In battery management systems, a common question arises: how can thin sampling wires handle voltage monitoring for large-capacity cells without issues? The answer lies in the fundamental design of ​​Battery Management System (BMS)​​ technology. Sampling wires are dedicated to voltage acquisition, not power transmission, similar to using a multimeter to measure battery voltage by contacting terminals.

For a 20-series battery pack, the sampling harness typically has 21 wires (20 positives + 1 common negative). Each adjacent pair measures a single cell’s voltage. This process isn’t active measurement but a passive signal transmission channel. The core principle involves high input impedance, drawing minimal current—typically microamperes (μA)—which is negligible compared to cell capacity. According to Ohm’s Law, with μA-level currents and wire resistance of a few ohms, voltage drop is merely microvolts (μV), ensuring accuracy without affecting performance.

However, proper installation is critical. Incorrect wiring—like reverse or cross-connections—can cause voltage errors, leading to ​​BMS protection​​ misjudgment (e.g., false over/under-voltage triggers). Severe cases may expose wires to high voltages, causing overheating, melting, or ​​BMS​​ circuit damage. Always verify the wiring sequence before connecting the ​​BMS​​ to prevent these risks. Thus, thin wires are sufficient for voltage sampling due to low current demands, but precision installation ensures reliability.

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