20 minutes ago, Denns said:

Believe it or not, I actually averaged about 900kWh a month before getting solar. With solar, not counting the geyser, I use about 200 to 250kWh a month (Monthly PV generation for this month is about 900kWh). Geyser when I had it on the grid was about 200kWh a month so in total now about 450kWh. Halved my consumption!

As for the savings, its true it does look nice on a spreadsheet to have big savings by inflating the costs but I accepted it. Same way I accepted that 2/3 of my solar generation is wasted every day. But it saves me when the rain and clouds start.

Here is my consumption for the month. 

In my area this month has been very poor, lots of cloudy and rainy days. it's been the lowest production since installation 4 years ago.

Here is my dashboard for this month.

Previous month.

1 hour ago, Denns said:

I would have imagined your inverter should only switch to the grid when it hits the battery cut-off. Interesting that it does that with a low load.

It's designed that way. IDK why. Goodwe inverters usually have four different modes of operation. If I run in the default general mode then it balances grid, PV, and battery. And for some reason switches back to grid when demand is very low. If I run it off-grid mode then, of course, that doesn't happen. That's why I'm thinking about a way to switch modes at a certain time of day. At present I have to switch modes manually - and remember to reverse the switch again in the morning.

@Denns You don't waste a single watt 😃

The lowest i can get my load is ±750w- Alarm, Cctv & Monitors chew about 500w rest is for fridge & freezer. All my lights is on separate system. So ya - i will never get to your figures!

My Nov figures, sun is good this month.

Edited November 25, 2025Nov 25 by Demo
Wrong Pic

19 minutes ago, Demo said:

My Nov figures, sun is good this month.

I see a major difference between us. Apart from size I use 53% of my consumption from battery. Few loads on during the day. Can only increase my loads from PV during weekends. This month had at least 10 not so good days due to cloud.

We both share the positive that we get more from PV than what our consumption is.

3 hours ago, Scorp007 said:

We both share the positive that we get more from PV than what our consumption is.

Yeah, on nice sunny days i let the air-cons work - free cooling !

15 hours ago, Demo said:

@Denns You don't waste a single watt 😃

The lowest i can get my load is ±750w- Alarm, Cctv & Monitors chew about 500w rest is for fridge & freezer. All my lights is on separate system. So ya - i will never get to your figures!

Inverter based fridges are a must these days. My fridges when running use about 70W of power each. Older ones are very inefficient. Alarm uses about 15W when I measured it. Most of the power is to float charge its own backup battery.

Edited November 26, 2025Nov 26 by Denns

Here's why I need more batteries....

Installed the 4 x 600w JA panels middle of September, now I'm generating way more power and pushing back to Eskom more than I'm consuming :eek:

Its time to go off grid.... Dont want to be involved in "feeding" that corrupt SOE.

PS: the bad dip in generation on month 4 to 7 was due to tree's shading my panels, I built a new roof higher up to compensate for the shading and got immediate returns as you can see in month 8

Id love to stay with Volta batteries, however I cant take the chance that they change the BMS again in the next 4 years and screw up my upgrade plans again...

Edited November 26, 2025Nov 26 by SulacoMcClaw

This is a good representation of a fair day's generation on my system, base load is just over 500W I buy approximately 6 Kwh from Eskom per day, and feed back 20Kwh per day on average. Currently not drawing power from my 5Kw battery at all as I have been too lazy to change the setup from my old loadshedding setup. SOC of battery is 100% all the time (laziness again LOL)   

2 hours ago, SulacoMcClaw said:

SOC of battery is 100% all the time (laziness again LOL)   

This is very bad for your batteries! Proper batteries need to cycle, every day.

Just now, Demo said:

This is very bad for your batteries! Proper batteries need to cycle, every day.

:eek: Did not know that...

Ill change the settings to pull from battery at night.

We use about 4Kwh at night so the 5Kw will do the trick if I set it to 80% DOD

It used to cycle with the 8 hour loadshedding we had in the past, so its only a recent "problem"

Me: Scurrying off to inverter to set the schedules...

Edited November 26, 2025Nov 26 by SulacoMcClaw

Watch this video - https://www.youtube.com/watch?v=UbZiHzflKMY

On 2025/11/25 at 10:09 AM, Scorp007 said:

Why would you not want to use the existing BMS that is still functioning well even if there is no comms to the inverter when using voltage mode?

11 minutes ago, Demo said:

Watch this video - https://www.youtube.com/watch?v=UbZiHzflKMY

Nice info in that video, doesn't really say that keeping it at 100% is bad though (Or did I miss something), just that you should use the stored power as the battery degrades over time in any case so why not use it.

10 hours ago, SulacoMcClaw said:

:eek: Did not know that...

Yeah @Demo is right. Lithium isnt like Lead acid so keeping it at 100% is one of the worst things you can do. If you kept it at 80% its way better for the battery long term.

10 hours ago, Demo said:

This is very bad for your batteries! Proper batteries need to cycle, every day.

I've been interested in this. I started wondering about such things when I had a smart phone with a Lithium but not LiFe battery and I destroyed the battery life quite quickly. By, it seemed to me, keeping the thing on charge all day.

With my current phone there is a feature you can turn on so that the battery never gets fully charged. Even if you plug it in when you go to bed at night, it will only charge to 85%, then stop drawing from the charger until SOC hits 80%. Then it will charge again. The explanation here is that you will get less battery life per day (though topping up as and when you can is recommended) but the battery will last longer.

So I did what any sane, reasonable person would do. I asked AI.

AI tells me that the way this is solved for modern batteries used in domestic applications is that the BMS basically lies. It tells you that the battery is at 100%, but it isn't. It's probably low 90s. As long as whatever is declared as 100% delivers the promised amount of power, everybody is happy. In such a scenario you probably don't want to keep it at a reported 100% all day, but you are never going to get it to a true 100% charge.

Is this true? IDK. Why then does the BMS do cell balancing?

And why don't the makes of my phone do that? Because the phone casing would get bigger and either too fat for contemporary tastes, or need a bigger screen which will put the price up?

Edited November 27, 2025Nov 27 by Bobster.
Sppelling

@SulacoMcClaw ,

Agreed, you need to start seriously cycling your batteries.

Looking at your monthly graphs, I could not understand why you are consuming vast quantities of grid (which you have to pay for).

Lucky that the grid feed-in compensates somewhat, but in my book, grid usage should be very close to Zero.

When I saw you daily consumption graph, it all made sense, you are (hopefully by now - where) using grid during the nights.

Fix that setting, and smile all the way, and hopefully you batteries are not compromised by the "keep it at 100%" scenario you had. Keep a lookout what your SOH is doing.

4 years and 830 hard cycles my SOH is still 100% on both batteries.

I ran my batteries down to 20% daily for years, while we could feed-in, and since feed-in tariff changes, it doesn't pay anymore, so the daily cycle is down to 50% on normal sunny days, with the occasional 20% during more cloudy days.

17 minutes ago, Bobster. said:

Is this true?

Thats how EVs work. They only operate between 20 and 80%. That battery SOC is what gives you the range stated by the manufacturer. As the battery degrades over time the BMS then allows you to use more and more of the battery, this is to meet the range warranty the car manufacturers claim. The battery is overspecced for the range.

10 hours ago, Demo said:

This is very bad for your batteries! Proper batteries need to cycle, every day.

Also, if you keep your battery at 100% you are not maximising your savings. Once the sun goes down you are running off of the grid, when you have all that lovely free power stored in your battery. A unit you buy from the grid costs a lot more than you get for selling a unit back.

When I had my system installed - 2019 - you really had to think about having enough to get you through a load shed. But modern inverters will let you reserve some of the battery. IE it does not discharge fully when there is grid.

My system is setup so that when there is grid the battery will not drop below 40% remaining SOC. When the grid is absent it will go down to 10% remaining (at which point the BMS shuts down anyway). So I will never have less than 3kWh in hand, and with a bit of discipline and with the pool pump (biggest single consumer of electricity in my home) on the non-backed up side, I can stretch that quite a long way. Average usage for my home is 13kWh per day. That's with the pool pump in use. Without the pool pump we'd be doing 9 to 10 kWh per day. So 3kWh in the battery can get us through a few hours.

So you can still set up like that if you're concerned about power outages and getting caught out by them.