Available PV not used.
Good day
Regarding the charging of the batteries of the system, in System settings, you can set the terms of charge required from the grid or generator over set times, power and battery SOC. This happens within parameters required from battery settings when incenting specifications of the battery you are using.
Barring prioritizing battery charge, why can you not use the same specification parameters to charge batteries from your solar(PV), example:
The system has a usable capacity of 7.5kwh (granted in optimal conditions), your load is 1kwh, the solar(PV) provides 1kwh for the load and 1kwh to charge the battery. When the load goes up, the PV goes up to support load and charge battery. Although conditions are good, the PV does not use what is remaining of available PV to charge the batteries, rather supply only what is needed.
Problem: The batteries charge is limited and in many cases, you sometimes end with batteries not fully charged because the available PV was not used to charge the batteries to full capacity(as it would when grid charging is enabled), even though there was adequate PV to charge the batteries faster.
To charge batteries to fast is not good, but why are there no capability to set specific power and SOC requirements to charge the batteries to full capacity within times set like with grid charging?
This will allow the system to use the available PV (that is going to waste because it is not used) to deliver charge to the batteries so that it can reach capacity within a certain time and then maintain and manage power usage to not overcharge the batteries.
OK, so I made some changes to the system by fitting a couple of Victron Busbars (a quarter of the price of the Sunsynk ones and its the same thing in a different colour housing...!), and beefed up the cable from the busbar to the inverter so I can safely push 250A through the system. Unfortunately, this made very little difference, and the BMS still limits the current to 83A. You can see the graph below as an example of what I am seeing:
I can't get any information on this, and I have exhausted the Sunsynk Chat support to the point where they confirmed everything was correct in my setup and system. I asked if they could make other suggestions, and they just said no! I finally want to know what defines the final current limit value on the BMS. I understand it's the temperature of the battery, the SOH, the cell voltages, the available solar, etc.. Still, everything is good: 12-20°C temps, only around 45 cycles on the battery, and eliminated the current restrictions on the installation with Busbars and cable sizes. So what is the BMS saying to limit to 83A when each battery can easily take a 50A charge current? There are 6 of them, so the 290A limit on the inverter should be doable (although, at that point, I would not have enough solar past 190A anyway).
Going through this has highlighted a potentially faulty battery. One of the 6 L5.3kWh LV batteries was dropping to the limited 20% SOC but continued to discharge, down to about 6%. I have tried several times to balance it with the system, using the grid, etc., but straight away, when discharging the batteries overnight, it keeps doing this. So, I removed it from the system entirely, which also has had no effect on the setup.
So... I know there are all sorts of good information on this forum but I reckon over the last 3 months of trying to work all this out, I have read pretty much all of it... lol
I would greatly appreciate any thoughts, feelings, or improvements that can be shared. This may be the system's limit, which means it's insufficient for my needs. When we have short charging windows in the UK, I need to charge the batteries as quickly as possible and to the system's full capabilities!
Thanks in advance.