Watching whales in the wild ocean is always exciting, but for a real thrill, try watching them through your drone’s camera while it’s 5,000 feet offshore when the battery level suddenly drops like a rock to 29 percent. There’s a real thrill for you; wondering if you will make it back to shore or if this little flight just became the most expensive whale watching trip you’ve ever taken.

With all of the power indicators available to you (in the app, on the controller, and even on the battery itself), it’s easy to forget that there really is no such thing as a battery “gas gauge.” All indications of battery power remaining are just educated guesses constructed from secondary measurements like output voltage, rated capacity, time since charge, amp hours drawn, number of cycles used, ambient temperature, etc. The only real way to know the level of a battery is to start charging it and see what it takes to fill it up. Of course, that’s no help at all while you are flying.

Pro Tip: Whenever you take your drone up, use a freshly charged battery that indicates it is at full capacity. Batteries discharge slowly just sitting in your bag, so even batteries charged just last week will not be at their peak. You want to use batteries charged today or yesterday. Otherwise, the battery may well have less capacity than shown on the indicators. Once you are high in the air or well out over water, the battery indicators will suddenly realize their error and correct themselves, leaving you with not enough power to get your drone home safely. Or, at the very least, high blood pressure.

Battery power is the limiting factor in drone flight time and distance, and once you are out of power, it’s “game over.” So, here are a few tips for getting the most performance out of your batteries:

Treat your batteries with respect. Although we get frustrated with the “limited” flight time provided by modern batteries, they actually hold a tremendous amount of power. If that power is ever released all at once, the result is catastrophic: explosion and fire. Never ever use a battery which shows signs of physical damage, including cracks or puffiness (bloating). Dispose of such batteries immediately and keep them in a fireproof container until you can.

Recognize that your batteries are temperature sensitive. When you aren’t using them, keep your batteries comfortable by storing them between 5C and 25C (41F – 77F). Letting them get too hot or too cold will reduce their power and may damage them permanently. If you are flying in cold weather, you will get a lot less power out of your batteries than you will if flying in warm weather, so be prepared for shorter flights. Also, don’t charge your batteries immediately after flight, when they are still warm. Give them at least half an hour to cool down before charging.

Finally, understand that batteries have a lifespan. Their capacity will decrease over time and they are only good for a certain number of charge/discharge cycles. DJI “intelligent” batteries have electronics built into them to keep track of usage and when they get to the end of their design life, they will simply quit working and require replacement. This is done to keep you (and the people below you) safe; it isn’t a trick to get you to buy more batteries. You can read this information in the DJI Go app to see how your batteries are doing.

Happy flying!