Documentation

Overview

The SHILLEHTEK 1x 18650 Battery Holder Box is a compact, single-cell plastic enclosure designed to hold one standard 18650 lithium-ion cell. It features pre-attached red (+) and black (-) silicone-jacketed lead wires roughly 150 mm long, making it ready to drop into any project that needs a portable 3.7 V power source. The body measures approximately 75 x 21 x 18 mm and uses spring-loaded contacts at both ends to grip the cell firmly without the need for soldering tabs.

This holder is intentionally simple: there is no on/off switch, no protection circuitry, and no cover. It is a passive mechanical mount for your battery, intended for makers, prototypers, and DIY electronics enthusiasts who want quick, swappable single-cell power for boards like the ESP32, Arduino, Raspberry Pi Pico, LoRa nodes, sensor loggers, or small flashlights.

Because the holder has no built-in protection, you should always pair it with a matching 1S BMS or TP4056-style charge/protect module for charging and over-discharge protection. SHILLEHTEK stocks compatible 1S BMS and TP4056 modules sized exactly for this holder's output current range.

At a Glance

Specifications

Wiring Guide

Code Examples

The snippets below read the pack voltage through an analog input and a resistor divider (e.g. 100 kΩ over 100 kΩ), so a 4.2 V cell shows up as ~2.1 V at the ADC pin - safely within range.

const int VBAT_PIN = A0;
const float DIVIDER = 2.0;   // 100k / 100k -> gain of 2
const float VREF    = 5.0;   // change to 3.3 for 3V3 boards

void setup() {
  Serial.begin(115200);
  analogReference(DEFAULT);
}

void loop() {
  int raw = analogRead(VBAT_PIN);
  float vAdc = raw * (VREF / 1023.0);
  float vBat = vAdc * DIVIDER;
  Serial.print("Battery: ");
  Serial.print(vBat, 2);
  Serial.println(" V");
  delay(1000);
}

#define VBAT_PIN  34
const float DIVIDER = 2.0;
const float VREF    = 3.3;

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);          // 0..4095
  analogSetAttenuation(ADC_11db);    // 0..~3.3 V
}

void loop() {
  int raw = analogRead(VBAT_PIN);
  float vAdc = raw * (VREF / 4095.0);
  float vBat = vAdc * DIVIDER;
  Serial.printf("VBAT = %.2f V\n", vBat);
  delay(1000);
}

from machine import ADC, Pin
import time

vbat = ADC(Pin(26))   # GP26 = ADC0
DIVIDER = 2.0
VREF    = 3.3

while True:
    raw  = vbat.read_u16()
    vadc = raw * VREF / 65535
    vpack = vadc * DIVIDER
    print("VBAT = {:.2f} V".format(vpack))
    time.sleep(1)

Frequently Asked Questions