Generator connection/use best practice w/ Skyboxx

True Hybrid Energy System
Post Reply
Mike Curran
Forum Emperor
Posts: 1803
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Generator connection/use best practice w/ Skyboxx

Post by Mike Curran » Sun Feb 02, 2020 4:55 pm

I just wired a generator connection to my Skybox, but I've never used one with either of my systems. So I'm wondering what is the best operating procedure for manually starting it and transferring loads to it?

The Skybox manual says if both grid and generator are connected, grid has preference, so I'm thinking under those conditions that if I just open the grid input breaker that the Skybox will then transfer loads to the generator.

Is it as simple as that? Any suggestions and recommendations are more than welcome. Thanks!
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

raysun
Forum Emperor
Posts: 2991
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Generator connection/use best practice w/ Skyboxx

Post by raysun » Sun Feb 02, 2020 4:59 pm

I'd be highly suprised (and disappointed) if it worked differently than you described. There's likely a programmable delay before the generator is connected. Past that, I'd expect the transfer to be transparent.

The generator will need to supply sufficient current to power both "house" load and charging demands

Mike Curran
Forum Emperor
Posts: 1803
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Generator connection/use best practice w/ Skyboxx

Post by Mike Curran » Sun Feb 02, 2020 5:17 pm

Thanks Raysun :smile:
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

Photon Kapture
Forum Member
Posts: 12
Joined: Tue Jan 14, 2020 4:54 pm
My RE system: 3.9 Kilowatt (13) Solar World sw300 Array.
Outback Skybox
(3) Simpliphi Lithium Iron Phosphate Batteries (2) 3.5 and (1) 3.8KWH
Location: Schroeder, Minnesota

Re: Generator connection/use best practice w/ Skyboxx

Post by Photon Kapture » Tue Feb 04, 2020 8:20 pm

Mike, I leave my generator breaker closed and start the gennerator manually with a key fob remote. (cheap firman 3500 portable generator) After a preset delay (30 seconds but programable on the generator tab as Rayson mentioned) Skybox automatically passes the generator thru to the critical loads. In order to use the generator to charge my Simpliphi batteries Skybox requires that the PV be switched off and a 600 watt minimum load be placed on the critical loads. Skybox then passes generator power thru to charge batteries and power loads. The minimum 600 watt load has to be in place the entire time the generator charges the batteries. Im off-grid so maybe this is different with a grid connection.

raysun
Forum Emperor
Posts: 2991
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
Suniva 330 watt panels (12 - 6 strings of 2 in series)
Hyundai 355 watt panels (6 - 3 strings of 2 in series)
Honda EU7000is gas fuel generator

Re: Generator connection/use best practice w/ Skyboxx

Post by raysun » Wed Feb 05, 2020 12:45 am

Photon Kapture wrote:
Tue Feb 04, 2020 8:20 pm
Mike, I leave my generator breaker closed and start the gennerator manually with a key fob remote. (cheap firman 3500 portable generator) After a preset delay (30 seconds but programable on the generator tab as Rayson mentioned) Skybox automatically passes the generator thru to the critical loads. In order to use the generator to charge my Simpliphi batteries Skybox requires that the PV be switched off and a 600 watt minimum load be placed on the critical loads. Skybox then passes generator power thru to charge batteries and power loads. The minimum 600 watt load has to be in place the entire time the generator charges the batteries. Im off-grid so maybe this is different with a grid connection.
The 600W load requirement seems odd to me, but I don't know much, if anything, about the Skybox architecture. Is there a reason for it?

Mike Curran
Forum Emperor
Posts: 1803
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 GVFX3524's classic stacked for 120/240VAC (2007)
- 12 Surrette/Rolls 2V x 1766Ah (2007)
- Hub10.3, Mate3s, FNDC, RTS, OpticsRE. Tigo Energy 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 (manual switch during grid outage only) from 14 Talesun 275W,
Enphase M215 microinverters, normally direct grid tied

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

Re: Generator connection/use best practice w/ Skyboxx

Post by Mike Curran » Wed Feb 05, 2020 4:27 am

The 600W load requirement seems odd to me, but I don't know much, if anything, about the Skybox architecture. Is there a reason for it?
Maybe unrelated, but in a different thread there's mention of high idle grid use with a Skybox.

I've found that with a small 300 watt load on one leg of the Skybox output and none on the other, Skybox uses 450 watts from grid over what my load consumes at night when there's no PV input. When I put a load on the other leg, grid use is reduced, and the more load there is, the lower the grid use. So it seems, although no one from OB has verified this with me yet (I have an active tech support case on this issue) that Skybox is very inefficient at low loads with no PV input.

Again, may be unrelated to the requirement for load in order to charge batteries. I get the feeling us Skybox owners are all Beta testers out here right now.
http://www.tigoenergy.com/site.php?95b2dca2-ca6c
https://enlighten.enphaseenergy.com/public/systems/Hctc107221

User avatar
Gwendoly Espe
Applications Engineering
Posts: 218
Joined: Wed Feb 22, 2017 10:04 am

Re: Generator connection/use best practice w/ Skyboxx

Post by Gwendoly Espe » Wed Feb 05, 2020 11:48 am

raysun wrote:
Wed Feb 05, 2020 12:45 am
Photon Kapture wrote:
Tue Feb 04, 2020 8:20 pm
Mike, I leave my generator breaker closed and start the gennerator manually with a key fob remote. (cheap firman 3500 portable generator) After a preset delay (30 seconds but programable on the generator tab as Rayson mentioned) Skybox automatically passes the generator thru to the critical loads. In order to use the generator to charge my Simpliphi batteries Skybox requires that the PV be switched off and a 600 watt minimum load be placed on the critical loads. Skybox then passes generator power thru to charge batteries and power loads. The minimum 600 watt load has to be in place the entire time the generator charges the batteries. Im off-grid so maybe this is different with a grid connection.
The 600W load requirement seems odd to me, but I don't know much, if anything, about the Skybox architecture. Is there a reason for it?

From the manual:
The SkyBox must be connected to at least 5 Aac of loads before the generator will be used to charge. If the loads drop
below 4 Aac, the generator will no longer used to charge.

SkyBox doesn't want to connect to an unloaded generator. It will pass-through the generator to the loads and then charge the batteries. The loads do not need to be on the whole time, but if you do disconnect the loads as the battery charges, the generator becomes more unloaded and eventually disconnect.
Gwendoly Espe
Applications Engineer


Alpha Technologies Inc. / OutBack Power Technologies
3767 Alpha Way Bellingham WA 98226 USA
http://www.alpha.com

Post Reply