Adding battery storage - feasibility and payback

NedS

My understanding is that when commissioning the installation of these types of system (not specific to ECOFlow), there is an option to select if it's permanently wired or plugged in, which configures the software limits appropriately. In plug-in mode, they are generally limited to 800W but when permanently wired this may be 2.5-3kW depending on the device.

They get around the limitations by stating on their website that plug-in batteries are not (currently) legal in the UK and any local regulations must be adhered to.

Screwdriva

https://forums.moneysavingexpert.com/discussion/comment/82171476#Comment_82171476

Ah yes, I see. I could never recommend such a solution. I spend all my available time fighting against dodgy tactics to ensure homeowners receive the best possible experience with renewables via brands free of forced labour & the longest possible warranty durations that are honoured in the business.

That said, the day plug in batteries become legal (as an add on to my G99), I will be first in line to buy a good one. And will recommend them.

Martyn1981

https://forums.moneysavingexpert.com/discussion/comment/82171003#Comment_82171003

Yeah I probably should have explained that better. Firstly, it was just to say that they don't discharge at 800W if you don't have an energy monitor, you can choose.

But what I was really getting at, is that if you have a smaller amount of battery storage, such as the 2kWh (1.92kWh?) sheenas has, then you may not need to go down the monitoring route (unless you have PV too).

Take that 1.92kWh, probably about 1.5kWh useable (assuming 15% to 95% SOC is set), then that's ~100W per hour for the non-cheap rate period. That's probably baseload, so you avoid the leccy import cost anyway.

For me, once the heating period starts with the two A2A units operating (albeit at low and modulating rates atm) then my baseload is ~300W, and similar to the Ecoflow output.

Though in my case, I do have PV, but I have a large DC side battery balancing that anyway.

I would think/assume, that for most PV or non-PV households, you'd be better of with an energy monitor and demand responsive batts, perhaps at the 4kWh+ level? Hard to tell, all depends on what the PnP battery rules dictate (if it eventually happens), and the cost of the monitor and install. [I did get a free monitor as part of my battery package, but it's not needed.]

FFHillbilly

https://forums.moneysavingexpert.com/discussion/6686918/adding-battery-storage-feasibility-and-payback

reagrding a calculator to forecast returns, I find ChatGPT very useful for that sort of thing. you have already got alot of the figures, just stick them into ChatGPT and ask it what you want to know.

Get a few quotes for an AC coupled battery at your house, yes it's an entirely seperate thing to the solar panels you already have installed. the people who install them will be able to offer advice about how mch you need

sheenas

You really do need the electrician to install a fused spur and power meter currently. I suspect next year at some point it will be true plug-in via the standard socket. I didn't think £150 was an outrageous amount to pay and as other have said it then becomes a hardwired solution that you be configured upto 3kw output rather than the 800w default. I have kept mine at 800w for now as I don't see a major advantage in doing so.

72kit_co_uk

One thing nobody has mentioned that might affect the choice: most plug-in and grid-tied batteries switch off when the grid goes down, so they won't keep anything running in a power cut unless the system has a backup (EPS) socket or a proper changeover switch fitted by an electrician. If resilience matters as well as payback, it's worth asking about before buying.