It seems like most Phantomers are really careful about charging their battery when they can watch it, not leaving it charged, etc. I just charged my first one, placing it on a completely non-flammable surface, watching very carefully to see if it heated up or did anything else strange. It didn't (stayed cooler than most lithium batteries I'm familiar with, in fact). Then it struck me "isn't this thing pretty much a laptop battery?" The ratings are very comparable (the Phantom 3 battery is 68 watt-hours, 4480 mAh 15.2 volts, while laptop batteries range from about 50 to 99 watt-hours, and they are all in the 15-20 volt, 3000-6000 mAh range), and the chemistry seems to be as well (modern laptop batteries are broadly described as LiPo, just like the Phantom battery). The only odd thing about it is the very high maximum discharge rate (it can give up all of its juice in 20 minutes, which is normal for an RC battery, but much faster than any other application I'm aware of, except some large video lights ).
Given the description of what the battery does (monitoring charge rate, automatically balancing, monitoring remaining charge), it seems to be essentially a modern laptop battery (which is just a larger version of the smart battery in a digital camera). The charger is dumb, because the battery itself contains the important circuitry, which is also why it's a $150 battery.
Even the Pro's 100 watt charger is not an extremely high rate charger for a battery of that size - plenty of workstation-class laptops use chargers in the 130-180 watt range for batteries only a little bigger, and 300 watt chargers are not unheard of on big gaming laptops. The 100 W Phantom charger has a charge rate only a little over 1C - again, solidly in the range of a high-performance laptop charger. Some big RC chargers put out 1000 watts, divided among several batteries, and can charge at rates up to 5C or so (people ARE very careful with these chargers, and probably rightfully so)
The charging procedures people are describing are FAR more careful than anyone uses with laptop batteries, camera batteries, broadcast camcorder batteries two or three times the size, or frankly even the MUCH larger LiPo battery in my electric car(not a model car - I drive a Chevy Volt with a battery that holds 16.5 kWh of energy, approximately 250 Phantom batteries)! I walk away from my charging Volt all the time, and come back and get the car hours later, and it doesn't catch fire.Who doesn't leave their laptop plugged in overnight? Who hasn't left a camera battery on the charger for a week?
I can think of a couple of reasons for this abundance of caution, and I'd love to know which one's right...
1.) There's something odd about the Phantom's batteries that gives them their high discharge rate, and they really are more sensitive than garden-variety rechargeable lithiums.
2. )People coming from an RC background are used to dealing with "dumb" batteries and chargers, along with extremely high charge rates, which are much less forgiving than modern smart batteries.
3.) Since they only last 20 minutes on a charge (and may get charged and flown several times in a day), people are babying them more than they do laptop batteries - trying to squeeze out extra cycles.
4.) Due to the high discharge rate, they get fewer cycles in a lifetime than ordinary laptop batteries, and people are charging them extra-carefully to try and get extra cycles.
5.) The battery caution comes from previous versions of the Phantom, which may not have used smart batteries.
Of course, if it really is a laptop-style smart battery, it will cut off the charge current when it's full, and you can't hurt it by leaving the darn thing on the charger. You might get a few extra cycles out of it by charging at 0.7C with the P3A charger instead of 1.2C with the P3P charger, but that's about it - smart batteries take care of their own charging.
Similarly, smart batteries don't catch fire under ordinary circumstances. Charging a smart battery at 1C is not going to harm any ordinary, safe piece of furniture (and a smart battery won't let you charge it at "heat up" rates). When I felt mine, the battery didn't get hot at all (far less than my laptop or my iPhone), while the charger itself got about as hot as a laptop charger, which is safe on wooden furniture, or even on a rug or a couch, but perhaps not wrapped in very light drapes, tucked under the covers or sitting on a crate of 20 year old dynamite.
Am I missing something here?
Dan
Given the description of what the battery does (monitoring charge rate, automatically balancing, monitoring remaining charge), it seems to be essentially a modern laptop battery (which is just a larger version of the smart battery in a digital camera). The charger is dumb, because the battery itself contains the important circuitry, which is also why it's a $150 battery.
Even the Pro's 100 watt charger is not an extremely high rate charger for a battery of that size - plenty of workstation-class laptops use chargers in the 130-180 watt range for batteries only a little bigger, and 300 watt chargers are not unheard of on big gaming laptops. The 100 W Phantom charger has a charge rate only a little over 1C - again, solidly in the range of a high-performance laptop charger. Some big RC chargers put out 1000 watts, divided among several batteries, and can charge at rates up to 5C or so (people ARE very careful with these chargers, and probably rightfully so)
The charging procedures people are describing are FAR more careful than anyone uses with laptop batteries, camera batteries, broadcast camcorder batteries two or three times the size, or frankly even the MUCH larger LiPo battery in my electric car(not a model car - I drive a Chevy Volt with a battery that holds 16.5 kWh of energy, approximately 250 Phantom batteries)! I walk away from my charging Volt all the time, and come back and get the car hours later, and it doesn't catch fire.Who doesn't leave their laptop plugged in overnight? Who hasn't left a camera battery on the charger for a week?
I can think of a couple of reasons for this abundance of caution, and I'd love to know which one's right...
1.) There's something odd about the Phantom's batteries that gives them their high discharge rate, and they really are more sensitive than garden-variety rechargeable lithiums.
2. )People coming from an RC background are used to dealing with "dumb" batteries and chargers, along with extremely high charge rates, which are much less forgiving than modern smart batteries.
3.) Since they only last 20 minutes on a charge (and may get charged and flown several times in a day), people are babying them more than they do laptop batteries - trying to squeeze out extra cycles.
4.) Due to the high discharge rate, they get fewer cycles in a lifetime than ordinary laptop batteries, and people are charging them extra-carefully to try and get extra cycles.
5.) The battery caution comes from previous versions of the Phantom, which may not have used smart batteries.
Of course, if it really is a laptop-style smart battery, it will cut off the charge current when it's full, and you can't hurt it by leaving the darn thing on the charger. You might get a few extra cycles out of it by charging at 0.7C with the P3A charger instead of 1.2C with the P3P charger, but that's about it - smart batteries take care of their own charging.
Similarly, smart batteries don't catch fire under ordinary circumstances. Charging a smart battery at 1C is not going to harm any ordinary, safe piece of furniture (and a smart battery won't let you charge it at "heat up" rates). When I felt mine, the battery didn't get hot at all (far less than my laptop or my iPhone), while the charger itself got about as hot as a laptop charger, which is safe on wooden furniture, or even on a rug or a couch, but perhaps not wrapped in very light drapes, tucked under the covers or sitting on a crate of 20 year old dynamite.
Am I missing something here?
Dan