Gary Seven
Rocketman
Hey everyone. I'd like to get some feedback on what I'm missing here in terms of my understanding of LiPo batteries, especially brand new ones and how they behave. Some background:
Completed my first quadcopter build (F450 with DJI E300) a couple of weeks ago. In anticipation, I bought two Turnigy MulitStar 4000 mAh 3S 11.1V 10C and two Zippy Flightmax 4000 mAh 3S 11.1V 20C.
With the two Mulitstars I decided (mistakenly) to just use them in the just shipped state (ie, I guess about 60% charged) to do my first preliminary power tests in my yard. Nothing strenuous or fancy, mostly hovering and a little easy climbing. I ran the batteries down to around 3.5V/cell and put them on my Imax B6 charger. I was stunned to see that each battery took 4000mA on the recharge. So once charged, I attached my little "LiPo battery voltage tester/alarm", set the alarm for 3.6V, and again proceeded to do some easy flight testing, both in GPS and and ATTi modes. When the alarm starting beeping continuously (ie, even when I wasn't putting heavy loading on the motors), I brought the craft down. After allowing for about a 1/2 hour battery cool-down, I measure them and see the cells over 3.6V (around, 3.65 to 3.7V). Go to the charger, and they again take in what I consider a lot of mA....about 3800 to 3850.
Am I doing this wrong? Should I set my alarm for say, 3.7V? Do new LiPo's show this behavior until they "degrade" down to their nominal, stated mAh numbers?
Just ran my fully charged Flightmax battery today (for the first time) doing a lot of flying and lot's of vertical acceleration. I set the voltage alarm at 3.6V, and when it went off I immediately landed. After 20 min. or so I took a reading and each cell was at around 3.7 to 3.73 volts. Put it on the charger and it took 4200 mA!! Again folks, what am I missing here?
TIA to everyone who can throw some pearls of wisdom my way. ;-)
Completed my first quadcopter build (F450 with DJI E300) a couple of weeks ago. In anticipation, I bought two Turnigy MulitStar 4000 mAh 3S 11.1V 10C and two Zippy Flightmax 4000 mAh 3S 11.1V 20C.
With the two Mulitstars I decided (mistakenly) to just use them in the just shipped state (ie, I guess about 60% charged) to do my first preliminary power tests in my yard. Nothing strenuous or fancy, mostly hovering and a little easy climbing. I ran the batteries down to around 3.5V/cell and put them on my Imax B6 charger. I was stunned to see that each battery took 4000mA on the recharge. So once charged, I attached my little "LiPo battery voltage tester/alarm", set the alarm for 3.6V, and again proceeded to do some easy flight testing, both in GPS and and ATTi modes. When the alarm starting beeping continuously (ie, even when I wasn't putting heavy loading on the motors), I brought the craft down. After allowing for about a 1/2 hour battery cool-down, I measure them and see the cells over 3.6V (around, 3.65 to 3.7V). Go to the charger, and they again take in what I consider a lot of mA....about 3800 to 3850.
Am I doing this wrong? Should I set my alarm for say, 3.7V? Do new LiPo's show this behavior until they "degrade" down to their nominal, stated mAh numbers?
Just ran my fully charged Flightmax battery today (for the first time) doing a lot of flying and lot's of vertical acceleration. I set the voltage alarm at 3.6V, and when it went off I immediately landed. After 20 min. or so I took a reading and each cell was at around 3.7 to 3.73 volts. Put it on the charger and it took 4200 mA!! Again folks, what am I missing here?
TIA to everyone who can throw some pearls of wisdom my way. ;-)