Mark97564
lvl.4
Flight distance : 2067749 ft
United States
Offline
|
I always keep the battery warm inside this heated bag hobby king sells and then put it in my p3 and hover for 3 min or so about 5 ft off the ground and never had an issue.. On 85 degrees F days here all summer I land my p3 with 20 to 25% battery left and I can't squeeze it in my hand for more than a few seconds before it starts to burn me, hottest battery I've ever seen.. I've seen many batteries puff at half its temp, so how DJI does it I'm amazed.. Bottom line, that battery gets hot as hell during normal use so I'm pretty sure even on below 0F days that battery gives off enough heat to keep the inside of the p3 above freezing temps, lol or damn close to it, lol... Plus I set one of my trigger buttons under the p3 remote to bring up and down the battery stats page, so I'm able to easily monitor its temps.. I've had a cold p3 battery fully charged before show 3.55 volts per cell and after 5 min of flight the battery warmed itself up and the voltages went up the rest of the flight and were normal.. Plus the percentage will still reflect mah consumed, so as long as your above 3.55 volts and the percentage battery left still reads a good amount you will be ok. Flying in the cold you need to watch both..
I flew once when it was cold where the battery showed 3.5 volts per cell and I'm sure it was fully charged but I watched the temp of the battery continue to rise slowly and the voltage stayed between 3.5 to 3.55 that entire flight, so I just monitored the percentage remaining and kept flying.. The p3 will have noticeably less power at full throttle and your prolly going to want to avoid full throttle in the cold cuz it could cause the voltage to go way to low and your p3 may experience a brown out and drop out of the sky..
So bottom line, spend the $20 on the Hester battery bag from hobby King, it's located under battery accessories and contro how much throttle you use. If you see any cells voltage go below 3.5 land immediately.. But chances are if you preheat the battery and be nice to the throttle stick and fly slow you won't have an issue.. If you see the voltage drop under 3.5 when on throttle then let off a little and let it go back up, same with your pitch and roll speeds. You can easily monitor cell voltage cuz it's shown next to battery percent remaining if you have it turned on to show it there...if you take off and your cell voltage goes to low during a slow take off land and warm up the battery.. And you must make sure the battery is charged fully in a warm place.. I've learned a cold lipo won't charge right. It will take forever to charge or it will stop when it's 50% charged, so make sure you know it's fully charged before flying in the cold, cuz cell voltage isn't going to tell you how much battery is left like it does in the war,ear months like summer.. It may stay at 3.6 volts the. Entire flight, so use cell voltage just to know if the battery is to cold and to control throttle and speed ya know.. Use the percentage indicator or the battery screen to know how much mah has been used and what's left.. You want to be on the ground with 1200mah left in the cold, in summer you can push it til about 700mah remaining.. Winter will shorten your flights by t least 5 min.. Unless your battery somehow stays real warm and gets hot like normal you may only get 60% of its power when cold, again it depends on how cold.. I flew once when it was -15F and I had to land after about 9 min of flight.. Battery just couldn't give more than 50% that cold.. But I also didn't prewarm it.. I left it sit outside to get cold 45 min b4 flying it, which is a good idea to but keep the battery warm til your ready to fly.. I think the lipo heating bag at hobby King will warm up to 125 degrees F and it needs a 3 cell battery that can put out 4 amps continuos.. My 3 cell 5000mah 25c turnigy packs run it for about an hr or so.. Again depending on how cold the battery running it gets.. If you have room out that battery in the bag too.. Or use a Agm battery to run the heating bag... |
|