Battery Tech
I read with interest Jim Cavanaugh’s article on battery upkeep and battery minders in the September 2016 issue of Aviation Consumer. I am a big believer and have had great results (including eight years of reliable service) from two Concorde gel mat batteries set up in series in a 24-volt Beechcraft Sierra. My question to you relates to testing.
I had been told that using a 12-volt load tester on each battery is the approved method to test for battery condition. I was also told to fully charge the battery and then let it sit for a day or so before testing it with a load tester. This was not mentioned in your article and I am wondering if this is not a better test. As the article suggested, should I use hydrometer testing instead?
Paul Werbin
via email
Concorde’s Don Grunke told us the battery should be fully charged and let sit for at least 12 hours to stabilize the internal temperature. As for testing, Concorde suggests using a hydrometer that’s at the same temperature as the battery. For-hire flying requires a capacity test (not a load test) to determine that the battery is capable of maintaining 80 percent of its capacity.
Worth mentioning is parasitic load—a small, continuous flow of current—that takes power from a sitting battery, even when the aircraft’s master switch is off. Some clocks and onboard computers can draw enough amperage to kill a battery that sits for even a short time. This repetitive low-current drain causes the battery plates to sulfate and deeply discharges the battery more than normal operating loads.
Parasitic drain is measured with a calibrated, ammeter-equipped multimeter. Concorde offers a parasitic load test adapter (PLTA) for batteries with an MS3509 quick disconnect receptacle.
Your battery maintenance article in the September 2016 issue should be a huge resource for owners like me who struggled with nagging battery problems.
As your article warned, problems in the charging system can lead to the expensive shotgunning of batteries. I know this too well. My shop wasn’t properly equipped to test the charging system in my Cessna 177RG and I went through three batteries in a span of four years.
I ended up at another shop that diagnosed the problem to a faulty voltage regulator. The old regulator was barely flowing 12.5 volts at most power settings. A new alternator and regulator, plus an accurate adjustment, brought the charging system voltage right where the battery needs it to be.
Nick Cabrella
via email
Garmin G5 EFI
Would you explain the difference between Garmin’s non-STC’d experimental-category G5 electronic flight instrument and the new G5 that was just released with an AML-STC for certified aircraft?
Tim Boese
via email
The main difference is the G5 with AML-STC (approved model list supplemental type certificate) is intended to be used entirely as a standalone instrument. This means, unlike the version made for experimental applications, it won’t work with Garmin’s autopilot and it can’t be interfaced with an external GPS and navigational source.
The other difference is price. The STC’d version is $2495, while the non-STC’d is $1350, with optional battery.
FAA Face Slap
I have comments to add to editor Larry Anglisano’s commentary in the August 2016 issue of Aviation Consumer where he wrote about the FAA’s $500 ADS-B equipage rebate.
The agency’s $500 rebate is a slap in the face for every law-abiding proactive citizen who has already equipped his or her aircraft for the ADS-B mandate. First, we pay higher prices due to less competition and then we have to deal with the additional hassles of performing updates while the system gets ready for prime time. That’s all fine—it was our choice to equip early.
But, the $500 handout is not the FAA’s money. It is money that we—as taxpayers—pay to the government. So now, in addition to the activities to get the ADS-B system going, the proactive have to pay additional money to the procrastinators. No wonder the political climate is changing for the worse.
