96.7 % in amp-hours, 81.0 % in real energy: two figures, not one
On a variant close to this range (Multi-Ah Plus, set to 4 Ah mode, not the standalone reference 4511396 itself), a constant-current discharge at 15 A, voltage tracked through to full cutoff, gives: 3,869 mAh delivered out of 4,000 mAh rated, or 96.7 % in amp-hours, and 58.40 Wh delivered out of 72 Wh rated, or 81.0 % in actually recoverable energy.
The gap between the two figures has a simple explanation: voltage falls progressively during discharge (19.93 V at full charge, 17.33 V just before cutoff on this measurement), and the energy actually available depends on that voltage at every instant, not just on cumulative current. This is why a single "usable capacity" percentage is not enough to describe a battery accurately: depending on whether amp-hours or watt-hours are being discussed, the same product shows a result above or below 90 %.
A comparison between six 4 Ah packs, leading on safety and durability
A comparison covering six 4 Ah batteries from different brands, using the German school grading scale, places the Power X-Change in first position with an overall score of 1.9 ("gut", meaning good), with safety, durability and charging time all rated good to very good. This result points in the same direction as the capacity figures above: this battery stands out more for its robustness and stability than for an exceptional raw capacity, consistent with a coherent positioning rather than an isolated marketing move.
More than 300 compatible machines, one of the widest ecosystems on the market
The bet Einhell placed with Power X-Change more than ten years ago still holds: a single battery now powers more than 300 machines in the Einhell range, from everyday DIY to garden work, through to lighting and power inverters. Twin-Pack technology even allows two 18 V batteries to be combined to power certain more demanding 36 V tools, without leaving the ecosystem.
A signal of premature failure after two to three years, worth taking seriously
The most important point to know before buying is not about capacity but about lifespan. A share of Power X-Change packs, across all capacities, stop working correctly after two to three years of use: reduced runtime, longer charging times, outright refusal to charge. This signal comes up at regular intervals, in both France and Germany, never confined to a single forum or platform.
This pattern looks more like a spread in build quality than a systematic flaw: some packs also exceed five years of use with no reported incident. But the scale and regularity of the signal justify mentioning it clearly, rather than relying solely on the manufacturer's own communication about the absence of memory effect and self-discharge.
Sturdy housing, no charger included: a deliberate range strategy
The housing has an impact-resistant rubberised coating and a recessed handle that makes removing it from the tool easier. The 3-segment charge indicator remains basic next to the detailed LCD displays of other product categories, but is enough for a quick check before heading out to a job.
This reference is sold without a charger, a common practice for this type of battery sold on its own rather than a hidden catch: Einhell also offers starter kits pairing a battery with a charger, generally better value for anyone starting out in the ecosystem than the two bought separately.
Price seen and availability
The price seen for this reference alone sits around 37 €, consistent with an entry-level position in the Power X-Change ecosystem. The range now coexists with newer variants ("Plus", rated IP57, and "Multi-Ah", which covers several capacities in a single pack): these newer references should not be confused with this standard 4.0 Ah battery when comparing prices. No product recall was found for this model in the safety databases consulted.
Against the Ryobi RB18L40 battery
The most natural comparison is with the other major consumer ecosystem, Ryobi One+, in its equivalent 4 Ah format.
| Criterion | Einhell PXC 4.0 Ah | Ryobi RB18L40 |
|---|---|---|
| Capacity | 4 Ah / 72 Wh (96.7 % in Ah, 81.0 % in Wh measured) | 4 Ah / 72 Wh (claimed, no independent figure found) |
| Ecosystem | More than 300 machines | More than 200 tools |
| Charge indicator | 3 segments | 4 LEDs |
| Price seen | ≈ 37 € | ≈ 90 € |
On price seen alone, the gap clearly favours the Einhell. On capacity, the Einhell shows a figure that has actually been measured, which the Ryobi lacks, even though it concerns a close variant rather than the exact standalone reference. The Ryobi keeps the advantage of a slightly wider ecosystem in terms of number of tools, and its known failure signal (charging refusal after long inactivity) appears less severe than the 2 to 3 year failure signal identified here for the Einhell. The choice remains mainly a question of the ecosystem already owned, not a simple price-against-price trade-off.
Who it suits, and who it does not
It suits anyone who already owns Power X-Change machines and is looking for a 4 Ah format with a good price-to-runtime balance, or anyone discovering the ecosystem who wants to benefit from its very wide compatibility without paying a premium.
It does not suit anyone who needs an unreserved guarantee of longevity beyond two or three years: the premature failure signal identified above, while not systematic, deserves to be taken into account for professional use or a purchase meant to last.
