Are Home Batteries Worth It? A Cynic Debates A True Believer (Director's Cut!) 

absolutely love my battery its made a huge difference to the way my house uses electricity.

Eddie is nothing more than a snake oil salesman, and not a very good one at that! I ran the numbers on a Tesla battery and at 23c kwh the numbers don't work.

Which VPP did you choose?

Probably the biggest difference is the ability to use battery power in the morning before the solar PV's are generating enough to cover what you are using. This morning was a case in point, I turned the coffee machine on around 07:00 which is about the same time the sun is just starting to feather across some of our panels. I also used some other electrical stuff with the total power draw covered 100% by the battery. Later in the morning the panels were recharging the batteries, as well as running the house and workshop as there was plenty of excess power. Looking at the weather for tomorrow and knowing that there will be about the same amount of solar generation, we did a load in the washing machine, the dishwasher and some ironing. but ensured their SOC was around 50% at sunset by pulling short in the workshop by an hour (we are retired) (10kW flow battery x 2 for 20 kW total). By ensuring we had that amount SOC, we could cook dinner, electric oven, microwave (but still a gas cooktop). heating in most of the house is via heat pumps (reverse cycle air units in different rooms). We should be somewhere around 10% SOC to 18% SOC by 07:00 tomorrow morning, which is certainly enough to do breakfast and run the house until around 10:00 at the least. We generated 29kWh from the roof. Sent 20kWh to the batteries. Used 8.6kWh directly and sent 0.9kWh to the grid while at the same time we imported 0.4kWh from the grid. Wonderful day especially as we had some light rain, some cloudy periods, but some cloudy bright periods where we certainly produced some great power for a while. So even just in this one day, the difference between having batteries and not, is very different to just having panels and running around trying to use all that you can while the sun is shining. In short, if you set the dishwasher when it is bright and sunny, then halfway through clouds appear, you can be using grid power to finish the cycle; with a battery in the system, you can finish the cycle using your own generated and much cheaper power just for starters. In Melbourne, by the way with 7.7kWh of panels on the roof. We have certainly changed our way of doing things once we got our batteries. Had solar for almost 10 years and the batteries for 21 months.

Just another quickie, if there looks like there may be power interruptions, due to bushfires, big storms, then we ensure we don't go below enough power to see us through the time the storm or whatever is coming. We could in theory charge the batteries to 100% SOC from the grid, then weather out the storm and from the next day run a tight ship power wise running from our rooftop. We have a system that runs when the grid is down, which happens more than we thought it would. Batteries are clear winners in that situation!

@@allanhugh2044 this is all fantastic, thank you so much, what a wonderful insight into how life is with a battery. Thank you Allan! ☺️

Out of interest Allan, what battery setup do you have?

@@benjaminbailey-webb7161 We have two Redflow Z-Cell batteries. These are a flow battery, they have liquid flowing through them, they are not a dry cell type battery. Designed and originally built in Australia, they are now manufactured in Thailand, Redflow are in Qld. They are designed from the ground up as a small, but scalable battery system. Meaning you can have multiple batteries working as a single unit to supply whatever power needs you may have. Be that something to just keep the lights on, or the ability to run a manufacturing plant running on three phase power. Their main claim to fame as far as I'm concerned, is the one that allows these batteries to continuously supply constant power from 100% SOC down to 0% SOC. In practice, we know they essentially work from 102% SOC down to 1% SOC. When the sun shines and they are being charged, the fluid flows over a stack of plates and deposits zinc onto them, in effect electroplating. When power is required, the process is reversed and the zinc is removed. During that process electricity is generated, which is what we use to run our house. Another endearing feature is their ability to not degrade over time. They do degrade, or at least I've been told they will degrade, but the main degradation is their efficiency. In short, the first time we switched them on, we had 20kWh of potential stored energy and we are able to use 99% of that energy every day. After ten years of doing this every single day, we will still have 20kWh of potential stored energy. The major difference will be a slight drop in converting efficiency, meaning the batteries will take slightly longer to attain their maximum stored potential. At the end of ten years, actually most likely between 12 to 14 years with our usage, we will have the choice to refurbish the batteries for another ten years of use, or dispose of them. As a follow up from yesterday, we were at 14% SOC this morning at 07:00, however today is very cloudy and almost no rooftop generation. Had breakfast, coffee machine and all of that and at 09:00 the SOC is 11%. The house is consuming approximately 334W and the rooftop is generating approximately 336W. As the day gets brighter, things will get better, generation wise that is, but so far, today will not be a day to go into the workshop and suck electrons from the batteries....