Solar Clipping

GivEnergy Products GivEnergy Hybrid Inverters
1

Hi,

All, hoping for a bit of guidance on how best to make the most of my solar

My System Spec is:

  • 5kWh Hybrid inverter
  • 9.5kW Battery
  • 7.2kWp Solar

During my Solar install we were able to fit an extra couple of panels on the roof so my Solar peak went up to a little ove 7kWp, compared to the 6kWp we orginally expected. As i have a mix of a SE aspect and SW aspect i thought this would be ok with some of the panels ramping down as the others were ramping up, but i’ve already seen multiple days well above 7kW .

The hybrid inverter obviously has the the ability to handle this but when the battery is full uit can only export a max of 5kW and its just dumping the excess as heat. I can offset this by dumping a little of the battery capacity before hand to make sure there’s some space, however once it reaches the lower limit it stops supporting the house, but this means that on cloudy days i’m just discharging the battery for no reason or drawing off the grid when the battery has the capacity and then charging it again later.

Is there any way to have the battery stay at around 80%, export everything else and then only charge the battery when there is a solar level above 5kW and then discharge back to 80%, whilst continuing to support the house?

2 Likes
2

You can set a timed export down to 80% say between 10:00 and 15:00.
This way if solar gen is lower the 5kWh then the battery will discharge bringing export up to 5kWh.
If solar gen is over 5kWh then the battery will take the excess as charge if space.
If the sun goes away for an extended period, the battery will stop exporting when it gets down to 80%.

It’s a good way to extend the max export, reduce clipping losses and fill in any lower than 5kWh dips.

1 Like
3

Thanks, this is what I’m currently doing and it does stop the clipping as you describe, but when the discharge gets down to 80% it pauses all of the discharge, including supporting the house

It’s generally not that big of an issue, as most of the time when this happens there’s not a massive amount of usage in the house, but I have drawn off the grid a few times

Is there anyway to get it to keep supporting the house after the effort hit target?

4

Is ECO still switched on?
Export should only limit I thought export, not discharge…

5

Eco is on, I am using export to get to 80%. I have discharge as a setting in the App but I can’t set percentage for that.

I can’t see a separate discharge and export setting on the inverter via the portal.

6

I’ve just (this morning) configured a few Home Assistant automations to achieve this, similar setup to yours other than 2 9.5"s;

Automation 1
Set the inverter to export for 3 hours at 5:30am
As I’m just testing this I’ve just set the maximum export period for now but I need to scale this with the estimated excess solar available, which needs to be calculated, probably as a function of the estimated solar generation with one of the available solar integrations in HA.

Automation 2
I check, every 30s, if the solar generation is over 4900w and if the inverter power (this is export + home) is over 4800w then increment the battery charge level by 100w

Automation 3
I check, every 30s, if the inverter power is under 4800w then decrememt the battery charge level by 100w

This allows the the battery to soak up excess solar above the 5Kw export limit by increasing and decreasing the battery charge periodically to match the excess. I’ve just estimated the switching levels, theres probably a better way to calculate it.

I also, at 7pm reset the battery charge level to 3600w (max) ready for the night time Intellegent Octopus charge.

Below is today’s graph, I only had it running fully in the afternoon but you can see the solar exceeding the normal 5kw I’ve been clipping to.

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1 Like
7

Hi James, I have exactly the same issue/question with similar figures:

⦁ 10.5kWp solar
⦁ 8kW hybrid inverter
⦁ 10.2kWh battery (charges/discharges at max 6kW)
⦁ 5kW export limit

Also like you, doing as wrighar described in his post. This works brilliantly on the really sunny days. We manage to catch almost every photon and export most of them by emptying the battery first thing and not charging it at all until we are already at exporting 5kW.

But like you, found that setting an export percentage limit does not just limit export, it limits all discharge. So the house then draws from the grid when the sun goes in.

But it’s worse than that. Even if I toggle off the timed export slots so that I can’t even see the ‘export to’ slider, the battery still refuses to cover the house load if this percentage was set higher than the current battery SoC. Having any value set on this slider seems to override the reserve set for the battery operating range.

Eco is switched on. Timed discharge is set to 05:30-23:30. I have tried toggling timed discharge on and off (with timed export off) and get the same result. I have to turn export back on, move the slider right back down, and turn export back off again to get the battery to cover the house when the sun goes in but not drain the battery into the grid in the evening.

My workaround over the summer was to leave the ‘export to’ permanently at 4% and instead adjust the grid export limit slider up and down (depending on solar expectations) so that I didn’t accidentally drain the battery leaving us short before night rate kicked in. However mistakes were made.

Another disadvantage of this workaround is that the battery is working a lot harder than it should need to on all but the sunniest of days when it unnecessarily drains to maintain the export when the sun goes in and then needs charging back up again.

This week this workaround stopped working anyway as reducing this slider has suddenly started resetting the hard max export limit of 5kW down to whatever the slider was last set at. After the second time in two days of asking the installer to reset it back to 5kW, I’m now leaving it alone.

I do use home assistant, but there are still connections issues with GivTCP. Same with my phone - it can’t access ‘home’ - it’s a bug that they supposedly fixed a week or two back and it’s better but still not reliable enough to rely on HA automations.

But I feel that I shouldn’t need to resort to home assistant for this. It should all work as required if the “export percentage limit” only applied to export and not to covering the house load too. This would also avoid excessive, unnecessary cycling of the battery on less sunny days which can’t be great long term.