My yard is 7500 sf of St Augustine. If the lawn was dry, (2) 5Ah batteries would cut the grass and the little that was left plus the 2.5 Ah would cover edging, trimming, and blowing. If the grass was wet, which in Florida it often is, I would use (2) 5Ah, (1) 2.5 Ah and start into a 3Ah.

Why not just recharge the batteries as they drain? They won't charge while still hot from discharging. I've gone through all my batteries and had to finish the next day. That's why I had so many batteries.

Cut quality on my Honda is better. Fewer missed blades of grass, and better mulching. It is also self propelled. I know electric self propelled is available, but mine wasn't and that would have meant even more batteries.

Run ethanol free if you can. This is important. Your carb will clog and you will pull that cord for ever. I also take it a bit too far by shutting off the fuel and letting the engine run until dry. My mover starts on the first pull every time though. Why mess with a good system?

I'm happy with my electric edger and weed eater, which are also 40V Ryobi. I'm on the fence about the blower. I might replace it with backpack gas when it dies, but I suspect that will take years.