Can Skybox support main panel loads without export?

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Dforster
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Can Skybox support main panel loads without export?

Post by Dforster »

I have been reading a little about this but I haven't found a clear answer.

I don't want to export because it is not cost effective with my electric coop as they charge $30 just to do net metering, plus I'll have to get a $1m liability policy for probably another $50/month.

Most of my circuits are in my critical loads subpanel, but altogether they only draw about 500 watts during most of the day, usually less. So my 5kw of panels are only going to supply 2-4kwh during the day. So until I get some batteries installed I will be wasting a lot of excess production unless I can supply some of the loads in my main panel.

My AC unit, electric dryer, and hot water heater are all that is in the main panel but they are most of our usage.

When I ordered the skybox the applications engineer told me I could definitely support the additional main panel loads with Skybox, but he didn't tell me I'd probably have to use CT's to set that up.

So my question is, can it be done this way, and how do I set it up? I planned on ordering the outback power CT's to set it up. I know the documentation says that if the CTs are installed you can use it for export control. "Many AC profiles allow the SkyBox to support the main panel (non-backup) loads (F to C) without selling power" But I'm not sure exactly which AC profile to use and how to set it up yet.

Thanks for any help!
gasolarenergy
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Re: Can Skybox support main panel loads without export?

Post by gasolarenergy »

Read about the non-export mode and see if that isn't what you are looking for. It's one of the 4 modes you set in grid (net metering with backup, self consumption, non export, maximum independence). You will need the 2 CT's on the main feed line into your main panel to measure the flow.
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Ampster
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My RE system: 5.7K solar system with Solaredge inverter. Heat pump water heater.
28 kWh pack of LFP batteries powering a Skybox which is used for load shifting and backup.
Location: Sonoma, Northern California

Re: Can Skybox support main panel loads without export?

Post by Ampster »

My guess is that your could use any mode to accommodate your purpose of back feeding your main panel but not export to the grid. You would have to install and configure CTs between the meter and the main panel. Two modes, Non Export and Maximum Independence do not appear to export so no additional settings would be required. I have not used those modes so I do not know if their other features meet your purposes.

From my notes and experience the other two modes accommodate export, but export can be limited or set to zero. Those modes are,; Net metering with Backup and Self Consumption. From your posts on the other forum I seem to recall that you will not be using batteries so I am not sure how the Skybox will even work in those modes without batteries. Perhaps @Kim Foster can clarify. memberlist.php?mode=viewprofile&u=14265 or you can reach out with a PM.
Drive Tesla Model X and Model 3 which are charged at Super Off Peak rates.
Dforster
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My RE system: Outback skybox

Re: Can Skybox support main panel loads without export?

Post by Dforster »

gasolarenergy wrote: Tue Feb 23, 2021 1:10 pm Read about the non-export mode and see if that isn't what you are looking for. It's one of the 4 modes you set in grid (net metering with backup, self consumption, non export, maximum independence). You will need the 2 CT's on the main feed line into your main panel to measure the flow.
That makes sense. I expected to read something like that in the manual but it just isn't very clear. I do have the CTs on order.
Dforster
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Re: Can Skybox support main panel loads without export?

Post by Dforster »

Ampster wrote: Tue Feb 23, 2021 3:23 pm My guess is that your could use any mode to accommodate your purpose of back feeding your main panel but not export to the grid. You would have to install and configure CTs between the meter and the main panel. Two modes, Non Export and Maximum Independence do not appear to export so no additional settings would be required. I have not used those modes so I do not know if their other features meet your purposes.

From my notes and experience the other two modes accommodate export, but export can be limited or set to zero. Those modes are,; Net metering with Backup and Self Consumption. From your posts on the other forum I seem to recall that you will not be using batteries so I am not sure how the Skybox will even work in those modes without batteries. Perhaps @Kim Foster can clarify. memberlist.php?mode=viewprofile&u=14265 or you can reach out with a PM.
Thanks. I don't know where I got the idea that the skybox wasn't normally capable of feeding back to the main panel without exporting. I think it was a reply from one of the other forums that made me think that. But it makes sense that the normal modes should be able to feed the main panel or the critical loads panel.

I don't plan to use batteries right away. But after reading some of your posts over on the other forum, I did order some cells from a guy on that forum and plan to get a 14kwh battery setup as soon as I get all that stuff together. I ordered 16 of the 280ah cells. Hopefully I am going about this hybrid setup in the right way!
Ampster
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Re: Can Skybox support main panel loads without export?

Post by Ampster »

That Solarpaneltalk forum is populated with a lot of off grid people that don't really understand grid interactive stuff that well and are skeptical because a generator works for them. They probably only have one electrical panel. There are also some experienced GT solar installers as well but hybrids are a newer and growing niche. I am sure what you are trying to do is feasible. There is enough support on this forum to get you through the process. Good help on integrating your batteries is also available on diysolarforum.
Drive Tesla Model X and Model 3 which are charged at Super Off Peak rates.
Ampster
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Location: Sonoma, Northern California

Re: Can Skybox support main panel loads without export?

Post by Ampster »

It just occurred to me that the only limitation would be when the grid is down the main panel would not be backfed. Is your Skybox set up yet? Do you have a clamp on Amp meter? Even without batteries you could do a test on the main panel support by just putting The Skybox in one of the modes that exports and see if you can measure current. The software definitely can control export so then the only issue is whether the CT can be configured at the service panel but logically I do not know of a reason why it should not work.
Drive Tesla Model X and Model 3 which are charged at Super Off Peak rates.
SHunsader
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My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Re: Can Skybox support main panel loads without export?

Post by SHunsader »

DF,

Glad I was just browsing to see if anyone had any new information on Skybox installations. Although I'm relatively new to Skybox installations, I've taken a crash course in the setup part of the system, currently on day 17, and have had some great breakthroughs.

First, external CTs aren't a problem, unless you can't find a nice way to get back to your main panel. Mine took a decent part of a half day, 2 pairs of 70' of wire, and a fair amount of patience. BUT, once installed, it's like everything lights up.....you can instantly see how much the rest of your house is using.

As for mode, everything those above this post have said makes sense. I live in the city and have a sizeable installation (2 skyboxes, Discovery batteries, and a 25kw generator), and want to use the grid to store some of my energy, but also want to use the batteries in the evening during peak pricing.

I'm guessing that you've already seen the programming guide: https://www.outbackpower.com/downloads/ ... rg_web.pdf
Refer to AC Profiles page 28, with a nice table and description on far side (pg 29). Non Export should work just fine. If it doesn't work for you immediately, you'll need to tweak slightly. I haven't used this mode (yet), but have gotten quite familiar with the first 2 modes over the past 2 weeks (pretty much around the clock for 17 days now).

Give me a shout if you have any issues, glad to share all I've learned recently.

NOTE: Make SURE that you update the firmware once you have a network connection. V 1.5.11 didn't have the network bugs, or some of the settings worked out yet, and I struggled for a week because Outback didn't install the 'certification file' that was needed to 'allow' me to update firmware. The on system console is a dog, but once you have new firmware, you can see the EXACT console on your desktop, and it runs 10x as fast.

Oh, and if you haven't ordered the CTs from Outback yet, I might suggest you get these instead:

https://aimdynamics.com/product/JC24F-mA/

They're only $30 ea (so you'll need 2 of them), and they can get them in the mail same day, or next day if you call them later in the day.

Outback told me themselves that it might be weeks before you receive them. Aim had them in just a couple days...bought them on Monday, and installed them on Friday, very easy to install (no, I'm not a salesman, just like it when the people on the other end of the phone know what they're talking about and can make it happen in a flash)

- Steve
Dforster
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Re: Can Skybox support main panel loads without export?

Post by Dforster »

Ampster wrote: Wed Feb 24, 2021 5:49 pm It just occurred to me that the only limitation would be when the grid is down the main panel would not be backfed. Is your Skybox set up yet? Do you have a clamp on Amp meter? ....
I’m behind on reading replies. Also I don’t get emails when I get replies on this forum. Probably a setting somewhere. Or I’ll just have to check more often.

I do have the skybox wired up to the grid and can turn it on. I don’t have it feeding the subpanel yet because I’m currently installing my Unirac mounting system. Man that is a chore! Probably the hardest part of the install yet. Anyway, that’s another post.. I have a clamp on meter so when I get my panels installed I can test that out pretty easily. I also have an energy monitor with 16 clamp on meters I can use to continuously monitor. I’m not sure if that would pick up back feeding or not. I’ll see.

I have turned it on and set up the basic stuff. And got the inverter turned on just to test it. I heard it click on but of course it’s got no input or loads yet.

What you’re saying makes perfect sense and is how I thought it should work. I don’t need the main panel loads during an outage. It’s just dryer and Ac and the instant water heater. Basically all the 220v loads. Everything else is in my subpanel.
Dforster
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Re: Can Skybox support main panel loads without export?

Post by Dforster »

SHunsader wrote: Wed Feb 24, 2021 11:27 pm

Oh, and if you haven't ordered the CTs from Outback yet, I might suggest you get these instead:

https://aimdynamics.com/product/JC24F-mA/

- Steve
Darn! Yes I ordered the outback version already for about $220. They are arriving Wednesday I think. But I could probably return. I’ll have to check with Solaris where I ordered. Not sure about their return policy.

I dont have the network connection setup yet. But I just need a network cable. My router and main panel are all in the same mechanical room with the skybox so all my CT and network stuff should be pretty simple.

I’ll definitely get back with questions and discussions.

Thanks!
Ampster
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Location: Sonoma, Northern California

Re: Can Skybox support main panel loads without export?

Post by Ampster »

@Dforster, I would not be concerned about the comment by the other poster on that other Forum. His circustances are entirely different than yours and he seems to be jumping onto a lot of threads there with irrelevant comments. The Moderators should encourage him to start his own thread. He was backfeeding the grid before he was approved and it may have been his Tesla Powerwall installers testing the system or a misconfigured install.
Drive Tesla Model X and Model 3 which are charged at Super Off Peak rates.
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Kim Foster
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Re: Can Skybox support main panel loads without export?

Post by Kim Foster »

Hi All,

This is a great discussion so far! One point I'd add is that the only profile that works correctly without energy storage attached is net metering with backup.

If you're trying to limit PV without batteries the system won't have any place to put the PV power when the loads fluctuate so you may see some faults or export to the grid. If you can, I would wait until you have batteries connected before trying to power any main panel loads.
Kim Foster
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- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

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Outback Skybox - Barn roof: (2019)
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Re: Can Skybox support main panel loads without export?

Post by Mike Curran »

Hi Kim - I get your second paragraph, but this confuses me:
One point I'd add is that the only profile that works correctly without energy storage attached is net metering with backup.
If you say it works I'll believe you, but seems counterintuitive - how can "without energy storage" work with "net metering with backup"?
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
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Kim Foster
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Re: Can Skybox support main panel loads without export?

Post by Kim Foster »

Lack of a better name? I should have clarified that the backup portion of 'net metering with backup' won't work without energy storage. But on-grid, one intended use case was to add batteries at a later date after installation. Basically, a SkyBox without batteries/energy storage makes for an overbuilt grid-tied inverter and the only profile that does not rely on batteries when on-grid is net metering with backup.

Does that clarify things? It's sometimes hard for me to explain via the written word.
Kim Foster
Systems Engineering
Mike Curran
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Posts: 2123
Joined: Sat Aug 28, 2004 6:28 pm
My RE system: Outback - Garage roof:
- 8 (2x4) Evergreen 180's into one FM80 (2007/2020 - replaced MX60)
- 6 (2×3) ALEO S79-300's into one FM80 (2017)
- 2 grid-tied VFXR3524A-01's series stacked, replaced GVFX's (2020)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS. Tigo ES maximizers on each PV module.

Westinghouse Solar - Barn roof: (2012)
- 30 (2x15) 235W panels with Enphase M215 microinverters, grid-tied

Outback Skybox - Barn roof: (2019)
- 14 Talesun 275W in series (DC array input to SB inverter/charger)
- 3 SimpliPhi 3.8 batteries, 48V, 225Ah total
- AC coupled input from 14 Talesun 275W, Enphase M215 microinverters

All self-designed and self-installed
Location: Chagrin Falls, Ohio

Re: Can Skybox support main panel loads without export?

Post by Mike Curran »

Perfect, thanks!
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221
SHunsader
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My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Re: Can Skybox support main panel loads without export?

Post by SHunsader »

Kim,

What's unfortunate is that "Netmetering with Backup" only assumes that the 'backup' part is batteries, and throws the idea of having a backup generator to the wind. My perfect energy management 'solution' is to have batteries cover the expensive 'dusk to 9pm' window of the grid by 'exercising' the batteries. If one has a generator, it can be used as the 'backup', so having partially/fully drained batteries after 9pm isn't an issue. The only way to get close to this scenario is to NOT use Netmetering, but use "Self Consumption" instead. Unfortunately, there's no provision to use 'time of use' in this scenario, so I end up completely draining my batteries by morning. Yes, I could 'tweak' the "Gridzero Max Thresshold" setting in the Grid Pane, which I've already done, but in doing so, I have to think about maximum usage during that window in the evening. NOTE: Funny as it may seem, the 1.5.11 version of the software used 'time of use' in the Self Consumption mode by accident apparently, so it worked the way I wanted it to right up to when I upgraded. BUT, there were a lot of other good things that 1.5.23 has to offer which outweigh what I've given up. - Steve
Dforster
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Re: Can Skybox support main panel loads without export?

Post by Dforster »

Ampster wrote: Wed Mar 03, 2021 9:33 am @Dforster, I would not be concerned about the comment by the other poster on that other Forum..
Agreed. His post seemed a little out there.
Dforster
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Re: Can Skybox support main panel loads without export?

Post by Dforster »

Kim Foster wrote: Wed Mar 03, 2021 10:20 am Hi All,

This is a great discussion so far! One point I'd add is that the only profile that works correctly without energy storage attached is net metering with backup.

If you're trying to limit PV without batteries the system won't have any place to put the PV power when the loads fluctuate so you may see some faults or export to the grid. If you can, I would wait until you have batteries connected before trying to power any main panel loads.
So how do I have the skybox not power my main panel loads? It is connected to my main panel/grid via the 60 amp breaker. Do I just shut that breaker off? I don’t think that makes sense because then I don’t have power to my critical loads panel when the sun goes down. I had just planned on using a non export mode but from what you say here it sounds like it may still export at least something until I have storage connected. So essentially I can’t use the skybox without storage unless I want to do net metering?

Sorry, I don’t have any experience with it yet other than installing and turning it on to do some initial setup, so I might be misunderstanding. I’m still working on the rest of the install, panels, CT’s, etc. Things might become more clear as I finish setting up the skybox and using it. But I’d really like to avoid back feeding the grid at all in my situation. I don’t even want the poco to have a reason to tack on a $30 charge to my bill. That’s what they do for net metering.

Thanks!
Ampster
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Posts: 160
Joined: Sat Apr 11, 2015 5:14 pm
My RE system: 5.7K solar system with Solaredge inverter. Heat pump water heater.
28 kWh pack of LFP batteries powering a Skybox which is used for load shifting and backup.
Location: Sonoma, Northern California

Re: Can Skybox support main panel loads without export?

Post by Ampster »

Until you get batteries do not use the external CTs and any slosh that happens may be absorbed by the main panel. That way the main panel will be the buffer and you can evaluate how much sloshes over to the main panel before you either add batteries or external CTs or both. When Kim discussed the slosh issue on another thread it was a situation with batteries but the slosh was very short. @Kim Foster can verify my speculation above or correct it. I would guess it could be an issue when either solar production fluctuates or loads drop.
Drive Tesla Model X and Model 3 which are charged at Super Off Peak rates.
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