All things Sunsynk (Deye, Inge, etc...)

Renier said:
Yes, I've definitely seen the SoC behave weirdly at the top end.

View attachment 1584548
Like here my SoC went from 89% to 98% in the next 5 minute interval. Literally impossible.
Click to expand...

That's proof that SOC is an inferred value (not an actual physical measurement), based on voltage and charge history.

Such fluctuations are common in various systems, and covered by this term:
en.wikipedia.org

Hysteresis - Wikipedia

en.wikipedia.org en.wikipedia.org

If you zoom in on the SOC and voltage curve, it looks something like this:
Ehysteresis.PNG


Reference:
en.wikipedia.org

State of charge - Wikipedia

en.wikipedia.org en.wikipedia.org
To overcome the shortcomings of the voltage method and the current integration method, a Kalman filter can be used. The battery can be modeled with an electrical model which the Kalman filter will use to predict the over-voltage, due to the current. In combination with coulomb counting, it can make an accurate estimation of the state of charge. The strength of a Kalman filter is that it is able to adjust its trust of the battery voltage and coulomb counting in real time.
Click to expand...
 
Renier said:
Yes, I've definitely seen the SoC behave weirdly at the top end.

View attachment 1584548
Like here my SoC went from 89% to 98% in the next 5 minute interval. Literally impossible.
Click to expand...
Most (but not all) battery management systems determine SOC based on counting coulombs and not based on voltage.

During the carging cycle the BMS will determine if a battery has reached 100% SOC based on certain measurements, mostly voltage related.

So say the reported SOC is at 90 % based on counting coulombs, but one of the criteria telling the BMS that SOC should be 100% is met (like a single cell reaching 3.65v or the pack voltage reaching 55.2v as examples) the BMS will automatically adjust the SOC upward. This is normally when you see large movements in the SOC in a short period of time. The same happens at the lower end of the SOC range and can cause large and sudden drops in reported SOC.

It gets more complicated in multi battery set ups where individual batteries in the pack can be at different SOC, based on counting coulombs, but have a very similar voltage. Ultimately any differences will reset once all batteries reach 100% SOC as determined by the BMS.

Generally, in multi battery set ups, the BMS will report the SOC of the battery with the highest SOC to the inverter when charging. Likewise, when discharging the BMS will report the SOC of the battery with the lowest SOC to the inverter. This can also cause swings in reported SOC as the system cycles between charging and discharging.
 
Koosvanwyk said:
Have you tried to use the batteries in AGM mode (turn off the communication and disconnest the communication cable) just as a test to see if the behaviour that you describe is due to intentional instructions by the BMS to the inverter.

Just make sure the charge setting are correct before you do so.
Click to expand...
I haven't tried that yet (way too chicken) but I guess as long as it doesn't drop to 50% or something then it's all good - just seems so random that some days it'll get to a set % and then charge back up again and some days it'll wait it out for longer.
 
Renier said:
Yes, I've definitely seen the SoC behave weirdly at the top end.

View attachment 1584548
Like here my SoC went from 89% to 98% in the next 5 minute interval. Literally impossible.
Click to expand...
Yeah I see this happen often as well! Been advised that it is perfectly normal, and it does seem to be working just fine.
 
Noticed something weird today. When loadshedding my chint indicator for eskom is obviously off.

But today I wanted to show how my inverter works to a friend. When I switched the mains in the dB off, the red indicator is still on, albeit at half intensity as compared to the power being on. All ready contacted my installer and they will be coming out. But what could the cause be of this?
 
Grubscrew said:
Noticed something weird today. When loadshedding my chint indicator for eskom is obviously off.

But today I wanted to show how my inverter works to a friend. When I switched the mains in the dB off, the red indicator is still on, albeit at half intensity as compared to the power being on. All ready contacted my installer and they will be coming out. But what could the cause be of this?
Click to expand...
Incorrect (or no) earth-neutral bridge
 
Grubscrew said:
Noticed something weird today. When loadshedding my chint indicator for eskom is obviously off.

But today I wanted to show how my inverter works to a friend. When I switched the mains in the dB off, the red indicator is still on, albeit at half intensity as compared to the power being on. All ready contacted my installer and they will be coming out. But what could the cause be of this?
Click to expand...
Does your inverter still show AC voltage present, if it is does it should be very low. Assume the AC light on the inverter does go off
 
Pulled up at the NAMPO Agricultural Expo and need to get me one of these.will check them out and the output of the wind turbine. 20230911_162456.jpg
 
Where would you start if you had R100k? Which one is cheaper to upgrade and better in the long run?

Option 1:
  • 5KW Inverter (with the intention of adding another 5k inverter in the future)
  • 6x 455W Panels
  • 1X 5kWh Battery
Option 2:
  • 8KW Inverter
  • 8x 455W Panels
  • No Battery.
I will add more panels and batteries in the future.

Edit. I think option two is not doable because I need a battery, unless things have changed?
 
Last edited:
Fuma said:
Where would you start if you had R100k? Which one is cheaper to upgrade and better in the long run?

Option 1:
  • 5KW Inverter (with the intention of adding another 5k inverter in the future)
  • 6x 455W Panels
  • 1X 5kWh Battery
Option 2:
  • 8KW Inverter
  • 8x 455W Panels
  • No Battery.
I will add more panels and batteries in the future
Click to expand...
I did 1 with a bigger battery. No battery doesn't help at all... don't go hybrid without a battery.
 
Fuma said:
Where would you start if you had R100k? Which one is cheaper to upgrade and better in the long run?

Option 1:
  • 5KW Inverter (with the intention of adding another 5k inverter in the future)
  • 6x 455W Panels
  • 1X 5kWh Battery
Option 2:
  • 8KW Inverter
  • 8x 455W Panels
  • No Battery.
I will add more panels and batteries in the future.

Edit. I think option two is not doable because I need a battery, unless things have changed?
Click to expand...
Yes, an inverter needs a battery to cover dips in PV production when grid is not available - won't work without a battery.

I'd go: 8kw Inverter + 1x 5KWH battery and if you have change, install the PV/DC combiner box. Panel prices will continue to drop.

The way I look at it is that the inverter and battery help you through LS. Panels start paying you back.
 
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