sunset1

I only ordered the cells and bmses and screens.
I ordered 32 cells, 3 bmses and 3 screens. Totals were
Items 1404 usd
Shipping 370 usd
Total 1774 usd
There were no import duties, fees or taxes.

Are there places in Cape Town who can check batteries for dud cells and replace them?
Have 4 batteries (SHOTO 5.1kWh) and battery two never reaches 100% SOC

I could not help myself 🤣
He probably runs the most useful channel I know of when it comes to lifepo4 batteries and bms's
Definitely the 1st stop anyone should have when doing any sort of research about batteries :)

For anyone who has not yet seen Andy's channel... Here is the link.
https://www.youtube.com/@OffGridGarageAustralia

That is exactly what I was telling @sunset1 about how you will see a weak or bad cell when you have some nice graphs :)

That home assistant? Very nice dashboard

I set my Sunsynk inverter to discharge down to 20% during the evenings however I did not know nor was I informed before hand the SOC you get on the inverter is only the avg SOC accross my batteries. You would expect the BMS to keep the battery levels in check accross all 4 but that is not the case it would seem. With it being winter I don't always get to 100% each day to "sync up" the SOC's accross the batteries, so every day you only partially charge and discharge the variance between the batteries gets bigger and bigger.
One would expect that if the inverter is set to 20% the BMS would prevent the individual batteries going below 20% but that was not the case and it would run things down until the avg SOC reach 20% irrespective if one or more of your batteries are already below 20%. So without knowing it 2 of my batteries was running down to the point the the batteries BMS would actually put the battery in a protected shutdown state on while I thought everything was cool as the inverter showed I was above 20% things was far from it. I only noticed it when I saw my SOC graph the one day drop from 20 to 18 instantly. Needless to say cells got damaged and is being replaced hence the 2 offline batteries.
Below you will see the massive gaps between the 4 SOC's that would creep in after 2 or more days not charging up to 100%. This would register as 36% on the inverter.

See how the SOC starts to deviate between the 4 batteries (this was after the damage was done but this shows what I'm looking for and monitoring now).

I have an automation set to adjust my SOC on my Slot 1 to match the avg SOC as soon any one of the batteries reach 20% or any one of the 64 cells reach 3volts or if any battery reaches 49V.
And if the variance between the max SOC and Min SOC is more than 10% it would set slot 5 to 100% and enable grid charge to force a top up of the batteries now.
A bit overkill but once bitten, twice shy.
Never let things go this far:

esp32 with a rs485|ttl converter and running the code from https://github.com/txubelaxu/esphome-jk-bms/tree/main

I had a few weak cells 4 to be exact (1 on one battery and 3 on the second battery) replaced the weak cells with new ones and added a 16th cell to each battery.

When you have graphs running which shows the cell voltages throughout the full charge/discharge cycle you can quickly spot the weak cells when the batteries are almost empty on the one end and when they are almost full on the other end.
The weak cells will jump out at you, you cannot miss them.
They are usually the ones that deviate a lot away from the good cells.
I will see if i can find my old posts where I had pics of that happening.

I never had sight of the cells before changing over to the JK BMS's so never even knew I had issues, I just thought my 2 batteries lasting 12 hours was normal.
They now last almost 24 hours if the sun behaves.

Cells get damaged quickly if your bms has the wrong settings. Most of the batteries factory bms settings are WRONG.... You need to do whatever you can to get into the bms to set them correctly to help ensure your cells last long :)
See the new cells indicated, here you can see they are stronger than the rest. Opposite will happen with weak cells.

Very cool and nice graphics. I must get a dashboard like that one day ;)
Im using my partner's discarded laptop with broken screen as my home assistant server
Been working a treat frigate and some sonoff devices. Have solat assistant connected to my axpert inverter
How are you pulling data from your jk bms and inverter into HS?

May I ask what the issue was you had with the batteries and what it shows you now that avoids future problems?

Short video of the main screen in action to show off the almost real-time data.
No more worrying about the sometimes online sunsynk portal.

Yes this is latest Home Assistant on RPi5 with nvme drive to make it nice and quick and to handle the sheer volume of live data, this is the latest version of my layouts with multiple tabs to access all the data and settings for the batteries and inverter all on a single dashboard.
No more running to the garage to check and adjust settings :)

Battery Screen.


Power Charts


Battery Settings - not all added yet.

Changed the main screen a bit to use the full power flows, looks better IMO 😄

That home assistant? Very nice dashboard

Also enjoying the sun

Loosing power on PV 2 because I positioned that string like an idiot and now a shadow is casting on the bottom of 2 panels

What area of SA are you located?
Maybe rather get jk bms, much more suited for these types of DIY builds :)
Just my opinion as I have had major success with my Narada upgrades :)

Why not just add a diy case to your order, they are super easy even for a novice diy'er :)
And they come with everything needed to build a quality DIY battery

A little bit of a strange one buy am looking into getting some cells from Alibaba, will be 16x 3.2v 280A from a well known supplier. Plus Daly bms.
The price is significantly lower than the standard Hubble Svolt Dyness etc.
I've built my own 12v system 5 years back and its still goigg strong despite a couple sparks. In saying that this feels a little out of my depth and don't want to mess things up.
Would someone with diy knowledge be interested in building it of course for a fee?
Shipping, sundries etc would be on me of course. Whatever is needed to build it correctly and is safe.

I have never been able to buy LED downlights that last longer than 1 year yet the Eskom free issue 14 yrs ago are ALL still working fine. These were marked not for resale and the Philips brand.
Then I have found some other type of China LED lamps that I use through the night generally last only up to 1 year. But if the same lamp is used for only an hour or 2 they do last years.
My guess is it is related to the actual heat build up while on.

Thanks for your detailed, and well thought-out and articulated response - and I agree that there are some very good (ethics and value wise...) installers, but the problem arise when an inexperienced new PV owner-to-be decides to bite the bullet and install "some solar".
When I installed my first inverter (for myself) way before Loadshedding was even a word (around 2007 if I remember correctly...) there was very little information available on designing a system, and on available components. I basically had to bite the bullet and chose my inverter just based on country of manufacture (a Swiss made Studer XPC 2200-24...). Even in those days the batteries were ridiculously expensive, and I had to settle for 4x 12V telecoms type deep cycle VRLA sealed units that were made in China (and that lasted a good 16 years, I'm happy to say...). Although I did do my homework as best I could, given the scarcity of any decent reviews and data, it was still a gamble. Solar panels in South Africa were as scarce as chicken teeth, and I thus just used my system as a backup for some critical equipment that I wanted to always have power, fed from a rather reliable grid...
I designed my current system myself, based on what I learned through my trial and error first system, and after having done a lot of online research over a period of a few years, and only once prices dropped to more reasonable levels after Escom managed to eliminate most load shedding (mid 2024...). I thus specified the equipment to be quoted on, and the installation was done by a licensed electrician that came highly recommended by some happy clients that I know very well. Even so, to this day I don't know if my choice of equipment was the best "bang for the buck", or if the installation could perhaps have been done better - after some 10 months everything is still working as expected, but 10 months is a very short time in the life of a PV system...
So, from personal experience, I would have been much happier if I had access to unbiased feedback from experienced people on a Forum such as this, and I am still of the opinion that a "quality vs price" matrix of equipment would be of value to the majority of people just starting on their journey into solar.

Yes and I don't mind, whats your daily peak temperatures right now, for instance...here, right now, 32degC in the shade and yesterdays peak around 36.5degC in the shade... refer to refrigeration mentioned above... in summer our night average will be around the 1kW constant mark...., since our daytime temperatures will peak above 40degC every day, just about and night time can remain above 30degC on the minimum, can't compare Slaapstad with the Kalahari....

I have been contemplating this method. My first will be insulating the pipes well. Then seeing what the new temp is.
Tell me what does your geyser element draw for preheat? I know they are 3kw. I ask this is we have a smaller system. Be great if it just did 1kw.lets say

The Hubble AM 2 is about 16k at voltex.
Coild be wrong but OP batteries should go for about 7k-10k depending which one and considering usage, risk etc
Market will decide either way.

I will manually charge all 5 cells separately to 4.2v, to balance the pack, and chances are good that the battery pack still have alot of life left in it, I would use it a couple of times and see how many charge cycles it does before the capacity becomes unusable again, if the pack goes horribly out of balance again within +-30 cycles, then will I add a balancer.
If it goes out of balance within the first or second charge/discharge cycle after manually balancing, then im afraid the balancer will be of little benefit if any. new cells is the only way forward then.
I have recovered plenty of cells that had a voltage of 2.4 volts, below 2v I chuck it in the trash, I dont even attempt to revive or capacity test.
I assumed that 2.4v is the standard low voltage cut off for majority of bms'e (actually in this case is just a battery protection board) because I also found a lot of battery packs (powertool and laptop) that the packs was dead, and inside it was one string or cell at 2.4v and the rest at 3.xx volts

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