Favorite Battery Charger/Maintainer/Power Supply & Battery
Here's a great 20 Amp battery charger/maintainer that can
be left on indefinitely. It's internal circuitry monitors charging voltage and
maintains a safe voltage.
IMHO, the Guest Marine Model 2620 (Now made under Marinco Model #28220, see more detail below) is an excellent
24v choice for maintaining your batteries. It will not boil or overcharge your
battery and has a 20 amp capacity (10 amps per battery). And it's a great
battery assist for doing gear swings. See videos of my gear swings with the
Model 2620A Charger/Maintainer by scrolling down.
I had been using my Model 2620 for nearly 6 years
before it died. I was so impressed with this unit that I replaced it with their
Model 2620A. As of April 2013, I have about 8 years behind these Guest Marine
units keeping my Concorde batteries in top maintained shape. By the way, my
Concorde batteries are still going strong!
UPDATE: 12/2013 - My CB25XC batteries have been
retired after almost 9 years of service. Their positive terminals swelled and I
felt that was a sign that they had given all they could give.
Check out the article
HERE on why AGM
battery technology is the way to go.
Here is the verbatim guidance from AC23-27,
page 12, regarding batteries: "BATTERIES. If one type of
series 35 battery (e.g. a Gill 35) is approved as original equipment or a PMA
part, and another type of series 35 battery (e.g. a Concord 35) is PMA approved
for some aircraft models but not your model aircraft, you may install the
alternate type of series 35 battery and document the installation with only a
logbook entry. This applies to all series 35 batteries. This philosophy also
applies to other series, such as series 25 batteries. However, this part
substitution is permissible only as long as the batteries are the same weight,
within plus or minus one pound, and have such similar physical characteristics
as to enable the use of the same securing or attaching devices, mechanisms, or
Approval: This is a minor alteration and you may document it by a logbook entry.
The logbook entry must reference the original and replacement manufacturer's
identification or the performance specifications of the original and replacement
With the new
Part 23 rules AC23-27 (signed into law by Congress and the President) are enacted by
the FAA some may choose to use the
YTX30L-BS AGM technology battery options @ $105 or $80, respectively, w/Free Shipping
and a capacity of 26 Ah or 30 Ah, respectively, and 400 or 385 Cold Cranking Amps,
respectively. With weights of about
23 or 22 pounds, respectively. Read about AGM basics
Dimensionally, either will fit where a
Gil G25 battery would go
wood spacers to take up a little of the slack. See the Gil vs. Concorde weight
ETX30L Dimensions: Length: 6.65"
x Width: 5.16" x Height: 6.89"
Here's another AGM candidate that some may choose
to use the
MTX30L AGM technology battery option @ an incredible $95 w/Free Ground Shipping from Battery Mart
with great 30 Ah, and a whopping 420 Cold Cranking Amps performance specs and a weight of about
24 pounds. However, NOT made in the USA. Read about AGM basics
MTX30L Dimensions: Length: 6.55"
x Width: 5.16" x Height: 6.89"
Here's a phenomenal AGM candidate that some might
consider, the Chrome Battery
YTX30L -BS @ an incredible $80 w/Free Ground Shipping from Chrome Battery
with a great 30 Ah capacity and a whopping 385 Cold Cranking Amps performance
with a weight of
22 pounds (PS: this is within the +/- 1 pound limit of the original Gil G25). Read about AGM basics
YTX30L-BS Dimensions: Length: 6.54"
x Width: 4.96" x Height: 6.89"
Dimensions: Length: 7.68"
x Width: 5.12" x Height: 6.46"
Weight: 23.5 lbs
See the, now discontinued, Guest 2620A powering my roughly 4 second gear swings
In my opinion, the Guest is a good modest priced choice for
augmenting your battery during gear swings (because the amount of free play in
the hand crank is very dependent on system voltage) or when at
the avionics shop, or when doing heater testing on the ground or in cold weather climates for that extra "edge" in cranking
Here is the latest Guest Model 2720A, 20A Two Battery
Bank unit, available for
$163 on 11/29/2023 at Amazon
Here is another option popular with 28 volt Beechcraft
owners, the Samlex Charger/Power
Model SEC-2425UL which offers 25Amps. See the Technical Specs
Samlex's "smart" battery chargers are designed to operate with lead
acid and gel batteries. Smart chargers evaluate the state of the battery’s
charge level, and apply the appropriate charging current. They will maintain and
condition the battery to maximize battery life. Protective features prevent
excessive heat buildup during charging. The Samlex unit is available from