40V 4AH Lithium-ion Battery

Model: #OP4040A

4.7 | 438 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.


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

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  • 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 437.
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 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 Solid battery with great capacity I power a weedeater with this battery and couldn't be more pleased. I bought an extra one because i was sure i would need it. Turns out, I can do my yard and my old neighbors yard next door and still have over half a battery remaining. This battery barely gets warm even after an half an hour of continuous use! Plus, it has a built in battery meter that tells you how much juice you have left! And don't even get me started on the great 40V weedeater Ryobi makes!! But that's for another review! This battery gets 2 thumbs up!!
Date published: 2020-05-26
Rated 5 out of 5 by from I purchased a Ryobi 40 V, 21" snowblower st the urging of my daughter. It was either that or continue the old-fashioned way - with a shovel, and in Michigan I expect the snowblower to get plenty of use. And I'm tired of the hassle of gas-powered equipment. In early November we got about 8 - 9 inches of heavy, wet snow, so the initial trial on my new snowblower happened earlier than expected. I wasn't completely confident that it would perform in that kind of snow, but I was pleasantly surprised. Taking my time with it, the snowblower worked even better than I hoped. I was able to clear my whole 80' two car width drive with a single charge of the double batteries. Definitely a worthwhile purchase!
Date published: 2019-11-27
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 Top Performance Initially invested in Lawnmower with 5AH battery. Fell in love, no more gas. Then needed to start trimming and edging yard again so didn't hesitate to buy Trimmer with 4AH battery. 0.5 acre cut, trimmed, edged in 1.5 hours using both batteries. Can bog down if lawn is not maintained but no big deal. Looking to add 6AH battery. Go green! I happily own big set of Ryobi 18V power tools, their reliability played a role in helping me choose the 40V lawn tools. Also after sales support from Ryobi is excellent. My 4AH battery crapped out and they sent replacement within 2 weeks.
Date published: 2020-08-11
Rated 5 out of 5 by from So far so good I had some issues with a previous battery that customer service was able to help resolve, but since then, the trimmer and battery pack has been great. Followed a couple of tips for maintaining the battery, and it seems to be working much better than before. Would normally have given a lower rating just for having the issues previously but the customer service in dealing with the complications and resolving those issues put it all on this level. Nothing works perfect forever but being able to rely on the company's agents to help resolve problems you encounter is a huge help.
Date published: 2020-04-28
Rated 4 out of 5 by from Solid battery life I bought a leaf blower and a lawnmower that both came with a 40V battery. So far the battery life is holding up well. I own about 2/3rds of an acre and 1 battery is generally enough for my leaf blower to get through it all. The lawnmower however only makes it halfway through that yard with this battery. Luckily, with the on-board storage, I can switch over to the other battery halfway through. Would be nice if it lasted a little longer, but overall its pretty good.
Date published: 2019-05-15
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