Essential Tie Breaker

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LTek1
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Essential Tie Breaker

Post by LTek1 »

Just need a little sanity check from you guys, please:

Today I managed to fly for about an hour with the alternator switch off; when the voltage warning chimed, I immediately realized what I did and flipped the switch on. Amp draw jumped up to 52 amps, presumably as the battery drew current to charge.

Within a minute or so, the 25a 'essential tie' breaker popped. Looking at the diagram, this seems to make sense: the path from the alternator to the battery is through the tie switch.

Sound right? Just seems like a heck of a lot of charging current for a battery that was reading 23.2v.

I left the plane on the external power overnight, with the battery breaker pulled; of course, looking at the diagram now sitting in my living room, I realize that without the battery switch on, the grounds aren't connected, so it's not charging. I'll have one of the line guys turn the battery switch on tomorrow for a few hours before giving it another shot tomorrow.
Lee Dickinson
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Avidyne Entegra (!), Dual GNS430, KAP140
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Steve
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Re: Essential Tie Breaker

Post by Steve »

Lee:

I'm surprised your voltage warning took so long. Mine goes off if the bus voltage goes down below about 26 volts. At 23.2 volts, your battery was mostly discharged.

To answer your question, yes, I would expect the Essential Tie breaker to pop under those conditions. On those occasions when my battery was run down (say from several unsuccessful starting attempts) I kept the RPM down when initially charging, to limit the current supplied by the alternator to the bus, thus preventing the Essential Tie breaker from popping.

In flight, obviously you can't decrease the alternator output, so all you can do is decrease the (non-charging) draw by powering off everything you can, until the charging current draw from the battery decreases. In my aircraft this is pretty easy, since I just turn off selected radios, the DME, lights, etc. Not sure about the G1000 models.

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Re: Essential Tie Breaker

Post by LTek1 »

Thanks, Steve.

I don't remember exactly where the alert went off; it was 23.2 by the time I landed.

Makes perfect sense, though, having had a minute to look at the diagram while not also flying.
Lee Dickinson
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Re: Essential Tie Breaker

Post by Joey »

I had a similar situation happen when we first bought the airplane. You cannot really do anything about it airborne w a g1000. The fix was to simply run the engine on the ground at low rpm to keep the charging current low so as to not pop the breaker. If you have a trickle charger hooked up that would work too.
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Re: Essential Tie Breaker

Post by Sandy »

I just had a similar issue with my ESS Tie breaker popping due to a low voltage condition only a few weeks after I had a new battery installed, as set forth in this thread viewtopic.php?f=8&t=5091&p=69788#p69788.
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