Quick answer
Buy a genuine Ryobi 40V battery if you can, and treat aftermarket 7.5Ah listings as unverified (Ryobi's own 7.5Ah pack, the OP4075A, is discontinued). Ryobi says its 40V batteries are compatible with any Ryobi 40V product, so a pack built for the right platform should fit. The two aftermarket listings we checked print a 7.5Ah capacity, and neither listing's reviews were reliably about a 40V pack.
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Genuine Ryobi 40V options
Ryobi's 40V battery page states that its 40V batteries are compatible with any Ryobi 40V product, and its 40V collection lists mowers, chainsaws, blowers, trimmers and more. Ryobi's current lineup includes 4Ah, 6Ah, 8Ah and 12Ah 40V packs, and Ryobi's site also shows a 7.5Ah pack (OP4075A) that it marks as discontinued.
On Amazon in our check, Ryobi 40V packs came from third-party sellers, not Ryobi. We could not find a genuine OP4050A, OP40601 or OP40602 listing, so we are linking packs we could verify.
View the Ryobi 40V 4Ah battery on Amazon (paid link)
View the 40V battery and OP403A charger kit (listing names OP4040) on Amazon (paid link)
Aftermarket 7.5Ah listings we looked at
We confirmed on 2026-10-06 that both pages exist and match their titles. We are not recommending them.
| Listing | Capacity as printed | Fit claimed | What we noticed |
|---|---|---|---|
| OHYES BAT | "7500mAh" | OP40601 / OP40602 | Reviews on the page are mixed with other brands |
| Munikind | "7500mAh" | OP4026A | Reviews are for 20V batteries from another brand |
Check the OHYES BAT 7.5Ah listing (paid link)
Check the Munikind 7.5Ah listing (paid link)
Genuine vs aftermarket: what to check
- Model fit. Find your tool's current battery model number and match it to the model the listing names.
- Capacity. Ryobi's current 40V packs on its pages are 4, 6, 8 and 12Ah. Ryobi also made a 7.5Ah pack (OP4075A), now marked discontinued on its site, so 7.5Ah is a real past size. Ask the seller what the number is based on (cell type, cell count, watt-hours) and whether the pack is a copy of that model.
- Reviews. If the reviews talk about another brand or a different voltage, the star rating tells you nothing about this pack.
- Charger. Ryobi's P137 dual-platform charger works with 18V ONE+ and 40V batteries. How an aftermarket pack behaves on a Ryobi charger is something to check in reviews and with the seller.
- Seller terms. Read the seller's return and warranty terms. A third-party pack is not covered by Ryobi's battery warranty, whose terms are on its own site.
If a replacement pack won't charge, start with the Ryobi charger troubleshooting guide.
FAQ
Do 18V ONE+ batteries fit Ryobi 40V tools?
No. They are separate platforms; Ryobi's dual-platform P137 charger lists 18V ONE+ and 40V batteries as two platforms. Use the battery compatibility checker to confirm your platform.
Is a 7.5Ah aftermarket 40V pack the same as a Ryobi pack?
We can't tell from the listing. Ryobi's current 40V packs are 4, 6, 8 and 12Ah models, and its discontinued OP4075A was 7.5Ah. Ask the seller for the cell type and a watt-hour rating.
Can I use a 40V HP battery on a standard 40V tool?
Ryobi's 40V pages describe HP as a performance tier within the 40V system and state no special battery requirement.