Mighty Max 12V 22Ah Rechargeable SLA Battery 4-Pack for Access Point AXS8000 - Power Backup for Networking Equipment, Security Systems & Solar Applications

I replaced the two 12V SLA batteries in my old Black & Decker CM1000 lawn mower with these because it had a higher capacity (22Ah compared to 18 or 20Ah on the original batteries; I forget the exact original capacity) and even though it was slightly larger I could still make it fit. It worked great initially and I could tell the new batteries provided a little extra mowing time. I have a typical 1/4 acre suburban lot and could mow front and back on one charge. After about a year or two the capacity dropped off a bit; I could still mow front and back if I didn't let the grass get too tall. After about 2.5 years of service I had to mow the back yard (which is thicker and larger than the front yard) in 2 or 3 charge cycles. But the batteries pretty much died at 3 years of use. I could leave it on the charger for several days, but could only mow about 15 feet and it would die. At that point I noticed the charge indicator would stay red instead of going green to indicate a full charge, so it appears the batteries can no longer charge fully. 3 years is on the low end of the typical expected lifespan, so I'm satisfied with the product, but just wish that it would have lasted a little longer and also that it would have provided full performance throughout the lifespan. I think the original batteries lasted a good 5 years or so.This product is the Mighty Max ML22-12 and shows an ASIN of B00DIGN712. That same ML22-12 part is show with an ASIN of B00K9Q7SUA at https://www.amazon.com/dp/B00K9Q7SUA with the same specs, same price, same vendor. I'll leave my review there as well.I was looking at new cordless electric mowers and noticed a graphic for one that showed expected battery lifespan and performance. It was down to 30% performance in something like 100 cycles and fully discharging the battery each use; but it took 200 or 300 cycles to drop performance to 30% when the battery was only depleted about 70% each use. So perhaps more lifespan can be obtained by being careful to avoid fully depleting the battery's charge each use. But that might have been with a lithium battery; can't find that page now.