Comparison Panasonic ES-GA21 vs Panasonic ES-8813

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.

Model of replacement head(s) compatible with electric shaver. This data will be useful primarily when looking for spare nozzles.

— 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.

Type of power source used by the shaver:

— Mains. The shaver is typically powered by a household supply of 230 V, though other voltage variations are possible. When connected to this power supply, users don't need to worry about limited device operating time since the razor operates as long as there's mains voltage. This eliminates the concern of battery depletion. However, these razors rely on a power source and the cord can restrict movement. Modern models sometimes feature a hybrid system combining mains and battery power for greater flexibility.

— Battery. The shaver operates using its internal battery, offering maximum autonomy without needing an external power source. This design provides freedom of movement by eliminating the need for a mains cable. However, the battery's lifespan is finite, requiring periodic recharging. Inexpensive models lacking charge level indicators during use might pose a risk of running out of power unexpectedly, such as mid-shave, necessitating a recharge wait.

— Batteries. The shaver is powered by replaceable elements (batteries). Such devices, in their advantages and disadvantages, are in many ways similar to rechargeable ones: on the one hand, they are autonomous, on the other, the operating time is limited. The main difference is that a “dead” battery can be easily replaced if...you have spare ones with you; the built-in battery does not provide replacement, and the only option is charging, often quite long.

— From the cigarette lighter. Power supply from the car's on-board network through the cigarette lighter plug (or a separate auto socket of the same size). Shavers with this power supply can be charged and/or used directly in the car, which can be useful for those who spend a lot of time behind the wheel.

— 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.

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.

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.