not even be necessary. I went ahead and added them to protect that expense 4/0 cable. Made me feel better anyway. Probably not giving up much safety factor if you did not use them.
And I presume you don't want to use 200a, because if the Sol-Ark gets heavy load and pulls 275a, then they will blow, so I guess at a minimum they need to be 300 to hold up to heavy demand from the Sol-Ark.
 
And I presume you don't want to use 200a, because if the Sol-Ark gets heavy load and pulls 275a, then they will blow, so I guess at a minimum they need to be 300 to hold up to heavy demand from the Sol-Ark.
That was my thought but on the other hand my Trophy batteries have a 200 amp BMS so actually a 250 amp fuse on each battery lead would be perfect.
 
Sorry I forgot. So IMO the closed vs open loop thing is a non issue. So the Trophies do not have direct communication with the Sol Ark yet. Dan at Trophy has signed up with the Sol Ark integration program and is just waiting on Sol Ark to do testing. Now before you say oh no let me explain my real world experience. So what I need to know when I’m using batteries…..SOC (state of charge) that’s it end of story. Now if is closed loop when you plug it in it will set the charge rates and feed the BMS SOC to the Sol Ark. Now that would be great on the face of things but if your batteries don’t communicate what do we do? We set the charge rates according to the manufacturer (this is done one time on installation). So when you install the batteries the Sol Ark goes into a learning mode for 3 days to learn the charge/discharge profile of your batteries. Then it estimates the battery SOC. I will say it works very good usually within 0-4% of the actual SOC. The only time I have seen bigger discrepancies is on cloudy low solar days when the batteries do not get to 100% SOC. Well I wanted a little more than that and I wanted the ability to download more of my data so I bought Solar Assistant. That was the golden ticket. So what I have now is the Trophy Batteries connected to the Solar Assistant. I have the Sol Ark connected to Solar Assistant too. Solar Assistant sets in the middle between the Batteries and the Sol Ark. Solar Assistant can communicate with both. So I can see the true Battery BMS SOC info and my Sol Ark info in real time. If I use the Power View program that comes with Sol Ark is nice but only reports in 5 min increments. So I have closely watched my SOC on both the Sol Ark and the SA. They stay very close to each other. If you can afford it the Solar Assistant is a great addition. I use both Solar Assistant and Power View for different things. If you decide to order be sure you order the Sol Ark cord and the proper battery BMS cords from them. If you buy Trophy the cord that comes with their batteries will work for the Solar Assistant.
 

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Just to complicate things more I have a Victron Smart shunt attached too. This gives me another source for SOC. It measures electrons I think so it knows what goes in and out of the batteries.
 

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I'm in between Las Vegas, San Diego, and our under-construction home in San Felipe Mexico. Where we're building there is no grid, so we've got to bring the solar. There are peeps down there doing it, but many are really vendor allegiant and I'm not sure they're looking at what's cutting edge in the states. So I'm doing my homework to design it all out, and then make sure the house has all holes, ports, plugs, grounds, etc for everything to drop in nicely.
we do have solark comms demonstrated and working
 
Someone I have been working with suggested running 4 AWG wires from each ground mounts to the next, then eventually 2 earth grounds approximately 10 feet apart from each other.

View attachment 121334
Thanks for the feedback. I am not qualified to answer but that diagram makes sense to me. I struggle with grounding because (it is probably my ignorance) it seems like the NEC code can be interpreted different ways. I also struggle with the concept of an earth ground any distance from the ground mount earth penetration. To me it seems like if lightning can travel miles to hit my solar array it will most likely follow the metal posts that are driven into the ground already (as opposed to an additional grounding cable). I guess the grounding cable is more for personal safety and discharging leakage from a damaged panel or perhaps a static charge of some type. Are you using any type of combiner box? I am guessing the combiner box attached to the grounding wire factors into surge protection and allowing overcurrent from lightning, etc. to bypass the solar DC wiring in favor of following the grounding wire to earth ground but I don't fully understand surge protectors. Again I figure if the lightning travels miles to hit my array I wonder if the surge protection is worth the effort. It may be a great feature I just don't fully understand how it works.
 
Update and more questions on the design:

View attachment 119137

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The Sinclair ground mount kit shows up tomorrow. Planning on the surface ballast method as there are a lot of rocks in the soil here and I don’t want to attempt to drive the posts.

Installed a tornado shelter and set up the EG4 batteries in the cabinet. Has been staying 20 degrees or more cooler than ambient (around 85F). Batteries not terminated yet. All show the same state of charge which I think is good. I was not sure if I had to top balance the batteries before connecting to the Sol Ark but I am guessing it is a non-issue since state of charge is the same on all 6 batteries.

I am thinking of attaching the Sol Ark to the side of the battery cabinet. Would seem to be easier than mounting to the concrete wall. Curious if anyone else has done something similar. I have seen on the EG4 commercials where they mount the inverter inside the cabinet with the batteries.

I am liking the Victron Lynx for the extra fuse protection and to split the positive and negative into two leads for each. The Sol Ark 15k requires two sets of leads if the load exceeds 160A. It looks to me like if all 6 batteries are charging that the load could hit closer to 200A. I think I would also mount it to the EG4 Battery cabinet unless I am missing something there.



I did my best to show the equipment in a diagram. Starting with the 30 solar panels I think I am OK getting those mounted and connected. I will have to get some 10 AWG wires and connectors to get them wired over to a combiner box. I am a little unsure on what type of box to use. The Sol Ark has 3 MPPTs so I need to end up with 3 sets of pos/neg 10 AWG leads. It is supposed to limit Amps to 26 so even though the panels can theoretically produce 28 Amps (likely very rarely) max the lines would likely never exceed 26 Amps. The run is about 100 feet from the ground array to the Sol Ark 15k. My questions are around fusing and grounding. Is it better to go with branch connectors and in line fuses or would it be better to put the fuses in the combiner box. I don’t see any pre-fabricated boxes for 3 sets in/out or 6 sets in / 3 out if I didn’t use branch connectors. The other part that confuses me is the grounding. Looking at NEC code it looks like they recommend an earth ground near the ground mount tying the panel frames to ground (as opposed to running it all the way to the same grounding point as the AC side). That part makes sense to me. I assume I would connect the ground in the combiner box to the same earth ground connection near the panels. Just a little confused about whether the combiner box provides some sort of ground fault detection that trips the breakers? Sol Ark also does not recommend connecting the solar panel array ground to the Sol Ark as a lightning strike might fry the Sol Ark.

From the combiner box the 3 pos / 3 neg 10 AWG wires would run to the Sol Ark.

From the Sol Ark the battery wires have to be split into two positive and two negative leads that get combined to go to the batteries. Someone recommended the Victron Lynx for that purpose and that makes a lot of sense to me. I am curious anyone’s experience connecting the positive and negative leads to the battery pack (6). I have seen on some videos that the batteries will charge / discharge more uniformly if one side (pos) connects at the top of the bus and the other side (neg) connects at the bottom of the bus. I have read that EG4 says it does not make a difference.

Finally I need to size the AC power line / ground from the Sol Ark to the panel box. Just have not gotten that far yet. I am guessing it is about a 12 foot run from the inverter to the panel box. I am guessing I ground the panel box and then I can start installing breakers and wiring the cabin.



Comments and feedback would be welcome. I am enjoying this process, but I know there is a lot that I don’t know.
In case anyone is going off grid and looking at temperature controlled battery storage I got some good data this past weekend. The tornado shelter (pictured above) inside was 59F this weekend. The ambient at the same time was 32F. This is the first cold spell we have really had but wow what great temperature protection. Well above freezing with no special insulation or battery heaters. The system is not up an running yet so there was no additional heat from the batteries or inverter. Hopefully it will stay cool this summer.
 
Thanks for the feedback. I am not qualified to answer but that diagram makes sense to me. I struggle with grounding because (it is probably my ignorance) it seems like the NEC code can be interpreted different ways. I also struggle with the concept of an earth ground any distance from the ground mount earth penetration. To me it seems like if lightning can travel miles to hit my solar array it will most likely follow the metal posts that are driven into the ground already (as opposed to an additional grounding cable). I guess the grounding cable is more for personal safety and discharging leakage from a damaged panel or perhaps a static charge of some type. Are you using any type of combiner box? I am guessing the combiner box attached to the grounding wire factors into surge protection and allowing overcurrent from lightning, etc. to bypass the solar DC wiring in favor of following the grounding wire to earth ground but I don't fully understand surge protectors. Again I figure if the lightning travels miles to hit my array I wonder if the surge protection is worth the effort. It may be a great feature I just don't fully understand how it works.
I'm not considering a combiner box at the moment, the Sol-Ark suggests a direct connection from your panels is fine see page 21 in the linked manual. On this page, they mention the ground for panels, smaller wire than I had mentioned but at least something to ground the panels elsewhere from the inverter. I guess the thought is that while lightning might go both directions perhaps most of the current would travel the easiest path through the grounds to earth rather than through the panels to the inverter. In my case I just refer to the Sol-Ark as the inverter, the panels are actually connected to the mppt inputs. A combiner box would need a separate ground to be useful at limiting the surge from hitting the inverter, so perhaps I'll consider both as extra caution.
 
I'm not considering a combiner box at the moment, the Sol-Ark suggests a direct connection from your panels is fine see page 21 in the linked manual. On this page, they mention the ground for panels, smaller wire than I had mentioned but at least something to ground the panels elsewhere from the inverter. I guess the thought is that while lightning might go both directions perhaps most of the current would travel the easiest path through the grounds to earth rather than through the panels to the inverter. In my case I just refer to the Sol-Ark as the inverter, the panels are actually connected to the mppt inputs. A combiner box would need a separate ground to be useful at limiting the surge from hitting the inverter, so perhaps I'll consider both as extra caution.

I'm not considering a combiner box at the moment, the Sol-Ark suggests a direct connection from your panels is fine see page 21 in the linked manual. On this page, they mention the ground for panels, smaller wire than I had mentioned but at least something to ground the panels elsewhere from the inverter. I guess the thought is that while lightning might go both directions perhaps most of the current would travel the easiest path through the grounds to earth rather than through the panels to the inverter. In my case I just refer to the Sol-Ark as the inverter, the panels are actually connected to the mppt inputs. A combiner box would need a separate ground to be useful at limiting the surge from hitting the inverter, so perhaps I'll consider both as extra caution.
Yea I had the same thoughts. I am probably over thinking it. I am eager to get the system up and running so I might just leave a little extra wire between the MPPTs and the panels so I can splice in and add a combiner box later (if I want to). For sure I am going to ground at the array (its about 120 feet from the cabin) and I will have a separate ground at the cabin (at the breaker panel). With the Sol Ark 15k with the 3 MPPTs you would need 3 outputs from the combiner box. I have 6 arrays so I would need a 6 to 3 combiner. I like the concept of a breaker there and maybe surge protection but I don't see any 6 to 3 combiners off the shelf with the 28 Amps per output that I would need. Probably easy to build but I will have to do some more research.
 
Yea I had the same thoughts. I am probably over thinking it. I am eager to get the system up and running so I might just leave a little extra wire between the MPPTs and the panels so I can splice in and add a combiner box later (if I want to). For sure I am going to ground at the array (its about 120 feet from the cabin) and I will have a separate ground at the cabin (at the breaker panel). With the Sol Ark 15k with the 3 MPPTs you would need 3 outputs from the combiner box. I have 6 arrays so I would need a 6 to 3 combiner. I like the concept of a breaker there and maybe surge protection but I don't see any 6 to 3 combiners off the shelf with the 28 Amps per output that I would need. Probably easy to build but I will have to do some more research.
How many panels do you have and what is their wattage?
 
Yea I had the same thoughts. I am probably over thinking it. I am eager to get the system up and running so I might just leave a little extra wire between the MPPTs and the panels so I can splice in and add a combiner box later (if I want to). For sure I am going to ground at the array (it’s about 120 feet from the cabin) and I will have a separate ground at the cabin (at the breaker panel). With the Sol Ark 15k with the 3 MPPTs you would need 3 outputs from the combiner box. I have 6 arrays so I would need a 6 to 3 combiner. I like the concept of a breaker there and maybe surge protection but I don't see any 6 to 3 combiners off the shelf with the 28 Amps per output that I would need. Probably easy to build but I will have to do some more research.
I’m not sure if you mean by array, “string”? If you have 6 strings they can all connect to the Sol-Ark, no combiner necessary. Basically you can connect 12 wires (6 positive)/(6 negative) to the Sol-Ark across all three (3) mppts’.

The tool on Sol-Arks website will show you exactly how many panels in each string to connect to each mppt when you either choose from the list your panels or input their numbers if your panels are not in the drop-down.

 
30 panels at 445 watts each. They are bifacial Canadian Solar. At base rating I am under powered but they are rated up to 30% above the base rating. From what I am reading 10% to 15% above base rating is realistic but if they were to max out I think that would be the most the Sol Ark could handle. It may be a little on the conservative side but I just punched in the panel model and set it up the way Sol Ark recommended. Plenty of room on the VOC but the Amps goes up with the bifacial. Planning on 3 inputs to the MPPT 5S2P each. Could hit 28 Amps each input on the top end but the Sol Ark regulates the max to 26 Amps.
 
I’m not sure if you mean by array, “string”? If you have 6 strings they can all connect to the Sol-Ark, no combiner necessary. Basically you can connect 12 wires (6 positive)/(6 negative) to the Sol-Ark across all three (3) mppts’.

The tool on Sol-Arks website will show you exactly how many panels in each string to connect to each mppt when you either choose from the list your panels or input their numbers if your panels are not in the drop-down.

I actually didn't know I could connect 6 pos and 6 neg. inputs to the Sol Ark. I was thinking of using some branch connectors at the array so I would have 3 sets 10 AWG pos/neg wires total. Each input (3 total or 6 wires) would be from 5 series + 5 series connected with branch connectors. I may not be using the correct terminology. That is what the tool on the website recommended for the panel model. I have to run approximately 120 feet from the panels to the cabin (which I input into the tool).
 
30 panels at 445 watts each. They are bifacial Canadian Solar. At base rating I am under powered but they are rated up to 30% above the base rating. From what I am reading 10% to 15% above base rating is realistic but if they were to max out I think that would be the most the Sol Ark could handle. It may be a little on the conservative side but I just punched in the panel model and set it up the way Sol Ark recommended. Plenty of room on the VOC but the Amps goes up with the bifacial. Planning on 3 inputs to the MPPT 5S2P each. Could hit 28 Amps each input on the top end but the Sol Ark regulates the max to 26 Amp
Check out this post that shows the A/B connection variations.

Thread 'Sol-ark 15k MPPT connection question'
https://diysolarforum.com/threads/sol-ark-15k-mppt-connection-question.48546/
 
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