CORE Sensor Battery Life
The battery life of your CORE sensor depends on how often it is being used and whether Standby Mode is enabled.
- During continuous use: If you wear the sensor and use it continuously for training, the battery typically lasts around 5–6 days on a full charge.
- When Standby Mode is enabled: Standby Mode is turned on by default in the sensor settings. When the sensor is removed from your body and remains inactive for approximately 20 minutes, it automatically enters a low-power state to conserve battery. In this mode, the battery can last up to 25–30 days, depending on usage.
Think of it this way: when the sensor is actively measuring your body temperature, it uses more power. When you are not wearing it and it enters Standby Mode, it uses much less power. Therefore, the battery will drain faster if you use the sensor continuously than if you leave it in Standby Mode between training sessions.
Important to note: Battery life varies depending on usage. If you use the sensor regularly for training, you should expect to recharge it more frequently than if you use it only occasionally. We recommend charging the sensor regularly and syncing your data daily, especially if you cannot charge it frequently. Any unsynced data will be lost if the battery runs out completely.
Charging
CORE App and CORE Sensor information
In the sensor settings section of the CORE App, the on-screen information will show the battery charge, whether it is connected to a heart rate monitor and if it is downloading data.
The battery level shown in the CORE App should not be fully relied upon when charging the sensor. Due to the current flowing through the circuit, this will be marginally higher that the actual level.
Battery indicator when charging
Battery indicator not charging
Charging the CORE sensor
The CORE sensor uses a non-replaceable rechargeable battery. It is supplied with a magnetic charging cable (USB-A for CORE 1 and USB-C for CORE 2) that can be plugged into standard USB outlets (on a computer or wall-socket / power point). Recharging typically takes about 3-4 hours depending on level of initial charge, charger and age of battery.
Please take care with the charging cable, unplug it when not in use and avoid the magnetic contacts from connecting to metal items, causing a potential short-circuit.
Please make sure the charging cable pins are properly moving/spring loaded, clean and free of debris. Please also make sure the golden pins on the CORE device are clean and undamaged. You can use alcohol to clean them.
In general, USB power banks will not work for recharging. The CORE sensor draws such a small current, it may be too little to trigger / wake-up the power bank. The same can also apply to some mobile phone chargers and "smart" plugs whereby they don't recognise an attached CORE and subsequently turn themselves off.
Charging indicator
CORE 1 - Depending on level of charge, the sensor may require up to 10 minutes before the green LED starts flashing to indicate charging is underway. When fully charged the LED will switch off
CORE 2 - A red LED will turn on shortly after connecting the sensor to the charging cable. This LED will turn off when the sensor is fully charged.
To preserve the battery life, it is recommended to recharge before the battery is completely empty.
Make sure the ambient temperature is between 15-30 °C. CORE has in-built safety charge protection that disables the charging circuit if the battery temperature is too low or too high.
Standby Battery Mode
By default, the CORE sensor has standby mode activated. This means CORE will automatically enter a low power state after it has not been worn for 20 minutes.
During standby mode, all data communication is disabled.
Standby mode can extend the time between recharges to up to 1 month though this will depend how often the CORE sensor is used.
Wake your CORE from standby mode by shaking the CORE, connecting it to a charger, or resetting it.
Note that switching off standby mode will significantly reduce battery life to around 5-6 days as the sensor is permanently recording data, irrespective of whether it is being worn or not.
Understanding the sensor LED
LED Behaviour
When the CORE sensor is shaken or connects, the green LED light blinks to provide indications for:
- Battery level and heart rate monitor detected
- Charging Status
- CORE connects to a paired device (4x rapid blink)
- CORE App downloading data (continual fast blinking)
- CORE sensor reset
LED - Battery Level
When you shake your CORE to wake it from standby, the LED indicates how much battery is left.
| LED behaviour | Meaning | Residual capacity | Operating time left | Standby time left |
| 3x short blink | Critical | <10% | Less than 12 hours | Less than 1 day |
| 1x longer blink | Low | 10%–25% | > 12 hours | 1–5 days |
| 2x longer blink | OK | 25%–50% | > 36 hours | > 1 week |
| 3x longer blink | Full | >50 % | > 72 hours | > 2 weeks |
LED - Heart Rate Monitor connection
Following the battery status, the CORE sensor will also blink (for 2 minutes) to indicate if a heart rate monitor is currently paired. This is important as a heart rate monitor is recommended for sports-use to increase the level of accuracy:
- No Heart Rate Monitor detected: single blink every 2 seconds (everyday living mode)
- Heat Rate Monitor connected: double blink every 2 seconds (sports mode)
LED - Charging & Connection Status - CORE 2
- Currently Charging: Red LED on
- Charge complete: Red LED off
- Connected to USB: Blinks 5x long.
- CORE app connects to CORE: Blinks 4x within 1 second
- CORE App Reset: Short blink followed by battery level
LED - Charging & Connection Status - CORE 1
- Currently Charging (only CORE1): LED blinks 1 second on and 1 second off
- Charge complete: LED off
- Connected to USB: Blinks 5x 1 second on and 1 second off
- CORE app connects to CORE: Blinks 4x within 1 second
- CORE App Reset: Short blink followed by battery level
Disposal and Safety
CORE and battery disposal
The CORE sensor and the battery has a lifespan that is impacted by the level of care and charging. The battery life will naturally degrade over time and at the end of the lifetime, the complete CORE sensor can be disposed of in battery recycling.
Battery Safety Instructions
The following precautions are necessary to ensure safety when using and storing the CORE sensor:
- replacement of the battery with an incorrect type that can defeat a safeguard (for example, in the case of some lithium battery types);
- disposal of a battery into fire or a hot oven, or mechanically crushing or cutting of a battery, that can result in an explosion;
- leaving a battery in an extremely high temperature surrounding environment that can result in an explosion or the leakage of flammable liquid or gas; and
- a battery subjected to extremely low air pressure that may result in an explosion or the leakage of flammable liquid or gas.