This page is a work in
progress. As time allows, we will update it with science
and supporting data. For now, please accept our
apologies for vagueness and generalization.
Aviation Consumer recently
compared the two leading brands of certified aircraft
batteries. There is a clear winner.
Wet Cell (flooded), Gel Cell, and
Absorbed Glass Mat (AGM) are various versions of the lead acid
batteries come in 2 styles; serviceable, and maintenance free.
Both are filled with electrolyte with serviceable types
allowing the addition water to and the ability to check the
specific gravity of the electrolyte with a hydrometer.
batteries are completely sealed and feature electrolyte that
is suspended with a silica additive that causes it to set up
or stiffen. Gel Batteries are best used in VERY DEEP cycle,
low-amperage applications. Gel Cell batteries were among
the first completely sealed battery designs to find their way
into typically experimental aircraft applications. They
gained particular popularity in experimental aerobatic
aircraft they can be installed in any configuration (or
operated in any attitude). Gel Cell batteries store very
well and do not tend to sulfate or degrade as easily or as
easily as wet cell. There is little chance of corrosion when
using these batteries; they are among the safest lead acid
batteries one can use. However, because of the chemistry of
the electrolyte gel cell batteries are typically not capable
of delivering large volumes of current in short bursts of
time. Quite the contrary, they are designed for deep
cycle operations such as wheel chairs that must delivery small
volumes of current over very long periods of time.
or, Absorbed Glass Matt, construction allows the electrolyte
to be suspended in close proximity to the lead plates
material. Also, due to the stiffness provided by the glass
matt material, AGM batteries such as the Odyssey often utilize
a greater number of thinner lead plates than other types of
batteries while still offering a reliable, long-lasting
performance. The result is a battery that can deliver
very large amounts of current over very quick periods of
time.. Popular usage includes high performance engine
starting, power sports, deep cycle, solar and storage
Today, AGM batteries have all but
replaced Gel Cell technology in experimental aircraft
applications largely due to, you guessed it, the advent of the
lightweight, high-performance starters.
pair a Gel Cell with a High-Performance starter
This statement is specific to
true "Gel Cell" composition batteries. These
are the types typically found in wheelchairs and the likes.
This statement does NOT regard
newer, sealed lead-acid batteries typically of the "
recombinant gas or AGM varieties.
While often attractive to the
home builder due to their characteristic lightweight, small
size, high amp-hour ratings and spillproof design, gel
electrolyte does not move electrons quickly enough to provide
the large volumes of inrush current some high-torque,
lightweight, high-performance starters require for proper
performance. For example, a permanent magnet starter
such as Sky-Tec's LS or PM starters require in inrush current
in excess of 300 amps in many cases. Gel cell batteries
are often incapable of delivering such "quick hits"
of current. Conversely, today's Concorde RG and Odyssey
AGM batteries do a rather fabulous job delivering the required
energy to the starter for maximum performance.
customers tout which batteries are the best
In speaking with thousands of
Sky-Tec customers through the years, it has become obvious the
best battery for use with Sky-Tec starters appears to be
Concorde RG XC batteries (recombinant gas, extra cranking) and
Odyssey-type AGM batteries manufactured by Hawker Energy
(PC-680, PC-925, etc.). We base this largely on the very
limited number of issues experienced with these batteries in
combination with Sky-Tec's high-performance, lightweight LS
and PM starters.
Sky-Tec NL model Lycoming and
C-model Continental starters do not demand nearly as much
inrush and initial cranking current and as such appear to work
well with most types and brands of batteries.