48V x 45A might yield 2kW output if the panel is rated for 2500~3000 W max. But if yours is 2kW max take 2/3 or these values. Solar Panels might be rated for best case Solar Power input which rarely occurs due to latitude, season, elevation angle and daily aiming error.
Low V battery causes higher transistor current losses to boost to 120Vac and 2x more to 4x for same kW rating. e.g. 600Vbat @800V can be 98% efficient at 3kW out but only 94% efficient at 400V while 80V bat.will be much worse but unknown.
It is far more cost effective and efficient to have DC current <10A which implies A much higher battery voltage.
e.g. 2kw/10A=200V and 120Vrms is 340 Vpp or 170Vp so high Vbat runs in buck mode while low Vbat must boost and amplify voltage and this draws more driver current.
The optimum Vbat is the one recommend by your choice of GTI and matching array of PV voltage.
LG Chem RESU 7H_R / 10H_R
350 -450 V CC
In spite of others named in top 10 Consumer grade GTI’s I think the single phase 2 or 3 kW version is what I might choose for best MTTP and GTI effectiveness with smart monitor remote features .
You do not need a Hybrid GTI from battery since you do not want UPS features.