------------------
>>>A few years back I did some research into batteries for an underwater
>>>propulsion device and I learned that the number of cycles that you got
>>>out of a battery decreased with the percent discharge of the cycles. So
>>>I am wondering what the effect on battery life is when you discharge it
>>>to 5-10% of its capacity. Is that the only way to test the battery?
>>
------------------
bn: It's true that a battery's life is improved by limiting the
bn: depth to which you discharge it on each cycle.
------------------
>So, then, what is different about the construction of a "deep-cycle"
>battery, such as those marketed as such for use in golf carts?
------------------
Deep cycle batteries pack more chemistry into the plate
structure . . . generally limiting the number of plates
per volume and increased spacing between plates which
translates into higher internal resistance and poorer
performance at low temperatures.
I suspect that as the battery technology evolves, the
the gap between batteries optomized for deep cycle
work and cranking service may narrow. Most sealed
lead acid batteries sold are used in deep cycle
applications (camcorders, cellphones, power tools,
etc.) so I'm sure the industry is working hard to
keep this performance arena working well. In larger
batteries (10 a.h. and up) there is also a need for
good cranking performance. One company in particular
has gone the extra mile in optimizing cranking
performance in VERY small cells (1.2 a.h.).
See http://199.239.60.165/
These tiny cells combined with two alternators make
it now possible to remove the pigs found on most
aircraft engines for starters and alternators and
to forego the classic 24 a.h. battery in favor of
light weight alternators, starter, and itty-bitty
batteries for a DUAL electrical system who's TOTAL
weight is about equal to the original 24 a.h. battery!
The only sealed batteries I'm aware of specifcally
made for deep cycle service are true gel-cells offered
by Sonnenschein and Johnson Controls (the old Globe
line). I think B&C still offers a couple of gels
for customers that like them but for my money,
the RG battery is the only way to go for an airplane
were deep cycle performance isn't an issue.
Bob . . .
////
(o o)
< Jurassic Park of aviation. >
< Your source for brand new >
< 40 year old airplanes. >
|