FLYZONE
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I've been putting in Concorde 35AXC batteries in my Cherokee for several years. I have found them to be longer lasting and with more charging and standby current. However, I think I may have found a downside to these batteries. Apparently they act very differently if you inadvertently leave your master on for a week and then want to jump start them.
I have a 72 Cherokee. To jump the plane we hooked the battery up to charger. The mechanic was surprised to see that the charging amps were low (like 5-10 amps) even though the charger was set for 30 amps. We left it on and after about 20 min. the charging amps slooowly increased. We left the charger in for 45 min. or so and the amps got up to 30. We expected to be able to start it then with the START setting on the charger and then let the alternator finish the job on the way home. We got it started ok.
As I took off with the engine at full power I noticed the ammeter going much further than I had ever seen it before. I've never seen more than a 30 amp load on the ammeter (actually technically a "load" meter). I left the runway and saw about 35-40 amps on the meter. Then I smelled smoke and looked down at the ammeter "glass" face which was black with soot and unreadable visually blocked completely by the electrical soot.
I immediately entered an emergency turn to return to the airport. I was only about 500 feet up so the return was quick since I landed at the departure end of the runway. The slowed engine kept the amps lower but still high. In hindsight I wished I had quickly flipped of the master but that was a lesson learned.
Anyway, I'm not sure I completely understand what happened but I do know these batteries act differently from automotive batteries and jump starting is probably not recommended.
My plane is in for repair. We expect the ammeter is shot but the mechanic found no burned wires behind it, a good sign. He looked to see if an AD on the ammeter had been complied with and it had so that was not in play.
I did ask the mechanic as to why the system didn't protect itself. He said that these systems are more voltage than amperage based which I guess explains that to some. I guess the battery did not get up to volts and the regulator just let the 60 amp alternator run away and continue charging the low volt battery. However that is just my guess.
Just thought I'd pass this along and wonder if others have had a similar experience.
I have a 72 Cherokee. To jump the plane we hooked the battery up to charger. The mechanic was surprised to see that the charging amps were low (like 5-10 amps) even though the charger was set for 30 amps. We left it on and after about 20 min. the charging amps slooowly increased. We left the charger in for 45 min. or so and the amps got up to 30. We expected to be able to start it then with the START setting on the charger and then let the alternator finish the job on the way home. We got it started ok.
As I took off with the engine at full power I noticed the ammeter going much further than I had ever seen it before. I've never seen more than a 30 amp load on the ammeter (actually technically a "load" meter). I left the runway and saw about 35-40 amps on the meter. Then I smelled smoke and looked down at the ammeter "glass" face which was black with soot and unreadable visually blocked completely by the electrical soot.
I immediately entered an emergency turn to return to the airport. I was only about 500 feet up so the return was quick since I landed at the departure end of the runway. The slowed engine kept the amps lower but still high. In hindsight I wished I had quickly flipped of the master but that was a lesson learned.
Anyway, I'm not sure I completely understand what happened but I do know these batteries act differently from automotive batteries and jump starting is probably not recommended.
My plane is in for repair. We expect the ammeter is shot but the mechanic found no burned wires behind it, a good sign. He looked to see if an AD on the ammeter had been complied with and it had so that was not in play.
I did ask the mechanic as to why the system didn't protect itself. He said that these systems are more voltage than amperage based which I guess explains that to some. I guess the battery did not get up to volts and the regulator just let the 60 amp alternator run away and continue charging the low volt battery. However that is just my guess.
Just thought I'd pass this along and wonder if others have had a similar experience.
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