Charging priority

[JohnW]

Can any of you guys advise please.

I'm just about to have my first battery fitted and don't understand what gets priority for the electricity generated from my PV:
Does the battery or household demand get first dibs?
Do the panels need to produce a minimum amount of electricity before the battery starts charging?

Cheers
John

[Tinbum]

Normally house loads first.

Battery will use up whatever is left over after house loads to charge.

[Oldgreybeard]

as above, but there can be a slight complication if you have hot water heated by an excess PV diverter, like the Eddi, Immersun or whatever. There can be an issue where the battery system takes priority over heating the hot water, which may or may not be the thing you want to happen. There are fixes for it, though.

[JohnW]

Thanks guys, that's helpful. As a fairly heavy user of electricity during the day (about 4-5kW) I guess I am not going to get the battery changed much at this time of year, yesterday the panels only produced 4.3kW off an East/West 5kWh array.

[Thebeeman]

Off Peak tariff and charge overnight.

[Stinsy]

Off Peak tariff and charge overnight.

This!

I know several people who have batteries but no solar. They've calculated that timeshiftimg cheap-rate electric pays off even better than storing solar!

[Ken]

as above, but there can be a slight complication if you have hot water heated by an excess PV diverter, like the Eddi, Immersun or whatever. There can be an issue where the battery system takes priority over heating the hot water, which may or may not be the thing you want to happen. There are fixes for it, though.

Whats the fix ?

[Thebeeman]

I know several people who have batteries but no solar. They've calculated that timeshiftimg cheap-rate electric pays off even better than storing solar!

I've just had batteries fitted on the assumption that during the summer we will import zero from the grid, based on our solar production and grid figures over 11 years, and will use "cheap" night leccy during the winter. All I need now is Octopus to fit the B***dy smart meter.

Edit for typo.

[Oldgreybeard]

as above, but there can be a slight complication if you have hot water heated by an excess PV diverter, like the Eddi, Immersun or whatever. There can be an issue where the battery system takes priority over heating the hot water, which may or may not be the thing you want to happen. There are fixes for it, though.

Whats the fix ?

Not easy, I've found. I've replaced our previous PV immersion diverter (an Apollo Gem) with an Eddi and a Harvi (because I needed the wireless grid CT feature) and that half fixed it, in that with an offset programmed in I could sometimes get the Eddi to take priority over the Sofar, but not reliably, as both units have a different, and slightly variable, response time (whichever switches first gets the power).

The fix that seems to be working was to add another CT to the Eddi to measure the battery power. That then allows the Eddi to be programmed to preferentially heat the hot water rather than allow the battery to charge first. The set up for this is described in the Eddi manual on pages 21 and 22.

[dangermouse]

I know several people who have batteries but no solar. They've calculated that timeshiftimg cheap-rate electric pays off even better than storing solar!

I've just had batteries fitted on the assumption that during the summer we will import zero from the grid, based on our solar production and grid figures over 11 years, and will use "cheap" night leccy during the winter. All I need now is Octopus to fit the B***dy smart meter.

I'm in the same boat, got a lovely new battery system sitting unused, because there's no point in powering it on until I can charge it on cheap rate. 2 weeks to go until the smart meter gets fitted, although there's a slim chance of getting an earlier cancellation, I'm not holding my breath though.