Help with PV setup

Thanks everyone, especially @wingnut771 . I have 'ordered the 'reputable' installer to come back. This is the kind of thing that happens when people like myself do not know much and the techies take shortcuts, as it seems here.
 
Pax said:
Thanks everyone, especially @wingnut771 . I have 'ordered the 'reputable' installer to come back. This is the kind of thing that happens when people like myself do not know much and the techies take shortcuts, as it seems here.
Click to expand...
You can set a lithium battery up without comms and use voltages, but is is not the greatest method, in short you basically lose 30% of battery capacity. Lithiums have a very tricky discharge / charge curve, and it is very difficult for the inverter to accurately estimate state of charge, because the voltage values between 80 and 20% are miniscule, and added the fact that the battery cables cause voltage drop. You also run the risk of damaging the battery. It's completely different for lead-acid batteries, there is a lot of latitude in its discharge / charge curve.

Ask your installer to set it up with battery comms, as far as I can tell the Growatt uses RS-485 comms and RS-485 is also supported by the Hubble, but I don't know if your particular (24V) Growatt has been certified to have comms with the Hubble, or other way around. You can also call Hubble support to find out if they have tested the AM-4 with your specific Growatt inverter. This is something that you ought to do before making a purchase though.
 
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RonSwanson said:
You can set a lithium battery up without comms and use voltages, but is is not the greatest method, in short you basically lose 30% of battery capacity. Lithiums have a very tricky discharge / charge curve, and it is very difficult for the inverter to accurately estimate state of charge, because the voltage values between 80 and 20% are miniscule, and added the fact that the battery cables cause voltage drop. You also run the risk of damaging the battery. It's completely different for lead-acid batteries, there is a lot of latitude in its discharge / charge curve.

Ask your installer to set it up with battery comms, as far as I can tell the Growatt uses RS-485 comms and RS-485 is also supported by the Hubble, but I don't know if your particular (24V) Growatt has been certified to have comms with the Hubble, or other way around. You can also call Hubble support to find out if they have tested the AM-4 with your specific Growatt inverter. This is something that you ought to do before making a purchase though.
Click to expand...
Only LiFePO4 (LFP) has a flat discharge curve, NMC is pretty linear so easier to see SoC like LA.
LFP discharge curve:
1638784562585.png
VS:
NMC discharge curve:
image-result-for-li-ion-discharge-curve.png


Not sure what chemistry AM-4 has though.

I found this on Hubble website but it's only for 48V, so I assume it's the same for 24V?

www.hubblelithium.co.za

Growatt inverter and Hubble setup

The following field guide will assist with the correct Hubble Lithium battery settings you should use when connecting with a Growatt Inverter.
www.hubblelithium.co.za

They only mention TL & ES series Growatt though.
 
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