Grid power saving - battery as buffer in SUB mode

[nazemnow]

Hi all

I'm using Anern 10.2 kw inverter, 20x330w solar panels and 14s2p 5 kwh lithium battery.

I don't know how, but some time this system had been working in something like mixed mode between SBU and SUB.
Battery had been charging a little over floating voltage and discharging when high load turns on.
e.g. load 5kw: sun 2kw, bat 2kw and grid 1kw.
I really dont know how it was, but after I changed my battery from 15s2p to 14s2p this feature disappeared.
This mode was very helpful for me to reduce electricity cost as I got 3kw coffee machine working all day. There are heaters which turns on for about 30s every 3 min.
This inverter doest have timers to change mode/levels due day/night. It only got SmartESS app and hardware lcd on it, no other control options.

Does anyone had experience with this inverters?

Attaching.
1. BMS power graph when this feature had been working:


2. BMS voltage graph when this feature had been working:


And now:

 

[BentleyJ]

What type of Li battery? Li-ion or LFP, makes a big difference in voltage. For example a 14S LFP battery only has 44.8V resting, when the cells are at 3.2V each. Maybe the battery voltage is below the minimum operating range of the inverter when trying to support loads. Without more information, this is only a guess.

 

[nazemnow]

What type of Li battery? Li-ion or LFP, makes a big difference in voltage. For example a 14S LFP battery only has 44.8V resting, when the cells are at 3.2V each. Maybe the battery voltage is below the minimum operating range of the inverter when trying to support loads. Without more information, this is only a guess.

I'm using LG Chem E63 (Li-ion NMC) modules from electric car. Operating voltage 3.0-4.2v x14 = 42-58.8 v
Yesterday I tried to use them in SBU mode and completely discharge to know minimum voltage level.
Discharging graph and battery settings on inverter attached.