The Ryobi P108 is a 4.0Ah high-capacity battery for the Ryobi ONE+ 18V platform. It’s one of the most popular Ryobi batteries and is commonly bundled with mid-range kits. Here’s everything you need to know about finding a replacement.
P108 Specifications
Voltage: 18V
Capacity: 4.0Ah (72Wh)
Chemistry: Lithium-ion
Platform: Ryobi ONE+
Fuel gauge: Yes — onboard LED indicator
Weight: Approximately 0.6 kg
What Tools Does the P108 Fit?
The P108 is compatible with all Ryobi ONE+ 18V tools — over 300 products spanning drills, saws, blowers, lighting, and more. Any Ryobi tool with the ONE+ battery slot will accept the P108. This includes both the standard ONE+ range and the newer ONE+ HP tools, which benefit from the higher capacity.
Replacement Options
Direct replacement (same spec): The Ryobi P108 is still widely available. If you want the exact same battery, you can buy it individually or in twin packs.
Upgrade options: If your P108 has worn out, consider stepping up to a higher-capacity Ryobi ONE+ battery for longer runtime:
- PBP007 (6.0Ah HP) — 50% more capacity than the P108 with HIGH PERFORMANCE cells for more power in ONE+ HP tools
- PBP2008 (8.0Ah) — Double the capacity for all-day jobs, though heavier
- PBP004 (4.0Ah HP) — Same capacity as the P108 but with HIGH PERFORMANCE cells for better output in HP tools
All of these are fully backward compatible with every ONE+ tool you already own.
Where to Buy
Search for Ryobi P108 on Amazon UK
Browse all Ryobi ONE+ 4.0Ah batteries on Amazon UK
Tips for Getting the Most from Your Replacement
If your P108 died earlier than expected, a few simple habits can extend the life of your new battery. Let it cool down after heavy use before charging, store it indoors at partial charge if you won’t be using it for a while, and always use a genuine Ryobi charger. For our full guide, see How Long Do Power Tool Batteries Last?
Related Guides
- Every Ryobi ONE+ 18V Tool and Which Batteries Fit
- Can You Use Ryobi Batteries in Other Brand Tools?
- How Long Do Power Tool Batteries Last?
- Can I Use a Higher Ah Battery in My Drill?
Video Guide
Frequently Asked Questions
Is the Ryobi P108 compatible with the latest Ryobi ONE+ HP tools?
Yes. The P108 (4.0Ah) is compatible with all 300+ Ryobi ONE+ tools, including the newer ONE+ HP line. However, ONE+ HP tools are optimised for HIGH PERFORMANCE batteries to reach their maximum rated specifications. The P108 will work but may not unlock peak HP performance.
What is the difference between P108 and PBP004?
The PBP004 is Ryobi’s newer 4.0Ah HIGH PERFORMANCE lithium battery, while the P108 is the previous-generation 4.0Ah. The PBP004 uses newer cell chemistry for better sustained output and longer lifespan, plus it has a slimmer profile. Both provide the same nominal capacity.
Can I use Ryobi ONE+ batteries in Ryobi 40V tools?
No. Ryobi ONE+ (18V) and Ryobi 40V are completely separate platforms with different physical battery connections. They cannot be interchanged. Each platform requires its own dedicated batteries and chargers.
How long does a P108 take to charge?
With the standard P118B charger, approximately 2 hours. With the rapid P117 dual-chemistry charger, approximately 1 hour. Ryobi also offers the P118B supercharger that can charge a P108 in about 90 minutes. Always use genuine Ryobi chargers or certified compatible chargers.
Key Specifications
| Specification | Details |
|---|---|
| Nominal Voltage | 18V (ONE+) |
| Capacity | 4.0 Ah |
| Watt-Hours | 72 Wh |
| Chemistry | Lithium-Ion |
| Weight | 0.52 kg |
| Battery Indicator LED | Yes |
| Compatible Platform | Ryobi ONE+ 18V (300+ tools) |
Signs Your P108 Battery Needs Replacing
Lithium-ion batteries degrade naturally over time. Here are the key signs that your Ryobi P108 battery needs replacing:
- Rapid discharge: The battery drains noticeably faster than when it was new, even after a full charge. If a battery that once lasted an hour now dies in 20 minutes, capacity has degraded significantly.
- Charges but dies quickly under load: The battery appears to charge fully but shuts off within minutes when powering demanding tools. This indicates internal cell failure where the battery can no longer deliver sufficient current.
- Excessive heat during use or charging: While some warmth is normal, a battery that becomes uncomfortably hot during operation or on the charger has damaged cells. Excessive heat is both a symptom and a cause of further degradation.
- Physical swelling or damage: Any visible bulging, cracking, or deformation of the battery casing means the cells inside have failed. Stop using a swollen battery immediately and dispose of it safely at a recycling point.
- Charger error indicators: If your Ryobi charger flashes red or shows error lights rather than charging normally, it has detected a fault in the battery. Most Ryobi chargers include diagnostic features that identify damaged batteries.
- Age beyond 3-5 years: Even well-maintained lithium-ion batteries lose 20-30% of their original capacity after 3-5 years of regular use. If your battery is approaching this age and performance has declined, replacement is worthwhile.
OEM vs Third-Party Replacement Batteries
When replacing your Ryobi P108, you have two main options: genuine Ryobi batteries or third-party compatible alternatives. Both will physically fit and power your ONE+ tools, but there are meaningful differences worth considering.
| Factor | Genuine Ryobi | Third-Party Compatible |
|---|---|---|
| Typical Price | £30-55 | £15-30 |
| Cell Quality | Tested to Ryobi standards | Varies by manufacturer |
| Warranty | 3-year Ryobi warranty | 6-12 months typically |
| Safety Certifications | Full Ryobi standards, CE marked | CE marked, meets EN standards |
| Expected Lifespan | 800-1,000 charge cycles | 400-700 charge cycles |
| Performance Consistency | Optimised for all ONE+ tools | Compatible, slight variation possible |
Choose genuine Ryobi batteries if you want the security of a full manufacturer warranty and guaranteed compatibility across all 300+ ONE+ tools. Ryobi batteries are tested specifically for the ONE+ ecosystem and offer consistent, predictable performance.
Third-party batteries make sense for budget-conscious users who want to expand their battery collection affordably. Ryobi ONE+ is particularly well-served by the aftermarket because of its massive user base. Reputable third-party manufacturers engineer their batteries to strict compatibility standards, and many users report excellent results at a fraction of the OEM price.
How to Get the Most from Your Replacement Battery
Follow these care tips to maximise the lifespan and performance of your new Ryobi P108 replacement battery:
- Complete the initial charge: Fully charge your new battery before first use. This calibrates the battery management system and ensures accurate charge level readings from the start.
- Store at 40-60% charge: For long-term storage, keep your battery at roughly half charge. Storing a battery fully charged or completely depleted accelerates capacity fade. Check stored batteries every 2-3 months.
- Avoid temperature extremes: Keep your battery between 5°C and 40°C during use and storage. Never leave batteries in a hot vehicle or exposed to direct sunlight. Cold weather temporarily reduces output but does not cause permanent damage.
- Remove from charger promptly: Once fully charged, disconnect your battery. Leaving it on the charger continuously causes unnecessary stress on the cells, even with Ryobi smart chargers.
- Use compatible Ryobi chargers: Always use Ryobi ONE+ chargers (P118B, P117, or the dual chemistry IntelliPort charger). These include essential safety features like temperature monitoring and overcharge protection that generic chargers may lack.
Frequently Asked Questions
Is the Ryobi P108 the best Ryobi ONE+ battery?
The P108 (4.0Ah) offers the best balance of capacity, weight, and price for most DIY users. It provides enough power for drills, impact drivers, and light saws without being too heavy.
How long does the Ryobi P108 take to charge?
Using the standard Ryobi ONE+ charger, the P108 takes approximately 2 hours. The Ryobi dual chemistry charger or rapid charger can reduce this significantly.
Does the P108 work with all Ryobi ONE+ tools?
Yes. All Ryobi ONE+ 18V batteries including the P108 are compatible with all 300+ tools in the ONE+ range, regardless of capacity.
