ZAGI 400 X ELECTRIC, Инструкция по сборке

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page 18
Battery Life and Power Management
Battery life is a determined by two main factors; charging and discharging. Both of
these functions produce heat. Warm is okay, hot isn’t. A hot battery has either been
charged or discharged too fast. First, charging. Make sure that the charger is designed
to charge the number of cells being charged. The best type of charger is the peak detec-
tor type. These chargers will charge the battery to peak at a pre-selected rate then drops
to a trickle. Chargers with timers will often over charge batteries causing excessive heat.
Manufacturers recommend charging batteries at the rated capacity
i.e. , a 500 mAh battery
should be charged for one hour at 500 mAh. The exception to this is the batteries with the
letter “R” at the end of the designation (500AR, or 2000SCR). The “R” means rapid
charge and discharge. “R” cells are either very expensive or not available. Hobbyists are
notorious battery abusers. Batteries that are not designed for rapid charge are routinely
over charged by charging and discharging them too fast. NiCad cells have a finite number
of cycles. Abuse will decrease the number of cycles. Electric flight hobbyists are willing
to accept the shortened life of the batteries for performance. There are ways to cut these
losses. Don’t charge at a rate more than twice the designated capacity of the battery.
Don’t charge a hot battery. Get enough batteries to fly one, cool one, and charge one. A
way to speed up the cycle is to make a 12 volt field battery cooler. Tape a 12 VDC muf-
fin fan to a 6 inch length of 2 inch PVC pipe.
(See Figure 19) The Muffin fan is avail-
able at Radio Shack or find an old computer power supply fan (but make sure it’s de-
signed for 12 VDC and not 110 VAC).
Figure 20
Discharging the battery at the rate of 10 to 15 amps is the other way electric flight hobby-
ists abuse batteries. These high discharge rates produce heat. Again there are ways to cut
your losses. Airflow over the battery during flight will help. Vent holes in the cowling is a
good idea. But more important is the throttle settings during the flight. Full bore for the
entire flight is definitely too hot. Try some throttle off time and some half throttle time.
This will extend the flight time and battery life.
Air
flow
12
12
12
12
12
12
12
12
12
6” Piece of 2” PVC plumbing pipe Battery Muffin fan
12 VDC