Although they are encased in metal and are safe to be used in everyday devices (phones, laptops. etc.) lithium-ion batteries have a high energy density and must, like all batteries, be treated with care to ensure proper operation and a long lifespan.
- Avoid discharging below 3.0 V/cell (12.0 V) and never below 2.5V/cell (10.0 V)
- Never charge over 4.20 V/cell (16.8 V)
- Do not puncture, crush, cut, or disassemble
- Do not burn or expose to temperatures above 60°C (140°F)
- Always use a lithium-ion compatible balance charger
- Do not leave unattended while charging
- Do not exceed maximum charge (20 A) or discharge (90 A*) rate
- Do not pick up by discharge leads, always handle by gripping battery body.
*See Discharging section below for more information.
Additional Lithium-ion Safety Information
Always use a lithium-ion compatible balance charger when charging, attempting to use another type of charger will damage the battery. Make sure to keep it away from flammable materials and monitor the battery as it charges, discontinue charging if it becomes hot or changes in appearance.
This battery can be safely charged at up to 20 A, which will bring it back up to full charge in about one hour. However, we recommend charging at 10-15 A (about two hours) at most regularly, in order to maximize capacity and lifespan. We recommend balancing the battery at every charge to keep all cells at the same level of charge, but this can also be done every few cycles if quick charging is a priority.
Our Lithium Battery Charger is recommended for use with this battery.
Once charged, connect the XT90 discharge plug to your vehicle, and the battery is ready to use. The battery can sustain a constant discharge of up to 90A, and up to 132A in short bursts of a few seconds. Make sure to never short the battery discharge plug or plug it into a circuit that may be shorted.
Note that the maximum safe discharge rating is dependent on adequate cooling to keep the battery below 60°C. If used in an enclosed space without airflow, constant current draw must be decreased appropriately to to keep the battery at a safe temperature. For example, in a BlueROV2 we recommend keeping full throttle thruster bursts at 100% gain to no more than 30 seconds each to keep the battery at a safe temperature and allow it to cool.
Temperature can be monitored on the R2 version of the battery with the integrated 3435K negative temperature coefficient (NTC) thermistor, which has a resistance of 10kΩ at 25°C.
Charge will be lost over time when the battery is stored, and care must be taken to ensure long term storage does not damage the battery. Storage temperature should always be below 60°C (140°F), and the lower, the better. Ideally, the battery should be stored at about 50% charge, or 3.7V/cell (14.8V). It should be periodically checked and charged to keep each cell above the 2.5V minimum. Short term storage at full charge is fine, and a couple days of storage at 100% charge will yield about 90-95% of a full charge.
Additional Lithium-ion Storage Information
Blue Robotics Forums – Batteries and Chargers