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On 05/25/2012 07:13 PM, bktrub@aol.com wrote:
-----Original Message-----
From: Brian Trubee <bktrub@yahoo.com>
To: bktrub <bktrub@aol.com>
Sent: Fri, May 25, 2012 5:11 pm
Subject: Fw: Batteries
I'm nearing the finish of my phase 1
testing, and am now looking for replacement
batteries. right now, I am using two of these:
http://www.power-sonic.com/images/powersonic/sla_batteries/ps_psg_series/12volt/PS-12180_11_Feb_21.pdf ;.
They are on separate contactors, so I can use
either or both when flying. I use both when
starting. They are two years old, and today
when I went flying I noticed that the voltage
was getting down to 11.6 volts. after landing,
the voltage was up around 12.3 volts. Usually
I show around 13~13.6 volts when running. I
always use a float charger specifically
designed for these batteries when the plane is
put away. Usually the float charger shows a
slow charge, but when I cam back from flying
today the charger was showing a fast charge,
meaning that the batteries were discharged a
fair amount. Any comments on the suitablitiy
of these batteries and suggestions on how to
test them out for holding a charge or
otherwise deterining their suitablity or not
for my plane. I have a 40 amp Nippondenso
alternator, and run an Xcom radio, a terra
transponder, Dynon D10, Tracys EM2 and EC2,
and one fuel pump(at a time unless landing or
taking off) that draws around 4 and no more
than 6 amps.
Thanks,
Brian Trubee
Hi Brian,
I've run a Powersonic 18 AH battery in an Lyc powered RV-4,
& it was 'adequate', but could have been better. They sell a
20 AH starting battery that is much better for flying (the 18 AH
models are really intended for UPS, rather than starting). You
won't need to parallel 2 of the 20 AH units for starting. The 20
AH unit is the same length, but slightly wider than the 18AH
units, and almost identical to the Odyssey PC680's (that are
twice as expensive) that a lot of RV guys use. The Odyssey is
kinda the gold standard for experimental a/c starting batteries.
Having said that, if you are seeing less than 13.5V in flight it
sounds like you have a charging problem, rather than a battery
problem. If you've been flying at less than that, the batteries
have never been fully charged by the alternator (it takes close
to 14 V to charge a 12 V lead-acid battery, both the old flooded
cell and AGM types).
It sounds like your alternator or regulator is slowly dying. The
batteries may or may not be OK after fully recharging them.
Charlie
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