Black + Decker CM2040 Battery Powered Lawn Mower Review

Important Info: The Black + Decker CM2040 is an old model and is no longer manufactured.

This review is left here for the purposes of second hand buyers.

If you are looking for a current model replacement I recommend checking out the Black + Decker 2043C

Disclosure: As an Amazon Associate I earn from qualifying purchases. However, this does not impact our reviews and comparisons. All opinions are our own we pride ourselves on keeping our articles fair and balanced. For more info see our disclosure statement.

Black & Decker CM2040 Review

Key Specifications

  • Battery Voltage: 40 Volts
  • Batteries Included: 2 x 2.5 AH Li-Ion batteries
  • Max Run Time: 30 Minutes
  • Deck Width: 20 Inches
  • Weight: 55 lbs

The black and Decker CM2040 often gets bad reviews, but in our opinion, these bad reviews are certainly not deserved. Not only is it a good cordless lawn mower, it is one of the best! In fact, until very recently it was in our best cordless lawn mowers list! Our feeling is that the negativity about this model is because people buy it without considering who it is designed for.

Black and Decker CM2040 comes with 2 x 2.5 AH 40V Li-Ion batteries. One battery is used at a time and the other one is stored in the storage compartment on the mower. When the first battery runs out of power it is simply a case of swapping them over, removing the need to go and find the second battery from the garage or shed. If you judge the runtime against the more expensive models, then, of course, you are going to be disappointed. But Black+Decker have done their best to keep the cost down and the weight as low as possible while still keeping the 20 inch deck.

The batteries in the Black and Decker CM2040 get very hot while in use, so hot in fact that they will not charge immediately after being used! This is a little odd, as the exact same batteries used in a Black & Decker Trimmer do not get anywhere near that hot, but this is no doubt to do with the higher current draw. So you will need to let them cool down before charging them, which in reality means a longer charging time.

The mowing power is a little limited on this power, so if you are the sort of person who let’s your lawn go for months without mowing it – then give this model a miss. It really is designed for users with a smaller yard who mow weekly. If you do hit a patch of long grass, you may find that the motor struggles a little bit.

The first time I used the CM2040 I could swear that I had bought a kids toy, it was so light and easy to push around – it just did not feel like a proper mower! But as I used it more Feels like a toy at first but is actually quite durable. The lightweight of this mower is great as it is super easy to push around obstacles and up inclines. It also makes it a breeze to lift up and hang on a storage hook if that is your preferred storage method.

The mulching mode actually works really well with this mower, the grass clippings are chopped up nice and small and almost no visible trace is left on the lawns when you are finished mowing.

It makes me sound really lazy, but I did love the fact that I did not have to go back to the garage to get the spare battery when the first one ran out. I simply took the spare battery out of the storage compartment and swapped them over and I was up and mowing again.


  • Very light and Maneuverable
  • Storage spot for second battery
  • Wide range of cutting heights available
  • 20″ deck width


  • Less battery life than more expensive models
  • Power is not as good as the more expensive models

The CM2040 electric lawn mower is available from Amazon and ACME tools.

Black + Decker CM2040 Review
This mower is designed for people with smaller yards who mow their lawns regularly. It’s easy to use, works well and is nice and quiet.
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Aaron Green
Aaron is the founder of and Essential Home and Garden. He likes to spend his spare time with his family, and doing DIY projects in the home and garden.

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