Shopping for lithium ion power tools can be confusing based on battery options alone even with the same brand.
Marketing would like to have you think voltage is all you have to know to separate the men from the boys. Voltage means less than the number of cylinders in your tractor engine. Just as you want HP for tractor, you want Wh (Watt-hours) for battery. Multiply volts times Amp-hours for Watt-hours. Watt-hours is not HP, it is closer to comparing the size of the gas tank.
The wife and daughter have put in an order for an electric lawn mower so I am now focusing my chainsaw research in the direction of going with the 80v Kobalt so I have battery compatibility and a local store option. I am finding Lowes often offers the same price but different AH rated batteries for the Kobalt line of saws, mowers, etc.
Same mower 15 miles away comes with a 5 AH battery but 25 miles away comes with a 6 AH battery for the same price. Singly the 5 AH battery is $300 and the $360 for the 6 AH. On their chain saws I have found the same 80v saw for the same price but batteries ranged from 2 AH to 5 AH which is huge difference in run time with some weight difference.
I have been using a 21" self-propelled Ego for 4 years, I believe. All Ego are 56V using interchangeable battery. Mower came with a 7.5Ah. Lately have noticed some new Ego mowers come with (2) 5.0Ah batteries. Two batteries is a good idea as 5.0Ah will mow 30-45 minutes while the other charges.
Bought a 15" Ego string trimmer which included a 2.0Ah battery. When new if I didn't let the grass get too tall the 7.5Ah would mow about an hour then the 2.0Ah would finish up the last few minutes.
A bit after getting the mower and trimmer had an opportunity to get the backpack blower with 7.5Ah battery on closeout for less than a new 7.5Ah battery cost. Ever since I have been lazy and rarely mow the front and back lawns the same day but when I do I just swap the battery.
The original backpack blower battery was replaced under warranty. Not for lack of capacity but for outright stopping in the middle of mowing. 10 minutes and suddenly the mower shut down. No low battery warning. Take battery out, cuss at it, put it back in and resume mowing. Sometimes no trouble until I'm finished, sometimes it happened again.
String trimmer is full size as gas. Its great but its big. Find myself using my old Worx 48V. Worry about finding a battery for it if needed because Worx only did 48V for a few months before upping the voltage so as not to be thought of as a lesser weaker product against 56V competitors.
I really really don't use my EGo 7.5Ah batteries in the trimmer. The 7.5's are
heavy.