Skip to main content

Powering your board from battery

All Unexpected Maker development boards support powering via single-cell Lithium Polymer batteries with charging capability through USB or external 5V sources.

Battery Connectors by Board​

Different boards offer varying connection options:

  • TinyPICO, TinyS2, TinyS3, TinyC6: JST PH connector footprint (solderable) plus VBAT header pin
  • FeatherS2, FeatherS2 Neo, FeatherS3: JST PH connector on board plus VBAT header pin
  • ProS3: PicoBlade connector plus VBAT header pin
  • TinyPICO Nano, NanoS3: VBAT pin only on carrier boards

The VBAT header connects electrically to the battery connector's positive terminal.

Power Priority & Charging​

When you have a battery connected and you also provide 5V to your board (via USB or an external 5V source into the 5V header pin), the battery will go into charge mode only and the board will only be powered from the 5V source.

The battery powers the board exclusively when no 5V source is present.

Compatible Battery Types​

Lithium Polymer (LiPo)​

Any single-cell LiPo battery will work. Larger capacity means longer runtime but slower charging. Always use batteries with integrated charge protection to prevent permanent damage from over-discharge. This is the recommended option.

Lithium Ion (LiOn)​

Technically possible but not recommended. The onboard charging IC (PMIC) is optimized for 4.2V LiPo maximum, potentially leaving LiOn batteries incompletely charged since they typically require higher voltages.

Nickel Metal Hydride (NiMH)​

Incompatible with the power management IC. Cannot connect to VBAT or the battery connector.

Alkaline AA/AAA​

Never connect to VBAT or the battery connector. They are non-rechargeable and risk hazardous charging if 5V is accidentally applied. These may connect through a 3V3 regulator to the 3V3 pin instead.

Multi-Cell Configurations​

Multiple cells cannot safely connect to VBAT or battery connectors since the PMIC is designed exclusively for single-cell 3.7V nominal (4.2V maximum) LiPo chemistry. However, three alkaline AA batteries in series (4.5V total) can safely connect to the 5V pin.