DEYE SUN-12K no decharge below 9%

[shadowmaker]

And you didn't get the idea SOC protection was there for a reason ?
In general Don't get why people feel the need to go again cell manufactorer, inverter manufactorer and battery manufactorer.
If you need to go that low, maybe it is time to add batteries

I understand one may want to do so for some testing once or twice..
But thats it

Yes, but it's Chinese engineering... (actually they have been very helpful every time I have asked help)

With SOC protection enabled my batts stopped discharging around 3,17-3,19V cell voltages. From all the reading I have done I concluded going down to 3,0V and with max 0,16C discharge it should still be safe with LFP and shouldn't affect cycle life much.

EDIT. And yes I certainly could do with more batteries (2x10kWh more ordered), but for summer 100-150kWh seems to be enough. For winter I'd need 600kWh to get through 3 days and we can have weeks without any decent sun. I'm grid tied like you already know, so moneywise 600kWh or more is not my best option.

 

[Janmn]

Yes, but only after disabling "SOC protection" not "SOC warning" from battery BMS. And mine will charge from the grid regardless Deye settings. I have closed loop connection, so it's the batt BMS who is in charge. Normally it won't charge from grid if grid charge is disabled from Deye and everything works as planned, but when batt BMS sees too low cell voltages, it forces Deye to charge from grid to protect battery. Not problem for me as I don't want my batts go that low anyway. I think this is BMS model related "problem". Not all BMSs do this.

What are your cell voltages/pack voltage @9% SOC?

I did this too. There was nothing to trigger charging no matter how hard I tried to find it. Then went through "protection list" and disabled "SOC protection" for the heck of it and got it working.

 

[Janmn]

All grid charging disabled

 

[Janmn]

Yes, but it's Chinese engineering... (actually they have been very helpful every time I have asked help)

With SOC protection enabled my batts stopped discharging around 3,17-3,19V cell voltages. From all the reading I have done I concluded going down to 3,0V and with max 0,16C discharge it should still be safe with LFP and shouldn't affect cycle life much.

It's absolutely true that it's safe to go down to 3,0V. it's also true, and very well documented, that you can't rely on the standard settings of inverters or battery packs. Of course some people prefer to live in blissful ignorance.

 

[shadowmaker]

I tried with no effect. see attached picture taken right before it starts to charge. This time i tried Lithium mode 12 to see if communication protocol influences the behavior.

I see your problem there in the picture. A very different looking BMS tool compared to mine (got it from the manufacturer, but don't know even know who's the manufacturer of my BMSs as my batts are prebuilts and very cheap ones, so they probably have cheap/shitty BMSs too).

Maybe your problem has nothing to do with my solution. It's just that your batts are behaving just like mine did before.

Of course some people prefer to live in blissful ignorance.

If you refer to @houseofancients, please don't. You'll find out he is one of the wise ones here and knows his Deye/Sunsynk stuff. Very grateful to him for helping me out many times.

 

[houseofancients]

I see your problem there in the picture. A very different looking BMS tool compared to mine (got it from the manufacturer, but don't know even know who's the manufacturer of my BMSs as my batts are prebuilts and very cheap ones, so they probably have cheap/shitty BMSs too).

this is a Seplos V2 ( would assume 10e)
and as stated many times , i run and have run these exclusively for a while now

 

[shadowmaker]

this is a Seplos V2 ( would assume 10e)
and as stated many times , i run and have run these exclusively for a while now

OK. I think there are many Seplos V2/Deye/Sunsynk users here so hopefully OP can get this sorted out. @~3,16V cell voltage he has still some safely usable capacity left in his batts.

@houseofancients are you running closed loop? If so how low does your cell voltages go?

 

[houseofancients]

OK. I think there are many Seplos V2/Deye/Sunsynk users here so hopefully OP can get this sorted out. @~3,16V cell voltage he has still some safely usable capacity left in his batts.

@houseofancients are you running closed loop? If so how low does your cell voltages go?

closed loop...
approve 3.0v ...

then again, i never go that low as i have ample capacity, and in my TOU is set never to go below 20% as advised by all manufacturers

 

[Janmn]

A short update. The Deye inverter is apparently not involved in the Force Charge. it's initiated by the Seplos BMS 2.0 sw 16.6. None of the monomer or packet low voltage values are reached. I disabled all safety features (for now) and other fetures that I think could influence the behavior.
what am i overlooking in the BMS settings that triggers force charge?

 

[DIYrich]

Disable comms, and run in voltage mode.

 

[Janmn]

I also considered this option. But there are some downsides to this.
Another option I considering could be an option is to "cheat" with the SOC value by changing the rated capacity of the cells. in that way I hope that I can use voltages of the cells to determine when the battery is decharged instead of an estimated soc of 9%