[jruiz]

There's alot of misinformation in this thread, some of which would at the minimum give you an unpleasant day on the water or at it's worst cause death or harm.

1. Lipo is a reference to the use of a polymer base electrolyte as oppose to a liquid base system + separator. It's inherently safer. Reason being it removes flammable liquid electrolyte from the equation. It does NOT charge at a different voltage.

2. All lithium metal oxide chemistry type cells charge to 4.2-4.1 volts. Lithium iron phophate charges to 3.6. What Harry is probably seeing on his rc batteries are the operating voltages per cell, not the charge voltage. He's probably mistaking 4.7 for 3.7. Charging to 4.7 WILL definitely cause a fire. Charging to 3.3 will probably discharge the cell.

3. Class D fire extinguisher is only needed for metal fires. These are group 1 or 2 elements like lithium, sodium, magnesium, and calcium. This applies only in their pure form. Lithium metal does not exist in lithium ion or lipo batteries. Lithium metal does occur in non-rechargeable lithium batteries. Most of the fire from a lithium ion battery is the electrolyte, hence why a class B extinguisher should be used.

I've been involved in research and manufacturing of lithium non-rechargeable batteries for over 10 years. Currently working on non-rechargeable and rechargeable lithium batteries for space applications.