40V 4AH Lithium-ion Battery

Model: #OP4040A1

4.7 | 553 Reviews
Compatible with all RYOBI 40V Lithium tools and chargers, the 40V 4.0 AH Lithium-ion Battery is the perfect addition to your RYOBI 40V tool collection. It's lithium-ion cells deliver fade-free performance from start to finish. The convenient on-board battery life indicator keeps you informed while you're out in the yard tackling your landscaping jobs. The 40V 4.0 AH Lithium-ion Battery's extra cell capacity is perfect for higher output tools like 40V mowers, blowers and chain saws. RYOBI 40V Lithium surrenders nothing but gas.


Ryobi three year warranty logo

This product is covered by a 3-year limited warranty.

The RYOBI 40V System features over 50 products, providing versatility to get the job done.

View our current promotions for new product releases and the latest RYOBI savings!

Ryobi Help+

Your one stop destination for tips & techniques, manuals, troubleshooting, FAQs and more!


  • Voltage: 40
  • Amp Hours: 4.0
  • Cell Type: Lithium-ion
  • Compatibility: All RYOBI 40V Lithium Tools & Chargers
  • Weight: 4 lbs.
  • Warranty: 3 Year Limited


  • 40V 4.0 AH Lithium-ion Battery
  • Operator's Manual


40V 4AH Lithium-ion Battery
40V 4AH Lithium-ion Battery is rated 4.7 out of 5 by 543.
Rated 5 out of 5 by from Excellent product I purchased my 20 in 40 volt Lawn Mower and battery included last month and it was the best investment I good ever invest in for my lawn care. I have a huge backyard, and this lawn mower and 40V lithium ION battery did not let me down like my other lawnmower did. By it being operated by not only a battery but a powerful long lasting battery that got me through my huge backyard without running out of power and some more battery time left to do my next door neighbors yard as well. I love love love my powerful battery lawnmower. I recommended this product to several of my neighbors and they said they would definitely purchase this product.
Date published: 2020-04-26
Rated 3 out of 5 by from On the Edge I had received this as a birthday gift and I was very pleased about the product. If you are debating about completing a task because you don’t think your regular battery can handle, then let me tell you that this product will make you rethink what you can’t complete. The only problem that I have is that the battery has died on me and not come back to life within 1 month. I tried to exchange it at the local Home Depot but since I was not the original purchaser they told me they couldn’t do anything for me. So with this being my issue I’m stuck between a rock and a hard place to decide if I love it or would pass on it.
Date published: 2020-12-09
Rated 1 out of 5 by from DOA How disappointing. I purchased a 40 volt brushless blower only to find that the 40v battery does not work. I called HD, who got Ryobi on the line. Yes they'll send me out a replacement battery in 14 business days. I repeat, 14 business days !!!! A lot of good that does for me now. I and searched the internet, seeing it's a common problem. A sleepy battery ??!!!! The solution, to plug and unplug constantly for about 30 minutes in hopes you can get enough mini-charges to get it past a minimum level. And there's no guarantee there. Really Ryobi, you need to do a better job here.
Date published: 2021-05-19
Rated 3 out of 5 by from Does the job on smaller yards. I like Ryobia tools and have purchased a lot of them--mostly construction tools. When my gas trimmer died, I decided to try yard tools. I own several but mostly use the trimmer. I have a larger yard and now have several batteries that I keep charged. I wish the batteries lasted longer but they do the job. If you have a small city yard, you could probably get away with one battery. I purchased a 6ah battery, which lasted a bit longer. One of these failed prematurely. The batteries are sometimes hard to pull out of the tools which could be an issue for women or older people (or people with arthritis).
Date published: 2020-10-22
Rated 5 out of 5 by from Amazing power! I bought 2 of the 40v batteries to go with the ryobi 40v chainsaw. And I was truly impressed on the run time. I am getting about 45 min of run time depending on the size of the tree or branches. I am getting longer use if it is just branches, but for the main parts of tree a little less run time. They may feel slightly heavy but honestly you don't notice when using in power equipment. Only downside is I have had to let the battery set for 10-15 min to cool down before putting on charger. I also recommend to have a spare on hand... you never know when you will need it.
Date published: 2021-11-04
Rated 1 out of 5 by from Expensive, unreliable batteries Started out with 4 batteries none of which lasted more than 2 years and a couple lasted less than one. After the first one failed I registered the rest on the website for warranty coverage. But since I did not also register the tools that were included with the batteries they would not honor the warranty. If you have to buy these batteries make sure you jump thru all their hoops and save paperwork.
Date published: 2019-06-19
Rated 5 out of 5 by from A real time saver! I have dozens of Palo Verde & Mesquite tress on my property of which have grown so tall that I use and extended ladder to reach. This little but not so weak pole saw did the trick in one day of cutting. I cut over 20 tress, 80 plus branches 2- 12 inch thick. Its angle is designed leverages its chain to hug the the branch cutting it with hardly any effort, amazing! One charge on the battery. It cost more to have the gardeners pick up the branches (two days) than the saw cost me. One of my best purchase of Ryobi yet! ty
Date published: 2020-07-07
Rated 1 out of 5 by from so disappointed, you will need multiple batteries I have been thinking of making this purchase for about a year. I have a set of power tools that I love. I was so looking forward to a complete suite of these tools. I started with a blower trimmer combo and got a chainsaw also. yesterday we went to clean up the park used the chainsaw to cut a small branch then switched to the leaf blower I was almost finished with that job after 45 min when I ran out of charge. I took about 5 hours to recharge it so no more working in the park that day. I took the trimmer with the brush cutting blade down there and was going to town on the blackberries in 15 minutes both blades broke and I was down to 3 bars of power. So it looks like I am going to have to have 4 batteries to just get a 1/2 days work done. I don't think I will be buying the pole saw and cultivator. This platform will not replace gas tools.
Date published: 2021-03-28
  • y_2021, m_11, d_7, h_19
  • bvseo_bulk, prod_bvrr, vn_bulk_3.0.19
  • cp_1, bvpage1
  • co_hasreviews, tv_44, tr_499
  • loc_en_US, sid_307973316, prod, sort_[SortEntry(order=RELEVANCE, direction=DESCENDING)]
  • clientName_ryobioutdoortools