Ryobi Charger Flashing Red and Green — Battery Defective

What Does This Error Mean?

Alternating red and green flashing on a Ryobi charger means the battery has been rejected — the charger has detected a fault and refuses to charge.
Try the battery on a different Ryobi charger first.
If both chargers reject it, the battery is at end of life or has cell damage.
Replacement Ryobi One+ batteries run $40–$100 depending on capacity.

Affected Models

Ryobi 18V One+ system
Ryobi P118 Charger
Ryobi OP401 Charger
Ryobi 40V Battery System
Ryobi Compact Battery

Common Causes

Battery deeply discharged below recoverable voltage
One or more cells failed — battery management system locks the pack out
Battery contacts dirty or oxidised
Battery has been damaged by impact, water, or extreme temperatures
Charger fault (rare — try a different charger to rule out)

How to Fix It

Wipe the battery contacts clean.

Pull the battery off the charger and wipe the metal contacts with a dry cloth.
Sawdust and dirt accumulate on power tool batteries quickly.
Sometimes a clean contact is the difference between charging normally and red/green flashing.
Try the battery on a different Ryobi charger.

Borrow another Ryobi One+ charger if you can — there are several models, but they all charge the same packs.
If the second charger also flashes red and green on the same battery, the battery is the problem.
If only your charger flashes, the charger is faulty.
Try a different Ryobi battery on your charger.

Take a known-good battery and try it on the same charger.
Charging normally = your charger is fine.
Red/green flashing on multiple batteries = the charger has failed.
Check battery age.

Ryobi batteries are rated for about 1,000 cycles.
Heavy daily users get there in 2–3 years.
If yours is in that age range and the BMS has rejected it, the cells have aged out — it's time for a new pack, not repair.
Replace the battery if confirmed faulty.

Ryobi's own One+ batteries are widely available.
Generic third-party batteries exist but quality varies — stick with Ryobi or established third-party brands with good reviews.
Genuine Ryobi 4Ah batteries run $50–$80; high-capacity 9Ah are $100–$150.

Frequently Asked Questions

Can a deeply discharged Ryobi battery be revived?

Sometimes.
If the battery was just used heavily and not stored at zero charge, the BMS may wake up after sitting on the charger.
Try leaving it on the charger overnight — some recover slowly.
If it's been at zero for months, the cells are usually past saving.

What's the difference between red/green flashing and steady red on Ryobi chargers?

Red/green flashing = battery rejected (defect or deep discharge).
Steady red = charging in progress.
Steady green = charged and ready.
Flashing red alone (no green) on some Ryobi models = battery temperature out of range, not a defect.