Minimising clipping

I have a recently installed system and I’m keen to minimise any clipping.
I have a
9.5kWh battery
3rd Gen 3.6kw inverter
5.16 kw solar array

It’s an all electric house with an ASHP.

Despite the fact I live in Scotland and the roof is facing SE I’m already seeing some clipping.
If I set the battery to (partially ) discharge to the grid (before it starts charging in the morning) and cut back on the charging rate from the panels ( neither of which I know how to do - yet), will that reduce the amount of clipping?

Yes, leave some space in the battery for when the clipping is at its worst - so some of the energy can flow into the battery and some into the home/out to the grid.

You could do that by setting a lower charge rate, I think, so the battery doesn't fill up too quickly.

Are you getting paid to export too? Hopefully can make some money out of whatever ends up in the grid.

TX200 I’m getting the fixed Octopus export so it will provide some return. I just need to figure out how to set it up for when it’s going to be sunny. Thanks for taking time to respond.

AGR It's relatively easy if you want to export only just enough to avoid clipping, but a bit harder if you want to maximise export, and charge the battery only enough to avoid clipping.

For the former, as mentioned, plenty of space in the battery, and perhaps reducing the charging rate to ensure the battery doesn't fill about before peak solar. The system has a 'timed pause' control - I used to have charging paused between 9am and 12am to ensure there'd be space in the battery starting at noon. (My array is SW facing, so peak solar is in the afternoon.)

The timed pause is only available via the remote control part of the portal (or the API). The charging power is available on the app.

For the latter, I'm now using a script running on a rpi to dynamically adjust the charging power so that only just enough is sent to the battery to keep the AC close to maximum.

See also https://community.givenergy.cloud/d/3960-does-grid-first-work-on-latest-gen-3-hybrid-firmware
https://community.givenergy.cloud/d/4331-at-what-kwh-should-i-expect-to-see-clipping

You may get more than the notional 5.16kW solar at the moment: that's at a specific temperature (perhaps 25 degrees ?), and you get slightly more if it's cooler.

DD Thanks DD, I’ll try the timed pause first and see how that goes. When I’m at home it should be straightforward but I’m away a fair bit over summer so I’ll need to be a bit more active about controlling things. I’ll look into reducing the charging rate, still not completely sure how it’s going to work.

AGR many here use home assistant for full custom automation over their system. I'm resisting, and use a few simple python scripts running from an rpi that's always-on anyway.
There are some external agents on the cloud that allow you to do run various schedules.

AGR Since your array faces SE, your peak sun will probably be around 10,30-11am BST, so if you slow the charge rate through the morning from around 9-1am, you should cover any clipping. This will be quite fortunate in your case as the battery will be used during the overnight period so there should be some space available. It'll probably be only necessary on really sunny days in spring and autumn, as during the warm summer days, you'll only get around 3.5-4kw from your panels as they get so hot, and output is reduced.
You can adjust the power in the App using the cog at the top right of the screen, click on the 'charge power' and adjust the slider to what you want to charge at - then save. My suggestion would be around 1500w between 9-1pm and see how it goes.
Good luck with it anyway!

TimHutchings Thanks Tim, I’ll give that a try.

What are the negatives when clipping occurs? Is it lost income from export? Is it stress to the inverter? In my case I’m generating 4.5kW but my Gen 3 5.2kW inverter can only process 3.6kW.

SteveClubley I’m generating 4.5kW but my Gen 3 5.2kW inverter can only process 3.6kW.

there isn't a 5.2kW inverter, its either 3.6 or 5kW

If its a 5kW inverter you have then your inverter can convert up to 5kW of DC to AC, and/or (gen 3) DC charge/discharge your battery at up to 3.6kW. So with 4.5kW of solar generation then up to 3.6 can go into the battery and 0.9 (minus house load) exported, or nothing in the battery and up to 4.5kW (minus house load) exported

Sorry yeah it’s a 5.0kW Gen 3. I have 14 panels that total 6.2kW but they’re split into two different orientations but can get over 5kW peaking in the summer. I’m sure I’ve only seen 3.6kW be exported as a peak though with less than 0.5 kW house load and full battery. Hence my question about negativities of clipping.

It won't do any harm it just means you are not using all the available energy from your panels.

Also if you only have G98 export approval the inverter will be configured to only export 16A max, which is 3.68kW.

nophead
Think it’s G99 and it talks about 4kW limit but I think the inverter is set to 3.6kW as you say. Thanks.

SteveClubley if you have the DNO approval then givenergy support can change the export limit for you if its been set wrong on the inverter

if you can get more from your panels than you can export then its worth you either pausing charging or setting a low charge rate to keep some space in your battery until the peak of the day, so maximising your solar generation and export income. Its exactly the approach I follow