Help needed - MPTT inverter feeding from battery

[sijiceh755]

Hey there, i have a question about my setup. I have a Huawei SUN2000 10kW M0 inverter with battery input but these are still not available so want to build my own battery. I use PV panels 380W 40V 10A. My inverter supports max 11A per MPTT so i was able to connect panels only in series an create 2 high voltage strings, 600V and 350V. My idea is to build a lifepo4 battery pack which will be charged via AC-DC charger, and then in case i will need the power from battery use DC-AC inverter ( same as UPS does). My questions are:

1. what would be the ideal battery pack voltage for this purpose?
2. would i be able to charge battery via mppt controller ( high voltage) ?
3. would it be possible to use the solar inverter to feed the correct voltage to mppt input? In this case i wont need to buy additional DC-AC inverter.

thanx for all suggestions.

 

[GXMnow]

I looked up that inverter, and it does have some nice features, but I can't find any details about what it expects from the battery. It just says "no compatible battery available yet". I did find a block diagram that shows the battery connection between the MPPT trackers and the inverter section. The fact it also uses the same MC4 style connectors for the solar inputs and the battery leads me to expect the battery bank will be a high voltage as the MC4 connectors are not for very high currents. I'll bet that their "compatible battery" will include some sort of charge controller and BMS that communicates with the inverter.

 

[sijiceh755]

I found it should be integrated 800V high-voltage battery connection so its no-go via this input. So what would be the best aproach here?

 

[GXMnow]

Are you running in 3 Phase or just using single phase? Single phase may be able to go AC coupled to a separate battery inverter, but I have not seen it done in 3 phase yet.

 

[sijiceh755]

My solar pv inverter is connected to all 3 phases else it would not work. The battery inverter i would like to attach to single phase only.

 

[GXMnow]

A single phase inverter can certainly work for backup power, but I don't think it would be able to AC couple and make the solar work with the 3 phase solar inverter.

 

[Ampster]

So what would be the best aproach here?

Wait until they come out with a battery or sell the inverter.