Wiring solar to SRNE hybrid HYP4850U100-H in 2+2 split phase parallel OG.

[zanydroid]

AC SPDs they have nothing to do with ground

AC SPDs have many different possible protection modes.

They can do L-N clamping, L-L clamping, L-G clamping (if not more). The more the merrier, probably. I've seen some claims (but no explanation to back it up) of either L-N or L-G being better than the other ?

And it varies by the type that you get. You can get L-N, L-L-N, L-L-N-G wiring ones. It's like razor blades.

I believe with SPDs there's also redundancy advantage with having multiple, as well as how quickly they can clamp in response to surges coming from various directions.

(Actually I think the same diversity would apply for DC SPD)

 

[42OhmsPA]

You can't go wrong with Mike's videos, great resource.

I need to watch more of them.

We all started out knowing nothing about solar. Once you are hooked, well, it is an addiction.

110% truth. This should be made into a sticker for forum members to put on their equipment.

You can't connect a 7S string with higher voltage to a 4S string with lower voltage.

I think the 4S string can be handled with a 250VOC rated SCC like the Victron 250V units or the EG4 100A-MPPT which is 500VOC rated. The Victron is of course higher priced. The EG4 unit would allow up to 7S for your panels.

Couldn't a 4s string be dedicated to a a single MPPT of the SRNE?
I know running 2p would be over the max recommended input current for the inverter but I'd also consider 5s2p. You'd be over paneled under ideal conditions but I don't see any damaging negative impacts just a loss of some potential energy.

The IMO switches can not be beat. One can mount the switch in a metal box if the AHJ requires it for inside a residence (some debate here in the forums about this). The IMO was designed for use with PV, not adapted as some switches are.

Where do you order yours from (sorry if you already mentioned it)? I really need to add these to my system to bring everything up to snuff. I'm currently using breakers inside and outside for disconnects.

@tialiden altE solar ships NEC compliant stickers for free if you plan to add them.

 

[Zwy]

I need to watch more of them.

110% truth. This should be made into a sticker for forum members to put on their equipment.

Couldn't a 4s string be dedicated to a a single MPPT of the SRNE?

With one MPPT in the SRNE, he already used each MPPT for the 7S strings.

I know running 2p would be over the max recommended input current for the inverter but I'd also consider 5s2p. You'd be over paneled under ideal conditions but I don't see any damaging negative impacts just a loss of some potential energy.

Yes, it will clip the amps. I'm not a big proponent of over paneling, just seems a waste of resources. (money, panels, potential yield, wire size). One will probably need to use 8AWG for PV on a 5S2P string (using these 620W panels) unless you combine in parallel right at the inverter. My opinion is this, if you are running 10AWG all the way anyway, it probably would be wise to just add a SCC and not parallel the strings. No clipping, always harvest the yield available. Come winter, with short days many that are cloudy, I want to capture as much PV energy as possible. If the battery bank can't consistently hit 100% SOC and you have clipping, one should add a SCC and capture that yield.

Where do you order yours from (sorry if you already mentioned it)? I really need to add these to my system to bring everything up to snuff. I'm currently using breakers inside and outside for disconnects.

@tialiden altE solar ships NEC compliant stickers for free if you plan to add them.

Signature Solar has the IMO. I originally bought 2 from here. https://www.industrialcontroldirect...onnects-317/?zenid=poastmsntasovjmmnn2c36as85

 

[tialiden]

Thank you for the quick and very helpful response. I appreciate that you pointed out the calc tools and numbers you used. Wow, I overlooked that it has 1 MPPT per unit, since I saw 2 PV inputs and have been looking at dozens of models, so great catch!
So in that case, your point was that I could drop from 8 runs (4s), and go to as few as 4 runs of 8s, at risk of overvoltage, which is a real concern, so now I'm seeing I need to drop to 5 runs: 4 being 7s, and with one inverter just getting PV input from 4s.
Based on that MSinc calc and adjusting for our temp extremes, that would give me:

7string series array:

...and the odd set of 4s:

This all has changed, now the latest idea would be to use (4) arrays of 10 9s panels of the Evo6 620W Bifacial Panels, it aligns much better with the voltage and amperage range of the HYP4850 SRN Hybrid 120V Split Phase parallel inverters I already have.

 

[Zwy]

This all has changed, now the latest idea would be to use (4) arrays of 10s panels of the Evo6 620W Bifacial Panels, it aligns much better with the voltage and amperage range of the HYP4850 SRN Hybrid 120V Split Phase parallel inverters I already have.

There you go. It pays to be patient, review what works best and then make the final decision.

I made some hasty decisions when I first started, some worked out to my advantage, some cost me time and a small amount of money.

 

[tialiden]

I don't understand why the close lightning hit would want to direct most energy into the local ground rod vs also sending significant amount to the one at the other end of the EGC. The EGC is much more conductive than the earth. Feels like it could even be 50/50 between both rods. I guess you could argue that 50/50 is better than 100% on one side, but that's also betting that 50% of the surge can be handled but 100% cannot. Perhaps you could achieve something similar by stacking 2x the SPD clamping capacity.

From what I've seen on the forum, most people seem to interpret Mike Holt as recommending against ground rod at the array. I think it gives more opportunities for a voltage gradient in the earth, induced by close-by strike, to send current through the EGC. The close-by strike could be in various locations. If there is no ground rod then there is no low resistance path for an earth gradient to induce voltage across the EGC (even if the voltage is high under the array there is likely no way for it to hop into the grounding system. Well, it could go up through the footings but I guess this is unavoidable and a higher resistance than a ground rod).

Thanks. you are right about the MH recommendations to only have one ground rod. I'm learning. Can't find where I got off track on that SPD to separate ground rod idea, but I've found so many references to why it's a bad idea to have a separate ground rod. Actually one thing that was enlightening was that the SPD shuts + to -. But I've found some SPDs which are also shunting (I believe simultaneously) to the ground from + and as well from -. This three-way shunt would divide up the voltage transient, during an event. I've been trying to update my posts to include corrections and more relevant or current info so as to not lead anyone down a wrong or bad path, plus it's good for me to use it to document what I've found along the way.