DIY: Nanjiren NJR-228 Shaver Review & Performance

If you're interested in the Nanjiren (南极人) NJR-228 shaver, feel free to check out this article.

Next, let's take a look at the process of disassembling this shaver and the materials used in its construction.

Here is an overall image of the Nanjiren NJR-228 shaver:

The back of the shaver is shown in the image below, which indicates the charging voltage, current, and event limits. The input voltage is 5V, and the input current is 200mA.

The foil of the shaver head is shown below. Philips' Type 5 battery can last for several years without needing replacement.

Here is an image of the inside of the shaver head:

When disassembling the main body of the shaver, the charging battery specifications are similar to the 14500 lithium battery.

The factory voltage is 3.9V.

The internal chip part of the main body is as follows:

The core chip is the CXWIC CX3358, a motor driver chip for electric shavers, integrating both a lithium battery charging IC and motor drive functionality.

Here are the details about this chip:

Overview: The CX3358 is a dedicated chip that integrates a single-cell lithium battery charging management function and button detection for motor drive applications. The charging current can be adjusted by modifying external resistors, and the chip has two built-in button control modes. The CX3358 includes protections such as input over-voltage, overcharge, over-temperature, battery under-voltage, motor stall, and short circuit. It also has a built-in battery low-voltage indicator. The CX3358 is a minimalistic, high-performance, and reliable single-cell lithium battery motor drive chip.

Features:

· Input working voltage: DC 5.0V ±0.5V

· Input over-voltage protection: ≥ DC 6.2V

· Static power consumption: < 2uA

· Programmable charging current up to 800mA

· Constant voltage, constant current charging with maximum current set for non-overheating conditions

· Preset charging voltage of 4.20V with +1% precision

· Charging current monitoring output for battery capacity detection

· Charging and operating status indicator pins

· 0.1C charging termination

· 3.0V trickle charge version

· Dual-button control selection

· Supports 0V battery charging

· Supports charging and discharging simultaneously

· Extremely simple application circuit

· Short-circuit protection, overheat protection, input over-voltage protection, battery under-voltage protection, and motor stall protection

· Package: ESOP-8L

Overall, this shaver provides a gentle shave with sufficient battery power for long-lasting use. It’s also designed for comfort. The remaining factors to consider are how long the blade, foil, and battery will last.