40V 4AH Lithium-ion Battery

Model: #OP4040A1

4.6 | 695 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 691.
Rated 5 out of 5 by from Senior issue no more gas, cost and prep issue. Less noise, just plug & play.
Date published: 2023-08-31
Rated 4 out of 5 by from Mostly pretty reliable battery, but not cheap I own quite a few of these batteries to power my Cross Cut Lawn 40V Mower, Leaf Blowers, String Trimmer, Hedge Trimmers etc. I generally try to use the slow charger to extend battery life--which is a good strategy as long as you have an inventory of batteries. Otherwise you may want a fast charger. When I only had 1 4-AH and 2 6-AH batteries I would *almost* make it through cutting the lawn and blowing the clipping off the sidewalk. Back then I'd need to wait a couple hours to slow charge the mower batteries. Then i bought more RYOBI stuff and now have a lot of spares so I can slow charge at the end of the weekend chores. Only bad point. I have had 2 of the 6-AH batteries refuse to accept charge but Ryobi replaced them without any hassle (they were maybe 2 years old). The batteries themselves are not cheap otherwise. Treat them well and they will hopefully serve you well.
Date published: 2023-08-21
Rated 5 out of 5 by from Long lasting I bought this a month ago and I'm happy with the battery charge.
Date published: 2023-08-06
Rated 5 out of 5 by from Awesome No issues with this battery, great performance as expected.
Date published: 2023-08-05
Rated 5 out of 5 by from Long life, lots of power I was hesitant about buying a battery powered weed wacker but decided to take the plunge. I bought the 40V HP BRUSHLESS 15" CARBON FIBER STRING TRIMMER KIT. I used this at our vacant land and it did an amazing job! It was super light and the batteries seemed to last forever! They are also quick to recharge. I highly recommend trying this out.
Date published: 2023-08-02
Rated 5 out of 5 by from 40v 4 ah battery Great product works perfect. Glad I found this for a much better price…
Date published: 2023-07-29
Rated 3 out of 5 by from Battery Reset I got this battery as part of a string trimmer purchase. It is about 2 years old. The battery showed fully charged (but blinking lights when pushing the power button.) I didn't realize that this indicated an issue. Ryobi doesn't describe a reset function. Youtube does describe a reset function that will get the battery back in operation. This battery is very expensive and if you didn't keep the receipt you have a brick with no help from Ryobi. My opinion is Ryobi you need to give people more information. If you didn't intend for the battery to be reset, why would you have a reset terminal under the cover. Without that information, I would have recycled this $150 dollar battery and had to buy a new one. I'll bet if I had been able to return this under warranty a tech would have lifted the cover and used a simple tool to that.
Date published: 2023-07-29
Rated 5 out of 5 by from Does the job for my yard I bought the 40v weedeater because my gas powered weedeater was on its last legs. To do my yard it's uses 2 bars. Works fine no issues ,will buy another 40 v tool in the future.
Date published: 2023-07-19
Rated 5 out of 5 by from Great Customer Service Had a battery that wouldn't take a charge almost out of warranty, called Ryobi and had a new in a couple days.
Date published: 2023-07-17
Rated 5 out of 5 by from Esmir This battery is powerful . The 40v battery let me do what I need with old my tool
Date published: 2023-07-15
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