Using Batteries

[malcyorks]

Hi all

I’ve had my system for just under a year now. 14 x 450w panels, 3.6 kw hybrid inverter and 5.4 kw battery.

The one thing I have noticed is when the battery is supplying power to the house there is always an additional cost to me from the supplier.

Even though this cost is small i estimate it adds up to about £100 a year.

Is this normal?

Cheers

Malc

 

[newfutile]

What cost do you mean? There is always a standing charge and there will be a per unit charge if you go over the 3.6 KW the inverter can supply or if you deplete the battery.
Sounds like a nice system

 

[ProDave]

And I believe some inverters will allow some import. If they set the bar too close to 0 they run the risk of exporting some of your battery power which would be worse.

 

[binky]

There are several discussions about this on here. In shorr, the inverters can't always respond fast enough to meet demand, plus ' maintenance' activity can pull some energy from the grid. So batteries don't completely prevent importing energy.

 

[malcyorks]

Thanks for the advice I’ll look into those other discussions. I have Octopus as my supplier and have the gadget that shows me usage every 30 minutes. When using battery power it shows a small amount of usage all the time. When I’m exporting it obviously shows negative usage.

 

[johnb2713]

Thanks for the advice I’ll look into those other discussions. I have Octopus as my supplier and have the gadget that shows me usage every 30 minutes. When using battery power it shows a small amount of usage all the time. When I’m exporting it obviously shows negative usage.

What make and model of inverter? does it use a power meter or CT for sensing? What are the export settings?

If youre talking about Octopus Mini as the gadget, you can get updates every 5 seconds or so.

 

[malcyorks]

Hi Johnb2713

It’s a Metz Invt 3.6 KW Hybrid Inverter single phase.

As for the other information I’m not sure where I would look up those details. The software provided only lets me see basic information and does not let me make adjustments. To do that I have to make them directly into the inverter or get in touch with the supplier who will do this on my behalf. I haven’t got the experience nor had any training with regards to the inverter so am hesitant when it comes to altering settings in the inverter.

I got the installer to charge the battery between 0200 and 0500 to get the cheap rate from Octopus. But as you can see from the attached screenshot I still use a small amount of power
When using the battery.

Cheers

Malc

 

[johnb2713]

Hi Johnb2713

It’s a Metz Invt 3.6 KW Hybrid Inverter single phase.

As for the other information I’m not sure where I would look up those details. The software provided only lets me see basic information and does not let me make adjustments. To do that I have to make them directly into the inverter or get in touch with the supplier who will do this on my behalf. I haven’t got the experience nor had any training with regards to the inverter so am hesitant when it comes to altering settings in the inverter.

I got the installer to charge the battery between 0200 and 0500 to get the cheap rate from Octopus. But as you can see from the attached screenshot I still use a small amount of power
When using the battery.

Cheers

Malc

My system (Growatt) used to do exactly the same. Mine had been configured initially for zero export which causes an issue if you want zero import. I have set my system up so that one inverter (Victron) maintains a steady 20w of export as its target and I allow exports from my Growatt, it's no longer set to zero export.

The net results looks like this:

Can you post a photograph of your meter cabinet and of your consumer unit so we can see how the inverter is monitoring your supply. If it's using a CT it will be difficult to hit zero, if its using a power meter it will be difficult to follow step responses like switching a kettle on.