I've got a Gen3 5kWh inverter and a couple of 9.5kWh batteries, with 2 strings of 9 panels in an East West direction with a G99 in place
A rookie question - It's been a rubbish couple of weeks post install weather wise, I get that I'll see clipping at 5kWh, that was well understood in all the research I did. Late last week I was seeing 6140w of pv power when it did brighten up a bit which is above the 5kWh I thought I'd ever see. In Eco mode how does the inverter deal with that kind excess?
Northwarks The inverter will clip the generation above it's threshold. Effectively, it's wasted.
Northwarks Was your battery charging at the time?
THALL
Yes charging, I noticed by chance this morning it was just short of 7kWh, with 4kWh going to the batteries and 2.8kWh going to the house and some of that was diverting to my Eddi. I assumed as @cluelesscris suggested it would be a max of 5kWh split between the batteries and house but that's not the case it seems ..
Northwarks The gen2 and 3 HY5s are able to handle 3.6kW PV to battery concurrently with up to 5kW PV to AC if there is sufficient PV and light. Once the batteries are fully charged the limit will be 5kW PV to AC. To maximise generation and avoid clipping this time of year, you can reduce battery charge rate to ensure that you can consume all available power when the sun is at the peak. This would result in export earlier in the day when batteries are still charging, but as long as the forecast says you'll have sun all day, the batteries will have time to charge by the end of the day and clipping will be minimised.
Northwarks So if I understand this correctly and I think there is a possible bug in the givenergy software regarding limited export. But your inverter can do 7500w of pv, 5kw ac limit so your house leaving 2.5kw that can go to the battery if if has space. Once the battery is full you will see 5kw max the PV. You should see less PV depending on your export limitation. Example, battery full, house load 0.2kw, PV generating 5kw, you have a 3.68kw export to grid limit (your G99 might say what you export limit is) then in theory the inverter should clip generation down to 3.7kw ish. 0.2kw house load, 3.68kw grid export.
@THALL - My G99 is for 5kw, so the expected behaviour is once the batteries are full it can export anything up to 5kw minus what the house is using. Yeah I'm happy with that I had assumed it was always 5kw all the time.
Just need some long sunny days now to see what the system can do !
THALL That is how I understand it. To avoid the clipping (5kW down to 3.68kW), just ensure that your battery isn't full during peak generation. If you could guarantee 9 hours of generation and your battery has 4.5kWh of charge that it could take, then setting the charge rate to 500W would fully charge the battery before the end of the day and minimise clipping. Alternatively, if you have an automation, you could set the charge rate to zero until you hit your G99 export limit, then ramp up the charge rate for the battery. @TheDragon (GivEnergy) has mentioned an automation that does this: maximise generation and only enables battery charge when G99 export limit is reached. While the concept is simple, a link to the automation hasn't yet been forthcoming.
Tim I find the last sentence quite harsh.
But here you go, link to the actual article author.
https://m.facebook.com/groups/615579009972782/permalink/775338717330143/
TheDragon (GivEnergy) I find the last sentence quite harsh
Apologies if the language was clumsy but two of us had asked for more information on the thread where you had given us the heads up. Not being a FB user means I’d have to rely on the goodwill of the likes of you to point me at the detail (thank you) to save hours of trawling.
Cant acces that page as not a FB user or member of that group
TX200, positor1 the FB page describes using an HA entity and some YAML to modify the battery charge rate, effectively diverting export in excess of the G99 limit to battery with updates every 20 seconds or so. I’m trying to steer clear of YAML but the concept should be fairly easy for me to replicate using Node-RED; HA entity for export (from Glow Smart meter as we have two inverters) and an HA call service to battery charge rate. Obviously only really works well when the forecast for solar is good but should maximise export and minimise clipping.
Tim I have done something similar Two input_number settings, 1) when do you want the battery full by, which dynamically sets minimum charge rate 2) a clipping setting, which keeps battery charge rate to the minimum required to clip to battery. Then a template that converts both of the above, with PV and current time and results in the larger of the two minimums. Automation then sets battery charge max rate to template result. Personally I only trigger it every 15 mins.
In reality, none of it is critical. My system can clip between 10 and 3pm, and I want the battery full at 3. I then only use the prediction for tomorrow to decide if there is likely to be any excess. As a bonus, I am pretty sure that the resulting slow charges are helping round trip efficiency in the battery. I seemed to be getting horrible in energy to out energy figures, 72% when max charge set to 3600w, full by lunchtime.
In this image the first day battery charge and time was controlled to avoid clipping, the second day shows clipping because the battery was charged too early and too quickly.
justpassing As I don't have a FB account would you be able to share the config you have done?
Northwarks no problem. As "it's just for me" use it as a guide, not as plug and play. Also ther are several steps, not just the automation. I'll post it when I get a moment
Hope that helps. The helpers can be set up in the GUI.
The template has a massively long line in it, you need to paste that in without line feeds.
justpassing Excellent thanks - Taken as-is and something to give me a head start.
I am not sure if this is seen as good protocol, but having looked at the facebook version ( above) its much simpler, so probably a better starting point. All rights to the original author as above
https://m.facebook.com/groups/615579009972782/permalink/775338717330143/