This is primarily about mowers that appear to be new to the market for 2017. The image above is a montage of various new and old models of just the 40 volt lithium ion battery types on the market now.
Along that line, here are a couple of 40 volt "Cloned Brothers From Other Mothers" I've run across on line that appear to be new to the market this year. They may be re-designs of same class previous models from these "makers".
Craftsman 40v 3 in 1
Black and Decker 40v 3 in 1
Is it just me or are these mowers IDENTICAL! They are the Craftsman and Black and Decker 40v LI battery cordless electric mowers currently advertised for sale. The only difference I can see is that the space behind what looks like a carry handle has a spare battery pack storage bin with the B&D model, and the color of plastic they are made from.
Here's a TRIO of 60 volt "Cloned Brothers From Other Mothers"
Greenworks 60v 21" 3 in 1
Snapper 60v 21" 3 in 1
Kobalt 60v 21" 3 in 1
Here we go again, almost. Another 3 identical cordless electric mowers from different "makers". It begs the speculation of a 3rd party making them all 3 for sale as Greenworks 60 volt 21" 3 in 1 mower, Snapper 60 volt 21" 3 in 1 mower and the Kobalt 60 volt 21" 3 in 1 mower. The only differences I see are the motor cap shape, color and labeling, and wheel "spoke" casting. That aside they look like VERY GOOD additions to the cordless electric mower market.
Black & Decker 20", 60 volt, 3 in 1 mower
4/18/2017 update: This machine, from Black and Decker incorporates active battery pack chambers for 2 packs loaded concurrently. They're only 2.5 Amp Hours / pack which provides only 300 Watt Hours of stored energy with 2 full chambers but it also includes circuitry to automatically switch from one battery to the other when optimal discharge level is reached.
Greenworks 20" 40v G-Max Twin Force mower.
4/18/2017 update: This Greenworks twin blade mower has been around for a few years and was my first pick for many folks new to mowing for some time even though it doesn't offer a side discharge option, only bag / mulch modes. It runs with 2 motors and 2 battery packs and has always had that automatic battery pack switchover feature for user convenience. The twin blade system is actually more efficient because it takes more energy to keep 1 20" blade spinning than it does to spin 2 10" blades. It's a basic centrifugal energy principle that load on / energy demand by a motor goes up exponentially as the distance from center of rotation to the center of mass of the rotating load increases. Simply put, each additional inch of blade length costs more energy to spin than the last. It's something I learned decades ago when I was doing a lot of work repairing medical laboratory centrifuges.
Some of you lawnmower neophytes may be asking in your mind, "What the **** does "3 in 1" mean?" It's very simply a reference to the grass clippings handling options the mower's design accommodates. Directly it means they offer bagging, mulching and / or side discharging operation. Obviously only 1 of the 3 at any one time. This feature is what you want. It allows you to save time and money and to use the machine for multiple purposes.
I use my Neuton 14" CE-5 SLA battery powered mower in side discharge mode most of the time. The 14" blade / deck generates considerably less suction to pull all the "layover" grass blades vertical for cutting so I have to do double passes in this and mulching mode.
I use the mulching mode of mine (for the above 5 machines that would be with the bag off, a plug inserted into the to-the-bag rear port and the side discharge port cover closed) mostly for reducing autumn leaves where they fall and driving the fragments down between the grass blades to feed the ever important beneficial organisms that build and maintain the soil quality for me.
As I said it's side discharge mode for me most of the time. That's for the same purpose my mulching of fall leaves is about as well as saving me from the burden of handling the clippings and burdening the waste stream with them and my pocket the cost of that.
I use the bagging function for grass clippings only when I need some for covering the soil around my veggie garden plants to keep moisture in the soil and weeds from growing. Another purpose for my "bag" mode is to reduce my neighbor's fall leaves before placing them in a bin for later use as "Brown" matter for my composting system.
Bagging also works for reducing dried hedge clippings and dead plant material from veggie and ornamental gardens to be used the same way as the leaf fragments from neighbors.
My main point here is that a rotary 3 in 1 mower can serve more purposes in your yard than just cutting the grass every week or so!
The highlighted brand names of the mowers in the text above are hyper-links you can click on to access further information and pricing on each per vendors of them.
My plan is to edit this with updated information as it becomes available including other notable new entries into this cordless electric mower market so you may want to check back once in a while for that.