splunker

Hi @splunker
You may be lucky and find the correct serial cable in you local electronics store. Even our local Communica shop doesn't sell the right cable. It has a db9 connector, and it needs a RJ11 one. I've ordered from Solar-assistant quite a few times and their deliveries are prompt + plus you know you have the right cable. 
Regarding the dongle, as mentioned, there is no dongle required for the battery. The dongle is only for the inverter. You can see it as a RS485 to Wifi bridge. If you have the USB serial cable for the battery, you can monitor the battery on you PC. Plug the same cable into your HA server, and with the correct integrations, the battery data can be visualised in HA.

The batteries need to be checked and firmware updated. Contact installer / battery manufacturer 

https://chat.whatsapp.com/I6d84vNl1f2AYhG9yW2aIs
There is volta battery support on this whatsapp community 

I've had this before on a different brand.  Can you somewhere check your State-of-Health?  In my case, when the SOC dropped like that, it was due to a short circuit within the battery and then afterwards, my SOH showed as 40-60ah.  After a firmware upgrade it was restored to 100ah temporarily, but the SOC would drop like that again after a week or so (or sometimes after a day). 
The issue only got solved after the batteries were repaired (with a bit of fighting, but it was done under warranty).  Short circuit was caused by loose cells within the battery that only got noticeable when the SOC dropped to certain levels.

I use a custom computer (SolarAssist) where it lets you look at each individual battery's details.  Don't think you can view that level of detail just on the inverter.

@splunker,
If you have/get the RS232 cable, just connect it to your master battery, and use something like pbmstools on your PC, at least you can see what the individual cells etc. are doing.
After 3 years of SA, I still like the product, but as with enquiring minds, one thing I miss most is to get a history of SOC% levels. SA give one a nice realtime battery SOC graph, but I don't have the time to watch it all day long... so I started experimenting with HA. Seeing you already have an HA server, together with smarthomeintegrations.co.za dongle and a RS232 to USB cable (get it from solar-assitant.io), you can monitor each battery's performance. You need a bit of HA, MQTT type of skills. I struggled in the beginning, but persevered . You won't be sorry, and if you like to code, HA can be magic (and frustrating at the same time:-))
I'm not affiliated to smarthomeintegrations or solar-assistant, but I like to support South African products (they both originate from Pretoria). Same goes for Thingwala, who is CTN based, I think.
 

Great, but with 4 green LED possibilities, you may still have a 25% error/deviation between batteries that you don't know about. Can you post a pic of the interface of the Volta battery. Hopefully it has the standard interface layout like so: HA likes those!!

@splunker,
No, the smartdeye dongle is for the Inverter and provides the go between Inverter and HA. Yes, the Inverter does provide battery information (provided you have an active comms (CAN) cable to Master battery - see last para), but it will be consolidated. e.g. if one battery is @ 50% SOC and the other @ 60% SOC, it will send the info as 55% SOc, i.e. the average.
To get individual Batteries you need to have the RS232/USB cable (one is sufficient per battery bank, as they should all be linked (via RS485 - as per you pic).
You need to see if there is an HA Integration for you Battery (well actually the BMS type inside your Volta battery). I'm not sure what protocol your Volta BMS provides.
Info as to what BMS is inside the Volta is not common knowledge, but if someone knows, please post here. The pic you displayed has got a slightly different layout (RS232 to the left, instead of in the middle. 
BTW, I assume that the pic of your Volta ports are from the slave battery. The Master should have two cables. One RS485 link cable and one CAN cable to the inverter. Please confirm. 

@splunker
The "activate battery" only refers to put the Inverter to Battery comms via the CAN port in operation.
AFAIK, the BMS "dictates" what happens. So each battery will "request" charging current, and start to taper as the battery reaches the full status (either by voltage or SOC, not sure). E.g. on this 4 battery system, each have different current, some zero, some charging and some discharging! 
If you don't get any info from Volta WA group, the best way to confirm HA compatibility is to use the RS232/USB cable ( or just a plain RS232 cable if you still own a PC with a RS232 port (the 9pin is good)
Then use the PBMStools V2.5 and if you get this screen, you may be in luck in that the Volta uses the same (Pylontech) protocols as the PACE BMS. 
 

Hope this helps!

Partial or random charging of a lithium-ion battery does not necessarily lead to degradation, but it can affect the overall lifespan and performance of the battery over time.
Lithium-ion batteries have a certain number of charge-discharge cycles before their capacity begins to degrade. Charging a battery partially or randomly can increase the number of cycles, as each partial charge could count towards a full cycle. This can lead to faster degradation of the battery over time compared to consistently charging it from a lower threshold to full capacity.

Thanks @HendrikBigChief, really appreciate that, especially the explanations. Puts my mind at ease.
Now I just need to get my head around how it's all wired together so I can confidently turn it all off...

Thanks for the chart. It seems that your Battery BMS is doing a better job than most other batteries. It looks like the SOC spikes you are seeing is the BMS doing minor corrections of the SOC based on the voltage it is seeing.

On the area close to the beginning we have Battery power 50W, SoC 79% and Voltage 53.1V

Using this chart for LFP lithium:

Looks like your BMS is correctly calculating the SOC based on voltage when current is low.
The spike upward of ~5% SOC that you are seeing seems to be caused by the battery power going up due to slight current increases (due to consumption). The BMS has to compensate for that, however that seems to be slightly off, but not by much.
Looking at how well behaved your BMS is, I don't think you will need to charge to 100% every day. Unless you see issues in the future.

Hello,

So the Battery Voltage and Amps chart is here:

On the Solarman app, go to Device on the left:


 
Then click on the inverter that is listed on the right. Then scroll all the way down, you will see a chart like this:


 
This chart does have the battery voltage and battery current:


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So the Activate Battery setting should be ok to leave on. That just helps it if the battery dies completely.
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The issue you have (my best guess without battery voltage chart) is that your SOC is estimated higher than what it actually is. This is a very common issue. The solution is to ensure you fully charge your batteries once a day. So in your work mode screen on the inverter, make sure you have a few hours a day scheduled where the battery is set to 100% and grid charge is ticked. I do mine at the end of the day from 6pm to 10pm. Then I know the battery is full and the SOC will then be correctly calculated.
 

Yes standard ethernet cable

The ramp up is the inverter utility charging the battery. There is something special about 95% SoC, I think it stops there if its calculation says it should be higher than 95%, but the battery voltage isn't high enough for that to be realistic. Once the battery voltage is high enough, then it changes instantly to 100%.
I would definitely use something to remove the blue oxide from the RS485 port. Preferably contact cleaner, but oil based spray at a pinch. Gently dry out with a tissue or cotton bud. 

Flip the Change Over Switch (<30ms). Switch off the inverter. If solar is 0W, isolate. Switch off the supply to the inverter. Switch off the battery (including breaker on the battery)... that should be a safe way to do it.

Get some IPA and a stiff art paint brush. Clean out that port and dry with hair dryer. Use a new network cable. 
Check other ports as well. 

Switch off the inverter and batteries. Unplug the cable. Use a hairdryer and dry out the ports at 50% heat. Reinstall the cable and restart. Put tape over all ports and holes.

The BMS has to guess the SoC between high and low battery voltages, because the LFP voltage versus SoC curve is nearly perfectly flat between 20% and 80% SoC. So it drifts a bit, then when the battery is full the BMS realises oops it's not 95% SoC, it's now 100% SoC. This is common and normal.
Hopefully over time, the BMS will learn the true capacity of the battery and track it well. When the battery is new, it's still balancing for the first few weeks.
There is a quite small chance that one or two cells are sub par, so it's worth keeping an eye on. 

The cable is a good start. The inverter should be set to lithium under batter settings. Also, the inverter must get charge limits under the Li-BMS menu.

What battery is this and how is it communicating with the inverter? If the inverter uses the battery voltage to estimate SOC then those dips can be due to increased current draw in the house. It looks like the battery is run down to 60% at noon before being charged to 95%.

Hiya @Erla, yeah I took the plunge and fiddled with mine. seems to work as expected thank goodness :). Good luck!

The 100A Max A Charge rate on the Batt Mode page is a global limit, and it's basically at the limit of what the 5kW Deye inverter can supply as charge amps.
If you have 2x Volta batteries, in theory each one can take a 100A charge all by itself, but on this inverter they are getting max just 50A each, which is a "normal" slower rate of charge for example for 0.5C batteries.
That's well below the limits of the battery's capability, but in reality I don't think you are going to be reaching even this. You have 3.2kW of solar power connected, that can supply maximum around 65A charge current in total, or 32A per battery. And then your grid charge current is currently 40A, or at most 20A per battery.
Personal opinion is to increase the grid charge amps so you get to a desired minimum charge level more quickly, whenever you then want to charge from grid. Maybe set grid charge to 80A, so you are also still operating the inverter well within its limits. Just my 2c, might be wrong, might mean nothing at all, just try out what works for you at own risk.
 

You can achieve what you want under the battery settings by limiting the charge amps to say 40A per battery.
Under the time of use, that's a max discharge rate from the battery, and if you need more power it comes from grid. For example if you want to cover baseload through the night from battery and want to keep some power for loadshedding later, but then feel like a midnight snack.

You could also either get an Esp32 (+-R200) or you could use the Solarman Dongle and and connect your inverter to Home Assistant. 
Will allow you to do all sorts of other automations with other smart devices on your network as well as giving you live data reporting. 
Can now also change the "System Work Mode"  settings on the inverter from Home Assistant.
Check out the automation video on https://www.youtube.com/@SolarIntegrations