Yes, for sure NiMh cells generally have lower impedance. But we are
talking about the GP2200 here. I routinely draw around 70-95 amps
from these things in my 10 and 12-cell electrics. A TD plane, fitted
with DS368s will draw a max of what, 5-6 amps?
--Jim
On Mar 8, 2006, at 6:13 PM, Simon Van Leeuwen wrote:
Hi Jim,
The most important specification to consider is the cell impedence.
You might be surprised to discover that cell (larger) surface area
in those bigger NiMH cells still does not make up for lower
impedence within an even smaller NiCD cell.
Add a larger (similar) NiCD cell "and" the lower impendence it
offers and you can actually measure the available voltage
difference at the servo when it is really needed...
Jim Laurel wrote:
True enough, Simon. But if you use large enough NiMh cells, there
is more than enough ability to deliver the kinds of currents we
need. I have always thought it was silly to see people using 4-
cell AA or even AAA NiMh packs in big TD ships, then adding lead
to balance. I always try to get as close as possible to the CG I
want using batteries rather than lead. In the Pike Superior, for
example, I use 4-cell packs of GP2200. WIth a JR R770 up front
and maybe ~3/4 to 1 oz of lead taped to the side of the pack, you
are usually right on the CG. There is no current draw issue with
those GP2200 cells! ;-)
--Jim
On Mar 8, 2006, at 5:40 PM, Simon Van Leeuwen wrote:
In a TX, NiMH offers superior performance given the relatively
low current consumption. On the other hand, NiMH is inferior on
the RX side when current demands are high when compared to NiCD.
Arne Ansper wrote:
Hi!
Must get new battery for TX. Current one is down to 500mAh
(from 750mAh) and lasts only for 2.5 hours. I can get 1100 mAh
NiCd or 1650 mAh NiMH (both Sanyo) at the same price. Which one
is better for TX?
Arne
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