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Permalink Reply by stewart smith on May 13, 2015 at 5:47pm

Good job.  What engine do u have in it ?

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Permalink Reply by John Richardson on May 13, 2015 at 6:01pm

I have a jabiru 3300. I was equally concerned about CHTs as they were gaining on a long taxi and I was #3 for departure. I was glad they stayed in operating range during the climb out. I need to figure out why my alternator breaker popped before my next flight. Apparently I flew most of the time on battery power.

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Permalink Reply by John Austin on May 14, 2015 at 6:44am

Congrats, John R.!

The Jab 3300's alternator only produces charging current above ~ 1900 rpm. So, if you have a long warm-up, long taxi, etc., you're running on battery all that time. When you finally get to take-off, if the battery is depleted somewhat, there may be an inrush of charging current when you go to full throttle. Although it's a "20 amp" alternator, supposedly it can produce up to about 32 amps or so.

I had the alternator breakered at 20 amps initially, and had no problems with an Odyssey PC680 battery (however, I have my own strip and no long taxi's, etc!). However, when I went to a small lithium battery, I had the same problems you did - the battery was too small in capacity, would get depleted, and then the breaker would pop after take-off. Also, lithium batteries have little internal resistance, so that aggravated the inrush of charging current further. Of course, the engine's ignition is magneto-driven, so lack of alternator or battery is no problem as far as keeping the engine going!

I found that my alternator wiring was actually good up to about 42 amps, so I increased the breaker to a 35A and got a larger LiFePO4 battery (EarthX ETX36D) that had similar capacity to my Odyssey and have had no more problems.

Congrats again and regards,

John

N750A

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Permalink Reply by Jerry Latimer on May 13, 2015 at 6:59pm

Congratulations.   Now the fun begins.

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Permalink Reply by Dan Dempsey on May 13, 2015 at 8:14pm

Way to go!

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Permalink Reply by Bob McDonald on May 13, 2015 at 9:25pm

Congrats on 1st flight

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Permalink Reply by Timothy D. McCall on May 14, 2015 at 7:20am

  Congratulations John!!   Enjoy.

 Drop in at K50 (Cook Field - Rose Hill, KS)  if you get down this way.

Tim

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Permalink Reply by John Richardson on May 14, 2015 at 7:36am

Thanks all. And to John Austin for the better understanding of my alternator system. I didn't realize it was not charging until the RPMs were up. I'll also check if my 5 amp breaker is going to an exciter field of the regulator or inline with my Odessey battery power. John Richardson

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Permalink Reply by Mack P. Kreizenbeck on May 17, 2015 at 1:10pm

Congrats from Idaho!

Blue skys ahead

Mack

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Permalink Reply by stewart smith on May 17, 2015 at 2:03pm

Once again-good job and have lots of good flying.  Looks like goo fun.

Does anybody know what speed a CH- 650 will give with a Continental ?

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