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Sell back to grid from battery at specific time?

  • 14-08-2024 11:48am
    #1
    Registered Users Posts: 331 ✭✭


    Hi all I l have a PV setup with 13 panels. In the summer on sunny days my 10kwh battery is full most of the day. When we go to bed at 11pm it's 90% full. I am on a night EV rate with my electricity provider so from 2am to 6am I can charge the my car battery and solar battery at 25% of the normal cost of a unit of electricity which is normally 32 cent a unit. So I can fill my 10kwh solar battery at 8 cent a unit form 2am to 6am. If I sell back to the grid I get 24 cent per unit. 
    I want to set the system so I can sell 6 or 7 kWh directly from my battery to the grid at midnight to 2am. I can then refill the battery back up on the cheap rate at 2am to 6am. It seems like I'm wasting a perfect chance to get additional credit each day by not doing it. (Correct me if I'm wrong please?)


    Is there a way to sell directly back to the grid from my battery during that specific time? Excess during the day from the pvs goes back automatically. When the sun is down I run off the battery but it makes little sense to keep it full and not charge it during the low EV rate.

    I have a Huawei Sun2000 5kh inverter and Huawei Luna 2000 10kwh battery. Thanks very much for your advice.



Comments

  • Registered Users, Registered Users 2 Posts: 15,331 ✭✭✭✭loyatemu


    Yes you can force your battery to discharge to the grid (I have Solis so don't know the exact procedure for Huawei).

    However when I asked about this on another thread here, it was suggested it wasn't really worth it as you're ultimately shortening the life of your battery.



  • Registered Users, Registered Users 2 Posts: 2,596 ✭✭✭bullit_dodger


    Well, you bought your battery to be used, so not using it……is akin to buying a new car and then not driving it as you'll wear down the tires. Sounds odd, but it's the same argument.

    Battery is there to save/make you money, so if you use it to perform that task that you purchased it for then that's using the device and helping you payback it's purchase price quicker.

    Most batteries are good for 5000-6000 cycles. Some like the Givenergy one garuantee the same capacity after 10 years daily use as the day it was bought. (They do that by under the hood giving you more than they advertise as capacity)

    But even 365 cycles a year, that's like 15 years or so before it's hit is 6000 cycles. Usually at that stage it's capacity has dropped off from when you purchased it, but only down to 75-80% of the original. So it's not that its defunct, just working with less storage.

    No, you should use your battery as much as you can and as often as it's financially viable. I won't bother if your charge rate was say €0.08/unit and export rater was something like €0.12 as with losses, it's not worth your time, but in your case…..have at it!



  • Moderators, Sports Moderators Posts: 19,482 Mod ✭✭✭✭slave1


    Battery needs to be worked, if the differential between purchase and resale of electricity is good enough then cycle it daily



  • Registered Users, Registered Users 2 Posts: 790 ✭✭✭conor_mc


    Bear in mind the tax allowance for FiT at €400 per person. Get a second name (or third!) on the bill if you’re planning to ramp up your export so you don’t have to declare a portion as taxable.



  • Registered Users Posts: 331 ✭✭Kildare787


    Thanks for the advice lads. Just trying to figure out how to force discharge at midnight. Hard to get a solid answer on it.



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  • Registered Users, Registered Users 2 Posts: 8,078 ✭✭✭con747


    ….

    Post edited by con747 on

    Don't expect anything from life, just be grateful to be alive.



  • Registered Users, Registered Users 2 Posts: 2,237 ✭✭✭lau1247


    I think the below is correct and if not mistaken the app doesn't allow you to automate it on a schedule.

    In the phone app (android), go to your plant > Device > Connected Devices > Battery 1 > 4 dot icon (top right) > Parameter setting > Under Basic tab (main tab by default) > Charge/Discharge.

    By default it is STOP, you can change to DISCHARGE.

    That should work.

    West Dublin, ☀️ 7.83kWp ⚡5.66 kWp South West, ⚡2.18 kWp North East



  • Moderators, Science, Health & Environment Moderators Posts: 4,757 Mod ✭✭✭✭Tree


    If you have home assistant, you can set it up as an automation with the huawei integration (updating HA right now so I can't tell you the plugin owner).



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