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B&C Alternator

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coolade1

Joined: 05 Aug 2010
Posts: 3

Posted: Mon Mar 28, 2011 12:15 pm Post subject: B&C Alternator

Has anyone experience with the 10 amp alt? Our A/C has the russian  

radio but all other avionics and instruments are US.  It has the small  

Dynon Efis, and electronic tach and a transponder.  will 10 amps keep  

the bat up?

dsavarese0812(at)bellsout
Guest

Posted: Mon Mar 28, 2011 1:38 pm Post subject: B&C Alternator

For the nominal price difference I think most people install the larger 

of the two alternators.  Better safe than sorry.



Don't forget, this is going to affect the W&B and would be a good idea 

to re-weigh the airplane and prepare a new W&B sheet.

Dennis



On 3/28/2011 2:46 PM, adrian hale wrote:

 	  Quote: 	
		   



 Has anyone experience with the 10 amp alt? Our A/C has the russian radio

 but all other avionics and instruments are US. It has the small Dynon

 Efis, and electronic tach and a transponder. will 10 amps keep the bat up?

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Mon Mar 28, 2011 2:00 pm Post subject: B&C Alternator

That sounds skimpy to me, depending on battery capacity.

On Mar 28, 2011, at 3:46 PM, adrian hale wrote:



 	  Quote: 	
		   

 

 Has anyone experience with the 10 amp alt? Our A/C has the russian radio but all other avionics and instruments are US.  It has the small Dynon Efis, and electronic tach and a transponder.  will 10 amps keep the bat up?

mark.bitterlich(at)navy.m
Guest

Posted: Tue Mar 29, 2011 8:31 am Post subject: B&C Alternator

Adrian, 



Short answer:  



Yes it will work fine.  



Long answer:  



I totally concur with Dennis's recommendation here and would advise the

B&C SK35 or SK50 versus the SK10.  The main difference is the voltage

regulation and safeguards.  The regulator for the SK35 and SK50 is the

LS-1A, with built in over-voltage protection and quiet linear

regulation.  It is a true alternator with a field voltage input, etc.

Really good stuff.  



If every ounce you put in your aircraft is important (as in you are

competing in the Worlds next year), then the SK10 is the E-Ticket ride.

It will power everything you have listed, as long as your batteries are

in Fair to Perfect condition.  If you do not take good care of your

batteries, and you allow them to degrade, you can run into some issues.

These issues can end up causing damage to your nice electronics.  The

SK-10 uses an external module regulator and it can fail if your

batteries go to crap and you overload the instantaneous operating

current of the regulator (transponders can do that).  The SK-10 has no

field winding.  It is really a permanent magnet alternator.  The faster

you spin it, the higher the voltage it produces.  There is NO control

over the output voltage FROM the Alternator itself (which is the case

with more typical alternators with a field winding instead of permanent

magnets).  This thus necessitates the use of some sort of external

over-voltage protection device.  B&C sells this too, and it is basically

a crow-bar circuit.  When the voltage goes over a pre-set limit, an SCR

type device fires, and puts a direct short on a line hooked to a circuit

breaker.  The circuit breaker then blows, which opens a relay, which

then disconnects the output of the voltage regulator from the aircraft.

Since circuit breakers are not instantaneous operating devices,

depending on the magnitude of the voltage surge, damage to external

components is possible.  



The SK35 and SK50 are more expensive, weigh a little more, but they

allow for expansion in the electronics as necessary down the road. 



Mark Bitterlich



--

mark.bitterlich(at)navy.m
Guest

Posted: Tue Mar 29, 2011 9:42 am Post subject: B&C Alternator

It is a tad on the low side Eric, but with 10 amps you get 280 watts,

which is enough to power what he has listed.  



The thing to keep in mind is the instant current demand versus the

average current demand.  The transponder is the biggest issue here since

output on it can be as much as +53 dbm, or about 250 watts.  Figure

about 50% efficiency and you are now up to 500 watts of peak demand.

However, the time the transmitter is on is very low (duty cycle in the

single digit range).  The radio is also a big current consumer when you

are transmitting anyway.  



Further, it is not really a wise choice to run the SK10 wide open with a

10 amp draw.  I don't think it will last very long that way!  



Thus.... as long as you have a decent set of batteries in there, (as you

mentioned) this system will work.  The batteries will provide the short

term current draws needed by the transponders and the radio, and all

will be good.  I have personally seen this system work on pretty much

exactly what he has described.  I have also seen a lot of bad things

happen if the owner does not stay on top of the battery condition.  



The same thing can happen with standard systems as well (battery failure

causing insidious problems), but not quite so quickly as it does with a

system running the SK10 and small batteries. 



Thus personally, I recommend the SK35 or SK50.  



Mark

  



--

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Tue Mar 29, 2011 11:12 am Post subject: B&C Alternator

Makes sense, Mark...



Without having done the calculations you did, I was thinking that it would have to be close, plus it it were charging a depleted battery, etc, and yes you're right, things running at 100% tend to not last. My later 52 came stock from Romania with gigantic VRLAs... never had a problem, even with the inverters and what have you.... but it also had the stock generator. Rick's SU-26M has one of the B&Cs and I converted that little green battery's lead-acid guts with a couple alarm batteries. Cheap, and worked for a couple of seasons before needing replacement. During start, it only needs the batteries for shower of sparks, but he does have the Dynon, comm radio and xpdr., and it seems to keep up with those. Daytime VFR only, so you're not taking that much risk if things went flat, of course.

On Mar 29, 2011, at 12:13 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote:



[quote] 

 

 It is a tad on the low side Eric, but with 10 amps you get 280 watts,

 which is enough to power what he has listed.  

 

 The thing to keep in mind is the instant current demand versus the

 average current demand.  The transponder is the biggest issue here since

 output on it can be as much as +53 dbm, or about 250 watts.  Figure

 about 50% efficiency and you are now up to 500 watts of peak demand.

 However, the time the transmitter is on is very low (duty cycle in the

 single digit range).  The radio is also a big current consumer when you

 are transmitting anyway.  

 

 Further, it is not really a wise choice to run the SK10 wide open with a

 10 amp draw.  I don't think it will last very long that way!  

 

 Thus.... as long as you have a decent set of batteries in there, (as you

 mentioned) this system will work.  The batteries will provide the short

 term current draws needed by the transponders and the radio, and all

 will be good.  I have personally seen this system work on pretty much

 exactly what he has described.  I have also seen a lot of bad things

 happen if the owner does not stay on top of the battery condition.  

 

 The same thing can happen with standard systems as well (battery failure

 causing insidious problems), but not quite so quickly as it does with a

 system running the SK10 and small batteries. 

 

 Thus personally, I recommend the SK35 or SK50.  

 

 Mark

 

 

 --

jan.mevis(at)informavia.b
Guest

Posted: Tue Mar 29, 2011 11:38 am Post subject: B&C Alternator

You're absolutely right, Mark! I have the 10 amp B&C on my Yak 50 and

although it works well, I'm going to replace it asap because the electronic

ignition is consuming more power and I'm on the edge.

Anyway, the 10 amp lightweight is only good enough for Sukhoi's that

participate in aerobatics contests.



Jan

[quote] --

mark.bitterlich(at)navy.m
Guest

Posted: Tue Mar 29, 2011 12:40 pm Post subject: B&C Alternator

I happen to really like B&C products, not only from their quality

standpoint, but also the owner is just a super guy who is always willing

to help anyone with a problem.  So, I tend to promote his products to

some degree.  I wanted to make clear that my experience prejudices me

towards this company.  



Your message is correct in every way.  



The thing about the SK10 is that it must be used by someone who realizes

that they are sacrificing one thing to get another.  The goal of the

SK10 is to get a changing system with the lightest weight possible.  The

sacrifice is that it can't be expected to replace a 100 amp DC generator

when it comes to current draw.  



The "good battery" issue is amazingly important.  If you allow the

batteries to degrade, it is very insidious and most people won't even

notice it is happening, because as you said ... all the battery does is

really power the shower of sparks coil (booster coil) and then it is

"not really used anymore".  



Well not so fast.   



A depleted battery means... AGAIN as you said ... the SK10 will try to

charge them.  And this means that the amount of current generating

capability to power OTHER THINGS is diminished.  Pretty darn soon, the

battery can no longer satisfy peak demands, and the SK10 will try to.

It can't.  What usually lets go in that situation is the voltage

regulator pass transistor, and sometimes it shorts.  



When it shorts, you now have unregulated voltage coming out of the SK10

to the main electrical bus.  At high RPM, your voltage will go WAY up,

and the battery will now charge very hard until it boils every bit of

electrolyte right out it (or them).  



Now your batteries are toast.



WAIT, it gets better!  Now you are hitting the avionics with unregulated

voltage higher than what is "good".  Hopefully, the over-voltage

protection will kick in and blow the circuit breaker.  When it goes, you

lose ALL power in the aircraft... because remember, your batteries are

now bad.  



So you reset the circuit breaker.  Most people would.  BAM, you now have

another over-voltage incursion.  Keep doing that, and your avionics are

not going to like that at all. 



And.. most people will suspect they have an ALTERNATOR problem and not

realize bad batteries caused ALL of this. 



The SK10 is meant for one thing... weight saving for competitive

aerobatic use.  At least that's my opinion.  Other than that, the SK35

or SK50 is the right choice. 



Just sayin. 



Mark Bitterlich

 



--

mark.bitterlich(at)navy.m
Guest

Posted: Tue Mar 29, 2011 12:42 pm Post subject: B&C Alternator

Thanks for the reply Jan.  



Always nice to hear from you, also always happy to hear that your

ignition system is performing well!  



Mark



--

radiopicture

Joined: 23 Jun 2008
Posts: 263

Posted: Tue Mar 29, 2011 1:35 pm Post subject: B&C Alternator

Cheap insurance, new batteries.



On Mar 29, 2011, at 3:58 PM, Bitterlich, Mark G CIV Det Cherry Point, MALS-14 64E wrote:



[quote] 

 

 I happen to really like B&C products, not only from their quality

 standpoint, but also the owner is just a super guy who is always willing

 to help anyone with a problem.  So, I tend to promote his products to

 some degree.  I wanted to make clear that my experience prejudices me

 towards this company.  

 

 Your message is correct in every way.  

 

 The thing about the SK10 is that it must be used by someone who realizes

 that they are sacrificing one thing to get another.  The goal of the

 SK10 is to get a changing system with the lightest weight possible.  The

 sacrifice is that it can't be expected to replace a 100 amp DC generator

 when it comes to current draw.  

 

 The "good battery" issue is amazingly important.  If you allow the

 batteries to degrade, it is very insidious and most people won't even

 notice it is happening, because as you said ... all the battery does is

 really power the shower of sparks coil (booster coil) and then it is

 "not really used anymore".  

 

 Well not so fast.   

 

 A depleted battery means... AGAIN as you said ... the SK10 will try to

 charge them.  And this means that the amount of current generating

 capability to power OTHER THINGS is diminished.  Pretty darn soon, the

 battery can no longer satisfy peak demands, and the SK10 will try to.

 It can't.  What usually lets go in that situation is the voltage

 regulator pass transistor, and sometimes it shorts.  

 

 When it shorts, you now have unregulated voltage coming out of the SK10

 to the main electrical bus.  At high RPM, your voltage will go WAY up,

 and the battery will now charge very hard until it boils every bit of

 electrolyte right out it (or them).  

 

 Now your batteries are toast.

 

 WAIT, it gets better!  Now you are hitting the avionics with unregulated

 voltage higher than what is "good".  Hopefully, the over-voltage

 protection will kick in and blow the circuit breaker.  When it goes, you

 lose ALL power in the aircraft... because remember, your batteries are

 now bad.  

 

 So you reset the circuit breaker.  Most people would.  BAM, you now have

 another over-voltage incursion.  Keep doing that, and your avionics are

 not going to like that at all. 

 

 And.. most people will suspect they have an ALTERNATOR problem and not

 realize bad batteries caused ALL of this. 

 

 The SK10 is meant for one thing... weight saving for competitive

 aerobatic use.  At least that's my opinion.  Other than that, the SK35

 or SK50 is the right choice. 

 

 Just sayin. 

 

 Mark Bitterlich

 

 

 --

mark.bitterlich(at)navy.m
Guest

Posted: Wed Mar 30, 2011 7:14 am Post subject: B&C Alternator

That is absolutely correct.  And if you have any doubt ... test them

UNDER LOAD, with at least 10 amps of draw or more and check the voltage

drop. 



Mark

--

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