Dear all,

 

We have recently had a 7.2Kw array installed with a GROWATT, Inverter and 12KWH HV battery system installed.

We are seeing issues with the system batteries, charging from the Grid when they hit 10%, we don’t seem to be able to have any discharge from the battery below this figure, and it then charges from the grid when there is no PV generation.

This does not seem correct given the only time electricity should go back to the grid is when the battery is full and the demand on the house is lower than that of the PV after charging the batteries.

The battery only seems to discharge at approx. 10% of charge when the battery hits 10% remaining (max 100Watts). Does this mean you can’t access the final 10% of the battery as such we have a 11kwh battery and not a 12kwh batter?

I have looked at the settings and the “AC charging” function is off; however the batteries are still charging from the grid?

Regards,

 

Stuart

19 minutes ago, ushmyster said:

Dear all,

 

We have recently had a 7.2Kw array installed with a GROWATT, Inverter and 12KWH HV battery system installed.

We are seeing issues with the system batteries, charging from the Grid when they hit 10%, we don’t seem to be able to have any discharge from the battery below this figure, and it then charges from the grid when there is no PV generation.

This does not seem correct given the only time electricity should go back to the grid is when the battery is full and the demand on the house is lower than that of the PV after charging the batteries.

The battery only seems to discharge at approx. 10% of charge when the battery hits 10% remaining (max 100Watts). Does this mean you can’t access the final 10% of the battery as such we have a 11kwh battery and not a 12kwh batter?

I have looked at the settings and the “AC charging” function is off; however the batteries are still charging from the grid?

Regards,

 

Stuart

What type of battery do you have? what is the recommended DOD. I personally think that you are going to far below the recommended OEM DOD.

Yes, the Growatt will try and get the battery not to go below 10% DOD, it will take a bit of grid to charge it and keep it at 10%  

I personally think that you are going far by discharging your battery bellow 10%

If you don't want to compromise your battery life, keep it at 20% or above.
Yes of course you could run them down but you will shorten the life. 
https://relionbattery.com/blog/tech-tuesday-depth-of-discharge

Antonio,

 

Many thanks, I don't have any of the kit model numbers yet awaiting this information, it is the HV 95KW)discharge versions, if its normal to have them sit at 10% that's fine just would have been good to know as we will now loose 10% of the total capacity of the system, something I will need to take up with the installers and designers I guess.

Assume this is normal in most battery systems.

also assume having it installed when there is little to no sun also does not help find the niggles?

Regards,

32 minutes ago, zsde said:

If you don't want to compromise your battery life, keep it at 20% or above.
Yes of course you could run them down but you will shorten the life. 
https://relionbattery.com/blog/tech-tuesday-depth-of-discharge

many thanks for this 

18 minutes ago, ushmyster said:

I will need to take up with the installers and designers I guess.

Some battery manufacturers actually state the full capacity and usable capacities which are typically 80-90% of the full capacity.
Unfortunately there are no laws mandating what battery manufacturers of Li batteries must declare.
Some are brutally honest, most just sell a product with a label that only gives you the total down to 100% DOD, unfortunately. Best to always work on 10-20% lower usable capacity when it's not clearly stated.

33 minutes ago, ushmyster said:

Antonio,

 

Many thanks, I don't have any of the kit model numbers yet awaiting this information, it is the HV 95KW)discharge versions, if its normal to have them sit at 10% that's fine just would have been good to know as we will now loose 10% of the total capacity of the system, something I will need to take up with the installers and designers I guess.

Assume this is normal in most battery systems.

also assume having it installed when there is little to no sun also does not help find the niggles?

Regards,

What is the make of your battery, Send us a picture.