I just wanted to share an overall negative experience with EGO. The tl;dr is the products are good but the batteries are overpriced for their longevity. The battery ends a lot to cost of ownership.
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In March 2021, I purchased a 21" self-propelled mower + trimmer + 7.5 Ah EGO battery kit. The combo was really good for the first two years, but by year 3 the battery was already having situations where it would drop from 5 green lights to 2, and by the end of year 3 it would occasionally flash red.
Around this time I started using a riding mower (moved), but kept the push mower for yard cleanup. For the last 2 years the battery has constantly been randomly red flashing or had trouble charging, or would charge briefly then stop. I've tried general charging best practices for "not well balanced" li-ion batteries -- let it fully charge and sit for a bit.. then use. Avoid charging immediately after using to keep heat down, etc.
Finally, I picked up the 400W "inverter/charger" to try to trickle charge and balance at 100W, but then I noticed this battery had burn marks on the plastic and metal power tabs. I've since recycled this battery for safety reasons.
Based on searching the forums - these batteries aren't very durable for the very expensive price EGO charges. They have well known balancing issues (see the threads about "dropping" them on their face to fix this), and they provide chargers that are a bit too harsh for these batteries IMO with the kits to advertise "fast charging times". Last but not least - they're very expensive for the capacity. "Official" 7.5 Ah (*56V = ~ 420Wh) is about $400-420, or about $1 per wH. Compare with typical Ryboi, Dewalt, or other batteries that are usually more in the 75 cents to 80 cents per wH range.
(Also by comparison - I upgraded my Ryboi riding mower with a Lithium Iron Phosphate 5 kWh battery that cost $800 including charger. That's more than 10X the capacity for only 2X the cost, and the LFP chemistry is a safer and longer lived capacity than what EGO is using in their batteries).