Lithium-ion batteries are the newest battery technology and offer better performance than Nickel-Cadmium (Ni-Cad) batteries. The main advantage is, they won't lose power as the battery loses its charge.
Performance of Ni-Cad batteries suffer as the battery dies. They also can take up to 12 hours to charge. Lithium-ion batteries can recharge in about an hour so you can get back to work.
Automatic Bar Oiler
Due to the constant metal-on-metal friction between the bar and chain of a chainsaw, the bar needs to be continually lubricated with oil. This allows the chain to run smoothly. Without it, chains break easily.
Look for a rechargeable chainsaw with an automatic bar oiler, which will constantly apply oil to the bar. Without one, you need to be vigilant about stopping to oil the bar, slowing you down.
Voltages & Amp Hours
Cordless saws may not have horsepower like a gas saw, but they've still got power! What to look for is the voltage and the number of amp hours.
Certain manufacturers today even produce 80-volt cordless chainsaws that can outlast most other models, so be sure to check voltage and amp-hours to determine if it's got the "muscle" and stamina to keep up with your work load.
Weight with Battery
Lithium-ion batteries are lightweight. This can be a big deal if you're not a muscly-armed lumberjack who's used to toting around a 20-pound machine eight days a week!
Some of these lighter-weight saws may feature shorter battery life, but if you're looking for something you can easily work with, be sure to check the weight in the "specs" tab on the product page to determine how heavy the saw is.
If you have trouble finding a cordless saw that's light enough for your liking, consider a corded-electric model for reduced weight.
Tool-less Chain Tensioning
Some models of battery-powered chainsaws feature tool-less chain tensioning, which allows you to tighten the chain without having to dig out a screwdriver or multi-tool.
This feature is extremely handy, no matter how experienced you are. If you're out in the field cutting a tree and you notice your chain getting loose, wouldn't you rather reach to the side of your saw and turn a dial than hike back to your truck or house to find a screwdriver?