Cessna 182A starter current draw

weirdjim

weirdjim

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weirdjim
Does anybody know or can you point me to a source that says what the starter draw on a 182A is during a normal start? Neither the airplane nor engine maintenance/service manuals list the nominal current.

Seems to me that once upon aeons ago (when dinosaurs were roaming about) I measured one and vague memory said something on the order of 50 amps, but that was a LONG time ago.

Jim
 
You can figure on 250 amps to 300 amps - and up to as high as 600 amps in cold weather with a fresh battery and booster cables.
 
Dr. O said:
You can figure on 250 amps to 300 amps - and up to as high as 600 amps in cold weather with a fresh battery and booster cables.
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That sounds awfully high, but if that's what it really is, that's what it is.

Jim
 
I'd get an inductive amp meter and check one. That said the Amperage drawn is related to work done, The new high compression engine in cold weather will certainly draw a lot more Amps than an old 60/80 psi worn out warm engine.
 
Dr. O said:
You can figure on 250 amps to 300 amps - and up to as high as 600 amps in cold weather with a fresh battery and booster cables.
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This conforms to what I have been told many times. But this is a tale without facts to back it up.

What gauge wire is in the recommended battery cable, and how much current can it stand before the insulation melts?

-Skip
 
Tom-D said:
I'd get an inductive amp meter and check one. That said the Amperage drawn is related to work done, The new high compression engine in cold weather will certainly draw a lot more Amps than an old 60/80 psi worn out warm engine.
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That is the one sure way. However, I just wanted a ballpark for some stuff I'm writing up. Let's say a mid-time O-470 with 75/80 jugs on a spring morning at around 55F. The solenoid INRUSH current is maxed at 300 amps, and generally inrush from dead start is 5x to 10x running current. It is running current I'm after.

Thanks for the answer...

Jim
 
What is the max the battery can produce - the loss of the cable and 2 solinoids
 
weirdjim said:
That is the one sure way. However, I just wanted a ballpark for some stuff I'm writing up. Let's say a mid-time O-470 with 75/80 jugs on a spring morning at around 55F. The solenoid INRUSH current is maxed at 300 amps, and generally inrush from dead start is 5x to 10x running current. It is running current I'm after.

Thanks for the answer...

Jim
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I don't have a 0-470/0-520 to check for ya, but the 0-300 on my test cell draws 300 initially, then drops to 200-250 as it cranks. that is a fresh overhauled engine on the initial run.
 
My IO-540 pulls 437 Amps while cranking. #2 ga wire running from behind baggage area to starter. Different engine but gives you an idea.
 
No idea what my O-320 does, but I've never paid attention to the ammeter during start... My attention is elsewhere :)

Not that is trust the stock Cessna ammeter for accuracy anyways.
 
mkosmo said:
No idea what my O-320 does, but I've never paid attention to the ammeter during start... My attention is elsewhere :)

Not that is trust the stock Cessna ammeter for accuracy anyways.
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Take a look at your POH, Matt... Starter current isn't routed through the ammeter.

Paul
 
I'm surprised my 8 year old battery is still cranking it after reading this thread. (O-320) Its been run dead flat more than once too from leaving the old master on.
 
GlennAB1 said:
Maybe it's 2/0?
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Could be, but the guy built the airplane himself. He ought to know what wire size he used. I just want confirmation before I go doing calculations using wrong data. BTW, with a 250 amp starter, that wire is dissipating 100 watts. No big deal for ten seconds of start, but I'd start worrying if we cranked for a minute or so.

Jim
 
weirdjim said:
Could be, but the guy built the airplane himself. He ought to know what wire size he used. I just want confirmation before I go doing calculations using wrong data. BTW, with a 250 amp starter, that wire is dissipating 100 watts. No big deal for ten seconds of start, but I'd start worrying if we cranked for a minute or so.

Jim
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Would you mind sharing the formula for calculating the heat dissipation of the #2 wire while it is carrying that 250 amp load? Thanks!
 
3393RP said:
Would you mind sharing the formula for calculating the heat dissipation of the #2 wire while it is carrying that 250 amp load? Thanks!
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www.rstengineering.com to Jim's Engineering Page to Wire Tables gives the resistance of ten feet of #2 wire as 0.0016 ohms. (Ten feet is an estimate of the distance from the baggage area to the engine per the OP's information.)

Current is 250 amps. Power dissipated is given by Ohm's law as current squared times the resistance. 250*250*0.0016 is a hundred watts. Temperature rise is not accurate at these currents and wire sizes, but just for planning sake it says that in a bundle this wire will get 233F hotter than ambient on a continuous duty basis. This is what I said about SHORT bursts of starter energy.

Jim

.
 
Starter cable on a typical lightplane is 1
weirdjim said:
www.rstengineering.com to Jim's Engineering Page to Wire Tables gives the resistance of ten feet of #2 wire as 0.0016 ohms. (Ten feet is an estimate of the distance from the baggage area to the engine per the OP's information.)

Current is 250 amps. Power dissipated is given by Ohm's law as current squared times the resistance. 250*250*0.0016 is a hundred watts. Temperature rise is not accurate at these currents and wire sizes, but just for planning sake it says that in a bundle this wire will get 233F hotter than ambient on a continuous duty basis. This is what I said about SHORT bursts of starter energy.

Jim

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AC43.13-1B, Chapter 11: http://www.faa.gov/documentLibrary/media/Advisory_Circular/Chapter_11.pdf

Page 31 has the chart for intermittent capacities. I have sometimes seen #2 cable on 12-volt aircraft. Bogert cables are #1.

http://bogertaviation.com/collections/low-loss-copper-aircraft-cable-kits
 
I would go with 1 ga if I built another RV-10 with a Skytec LS, 12 volt permanent magnet starter. I have a Skytec NL with a wound field on the shelf that I am going to install soon. It turns slower, but is more efficient.
 
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