2 Growatt 5000 ES in parallel. One is charging the other from the same battery!

[msidani]

Hello,

I have 2 Growatt 5000ES and 2 lithium batteries Felicity 8.7 Kwh each.

Both batteries are connected in parallel and act as one big battery

The inverters are connected in parallel and both are connected to the big battery.

All is working great! The problem is that each inverter is reading the battery slightly differently.

If inverter 1 is reading 90% , I notice inverter 2 reads 89% sometimes and so.

However I noticed when there is no load on both inverters, one would be discharging the battery at 100W and the other charging the battery at 48W.

Is this normal? And if not does this hurt the battery? Im worried the inverters are charging the battery from itself

I attached the images from the inverters

Thank you

 

[DThames]

That seems confusing. Do you have a clamp on DC amp meter? If so, check the battery cable amps for each inverter and see if you can varify this is actually happen as reported by the inverters. The inverters have internal consumption and my Growatt 3000 units, they take this power from the battery, always.

 

[msidani]

That seems confusing. Do you have a clamp on DC amp meter? If so, check the battery cable amps for each inverter and see if you can varify this is actually happen as reported by the inverters. The inverters have internal consumption and my Growatt 3000 units, they take this power from the battery, always.

I have a clamp in my toolbox, but can you guide me how to use it (I’ve actually never used it)?

Do I put it on the red or black wire? Thanks!

 

[timselectric]

I have a clamp in my toolbox, but can you guide me how to use it (I’ve actually never used it)?

Do I put it on the red or black wire? Thanks!

Either wire will serve this purpose. If the reading shows negative amps, you can switch to the other wire or turn the clamp around.
I wouldn't trust the reading from the inverters.
A shunt is the best way to know what is going on.
And if one is producing more solar than the other. Then it's not abnormal for one to be charging while the other is discharging.

 

[msidani]

Either wire will serve this purpose. If the reading shows negative amps, you can switch to the other wire or turn the clamp around.
I wouldn't trust the reading from the inverters.
A shunt is the best way to know what is going on.
And if one is producing more solar than the other. Then it's not abnormal for one to be charging while the other is discharging.

Thanks!! For a note this problem only happens at night and when there is 0 load on both inverters and no PV production. In the image attached you can see 0W from PV

 

[timselectric]

Thanks!! For a note this problem only happens at night and when there is 0 load on both inverters and no PV production. In the image attached you can see 0W from PV

Then, It's just a glitch in the readings.
If there's no power coming in, then they both must be discharging.

 

[DThames]

Then, It's just a glitch in the readings.
If there's no power coming in, then they both must be discharging.

I agree. My Growatt 3000 models use about 50-60 watts each with zero load. Anyone should expect some battery discharge at night.

 

[LydMekk]

On the side of this.
If interesting regd. shown values etc.: Growatt also gives you an option to "calibrate" the shown watts and or volts in the menus.
It is possible to go into each inverter in a "service" state to f.ex. adjust the show watts/volts from f.ex. batteries up and down in small increments to reflect the actual values with a multimeter measured on the input terminals on the inverters themselves (includes cable changes).
The recipe for this can be googled online.

As DThames says above, the inverters themselves usually consumes around 60-65ish watts when just idling. Same here.

 

[DThames]

On the side of this.
If interesting regd. shown values etc.: Growatt also gives you an option to "calibrate" the shown watts in the menus.
It is possible to go into each inverter in a "service" state to f.ex. adjust the show watts from f.ex. batteries up and down in small increments to reflect the actual values with a multimeter measured on the input terminals on the inverters themselves (includes cable changes).
The recipe for this can be googled online.

As DThames says above, the inverters themselves usually consumes around 60-65ish watts when just idling. Same here.

Can you tweak the volts measured as well? I need to do that.

 

[timselectric]

I don't even go by anything the Growatt reports.
I have one that is only connected to solar and battery. Yet, it seems to think that it's using 54 watts from the grid, today. lol

 

[msidani]

I don't even go by anything the Growatt reports.
I have one that is only connected to solar and battery. Yet, it seems to think that it's using 54 watts from the grid, today. lol

???

 

[LydMekk]

@DThames yes sorry, updated my post.
Most measured values by the inverters can be calibrated, both volts and watts if they deviate from f.ex. a multimeter.

 

[Olasitu]

On the side of this.
If interesting regd. shown values etc.: Growatt also gives you an option to "calibrate" the shown watts and or volts in the menus.
It is possible to go into each inverter in a "service" state to f.ex. adjust the show watts/volts from f.ex. batteries up and down in small increments to reflect the actual values with a multimeter measured on the input terminals on the inverters themselves (includes cable changes).
The recipe for this can be googled online.

As DThames says above, the inverters themselves usually consumes around 60-65ish watts when just idling. Same here.I

 

[Olasitu]

I have 2 x Growatt ES Inverters as well. The Growatt apps - Mobile and Web show the Batteries jumping from 75% - 100% - 75% within 15 mins with no load on the batteries. Please share guidelines on calibrating Growatt Readings with Batteries' Voltage. Thank you.