Rechargeable Batteries in the Hacklab

Rules

Charging:
- DO NOT leave charging batteries unattended.
- DO NOT charge cells/batteries in parallel without balancing circuit
- Multi-cell batteries must be charged using a proper balancing circuit.
- Charging only in the battery charging area in G1.
- Single cells may be charged using simple constant current and constant voltage.
- Battery charging must be contained within an appropriate fireproof battery charging bag.
  - Hacklab owns one such bag, kept in the battery charging area or the battery storage box.
  - If you wish to provide your own safety bag, it must be approved by Hacklab.
Storage:
- Batteries must be stored safely in the designated storage box.
- The terminals must be covered to prevent accidental shorting.

todo: Safety reccomendations for recovered batteries such as the hoverboard 18650 packs.

Safely dismantle and inspect
Check individual cell voltages
Look for parallel-wired cells
If internal balancer circuit is not trustworthy, replace with external balance connector

This is work in progress, do not take it as gospel until completed.

Overheating, fire and explosion risks for lithium batteries:

Risk	Mitigation
Battery Fire	Charging will always occur in suitable fire/heatproof containers
Over-charging	Charging will always be supervised. Users will apply appropriate voltage/current limits according to battery.
Individual cells may be overcharged when connected in series	Balancing circuit will always be used.
Batteries in parallel may not charge at the same rate, or unexpected current may flow between batteries.	Batteries will not be charged in parallel unless they are individually monitored.
Puncture damage	Batteries will be stored in their appliance or in a designated storage box to protect them. The box will be in a visible location. Plastic “hard-shell” batteries will be preferred where there is a risk of puncture in-situ.
High current flows if terminals are shorted	Batteries will be stored with the terminals covered with a cap or electrical tape.
High energy density - general risk	Projects that use high capacity batteries will be fitted with isolator switches and fuses.

The British Radio Car Association and British Model Flying Association both have very good writeups on battery safety and best practice. BRCA also have good documentation on ESC and brushless motor use/safety.

Tim Kerby suggested this RISCAuthority writeup (PDF) as a basis for our Risk Assessment.