How does a coulomb meter measure current? The working principle of the shunt.

2025-02-05

If relying solely on the voltage curve, like a voltmeter, to estimate battery capacity, inaccuracies often occur in many scenarios, as mentioned in our article "Why are battery monitors divided into voltmeters and coulomb meters?"

A coulomb meter, on the other hand, is different. A coulomb meter kit typically includes a display screen and a shunt. Current measurement is performed by the shunt, which sends analog signals to the display meter.

So, how does the shunt monitor the current?

The shunt contains a sampling resistor. When current flows through the sampling resistor, a voltage difference is generated across its two ends. Based on this voltage difference and the known, fixed value of the sampling resistor, the magnitude of the current passing through at that moment can be calculated. The MCU (microcontroller unit) can then use the integration method, based on current and time, to calculate the charging capacity and discharging capacity.

How to choose the appropriate shunt specification?

Battery Monitor With Shunt

Battery Information Collection Module

Battery Pack Monitor Display

RV Battery Monitor

Golf Cart Battery Monitor

Marine Battery Monitor

Motorcycle Battery Monitor

Forklift Battery Monitor

Wheelchair Battery Monitor

Battery Voltage Monitor

How does a coulomb meter measure current? The working principle of the shunt.

How does a coulomb meter measure current? The working principle of the shunt.