40V 4AH Lithium-ion Battery

Model: #OP4040A1

4.6 | 707 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 BATTERY is rated 4.6 out of 5 by 705.
Rated 4 out of 5 by from Review of Ryobi 40 Volt battery I have had two batteries replaced, so far under warranty.
Date published: 2023-11-28
Rated 5 out of 5 by from Great power to weight ratio Bought as a back up. Can never have enough batteries
Date published: 2023-11-17
Rated 5 out of 5 by from Good battery I have had good luck with these batteries, but I see others with dead versions of this. Of the Ryobi 40 volt batteries, the 4 Amp is the most popular. Good warnenty, just don't wait to long. it runs out faster than you think!
Date published: 2023-11-12
Rated 4 out of 5 by from Drop the price! I love all of my Ryobio tools........just wish the batteries weren't so expensive! Needing three batteries to clear my property of leaves makes this start to be out of reach.
Date published: 2023-11-09
Rated 2 out of 5 by from Some older tools do not work with newer batteries Some older tools do not work with newer batteries. Due to a redesign on the newer batteries I can not use this in my older 40v Chainsaw, I have not yet tested them to see if they fit my snow blower or lawn mover because they are in storage. To be able to use my chainsaw I will need to buy the newer 40v 2ah batteries to operate it, requiring 4 batteries to what two would do. I can not justify buying a new chainsaw that I use only a few times a year. I have also experienced reliability issues with the older model 40v batteries. Time will tell if the reliability issues have been corrected but multiple batteries have been recycled due to being out of warranty or unable to find receipts for proof of warranty especially those faded Home Depot receipts. I had around 8 4ah 40v batteries and am now down to 3 reliable batteries. At the price of these batteries you would hope a company would stand by them better. YouTube Ryobi 40v battery problems and you will find a lot of videos about them. I have started labeling my batteries with the date of purchase and where or how I bought them (ie in store, online or if they came with a product) to try and keep track better. I have not experienced the same reliability problems with my 18v products. With around a dozen batteries only one or two have been recycled due to their age. I would expect this however because the 18v tools get used more often. After multiple contacts with Ryobi support, they do not seem to care about the fitment issues with my older tools. They do however seem to care about the reviews of their products so I am taking out my frustrations here. I have 25+ 18v tools and about 10 40v tools from garden tools to snow blower. I also have several 120v Ryobi products; chop saw, table saw, router, sander, pressure washer etc... The fitment issue concerns me going forward especially with the poor lifespan of my previous 40v batteries. I am not sure if I can justify buying more of the 40v products if they are going to brick the tool with a battery design change. It seems to me that a lower profile on the outer plastic casing would have avoided this, but then Ryobi wouldn't be able to sell you new tools. I chose "yes I would recommend to a friend" because there was no maybe option, I would make sure they knew the problems I experienced.
Date published: 2023-11-01
Rated 5 out of 5 by from Great Battery This battery came in my Log Splitter when I ordered the splitter, I ordered it with the battery and charger. Works very well and holds a charge to let me split my firewood, without hassle.
Date published: 2023-10-27
Rated 5 out of 5 by from 40V battery system I have been using the 40V tool system for over ten years. It has worked for me and saved me from much frustration I had with gas systems. Ryobi has added so many new 40v tools over the decade, many I now have, they work every time you need them. I look forward to the battery's becoming solid state, faster recharge.
Date published: 2023-10-18
Rated 5 out of 5 by from Awesome Works very and it lasts long enough to do the whole yard in one charge.
Date published: 2023-10-17
Rated 2 out of 5 by from Garbage Batteries Love the tool, hate the battery. Used for less than a year and the battery failed to charge. Was working fine, then just quit. LED lights started blinking all green and fails to charge. Replacement battery cost as much as a new tool.
Date published: 2023-10-08
Rated 1 out of 5 by from Love my tools, so frustrated with the batteries. I really love using my Ryobi tools, I love not having to deal with gas and noise. I am able to mow later or earlier without disturbing my neighbors, and I love the little headlight. BUT!!! These 4ah batteries are not so great, I have 3 that have stopped working. I have called to speak to someone about replacements but have been on hold for nearly an hour with no representative response. I texted the number Ryobi suggested contacting and that was also a dead end in terms of help. I am to the point I can't use the tools I so love and depend on to keep my yard looking sharp.
Date published: 2023-10-05
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