Disable DC battery stage without loosing load side connection

[stormbreaka]

Hello together, I have the SG01HP3 hybrid inverter and I want to disable the battery stage in some times so I can have an overall better efficiency. The reasons are:

• Parallel Bat1 & Bat 2 is always sharing the exact half current that is currently needed for zero export; I don't know why they have implemented it like that but now I am searching for a method to deactivate the battery stage with a flag without interrupting the LOAD connection
• when discharging max current by BMS is set to 0A the Deye hybrid inverter is still pulling about 100W out of the battery; this is also a safety issue but Deye is not getting this simple thing fixed up to now

Do you have some ideas on how to disable the battery stage? I already tried to manipulate register 220, 221 and 220; they are marked as read and write but it seems that it is only read.
Setting the max discharge current to 0A in the battery settings is also not disabling the battery stage.
Do you have further ideas on how to 'deactivate' the discharging process with the modes registers?

[davidrapan]

Hi @stormbreaka, that's really not possible. There will always be a few watts flowing here and a few watts there. I'm not sure if it's exactly Zero Export power (I have it set to 50 W everywhere), but mine is somewhere around 20 W idle.

The power flow is voltage controlled, so it really depends on how accurate the inverter can be, but I'd say 100 W is within the margin of error. No inverter will control the flow down to 1 W or even zeroes.

The 220 and 221 are BMS controlled. That's why they are writable.

[stormbreaka]

It is voltage controlled in charge/discharge voltage level but not between these. Here it is current controlled. What I want to reach (and what mostly all other inverter do) they shut down the power stage by setting no PWM actuation at power electronics to have the minimum power flow. When a BMS error occurs or if you pull the cable we can see this. Then I also see a zero current in the BMS because the power stage is not actuated. That is also what I want to reach when zero current targets are sent by BMS.
The 100W of power that is needed to run the device should be pulled from the grid or PV input but not from the battery if the discharge target current limit is zero.
Deye also have big problems with over/undercharging batteries due to this issue. Here you can see a thread where overcharging is happening with official BYD HVS battery: https://dy-support.org/community/postid/22969/
The power stage has not been set in idle/standby and had a minimum PWM cycle set at power electronics which leads to a minimum power flow of 0,5A. Over a sunny day this could lead to an overcharge condition because the balancers can not shift or waste this amount of energy.

[davidrapan]

What firmware version are we talking about here?

[stormbreaka]

HMI: Ver 2001-C044 was the highest; due to problems with BYD storage now C040
MAIN: Ver 3103-1097-1E08

[davidrapan]

Haven't you considered updating?