The internal resistance also gradually increases throughout the lifetime of the battery due to chemical decay and accumulated damage from over-discharging. These effects can be minimized by always storing the batteries at 50% charge in a cool place, and by not completely draining the batteries in flight. The Elios 2 smart batteries will automatically discharge to a suitable storage charge when not in use. The first “low battery warning” is shown when the battery reaches 25% remaining capacity. The “battery critical warning” is shown when the battery reaches 10% remaining capacity. However, the drone will immediately show the “battery voltage critical warning” if the voltage drops below 10.4V on Elios 1 and 17.5V on Elios 2.

• The temperature has a direct effect on the internal resistance
• The colder a battery gets, the higher its internal resistance gets and the lower the voltage will be for a given remaining charge
• It is therefore recommended that the batteries are around 20-25°C at the beginning of a flight
• If the temperature is too low then the battery will not be able to sustain flight
• With Elios 2, warnings appear on the cockpit display if the temperature is outside of the allowable range