Using LFP to power an off grid hybrid inverter while using grid power to charge the batteries

[Skid]

I move into a house in India next month. The grid is horrible and I want the house more or less isolated. My all in one inverter just arrived, built in India with MPPT, pursing, lithium programmable profiles priority settings in a box looking like a Bollywood version of an 80s stereo- in green, red, yellow, gold. Must be LF because 1500w and 50lbs, with multi second surge capacity. No China things here.

I want it wired to the house panel and charging from the utility but running 24/7 off the battery so I have pure power. Elementary question, I know, but will there be an issue with the inverter charging the batteries from the grid panel while using the batteries to power the panel? This is my first experience with a grid connection.

After getting settled in and when monsoon ends I'll have 100% solar so this is only for a few months.

 

[meetyg]

I'm not sure how LF inverter/charges work, but I know that some (most?) HF use the inverter in reverse for AC charging. So they can't really power loads from the inverter while AC charging the battery.
They usually switch to "bypass" mode (connecting AC IN to AC OUT) to power loads from the grid while using the inverter backwards to charge the battery.

If you want clean AC power, I think what you need is a double-conversion inverter or UPS.
These types take "dirty" AC power, convert it to clean DC and then convert that clean DC back to clean AC.

 

[DIYrich]

Elementary question, I know, but will there be an issue with the inverter charging the batteries from the grid panel while using the batteries to power the panel?

No (mostly).

Grid -> Charge Controller -> Battery -> Inverter -> Load (house panel)

Inverter will steal power from the Charge Controller before it gets stored in the battery.

There is something called "ripple", that should not cause a problem, but in theory could. Set the charge voltage that equates to about 50-80% SOC of the battery. This will keep the battery from cycling at 100% SOC.

To cut down on conversion losses, it might be worthwhile to look into a High Voltage DC system. Might have to buy two hybrid Inverters, and use one to charge the battery, and one to invert from the battery.

 

[Skid]

Thank you. Kind of what I thought and feared but better to ask. This is new territory for me. I suppose I could use SBU mode for now. No solar yet, Battery until down to 20% and then U to charge. Just some juggling to get high current things done on a full battery. Once I have the shed built for panels, there should be no problem.