Comparison Braun Series 3 3020s vs Panasonic ES-RT37

— 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).

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.

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

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.