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-   -   What killed this PC680? (https://vansairforce.net/community/showthread.php?t=99810)

Brantel 05-17-2013 12:00 PM

What killed this PC680?
 
My original PC680 lasted about 2 years of storage/building and 2 years of flying.

Its failure mode was to be able to charge very quickly up to full voltage but it had very little capacity. It would almost instantly drop down to low voltage with only a light load applied.

I replaced that battery in Oct. of 2012 and the replacement battery has fully failed today with the same symptoms. Last week it started acting like it was going to die and today it gave up the ghost. (with 3 of those months being panel upgrades and tests)

It has the same issue. It will almost instantly charge up to full voltage but it does not have any capacity to do any real work.

I took it to Advance Auto and they tested it with their tester and they said it only had 35% of its rating in capacity left.

I have always used the Odyssey Ultimizer 6amp charger. I keep it attached nearly all the time the plane is in the hangar. My aircraft electrical system runs at 14.3 to 14.4 volts in flight.

So what killed these batteries that are suppose to have a long life cycle?

Mike S 05-17-2013 12:02 PM

My money is on the fact you keep it on the charger "nearly all the time the plane is in the hangar"

Captain_John 05-17-2013 12:20 PM

Quote:

Originally Posted by Mike S (Post 771627)
My money is on the fact you keep it on the charger "nearly all the time the plane is in the hangar"

I will second that comment.

:rolleyes: CJ

Don 05-17-2013 12:24 PM

Brantel,

There's an EAA Webinar on battery maintenance that I believe they have archived. You might be well advised to listen to it. I need to listen again to clarify a few things but what I got out of it was keeping a glass mat battery fully charged is a good thing but you need to be careful about how you do it. Apparently even a trickle charger will over-charge. The guy giving the webinar makes some specific recommendations about how to accomplish it.

The gist of the problem is, when you run a sealed, maintenance free battery down, you need to recharge is slowly and apparently there's points where the speed of the charge changes. If you charge too fast, either by using most conventional chargers or (worse) by letting the alternator recharge your battery, gas is produced and is vented. This loses some of the potential to store energy. Each time you do it you lose a little more and since it's maintenance free you can't add more fluid.

The bottom line is you need to get the right "smart" charger for your battery to maximize its life. I believe they're right, too. I have been doing this with a Concord RG35 battery and I got 12 years out it.

Now, other than my one experience, this is all second hand info and I'm 99% sure someone will disagree with me, which is fine. My only advice here is find and listen to the EAA webinar and make up your own mind.

Brantel 05-17-2013 12:29 PM

Guys,

I am using the charger made for these batteries and sold under the same brand. They actually recommend that the battery be kept on this charger.

Right off the Odyssey website (I use the 6 amp version):





Straight from the battery manual:
"To get long life from the ODYSSEY battery, it is important that the battery is kept near full charge, approximately
12.8 volts. If there are electrical loads during storage, then the negative battery cable should be disconnected or an
independent float charger used. Low power 2.0 amp chargers for storage charge will keep a fully charged battery fully
charged but cannot recharge if the ODYSSEY battery becomes discharged."

Straight from the charger manual:
"The charger then enters into the trickle
charge phase at 13.5-13.8V. The battery can be left connected to the charger
indefinitely."

&

"TRICKLE CHARGE MODE: When the
CHARGED (green) LED is lit, the charger
has started this mode. The battery can be
left connected to the charger indefinitely
without hurting the battery."

flyer174 05-17-2013 12:41 PM

Soooo.....Im guessing by this post you didn't get to fly this morning?........

bsacks05 05-17-2013 12:45 PM

I am on my second PC680 in almost 7 years. The first one lasted about three years and I used a regular car batt charger on occasions to charge it. With my current PC680, I use a trickle charger and keep in plugged in most of the time in the hangar.
I have heard from various people and on VAF that these batts work best with slow / trickle chargers. It's been working well for me. I recently left an ignition switch on which drained the batt down to about 4 volts, charged it overnight and it still works great.

Brantel 05-17-2013 12:54 PM

Quote:

Originally Posted by flyer174 (Post 771642)
Soooo.....Im guessing by this post you didn't get to fly this morning?........

No, my vacation day to do some flying turned into a troubleshooting session....you know, pull cowl, check all the easy stuff first/clean all connections/check all points of failure before accepting that the battery is toast. The auto store pretty much confirmed the witch is dead.

The good news is that BatteryMart.com is handling the warranty and these things have a 2 year non pro-rated warranty....bad news is the downtime till the next one gets here.

Mike S 05-17-2013 12:57 PM

Do you have any "Keep Alive" circuits in the plane, or is the battery truly off when you kill the master??

Brantel 05-17-2013 12:58 PM

Quote:

Originally Posted by Mike S (Post 771649)
Do you have any "Keep Alive" circuits in the plane, or is the battery truly off when you kill the master??

It is off...nothing can flow without the master. The G3X does not have keep alive inputs.


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