Comparison Xiaomi MiJia Electric Shaver S500 vs Xiaomi MiJia Electric Razor Rotating Double Head

Electric shavers are divided into types depending on the design and principle of operation of the shaving heads.

— Rotary. Rotary shavers have characteristic round shaving heads inside which blades rotate. Their main advantage over foil is a better fit of the blades to the skin and, as a result, a more efficient and clean shave. And rotary models are generally less noisy. On the other hand, rotary heads can be uncomfortable for people with sensitive skin; this is especially true for inexpensive models — advanced products usually use special tricks designed to minimize irritation from shaving.

— Foil. In foil shavers, the blades do not rotate, but vibrate finely under the foil with small cells. This design is considered more gentle compared to the rotary, because foil reduces irritation and reduces the risk of cuts. However, in terms of shaving cleanliness, foil models, especially low-cost ones, can be noticeably inferior to rotary ones, and they are worse for wet shaving.

— Shaver (travel). Compact and lightweight electric shavers, free from extra attachments and trimming blades for longer stubble, are intended for a close and smooth shave. These shavers, often termed "safety razors," are favored in professional barbershops and are even nicknamed "road razors" for their ability to provide a shave without the need for foam or other products. W...ith their mesh head design, they can trim bristles to an almost bare minimum (around 0.1 mm). These razors are effective for facial shaving, refining beard and mustache outlines, and even edging hairstyling. They excel at handling short hair but might struggle with long and coarse growth. These razors are commonly used for defining haircuts and shaping sideburns and whiskers.

— Shaving trimmer. Shaving trimmers usually have a small head with cutting elements that allow you to precisely remove hairs or shape them into the desired shape. During operation, the hair is cut with the trimmer knives flush with the skin, and some models allow you to set the desired cutting height. Trimmers are good for creating contours of a beard and mustache, trimming eyebrows, sideburns or any other “vegetation” on the face. Some models can be equipped with attachments to change the shaving width or height.

The number of individual shaving heads (for rotary models) or foils (see "Type") in the shaver design. More heads/foils allow for more coverage and a better shave. Note that rotary shavers traditionally have at least 2 heads, but there can be one foil. The most popular are 3 head/foil models.

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.