dknovick
Posts: 727
Joined: 1/19/2005
From: Albuquerque,
NM, USA
Status: offline
|
quote:
ORIGINAL: dodgemcopter
...it is possable each one has been discharged to far as each one has seen close to 100 flights (2x CX2's and the FP). Not game enough to use the 20c as this caused probs with one of the CX2"s, my guess is it will fry something in the 4in1,
It's possible that the batteries are on their last legs. The 7.4A 20C shouldn't cause any more problems then your other batteries (unless there's something wrong with the battery). The 'C' rating is the maximum current the battery can supply. So, for your 800mAh battery, the 20C can supply a maximum 20*800 = 16000 mA (16A). You draw current from a battery, the battery will NOT supply it's maximum current. So in this case if your bird only takes 10A to fly, that's all it will get.
You size the battery for the load. In the previous example, you would want to get a battery that could supply 10A or more (more for a safety factor). If you where using a 10C battery, it could only supply 10*800 = 8000mA (8A), and you would be "starving" your electronics and motors.
Get it?
quote:
ORIGINAL: dodgemcopter
What voltage should they read after full charge and min discharge? Ill check next time I fly. It come with a 8.4v so if new batteries are called for am I better off going for same v but higher capacity and what will mostlikely be the downfalls of higher v and discharge rate?.......
The lipo cell voltage range:
Dead = 3.0V (going below can damage the cell)
nominal = 3.7V
fully charged = 4.2V
So a 2S pack has a nominal voltage of 2*3.7 = 7.4V
Higher voltage (11.1V lipo) may burn out the MOSFET controlling the main motor (however, some have burned it out @ 7.4V). Many people fly w/ 11.1V without any problems (myself included). If you don't chop the throttle just before you crash, stalling the main motor may burn out the MOSFET used to drive it. I can recommend a replacement (or fix it), if you do go to a higher voltage.
Larger capacity means longer flight times, but you have to carry more weight. So there's a trade off, you can't put a huge battery on board, or you won't be able to take off 
_____________________________
What goes up, most come down. How hard depends on you!
|
Printable Version
All Forums >> RC Helicopters >> Electric RC Helis >> Walkera Helis - Dragonfly, etc.. >> RE: Walkera #4 Fixed Pitch Helicopter Forum 
RE: Walkera #4 Fix... - 
.......the batt's still get the 