Be careful you don't end up with all the gear and no idea, as I almost have. Getting loats of batteries could be like putting a V8 engine in a mini!! Not very practical!
I've just got a Sunsynk battery system around a week ago and still learning to fly it to it's best capabilities. 5kw inverter charger and 1 x 5.6kw battery.
At the moment I'm charging the battery on E7 and using it from tea time through the evening until just after our E7 switches back in at 2am.
Surplus solar in the daytime is covering the house baseline of 0.4kw and the battery is covering our evening 0.4kw, also surplus solar is topping up our MG ZS with once or twice a fortnight big charges on E7. With my setup the last thing I'm looking for right now is more batteries. But I might rearrange the whole system at some stage so the equipment needs could change.
I'm not saying don't buy more batteries, just keep in mind how you'll charge them and use them through the winter, and on days of low solar.
I'm am electrician and have installed all of my own kit so if you want any real world advice without me trying to sell you something, just shout.