Possibly an odd scenario but please bear with me....
Multiplus 2 48/5000 charging ~20kw batteries (4xUS5000 pylontech batteries) during specific cheap rate times. Outside of that time, multiplus to use battery storage for whole house use and extra from grid when needed or when run out.
The above is fairly simple, there is also solar (MPPT) but no more than 2kw during summer so unlikely to top up batteries most of the year. There could be a limitation of the cheap tarrif time not being long enough to fully charge the batteries so I am wondering that if there was another multiplus (say 48/3000) or perhaps a battery charger / smart solar charger or something similar (with its own cheap tariff / rate or say a generator - max 10-16amps 230v) could this be added into the mix to charge either at the same time as the original multiplus or on its own schedule? This inverter/charger would be for battery charging only, not providing power for the house or anything else.
Thanks in advance for any recommendations.