Smart Helmet Controller PCB Rev A

Use a battery system that supplies regulated 5 V—not a bare battery connected directly. Your current board’s J1 input connects straight to its +5 V rail, with a 3 A input design requirement.

Suitable choices

| Battery option | What you need | |---|---| | 5 V USB power bank — simplest option | Choose an output explicitly rated 5 V, 3 A, with a suitable cable/adapter to J1. Power banks are a conventional regulated 5 V battery source. [1] | | Protected single-cell Li-ion/LiPo pack — for an integrated portable unit | Add a 5 V boost converter, appropriate charger, and battery protection. A standard single Li-ion cell varies roughly from 4.2 V down to 3.0 V, so it cannot directly provide the required regulated 5 V. [2] |

My recommendation: start with a 5 V / 3 A power bank for prototyping. This matches the board’s intended supply requirement; it does not establish that the PCB’s current capacity has been validated.

Connect its regulated output to:

• J1 pin 1: +5 V
• J1 pin 2: GND

Important for this board:

• Do not connect a 9 V battery, 7.4 V pack, or 12 V battery directly to J1—it feeds the +5 V rail without an input step-down regulator.
• The present design has no battery charger or battery-protection circuit.
• The GSM connection assumes an external carrier that accepts 5 V; confirm the actual carrier model before powering it.

What battery runtime do you need—approximately 2 hours, 8 hours, or a full day?