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Battery and jumping it

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Howdy, 

I'm receiving my 2006 CTSW this week and I'm trying to get ahead of the game and learn everything I can about it so I might have multiple questions, thank you to all that answer. One of my concerns is the battery. The POH says not to jump it. Going through this forum, it looks like you CAN jump it. Something along the lines of connecting the positive to the wire dangling off the positive of the battery and the negative to the exhaust... um how does that work exactly? Or where did I go wrong in my understanding? Also, if I can jump it, can I use something like this below? Thank you in advance. 

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You can use one of those self contained jumper units or a car. I have done both since 2006. Yes just connect to the bottom wire at the bottom of the cowl for positive and the muffler for negative. Works just fine.

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I jumped my 2007 CTSW off a courtesy car at one of the local airports a few years back.  No issues.  Positive on the terminal provided under the cowl, negative on the exhaust stack.  The hardest part is having a (brave) assistant to crawl under the airplane after the jump with the prop spinning to pull the jumper cables off the airplane.

BTW, if you have a truly dead battery as mine was, you will start to run into load issues.  I found with the battery not holding a charge the alternator didn't have enough juice to run both the landing light and the flaps at low RPM.  It was fine while I was landing, but once on the ground at idle the flaps would not come up until I turned off the landing light.  My airplane only has a single Dynon D-100 and (at the time) 496 GPS, and no EMS unit.  In an airplane with a lot of gizmos you might want to consider turning off non-essential items until you make it to your destination.

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As mentioned in a previous post, I recently got back from a trip to Ohio which involved scrapping snow and ice off the plane for a couple of cold morning starts after the plane had be left out overnight. One, in Wooster, Ohio with the temperature at takeoff was just below 0 F and the other at Canadian, Texas in the single digits. My Odyssey battery, which had been (and still is) working fine out of a hangar in Southern California, was able to turn the engine over each time, but not fast enough to fire the ignition.

I don't think that's too surprising. Lead acid batteries lose half their energy at 0 F, and mine was probably soaked to a colder temperature than that.

The folks at Smith County brought a ground cart with big batteries out of a warm hanger. I set it to 12 volts and hooked the clamps to the positive lead sticking out from under the cowl and to the exhaust stack as a ground. The engine spun faster than it's ever spun before, fired right away and kicked back as it often does when starting at cold temperatures (I don't have a soft start). The kickback stopped the prop but the starter continued to spin on its own. This last part is the part that's surprising to me. Usually the kickbacks stop the engine and the starter. It happened 2 more times in Ohio before I got a good start. Then it happened again the next day with a plug-in jump charger at Canadian; the engine spun energetically, fired, kicked back and disengaged the starter.

When disengaged the starter sounds like on a car with a low battery or defective starter solenoid. I've never had this happen before (or in several flights since) on my airplane.

In the Illustrated Parts Catalog I see that there is a sprag clutch between the free wheel gear and crankshaft. Apparently, it was slipping or not engaging after these kickbacks during particularly energetic starts. Is this normal or an indication of a problem with the sprag clutch?

Mike Koerner

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That starting behavior is typical when attempting a cold start especially with a marginal battery.  I had a few events like this and then fuel line pollution which added more stressful starting.

I was convinced that that kick followed by just the starter spinning after it happened enough times was telling me the sprag clutch is problematic and getting worse.  I had Jeremy replace the sprag clutch and have never had such a start again.  I simply won't attempt a cold start or use a weak battery.  Based at 8,000' its good to take more precautions.  

 

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You should NEVER continue to operate the engine if the prop has kick back or you WILL ruin the sprag clutch and the engine must be removed to fix it and the rear of the engine must also be removed with special tools. This is expensive.

 

If you have prop kick back stop and fix it or pay the price and it may strand you. Once the spring in the sprag is stretched you aren't going anywhere.

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Yeah, how do you tell a kickback ? Given that rotax engines sometimes tend to stop as if they were was about seize ...😀 with a loud shudder ...

 

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its like one of those sudden stops but for more severe and happens on startup.

4 hours ago, Warmi said:

Yeah, how do you tell a kickback ? Given that rotax engines sometimes tend to stop as if they were was about seize ...😀 with a loud shudder ...

 

 

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a couple of video to explain

kickback 'live'

 

and some explanation about the sprag clutch

 

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Stop is fine. Kickback is when the prop rotates backward clockwise 1/2 - 1 turn. This stretches the sprag spring and it can only take that so many times.

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@Mike Koerner my experience is that you are likely to do fine at home due to mild climate but another trip with cold starts is less survivable.  Come visit me if you want to see.

Me and my new (500 hours) sprag clutch have decided that preheat is a must,  not worth a $700 bill for the clutch.

I now leave my pre-heater plugged in summer and winter.  In the summer I get all very soft starts from home now.

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 With the new 'personal jumping carts' like the device that started this thread the next step would be to wires or points in my cockpit to attach the jump charger and avoid the disconnect near a spinning prop.

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I don't know if it's standard fitment, but I've got an Anderson SB50 plug at the bottom of my cowl, secured to the bottom of the engine mount. It's connected directly to the + and - on my battery for easy charging and jump starting. 

 

I'm thinking about either moving it or adding another, possibly in the P2 footwell, where it'll be a very short wire run to the battery. 

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Nice video.  Thanks Jacques.  Keeping the engine warm is the key for preventing kick-back but warm starts aren't always possible when away from the hangar in cold WX.  How about connecting the lithium emergency start battery at the hanging wire to supplement the onboard battery for cold starts?

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Sleepy; Sorry to commandeer your topic.

Ed, Jacques, Roger; Thanks for your comments and help.

I don’t think my prop has ever turned backwards, at least not more than 5 or 10 degrees. What I’m calling a kickback is exactly what is depicted in several of the starts in the video Jacques provided. The engine comes to a very sudden and forceful stop.  It’s as if one of the chambers fires and reaches peak pressure before top dead center. If so, that implies at least one of the following:

1)      That cylinder fired too early

2)      The burn rate is unusually fast

3)      The engine was turning over unusually slow

Though number 1 & 2 seem unlikely, my most recent experience cannot be due to number 3. As I explained, the jumped starts when this occurred were very energetic, the fastest I've ever seen the engine turn.

The times I typically see these "rough" starts is when the engine is really cold, not just a cold start, but a very cold start. The two starts I referred to were sub-zero and single digit degrees F but it has happened at less severe conditions as well.

I have seen it under such conditions since as early as 2006. And I have no doubt that what is happening is not good for the engine. But so far I have not had to replace any engine components (I'm at 1800 hours now) and as I say, it still starts perfectly under more normal conditions. (I added a couple more starts on a trip to see the wildflowers this weekend.)

Dick, I think you’re right that these engines, or at least mine, don’t like to be started cold without pre-heating.

Is this true of the 912is fuel-injected engines as well?  What about planes with soft-start modules - can they get by without a preheat in cold climates?

Since I intend to travel year-round, and airports don’t have power plugs on the flight line. I need to find a cheap, light-weight, safe, effective, quick way to heat my engine. I used to have a little backpacking stove that burned unleaded gasoline. I could fill it from the gascolator. It’s certainly not safe (it burned a hole in my tent once) but 4 out of 5 is not too bad.

Mike Koerner

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Forgot to add a Poppy picture. This is north of Lake Elsinore. There are thousands of people strolling along the dirt road in the center of this photo. The freeway just below this frame is jammed with cars. Everyone has come out to see the flowers.

Mike Koerner

 

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Minimize hard starts by leaving the key in the start position for an extra 1-2 seconds after engine starts.

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My Genius jump starter only weighs ounces and is very small.  I want to have points in the passenger foot-locker to jump from.  If I fed it a usb charge and left it hooked up it would be like starting from a battery cart every time.  Would that work?

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