Hi,
I'm a real newbie here and all the subtle tweaks are a bit beyond me at the moment but I want to learn. My system has 10.4KWh solar array, hybrid inverter (GIV-3HY-11) with a 13.58KWh Givenergy battery (4 Stack) and I am currently on Octopus agile for import and fixed for export. Ideally I would like my set up to run as much as possible using solar (including fully charging the battery) so that I can use the battery overnight to power the house and then repeat the next day. If insufficient solar, then I think there should be enough in the battery to fill the day gaps in solar power by being able to use the cheap night rate to recharge the battery. I have 3 questions:
1) does this make sense?
2) Will the automation feature do this for me?
3) Should the battery only charge to a certain % e.g. 80% overnight assuming that some solar every day will top it up?
Any help or suggestions to optimise my system set up and to minimise my bill for electricity (or even to make some money from export) would be most appreciated
D
#2DD
ianisbambam My system has 10.4KWh solar array, hybrid inverter (GIV-3HY-11) with a 13.58KWh Givenergy battery
Is that solar array east-west split, or all in one direction? The inverter has a max input capacity of 7.5kW, so you may need to do a bit of work to minimse clipping losses. The large battery capacity should help there.
so that I can use the battery overnight to power the house
What are your consumption numbers like? 13.5kWh seems quite a lot for overnight use, especially since agile is usually relatively cheap overnight. (Need to compare against 15p export rate - if overnight import is cheaper, it makes sense to export solar and run the house from the grid overnight.)
If insufficient solar, then I think there should be enough in the battery to fill the day gaps in solar power
Again, depends on your consumption - at the moment, even on the dullest day, my 6.4kWp arrary provides more than my usage.
G
#3geoffreycoan
ianisbambam 2) Will the automation feature do this for me?
There is an automation feature in the GivEnergy portal that is ‘smart tariff aware’ but I don’t think it works very well.
You have two practical options for battery/inverter automation:
Home Assistant (running on a dedicated PC or Raspberry Pi in your house) using GivTCP to communicate to your inverter and either home-written scripts or Predbat to predict your solar generation, home consumption and to automate charging and discharging your battery to minimise your spending
Cloud based solutions that communicate over the internet to do much the same. Octopus R&D used to be the only option but the main contenders now are Wonder Watt and My Energy Optimiser
There is the option of manually controlling the inverter yourself or writing/running your own scripts to talk to the inverter, but for most people these are not really viable.
Personally I went down the home automation route and run Predbat on a small PC. Many people here use WonderWatt quite successfully.
Lots of other forum discussions on both of these topics
ianisbambam 3) Should the battery only charge to a certain % e.g. 80% overnight assuming that some solar every day will top it up
This all depends on the price of the import and export and the losses in your inverter for battery charge and discharge. You need decent battery optimisation to work this out for you! Charging overnight to say 80% means if its a dull day then you’ll always have enough electricity for the next day, but overnight on Agile the price can be as low as negative, or it can be around the 15p mark which means it would be more expensive to charge overnight.
Last night for example the rate was 16p most of the night but dropped to 11-12p from 4am-6:30am so that’s when Predbat charged my battery. Tonight its predicted to drop to 9p at 1am then down to 7p at 4:30, but in between it goes up and down so Predbat will be charging and discharging my battery to optimise my spend.
geoffreycoan using GivTCP to communicate to your inverter
Not quite sure how mature the GivTCP support is for the 3-phase inverter.
G
#6geoffreycoan
DD Good point, the 3-phase inverter is a new product and some of the control options are still work in progress.
The GivTCP 3-phase is in Beta test. I think there are still some issues though as is control of the 3-phase inverter via cloud API’s (and the ge_cloud HA integration). I know of one person from the Predbat github issues that has been trying both, but I don’t know how well it works yet.
