New Roof top install next week.

[Umpa]

Hi everyone,
Following the success of my off grid solar shed I am having a grid tie PV with battery installed on my house. I have some doubts though - and would like to know if anyone has any experience with regard to batteries and the grid.

I am wondering if the batteries are full (or not) and the sun clouds over - will the inverter export my energy from the battery to the grid as well as to my home ? If anyone would be so kind as to have a look at the inverter manual and let me know what you think.
The info is on page 55 from the manual. (which turns out to be number 30 in the left pane)
https://www.luxpowertek.com/uploads/LXP-Hybrid-usermanual1.pdf

Thanks
Ump..

 

[snoobler]

Modes start on P.53.

Default mode is 6.4.1, and it won't export battery to the grid ever.

Look at the arrows in the images. They show power flow. Will only export to grid when PV is sufficient to keep batteries charged and provide house loads.

The other modes allow you to customize export based on time of use (6.4.2) or establish hard export limits (6.4.3).

Mode 6.4.4 is basically off-grid or backup. It will only use grid as a backup power source if PV/battery insufficient, or it passes through grid and provides backup power when grid is down. It does not appear to export in any circumstance.

 

[Umpa]

Modes start on P.53.

Default mode is 6.4.1, and it won't export battery to the grid ever.

Look at the arrows in the images. They show power flow. Will only export to grid when PV is sufficient to keep batteries charged and provide house loads.

The other modes allow you to customize export based on time of use (6.4.2) or establish hard export limits (6.4.3).

Mode 6.4.4 is basically off-grid or backup. It will only use grid as a backup power source if PV/battery insufficient, or it passes through grid and provides backup power when grid is down. It does not appear to export in any circumstance.

I guess its because I don't understand the wiring, I don't understand how it can differentiate between mains and it's own output. If my load is less than the output from the battery/inverter won't that export regardless through the path of least resistance ? Or does the inverter sense what loads I have on and reduce it's output to match demand ?

 

[Ampster]

I don't understand how it can differentiate between mains and it's own output.

If it is like my hybrid inverter, it has measuring devices (current transformers or CTs). Those devices provide feedback to the software which follows whatever mode you set the device at. If the mode is non export it will reduce output to match loads. If the mode includes export it will sevice the loads and export the difference.

 

[Umpa]

If it is like my hybrid inverter, it has measuring devices (current transformers or CTs). Those devices provide feedback to the software which follows whatever mode you set the device at.

Yeah it mentions something about CT in the manual but did not really know what it was. That's good news coz I don't fancy giving them much and nothing at all from my batteries.

It Looks like the SEG is not worth it - so keen to export as little as possible.

 

[snoobler]

What am I missing? "SEG"?

Self-use mode:



The ONLY time you will feed back to the grid is:

Your loads are already being met by PV AND
Your batteries are full AND
You have surplus PV

PV priority:

1. Supplying local loads
2. Charging Battery
3. Exporting to grid

 

[Umpa]

SEG is the Smart Export Guarantee it replaced the FIT - Feed In Tariff.
I am not sure I can use the self use setting as I may need to charge the battery during the night using off peek. So I think I am looking at section 6.4.2, I am also having a changeover switch fitted so if the grid goes down I still have a limited form of electric use. I am not sure if that will use the EPS system or not - which seems to rule out 6.4.1 some more if it is based off this.

I will let you know how I get on at the end of next week.

 

[snoobler]

Thanks.

6.4.2 may make more sense.

FWIW, to circle back to the original question, I see no evidence that the unit will EVER export battery to the grid in any mode - ONLY surplus PV, i.e., PV you can't use for loads or battery charging.

I suspect the unit may need to be re-configured to operate as 6.4.4 in the event of a grid-down situation so you still have local power.

 

[Umpa]

Thanks all for the confirmation - role on next week..

 

[Umpa]

Hi guys - I have a problem.
Had a partial install, as in just the panels and inverter - now I am getting random RCD trips when the inverter is on. They are coming today to fit batteries and to look at the problem
Basics : - From the Inverter to the CU via a 16A MCB, I have an 80a RCCB AC fitted - should this have been upgraded to Type A ?
Cheers
Ump..

 

[Umpa]

All fixed....