Originally Posted by CrimzonRider
Good post as always, Denny.....perfect timing...lol....last night was reading about this in way older posts as I felt I needed a refresher
In your opinon, is this pushing the battery too much???.....
thunder pwr 3s 2250 45/90c pulling approx 43amps(actual 5 flights with this setup) previously batts have around 30 cycles never more than 30amps in the past....kept discharged,....usually charged right before flying....cells have never been below 3.60v unloaded... 1.5c charging
approx. 6 min flight times.....30secs 3/4 to WOT then glide with zero throttle for about a min then 30/WOT,...etc
within a couple mins of landing temp of battery 90.4(using infared thermo)
(inside motor 94.7,esc about 90,cant rembr exactly) physically battery feels warm, little puffing is noticeable, but within few minutes...completely normal looking and nominal temp.
I don't have anything that can tell me exactly how many amps I am actually pulling during flight( more or less...I don't know
)
2.25ah x 45c=101.25amps,.... so I am pulling less than half of max amps on the ground.
Thanks in advance........just trying to get as much life out of a (2) $70 batterys.
cr
I'm not an expert on LiPo's since every one of my models are using those A123 cells.
But, with your setup, C = Amps/Ampere Hours, or 45/2.2. That's C=19.5 a value that should be pretty safe with any decent quality LiPo battery.
The actual current pulled during flight depends on the model type, prop selection, and a lot of other variables. Interesting, even whether the model is level flight, climbing, or diving has a HUGE effect on the current pulled in flight. I've found on a full throttle shallow desent of mayby 30 degrees or so, the current pulled can drop to 20-30% of WOT.
My experience has been that on my models with 16X12 APC-E or 19X12 APC-E props, the full throttle current during level flight is about 80% of the current on the ground.
IMHO, what can really shorten the life of those LiPo or A123 cells is running them until the ESC low voltage cutoff kicks in. Those LiPo cells are always going to have one cell little bit less capable than the others, and that cell can go below safe limits before the ESC LVC kicks in.
As for me, I
never fly more than about 60-70% of the battery Mah during any flight. That allows for go-arounds, people on the field and so on. This way, never totally discharging those $$$$ batteries really reduces the chances of any cell going below safe limits.