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> a DIY hobbyist/quadcopter battery such as you might see if you bought a 6s 4000mAH lipo for a 8" FPV quadcopter. 6S 4000mAhr is getting seriously into "do no

> a DIY hobbyist/quadcopter battery such as you might see if you bought a 6s 4000mAH lipo for a 8" FPV quadcopter. 6S 4000mAhr is getting seriously into "do not fuck around with this" territory. they deserve to be treated like and equivalent weight of gasoline. My quadcopters these days are mostly small to tiny. (It's been years since I flew anything above the 250g size that changes the rules here.) In the past, I've flown medium/big hexa and octocopters with 7S 5800mAhr batteries (two of them on the big Octo) Those batteries never came in my house. They are stored and charged in a besser block and concrete tile enclosure in my garage which has a direct metal vent pipe to the outside. They get transported in the car in an ammo can half full of sand, never more than two in the one can. I've only once ever had one of those go off on me - in an ammo can while charging it at the field. Burying it with sand didn't put it out - it just happily burned away and got hot enough to distort the ammo can. I do not ever want that to happen anywhere near anything flammable that I care about. I still have 4 of those big packs, I use them on an electric bicycle. I kinda hope that if I ever get mown down in traffic while riding it, it'll set fire to the car that nailed me... I'm much less safety-nazi with my smaller lips batteries though. I store and charge 3 and 4S batteries in the 500 - 2200 mAhr range in my office - in metal tins with small-sh vent holes and watchable lids. I mistreat those batteries somewhat - my fastest quad can draw ~120A at full throttle on a fresh off charge pack (note that you do that for long, it's pretty much vanished straight up in about a second and a half when you do that. It's pretty much impossible to fly that one LOS, without the goggles I'd just lose it instantly.)

Dylan16807 5y ago
> 6S 4000mAhr is getting seriously into "do not fuck around with this" territory. they deserve to be treated like and equivalent weight of gasoline. I will note that your average laptop has a battery between half that size and matching that size.
- walrus01 5y ago
  serious professional UAS pilots who fly with large collections of batteries specifically choose battery packs that are approximately 99Wh per pack, which fits within common IATA requirements for carry on luggage. on really big UAS such as for cinematic filming purposes these will commonly be connected in series for a 12S string. An interesting loophole which is applied differently, by different airlines, is that you can have multiples of 99 watt hour battery packs individually carried into the cabin, as long as they are discrete units. another interesting note is that a number of $2000-3000 (USD) gaming laptops are also equipped with 99Wh nominally rated battery packs so that they're still legal to take on an airplane. I was recently shopping for a new gaming laptop and ran into this while evaluating the specs of 11th/12th gen Intel series things from the usual Taiwanese vendors (asus, msi) and their ryzen 5xxx based offerings.
- rootusrootus 5y ago
  I trust my laptop battery far more than the LiPos I get for my R/C cars, though. Laptop batteries don't seem to go up in flames nearly as often.
  - walrus01 5y ago
    Laptop batteries are also discharged at a much lower c rate, and are encapsulated much more robustly than a bunch of lipo cells welded together to make a 6s pouch
walrus01 5y ago
> 6S 4000mAhr is getting seriously into "do not fuck around with this" territory. yes indeed. I've recently been involved with the design of some fairly large 18650 and 21700 cell based battery packs for designs that closely approach the manufacturer datasheet rated maximum continuous amp draw per cell. my main message for the people who use these is the following: "any sufficiently advanced battery in serious amount of energy storage, becomes indistinguishable from a bomb or incendiary device, if you look at it from the point of view of watt-hours stored per kilogram of mass"

Dylan16807 5y ago

> 6S 4000mAhr is getting seriously into "do not fuck around with this" territory. they deserve to be treated like and equivalent weight of gasoline. I will note that your average laptop has a battery between half that size and matching that size.

walrus01 5y ago
serious professional UAS pilots who fly with large collections of batteries specifically choose battery packs that are approximately 99Wh per pack, which fits within common IATA requirements for carry on luggage. on really big UAS such as for cinematic filming purposes these will commonly be connected in series for a 12S string. An interesting loophole which is applied differently, by different airlines, is that you can have multiples of 99 watt hour battery packs individually carried into the cabin, as long as they are discrete units. another interesting note is that a number of $2000-3000 (USD) gaming laptops are also equipped with 99Wh nominally rated battery packs so that they're still legal to take on an airplane. I was recently shopping for a new gaming laptop and ran into this while evaluating the specs of 11th/12th gen Intel series things from the usual Taiwanese vendors (asus, msi) and their ryzen 5xxx based offerings.
rootusrootus 5y ago
I trust my laptop battery far more than the LiPos I get for my R/C cars, though. Laptop batteries don't seem to go up in flames nearly as often.
- walrus01 5y ago
  Laptop batteries are also discharged at a much lower c rate, and are encapsulated much more robustly than a bunch of lipo cells welded together to make a 6s pouch

walrus01 5y ago

> 6S 4000mAhr is getting seriously into "do not fuck around with this" territory. yes indeed. I've recently been involved with the design of some fairly large 18650 and 21700 cell based battery packs for designs that closely approach the manufacturer datasheet rated maximum continuous amp draw per cell. my main message for the people who use these is the following: "any sufficiently advanced battery in serious amount of energy storage, becomes indistinguishable from a bomb or incendiary device, if you look at it from the point of view of watt-hours stored per kilogram of mass"