Solis Hybrid Inverter question

[xcentric]

Seen the discussion thread on different modes, but not quite clear on the outcome.....

My use case:

* cheap rate electricity 00:00 - 05:00
* standard tariff in day

* off-peak - if batteries <100% charge batteries from grid; house gets power from batteries then grid (typically lowish usage overnight)
* peak - house gets power from solar then batteries then grid; excess solar charges batteries any left exported to grid
* grid outage - house gets power from solar then batteries

So essentially I run from batteries in the day charged by cheap rate grid overnight, with solar powering house to reduce demand on batteries, and topping them up if possible.

I saw a solution that used home assistant to achieve this - is there a setup on the inverter that will achieve the same?

thanks!

 

[rpdom]

The usual way of doing the first two is to set a charge timer (on the inverter or through the App or website if online) for 00:00 to 05:00. The batteries will charge from grid and the load will also be powered by the grid during this time.

The rest of the time the house will get power from PV, batteries, grid in that order. Excess PV charges batteries, if there's still excess it is exported to grid.

Grid outage is slightly harder. When the inverter detects a grid outage it turns off its main output. What you can do is to use the AC Backup output, connect that to a separate panel/CU with a local earth rod and RCD (as it will be isolated from grid earth) and use that to run "essential loads". That will keep running as long as there is sufficient PV and battery power.

 

[MSRConf]

All you require can be done from the inverter itself, As @rpdom said, set the charge timing to your over night schedule.

I have a Solis 3.6k with Batteries, using Octopus cheap night rates, it all performs exactly as you have requested.

 

[xcentric]

Thanks for replies.

Grid outage is a pain - don’t want to require consumer unit and house. Thought it went to off grid mode and so would run house accordingly

 

[SeaGal]

Grid outage is a pain - don’t want to require consumer unit and house.

A pain that it happens? Or a pain to come up with a solution? Also I don't understand exactly what you mean by bit I hightlighted - can you clarify?

The Solis will not be capable of powering the whole house - you will be restricted to essential loads only. Typically this will be done using a secondary circuit as @rpdom explained.

 

[xcentric]

Typo! Rewire.

Current inverter I’m returning (allegedly) detects when grid off and runs house from batteries/solar. I know I’m limited to about 3kW or so but that’ll keep most ticking along. Essentially working as off grid inverter, and not needing specialist circuit.

Does it happen? Yes but maybe not enough to really worry. Twice for a few mins this year - half a dozen times last winter, once for about an hour. Enough that I have router and access points on a ups. Lights and tv then would be nice but not essential.

 

[SeaGal]

Current inverter I’m returning (allegedly) detects when grid off and runs house from batteries/solar. I know I’m limited to about 3kW or so but that’ll keep most ticking along. Essentially working as off grid inverter, and not needing specialist circuit.

OK.

All UK approved grid-tied inverters will detect when the grid goes off. But they will then stop outputting any voltage on that grid connection. This is a key safety feature to prevent electrocuting line engineeers! Many inveters, Solis Hybrid included, will then power a back-up circuit from solar and/or battery until the sun and battery power run out. But, that is a different connection that will need a circuit of its own.

Also, be aware that the start-up load of inductive loads (thinking fridge / freezers etc.) will draw a power of up to 10x their rated power initially. Hence, you will not be able to simultaneously start up 3 or 4 fridges from a Solis 3kW back-up supply, so might have to factor that into your backup circuitry plans.

 

[xcentric]

yes, I think the claims made for the inverter were not accurate

Is it possible/easy to put a switch in to isolate the inverter from the grid and then run it as an offgrid inverter, without access to the grid, but going through the consumer unit as usual to save complex rewiring?

Essentially, turning off the grid input into the house? I do understand the startup loads - most of our draw is pretty constant though fridge may cause some issues. Don't have more than one though. And as for firing up the coffee machine, that'd have to wait for sure.....

 

[SeaGal]

Is it possible/easy to put a switch in to isolate the inverter from the grid and then run it as an offgrid inverter, without access to the grid, but going through the consumer unit as usual to save complex rewiring?

I'm not a sparky, but IMHO I don't believe that would be BS7671 compliant, nor meet with the DNO . There will also be issues with earthing of the backup supply unless you already have a TT earthing arrangement.

Suggest you get a sparky in to sort out the back-up wiring.

 

[xcentric]

Suggest you get a sparky in to sort out the back-up wiring.

too complex to put the various bits that are critical onto their own circuits - I'll manage with the UPS for now.

thanks for inputs tho.

 

[xcentric]

final q I hope - given the Solis can put out 6kw, I assume I need a G99 form, even if I limit it to 3.63kW?

 

[SeaGal]

final q I hope - given the Solis can put out 6kw, I assume I need a G99 form, even if I limit it to 3.63kW?

Yes. Any inverter capable of producing more than 16A per phase requires G99 application and approval before you install. You will then be told either OK or whether you need to limit export. Then have 3 to 4 months to install and commission and send G99 commissioning forms back.