Is it worth my while getting a battery?

For my own experience, I just got a 10kWh battery installed to complement my 6kWp of panels

Last month I generated 665kWh of which I consumed 417 (65%). This was while using the Zappi to charge my EV for free for nearly a month, giving me over 500km of free driving

I also imported 447kWh from the grid

In the past two days, I've imported 2kWh from the grid and my self use rate is over 90%. Multiply that out for a month and add in some extra for charging the EV you're probably looking at ~140kWh of consumption, almost all at the cheaper night rate

What I've found is that having the battery takes the thinking out of the solar panels, you just start the appliances sometime in the afternoon when the battery has charged up

Having the Zappi is a bonus, but I don't think I'll be getting the same levels of free driving as last month

Now in your case, you'll need to consider how much power you can get out of the panels on a good day and how big a battery this can fill, which will kind of determine the size of battery you should get

You may also need a new inverter if your current one isn't a hybrid inverter, which could add some consideration costs

For me the battery is a win as I charge it by night in the winter months on cheap electricity and use it by day, I reckon thou its only a matter of time until the night rate is reduced from the current 9hr window as with all the electric cars coming on stream there will be no requirement for the grid operators to sell surplus energy cheaply by night.

Depends on a few factors including your inverter size and how much power it can charge the battery with, and how much power the battery can be charged and discharged with

In general, a 5kWh battery would take 1 hour to charge from a 5kW inverter. A 2.5kW inverter (or if the battery is limited to this for whatever reason) would double the charging time

Do you know what model inverter you have? That'll probably be the determining factor

Btw, battery capacity is kWh not kW. Kilowatts are instantaneous power whereas kilowatt hours are energy capacity.

A 10kWh battery would need a 5kW hybrid inverter minimum to charge in two hours

A good analogy is kW is like horsepower for an engine, and kWh is the fuel capacity of the tank

It's the ES version.

I got 2 of these batteries, but tbh they're pretty much all the same these days

I'll PM details of who I bought it from and the price

PMs sent

You probably don't want to fully charge the battery at night, but you'll likely want to keep a charging window to ensure the cars don't drain the house battery

I've mine set to charge from midnight to 3am to give the cats 3 hours of charging, that's more than enough for now to keep up with any diving we're doing

I've set the inverter to charge the house battery to 40%. I could go lower but it means I've got some usable energy in the morning and it won't start importing from the grid before the sun starts shining

Bear in mind that day rate starts at 9am in the summer. So you are in effect using your battery with the 10% losses etc to provide "night rate" when in fact you could simply take it from the grid anyway.

Need to start at 9am Alan. In winter it's 8am alright.

Ahh good to know - didn't realize that, but I suspect Alan is on the old D/N meter like most of us as the smart meters "in D/N mode" will only be available from "Autumn 23".

Haven't got a battery yet but wondering how do you set it to charge say between 2am and 4am.

Thanks for your advice con747.

Found this helpful youtube

videoSolis Hybrid Inverter - Self-Use with Time Charging - YouTube

Hi could you pm the details of where you got the batteries please cheers