Increasing my electric service

snout71

I only ever push the incoming is when I am charging up the batteries during off peak at night 23:30-05:30 and if the two battery arrays are joined in parallel I won’t be able to charge both sets at the same time as they will act as one so I won’t be pushing through any more feed than I currently already do (unless I am understanding this all wrong, which wouldn’t surprise me)

snout71

So when would a 6kw inverter pull 26a?
when the solar is being converted (if generating enough) ?
when it’s using the grid to charge?
when it’s exporting to the grid?

just trying to understand if I can get away with 2*6kw inverters if they’re in parallel (one master and one as slave)
but both with 6kw of panels each charging one set of batteries

Qyburn

snout71 said:

So when would a 6kw inverter pull 26a?

When generating flat out it will output 26A. Whether two of those, total 52A export, is acceptable to the DNO will depend on the characteristics of your supply, and existing conditions at the transformer and network. The only way to know is to ask the DNO by making a G.99 application.

When charging batteries there may be some other limit, for example our system has a 6kW inverter but the battery can only charge or discharge at 5kW.

You could do a little test just for fun, if you have a meter or anything that can measure your mains voltage. I can read ours from the export meter. Anyway, not the voltage just before charging the battery, and again while the battery is being charged. Note the difference.

Let's say your battery will charge at 6kW, same as the inverter rating. In that case then worst case would be a voltage change of four times the figure just noted.

There were some figures that SSEN gave me, which aren't completely consistent. They gave 1.3% as maximum allowed voltage rise at the allowed export limit, and 2.3% at the total system size. However the actual G.99 off specified a max rise of 6V which is 2.5%. 

QrizB

Qyburn said:

snout71 said:

So when would a 6kw inverter pull 26a?

When generating flat out it will output 26A. Whether two of those, total 52A export, is acceptable to the DNO will depend on the characteristics of your supply, and existing conditions at the transformer and network. The only way to know is to ask the DNO by making a G.99 application.

The OP said back on page 1 of this thread:

snout71 said:

Currently I have a 6kw system (Solar and inverter) export is 5kw I believe.

If the DNO limited the export from their current 6kW system to 5kW, the chance of them permitting a further 6kW of export on top of that seems low.