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I'm going to build a drone project (no lead batteries) that will only run for 1-2 minutes, but probably at low temperatures (30C-60C C-rate and sometimes -20°C,) so I will need a nickel-cadmium battery or a supercapacitor.

Did I miss anything? What percentage of power will these two types deliver when used in such an intensive mode? How many cycles for NiCd? Are there any other battery types available for this type of application?

JRE
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Eimrine
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    So what are your physical, electrical , mechanical and cost limits? – Tony Stewart EE75 Aug 28 '22 at 18:24
  • All important requirements I have described, other limits seems not important for the sake of question. – Eimrine Aug 28 '22 at 18:29
  • no it depends on specs. "Are there any other battery types available for this type of application?" Yes but can you afford them? – Tony Stewart EE75 Aug 28 '22 at 18:36
  • To make sure we're not missing the obvious here: there is no power available before flight for heating the battery? – polwel Aug 28 '22 at 18:51
  • What power to weight ratio is required? How much power required in the typical case -- expected size, weight, cargo capacity? How will that typical case scale with battery characteristics? (The aeronautical parameters are unimportant, but they control how battery and motor capacity relate to carrying capacity and run time.) – Tim Williams Aug 28 '22 at 18:59
  • We will assume that supercapacitors are the top of what I can afford. Preheating is prohibited. Payload = 1kg in compact version. The shape of the load is drop-shaped, the density is approximately equal to the density of aluminum. The drone must, on command, raise the payload to a height of at least 300m as quickly as possible. After that, the life of the drone does not matter. The life of the drone matters if a "false start" command was sent before reaching a height of 300m - then a soft landing should occur, after which a person will come and replace the battery with a fully charged one. – Eimrine Aug 28 '22 at 19:40
  • You really really do not want to use NiCd batteries anymore. It's not the 80s, we have better technologies with less hazardous materials today. Use NiMH instead. And you get even better power density to boot! You can expect somewhere 20-50% capacity derating at -20° and quite some current derating. – Attila Kinali Aug 28 '22 at 20:05
  • Energy required at 100% efficiency = mgh. So (1kg + drone mass + battery mass) x 9.8 x 300m joule = 300 x kg joule. Assume 25% efficiency as a starting point. = 1200 x kg joules. Lower efficiency quite likely overall. High capacity LiPo RC batteries will deliver 50C (some more). Assume say 5kg all up mass. = 6000 joule +. Assume 30V system. Current = Energy / volts/time = 6000 / 30/ seconds to altitude. 0r 200A/seconds. Quite modest. Sure to be wrong :-). [A 5Ah battery should be fine. See RC model and drone pages for typical performances and lifetimes.] – Russell McMahon Sep 07 '22 at 09:00
  • If you immerse the battery in a water bath in a well insulated container OR "warm" it with circulating water from the water bath in a sleeve , you can achieve a 0 degrees C battery temperature for days at a time with modest volumes of water. With suitable design a battery could be removed from a water bath and installed in a drone in under 10 seconds. || I have recently been doing testing of water bath holdup rates at -25C ambient and have been pleasantly surprised how long I can achieve with a few litres of water and maybe 30mm thick insulation. (Theory and practice are not too far apart.) – Russell McMahon Aug 16 '23 at 12:19
  • @Eimrine My application was non military BUT did involve experiments which resembled your application close enough to be useful. I used a large chest freezer to provide the -25C environment. – Russell McMahon Aug 16 '23 at 12:21

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