Nabzo

Your battery should have a label on it stating the bulk, float and cut off voltages. Else those should be in the manual.
In Use mode set those voltages accordingly

i would like to know if any inverter has a RS485 port and the battery has the same and you know the pinouts for inverter and batter with that work communication  ? 

for shoto to know if its the bms if the run light is off and you check your soc on the solar man ap and if its spiking 100% then 0% its bms issue i change to bms so far on two different sites , december 2021 changed in march  22 2022 , 2nd site Jan 2022 changed 01 march 2022 
i dont like when this happens because customers think we giving faulty products . 
 
does anyone know where i can purchase some bms i need 6

just an update of my issue that was corrected . the neutral wires was done incorrectly and fixed and at the same time my bms on my shoto battery gave up and was replaced  and now everything is working 100%
how i noticed the bms was an issue was my soc was showing 100% then 0% 
 

Not sure then @Nabzo , maybe go and have a look on the Solarman log and see what the load was before load shedding
If it was too much load the inverter would keep on trying every minute until the load was reduced, that may be the cause of the 5 minute delay
From the Sunsynk Website - 
F18 AC over current fault of hardware This is an overload on the “Load Terminal” Possibly caused by heavy surge current from air-conditioners. This is also quite a common fault can also because by a battery issue but generally it's caused by an rush current to the Load. Switch on at the same time. We have had experience where people have had F-18 faults during the night again it is often caused by an heavy in rush current too many items switching on together. You need to separate your essential and non-essential load only have essential on the load connection and none. Essential loads such. As AC on the. Grid side. Remember the inverter sends power from both the Grid connection and a the load connection

What i remember of all the error posts before. Once the Error 9 pops up, its time to have the unit repaired. Normally nothing you do at home now will help the situation. Something inside is already damaged and needs replacement  before the error will go away. 

That sounds like a pretty normal voltage range to me. I suspect you would have been better off without the regulator at all. Perhaps the sudden voltage step changes confuse the code that tries to synchronise frequency and phase with the incoming AC.
I would disconnect the voltage regulator; sorry, I know you won't want to hear that. Then it's a matter of repairing the inverter; more bad news. It might be something simple, but most likely it's quite an involved repair. See for example this topic: PIP inverter repairs, and the hardware section of this huge topic: PIP-4048MS and PIP-5048MS inverters .

Nabzo check setting no 4 must be SdS for normal operation SEN is for power saving mode .The power will switch on and off if SEN is selected if the load is low or not detected .

Perhaps you just ran out of battery energy? What do the LEDs on the battery tell you?
Are you running ICC and a BMV? Your settings seem to be designed for "let ICC make all the decisions", yet you show a screen shot from Watchpower.
You may be suffering from the premature charge bug. It might be mitigated by using the absorb time setting.
It seems you are not running the latest version of Watchpower. You can get the latest version here. The latest version should allow you to turn off power saving mode (if that's part of your problem) and to set Charging Time in CV Mode. Start with perhaps 60 minutes.
It's an Axpert MKS 5K-48 (manufactured by Voltronic Power) without the 64 V option, There is no patched firmware available for this model. You reseller appears to be Solar MD (bottom of the sticker). It appears to be a genuine Voltronic model (not a clone).

I'll take that as a no, then 🙂
ICC is monitoring software, like Watchpower, but not free, and much much more powerful. http://iccsoftware.co.za
A BMV is a Battery Monitor made by Victron. For example, https://www.victronenergy.com/panel-systems-remote-monitoring/bmv-700 .
ICC can talk directly to the most common battery BMSs, certainly Pylontech, but there are so many battery brands, they'll never be able to support them all. So what you do then is you use the BMV to monitor the current and estimate SOC. It does a quite good job.
If you use ICC, you want your settings such that the inverter won't take action (such as switching off, or switching to grid power) except under extreme conditions. That's a little insurance in case ICC crashes or whatever, but mostly because you have to give some values to the settings. Those are the sorts of values you have. That's fine if you want to spend the extra on ICC and the BMV, but if not, you'll want different settings.
That's good.
You'll want to experiment with this one. Start with 49 or 50 V.
That's too high; you only charge to 53.5 V. So try 53 V, or 52 V, or FULL. It depends how full you want to keep your battery. If load shedding comes back, you may change your appetite for battery fullness.
That's 2.97 V per cell. You probably want it a lot higher. I'd start with 48.0 V.
These sound like standard values for 15S LiFePO₄ batteries, like yours.
That's for almost literally letting off steam for flooded lead acid batteries. You do not want this for your lithium battery.

It's at the top right of the settings screen, according to the latest manual. But it may have moved.