This long-term review compares the performance and longevity of genuine Milwaukee M12 batteries against a cheaper off-brand alternative. We put two Milwaukee batteries – a 3.0Ah and a 1.5Ah – alongside a 6.0Ah off-brand battery from a Chinese manufacturer through their paces, examining their performance over several years of use and a controlled load test. This comparison explores the significant price difference between the brands, analyzing whether the cost savings of the off-brand battery outweigh potential drawbacks in terms of durability and performance.Our analysis delves into the internal construction of each battery, comparing build quality, component materials, and safety features. We assess voltage stability under load, providing concrete data from our testing using an M12 soldering iron. The results reveal key insights into the long-term value proposition of each battery type, helping you determine which option best suits your needs and budget, whether you're a professional contractor or a weekend DIY enthusiast.
Pros And Cons
- Good quality
- Long lifespan (7+ years)
- More expensive ($42)
- Inexpensive ($15)
- Holds voltage well under load
- Lower quality
- Less durable
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Battery Lineup and Pricing
This review compares three M12 batteries: two genuine Milwaukee batteries (a 3.0Ah and a 1.5Ah) and a 6.0Ah off-brand battery from a Chinese manufacturer.

The Milwaukee 3.0Ah battery retails for around $42, the 1.5Ah for just over $30. The 6.0Ah off-brand battery is significantly cheaper, costing approximately $15.

Both Milwaukee batteries have been in use for approximately 6-7 years, showing significant wear and tear, especially the 3.0Ah battery used more frequently for camping trips. The off-brand battery shows wear consistent with its age and use.

Voltage Test: Initial and Under Load
Before testing, all batteries were fully charged. Initial voltage readings were 12.0V (1.5Ah), 12.2V (3.0Ah), and 12.28V (off-brand 6.0Ah).

The batteries were tested under load using an M12 soldering iron. The test lasted approximately 1.5 minutes for each battery.

The Milwaukee 3.0Ah battery maintained its voltage relatively well, while the 1.5Ah Milwaukee battery showed a more significant voltage drop. The off-brand 6.0Ah battery held its voltage surprisingly well.

Battery Disassembly and Cell Analysis
Disassembling the batteries revealed differences in construction quality. The Milwaukee batteries had a more robust design and included protective features. The off-brand battery showed a less durable build and lacked protective features.

The Milwaukee batteries appeared to use cells from either Samsung or LG, based on visual inspection. The off-brand battery's cells were not clearly identifiable.

The disassembly process highlighted the superior build quality and design of the genuine Milwaukee batteries.

Conclusion and Recommendations
The Milwaukee batteries, despite their age, outperformed the cheaper off-brand option in terms of voltage stability under load.

While the off-brand battery offered a significant cost advantage, its inferior build quality and shorter lifespan make the Milwaukee batteries a better long-term investment.
The choice depends on budget and priorities. For professional or heavy-duty use, the durability and performance of Milwaukee batteries are worthwhile. For occasional or light use, the off-brand option might suffice.