Milwaukee M12 REDLITHIUM 2.0Ah Battery (2-Pack) & Charger Kit vs Ryobi 40V Battery and Charger Kit, 4.0 Ah Lithium-Ion Battery Set OEM OP4040 + OP403A
Head-to-head spec comparison to help you pick the right battery for your needs.
Spec Winner
Milwaukee M12 REDLITHIUM 2.0Ah Battery (2-Pack) & Charger Kit
Wins on 2 of 3 spec categories
Spec-by-Spec Comparison
| Spec | Milwaukee M12 REDLITHIUM 2.0Ah Battery (2-Pack) & Charger Kit | Ryobi 40V Battery and Charger Kit, 4.0 Ah Lithium-Ion Battery Set OEM OP4040 + OP403A |
|---|---|---|
| Platform | M12 | 40V |
| Voltage | 12V MAX | 40V MAX |
| Capacity | 2 Ah | 4 Ah |
| Type | compact | kit |
| Genuine OEM | Yes | Yes |
| Fuel Gauge | No | No |
| Warranty | 5 years | 3 years |
| Price | $59.89 | $109.96 |
| Rating | 8.5/10 | 8.5/10 |
| Buy on Amazon | Buy on Amazon |
Pros & Cons
Milwaukee M12 REDLITHIUM 2.0Ah Battery (2-Pack) & Charger Kit
Pros
- Genuine Milwaukee M12 packs backed by Milwaukee's 5-year warranty
- Kit includes two batteries plus a charger — a solid starter bundle for the M12 platform
- Compact 2.0Ah cells keep M12 tools light for one-handed work
- Straightforward drop-in fit for any M12 tool
Cons
- 2.0Ah per pack is on the lower end for longer-runtime jobs
- Only compatible with M12 tools, not M18
- No fuel gauge on these compact cells
Ryobi 40V Battery and Charger Kit, 4.0 Ah Lithium-Ion Battery Set OEM OP4040 + OP403A
Pros
- Bundles a 4.0Ah 40V battery (OP4040) with a charger (OP403A) in one genuine Ryobi kit
- 4.0Ah is a mid-to-high capacity pack for the 40V outdoor-power platform
- Currently in stock on Amazon
- Genuine Ryobi OEM parts, not aftermarket
Cons
- Only one battery included — no second pack for hot-swapping on longer yard jobs
- 40V packs are heavier than ONE+ 18V packs, worth weighing if you're carrying it around
- We haven't independently timed a charge or measured runtime; 4.0Ah is Ryobi's stated rating
Our Verdicts
Milwaukee M12 REDLITHIUM 2.0Ah Battery (2-Pack) & Charger Kit
A genuine Milwaukee M12 two-battery-and-charger kit is the straightforward, warranty-backed way to get started or restock on the M12 platform — not the highest capacity, but the safest default.
Ryobi 40V Battery and Charger Kit, 4.0 Ah Lithium-Ion Battery Set OEM OP4040 + OP403A
A genuine Ryobi 40V battery-and-charger bundle with a solid 4.0Ah pack — practical if you're buying into the 40V outdoor platform or need a spare set.
Ryobi 40V Battery and Charger Kit, 4.0 Ah Lithium-Ion Battery Set OEM OP4040 + OP403A
$109.96