Sol-Ark 15K - where to put the grid side current sensors?

[JimP]

My sol-ark 15k is going inline in a 100A subpanel feeder but I will be net metering. I have a 400A service, which routes from the meter base to two adjacent outdoor 200A main panels, one of which has a 100A breaker that will feed the solark (inside) and subpanel (inside).

What are the pros and cons of putting the current sensors on the 100A feed before the sol-ark vs the 400A main feeder vs not using them at all? I'd need to order the larger sensors for the 400A service line. Does monitoring there just give me a way to double check the power company numbers for net metering? Does it help the Sol-Ark make decisions about when and where to route power, in essence making it aware of the additional loads after my meter? If I am net metering, does it matter?

I am asking because I won't otherwise have to get into the meter base, and I suspect that the sensors will need to be before the meter if the 2 200A panels are fed separately directly from the meter lugs. Does the power company allow anything on the grid side of the meter like that?

I am also curious about the answer to https://diysolarforum.com/threads/ok-to-parallel-ct-sensors-on-dual-sol-ark-15k-install.75387/ because if that works then I could put the sensors on the 2 200A panel feeds instead of the 400A service line.

 

[DIYrich]

The sol-ark (without CT's) will tell you the amount it exports to your 100amp line. If you want to know the net amount making it to the grid, you need something between the meter and all your loads.

 

[JimP]

I talked to Sol-Ark today at length and they do not recommend paralleling CT sensors at all. Very unfortunate, but that is what they told me. They cannot say how accurate or inaccurate it would be so they don't think it is a good idea.

I don't need to use zero export mode so accuracy isn't terribly important, but if the numbers aren't reliable there isn't a lot of point to doing it.

I am going to be net metering, so CT sensors are required (I don't understand why, unless you have set the export limit which I won't, but it is what it is), so I will set up the CT sensors on mains into the panel the Solark is backfeeding and maybe I will set up an Emporia monitor on the other panel and do the math myself.

I am sort of tempted to get a second pair and parallel them anyway to see how well it works, but they only sell 15/16" 200A CTs, while the 15K comes with 1-3/8" CTs. If the parts aren't identical they are very unlikely to add together properly.

I would love to hear from anyone who has/is trying it and can put a clamp meter on the wires to assess the accuracy of the CTs in that configuration.

Thanks

I also posted this in another thread on this topic: https://diysolarforum.com/threads/o...n-dual-sol-ark-15k-install.75387/#post-965977

 

[Cmiller]

You can get bigger 600A CT's from Sol-Ark. We used those on a 3 phase setup because of having double parallel generators that we were monitoring in limited to home mode. Just be advised that the Sol-Ark circuit board is unable to process higher current than 40kw.... well that was at 208 Y 3 phase... so a little over 100 amps... anything over that and the values logged by the CT's will pretty much clock at 40kw in our 3 phase application! I asked them about using CT's with a different ratio (like 6000:1 to be able to measure up to 120kw) but their response was that they don't recommend using other CT's..... ?

Just a note though, wherever the CT's are at will determine what the Sol-Ark will record as "sold" to the PoCo. So if you install on only 1 200A service, anything pushed through the CT's will appear to have been sold to the PoCo even if you used half of it on the other 200A service, with nothing pushing out through the meter. So just keep that in mind. If you use no CT's the "sold" power will be what the Sol-Ark pushed back towards the meter.

If you wish to see in Powerview what the Sol-Ark actually pushed out through the meter, you will need to have the CT's installed over both sets of 200A wires going to both 200A services. If you don't care about seeing that, (since you can see it in your electric bill) then I would just skip the CT's altogether. We have set them up that way quite a few times already. Works perfectly fine.

 

[JimP]

Thx