Comparison Zelmer ZSH7500 vs Xiaomi ShowSee Electric Shaver F1-BK

— Dry. Dry shaving is suitable for shavers specifically designed for use on dry skin, excluding the application of creams, foams, or similar products. It's important to recognize that these models might have moisture-resistant qualities and tolerate water washes (as described below), but these features don't imply compatibility with wet shaving.

— Wet/dry. Shavers that can shave not only "dry", but also on wet skin, which is applied with foam or other shaving agent. Wet shaving is considered more gentle and is well suited for people with sensitive skin. However, such shavers are much more expensive than “dry” ones — after all, the shaving head must have certain features (so as not to clog with foam and not smear it instead of shaving hairs).

Models feature waterproof casing with varying levels of protection, often indicated by two numbers. The first number pertains to dust resistance and is often marked as X. The second number reflects moisture resistance, particularly water. For instance, IPX3 and IPX4 offer splash protection, IPX5 and IPX6 enable shower use, while electric shavers with IPX7 can be submerged underwater for up to 30 minutes.

The speed of rotation of the electric motor of the shaver. A higher rotational speed (ceteris paribus) usually means a higher speed of movement of the blades, which has a positive effect on the closeness of the shave.

— Turbo mode. The function of a short-term increase in the speed of rotation of the motor. This increases the performance of the shaver, which can be especially important when working with thick hair or in hard-to-reach areas. Note that the turbo mode, usually, is not intended for long-term operation.

— Auto-detection of bristles. The electric shaver's head contains a sensor to detect bristle density or stiffness. Through the automatic stubble feature, the shaver's motor adjusts power according to the skin area's requirements. This capability facilitates effective one-pass shaving, even with thick stubble. As the shaving head transitions from dense to moderate bristles, the motor power decreases automatically. This not only conserves battery life but also provides a gentler experience for the skin.

— Floating head/foil. The floating or movable shaving head(s) are capable of moving relative to the shaving unit and shaver body. Such a system follows the contours of the face during shaving, which ensures a tighter fit of the shaving heads to the skin, as a result — a cleaner and better shave, especially in difficult areas.

— Possibility of washing with water. Possibility of washing the shaving unit with water. This method is often much more convenient and effective than dry cleaning with a brush or other method.... Note that being washable with water does not necessarily mean wet shaving (see above).

— Cleaning indicator. A special indicator that notifies the user of the need to clean the shaver.

— Self-sharpening blades. Blades made using a special technology, thanks to which they sharpen themselves, due to friction against each other in the process. Thus, the blades remain sharp at all times, and their maintenance is limited to the replacement of worn blades.

— Child lock. Shavers featuring a safety switch are designed to activate only when held in the user's hand and intentionally turned on. This design prevents unintended activations, such as during travel when the device might shake inside luggage, avoiding unnecessary battery drain during idle moments.

— Li-Ion. Currently, the prevailing battery type is Lithium-ion (Li-Ion), known for its high energy density, compact size, and light weight. Li-Ion batteries offer approximately 400 charge-discharge cycles on average. These batteries exhibit minimal self-discharge and lack a significant "memory effect" (capacity reduction due to charging a partially drained battery). However, they are sensitive to cold temperatures and require high-quality charging currents.

— Li-pol. Lithium-polymer (Li-Pol) batteries maintain stable output voltage even during significant discharge. These batteries offer an average lifespan of about 800 charge-discharge cycles. Unlike some battery types, Li-Pol batteries don't exhibit a memory effect, and they operate reliably within a wide temperature range of -20 to +40°C. However, they are sensitive to deep discharge and overcharging. To address this, specialized chargers employing suitable power supply algorithms for the lithium polymer context are recommended for maintenance.

— Ni-Mh. Nickel-metal hydride (Ni-MH) batteries excel in managing substantial charge and discharge currents, making them suitable for power-demanding electric motors and rapid charging. These batteries now boast impressive longevity, enduring around 1000 to 1500 charge-discharge cycles, while maintaining an eco-friendly nature. In comparison to Li-Ion, Ni-MH batteries appear bulkier and add weight to the device, yet they offer a more economical option.

While higher battery capacity theoretically extends a device's operation on a single charge, practical considerations are more complex. Ampere-hours are a specific unit, comparable only among batteries with the same voltage. For differing voltages, capacity must be converted to watt-hours for accurate comparison. Furthermore, actual tool battery life depends on consumption and performance, not just battery properties. Comparing battery capacity is meaningful only when models share the same voltage and capabilities. Operating time is a more informative parameter for comparison.

The average runtime of electric shavers on a full battery charge, without recharging, is generally overestimated due to factors like hair length, density, and trimmer usage. Manufacturer claims for runtime tend to be higher than actual usage. Longer runtimes require heavier and more expensive powerful batteries. Most shavers offer around 45 minutes of runtime, while some models provide up to 1 hour or as low as 30 minutes of operation.

Charging time for the electric shaver battery from a fully discharged state to 100% charge. If freedom of movement when shaving is most important to you in a cordless shaver, and you always have access to the power supply (for example, you rarely travel), this parameter does not matter much. However, if you often travel on trips in which you have to constantly move from place to place, you should pay attention to models with a short charging time.

The presence in the design of the electric shaver charge level indicator.

It's important to highlight that in this context, an indicator refers specifically to a visual representation of the charge level. This could manifest as a battery icon or a percentage displayed on the display. Such an indicator significantly simplifies battery monitoring, minimizing the possibility of being unexpectedly left with a depleted battery.