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Charging system trouble shooting
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occom

Joined: 26 Aug 2006
Posts: 404

Posted: Sat Apr 25, 2009 8:49 am Post subject: Charging system trouble shooting

Heres how your charging sytem works. I should caution that while it's 

extremely simple, if you have no idea how electricity works, maybe you 

should recruit someone who does.



You have a series of coils on your engine, by the flywheel. They come out to 

two wires one yellow and one yellow with a black stripe. Those wires have a 

resistance between them of about .5 of an OHM, on a cheap meter that as 

close to a short as you can see. You should then connect one side of your 

ohm meter to the engine block and the other side to one of those yellow 

wires, you should see an infinite resistance, an open. The magnets we'll 

take on faith.



When the engine is spinning you will get AC electricity generated out those 

two wires, the power available increases with RPM's voltage will top out far 

beyond anything you want (about 40V) when there is no load. This AC goes 

into the yellow wires on the stock rotax RR (rectifier/regulator), two of 

the yellow wires on a Tympanium, or the terminals marked input (ac) on your 

Key West. (the stock unit is also made by Tympanium, but they are not 

identical)



Each of these units will rectify AC to DC and in the case of the stock and 

Tympanium rectifiers dump all excess power to ground, supplying  12-14 V DC 

out the red wire on the stock unit and the black wire on the Tympanium.  The 

return path on the stock unit is the black wire which goes to the best 

ground you can find, on the tympanium the case is the return path, it must 

be grounded and running a separate ground wire to the electrical GND by the 

battery wouldn't hurt. For the Key West, the + terminal goes to the positive 

side of the battery and the - terminal goes to the best GND you can find. 

There should be NO resistance between the battery - and the rectifier - and 

a suitable gauge should be used for about 16A current on both leads along 

with suitable fuses and or relays. There is no indication of a requirement 

to ground the case on the Key West in any documentation that I can find, but 

it couldn't hurt, even if it's just to help shed heat. The Tympanium and the 

stock unit case must be grounded.



When the engine is running, if you are brave enough to get hear the big 

spinning thing, you will see up to 40V AC on the open circuit yellow wires, 

and you should see 12.5-14V on the output of the Tympanium and the Key West, 

that's between + and - with nothing else connected. With the stock RR you'll 

get a whole range of high voltages because it can't regulate without a load, 

connect a lamp (taillight or something similar) and measure across that and 

you should get the same 12-13 V.  After you connect it to the battery, you 

will of course see 11.8-12.8V in any case. You can see if the voltage rises 

across the battery while the engine runs, it should go up to 13.1-13.5 a 

little higher is OK.



There is a possibility that there exists a resistance in the AC side that 

cannot be seen until current is flowing, it will appear as low resistance to 

the meter but will restrict current flow, it's rare(ish) and I'd bet that 

it's not your problem. It will exhibit as lower voltage as load increases 

(without battery) but it is easy to fool yourself  as this is also normal, 

it's a matter of degree and it really requires experience to diagnose.



As far as your Hobbs goes, if you have run the engine for a couple of hours 

and no measured it, it's a sure bet you have it hooked up wrong or it's 

broken. The hobbs is a simple clock that runs as long as it sees the 

appropriate voltage (DC in most cases) on the terminals. if you hooked it to 

the master it will clock all the time the master is on. It should not in any 

case be hooked to the yellow wires.



I have no idea if this will help, and if your aircraft bursts into flames or 

you damage somethng by doing anything I've said, it's all on you!



If someone sees an error in the above point it out, don't get into the finer 

points of electron flow or power calculations, think grade school level of 

electrics.

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sat Apr 25, 2009 12:06 pm Post subject: Charging system trouble shooting

I'd still start with the grounding.  All regulators require grounding whether through a wire or through the case.  

   

Assuming your grounding is good put an AC volt tester across the two yellow or yellow and red tracer wires coming from the magneto end of the engine and run the engine.  You should see some AC voltage on your meter.  In fact you should see a decent voltage ??? 12 - 15VAC.???  If you don't see any voltage there with the engine running you definitely have a problem with the lighting coil in the magneto.  

   

Assuming you have good AC voltage in the two yellow wires then the problem has to be in the regulator.  Actuallyu it's a regulator/ rectifier bridge.  

   

   

Noel[img]cid:image001.jpg(at)01C9C5E1.312B3B00[/img]  

   

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Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

WurlyBird

Joined: 16 May 2008
Posts: 207
Location: North Pole, Alaska

Posted: Sun Apr 26, 2009 10:09 am Post subject: Re: Charging system trouble shooting

Occom, great reply, thanks.



Dave, I have not done a voltage check yet, today was the first day I have had time to pull it out of the garage.  I can tall you that I am getting 12.5ish volts off the battery while not running, according to the volt meter on the panel, and it never goes up when the engine is running.  When I check AC between the two yellow wires I have to disconnect one right?  Will there be any chance of arcing?



Here is what I have found new, I think it is pretty pertinent but it confuses me since, as always I don't have the appropriate wiring diagrams.  Here is a run down of all tabs on the back of my ignition which is as far as I can trace continuity from the RED wire off the Key West.



going clockwise and starting arbitrarily;



MAG-this is where the RED Key West wire terminates and I can verify continuity the whole way.

ACC-there is a thin red wire coming off of this that I did not trace, logic says it operates a relay for all the accessories.

GND-nothing attached, closed circuit with both MAG tabs when in the OFF position.

BAT-large RED wire going off to the Master switch on the panel.  The other end of the Master Switch is connected directly to the battery.

MAG-nothing wired here.  This tab has continuity with the other MAG tab in the OFF position.

SOL-big white wire going off presumably to the starter.



The only thing that ever happens to the RED wire from the Key West is that it is closed with a GND and another MAG that are both not wired to anything.  I checked at all ignition settings including START (the battery is out).  It seems that this would be used to ground out Mags to shut off the engine but it is not wired properly and this would not work using a voltage regulator if I understand it correctly.  I can not figure why this wire would terminate at the ignition.  Shouldn't this wire go directly to the battery?  Should there be any sort of interrupt so the regulator is not trying to develop a charge during the start?  I am pretty sure that this is the cause of my problems and even if it isn't it is the next step to remedying the charging issue.  



So, with this information, what are your thoughts?

 

By the way, I am reading .5 Ohms across the two yellow wires.

_________________
James
Kitfox 3 / 582 / 70" IVO 2 blade GA
50 hrs on the 582 swapping for HKS 700E and Avid Cowl.

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Apr 26, 2009 11:24 am Post subject: Charging system trouble shooting

I mentioned disconnecting one of the yellow leads so there would be no chance of the regulator loading the lighting coil and giving you a false low voltage.  If you are worried about arcing simply use a bit of electrical tape around the connections to the AC voltmeter.  

  

The fact you have continuity between the two yellow wires is good.  You can also check for continuity between either yellow wire and the ground...There shouldn't be any.  

About your ignition switch.. I think you have problems there.    

The two MAG tabs are for the two grey wires that come from your magneto.  These are the P-Leads that short out the ignition to stop the engine.  They are also used to do the MAG tests.  Grounding either grey lead turns off the MAG it is connected to.   

So when the switch is turned on both tabs should not show any ground.  When the switch is off they both should test as ground with the ohm meter.  Depending on the type of meter you have they should show a small fraction of an ohm in the off position between the tab and ground.  

ACC should power up your panel.  B+ (Battery + Terminal )  coming from your battery to the switch via the big red wire will be switched by the ignition switch to turn on and off your panel and Hobbs if you have one.  

GND is ground.  It should be grounded to the frame somewhere to turn off the MAGs and stop the engine.  

BAT is good.  This is where your B+ enters your ignition switch.  The master shut off is a nice touch.  That wire should be protected by a fuse (15-20A) at the battery end.  It is possible that the charging wire from the regulator/rectifier may be attached to this terminal also.  It is also a nice idea to switch that wire and label the switch ALT.  The alt switch should be located right beside the Battery master switch which you can label BAT.  

SOL  ...That is probably the starter solenoid.  Check if you can see a big white wire disappearing into the starter housing.    

NOTE:  There should also be a very heavy wire (probably red) between the battery and the starter.  Starter motors require a lot of current ergo, a dirt big wire.  

The  charging system and the ignition switch are by the way separate electrical systems with wires that disappear into the MAG end of the engine.  

Noel  

--

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Kitfox III-A
Aerocet 1100 Floats

Paul A. Franz, P.E.

Joined: 02 Dec 2008
Posts: 280
Location: Bellevue WA

Posted: Sun Apr 26, 2009 11:33 am Post subject: Charging system trouble shooting

On Sun, April 26, 2009 11:09 am, WurlyBird wrote:



 	  Quote: 	
		   Dave, I have not done a voltage check yet, today was the first day I have had time to

 pull it out of the garage.  I can tall you that I am getting 12.5ish volts off the

 battery while not running, according to the volt meter on the panel, and it never goes

 up when the engine is running.


	


Something is charging the battery. Is it keeping its charge or are you putting it on a

battery charger? If you're not having to maintain the charge with supplemental

charging then the system is working to some extent and that voltmeter is not

presenting a valid measurement because if it were charging when the engine is running

the nominal voltage would go up.



 	  Quote: 	
		    When I check AC between the two yellow wires I have to

 disconnect one right?  Will there be any chance of arcing?


	


Safest way is to check with them under load. Open circuit test might not give you

anything valid.



 	  Quote: 	
		   Here is what I have found new, I think it is pretty pertinent but it confuses me

 since, as always I don't have the appropriate wiring diagrams.  Here is a run down of

 all tabs on the back of my ignition which is as far as I can trace continuity from the

 RED wire off the Key West.


	


I can't be sure of what you're describing. I think you're going to have to do an

as-built wiring diagram before you can proceed with much confidence.

-- 

Paul A. Franz

Registration/Aircraft - N14UW/Merlin GT

Engine/Prop - Rotax 914/NSI CAP

Bellevue WA

425.241.1618 Cell



THE LAST WORD



"This year federal government spending will rise to 28.5 percent of

GDP, the highest level ever, with the exception of the peak of the

Second World War. The 44th president is proposing to add more to the

national debt than the first 43 presidents combined, doubling it in the

next six years, and tripling it within the decade. But to talk about it

in percentages of this and trillions of that misses the point. It's not

about bookkeeping, it's about government annexation of the economy, and

thus of life: government supervision, government regulation, government

control. No matter how small your small business is -- plumbing,

hairdressing, maple-sugaring -- the state will be burdening you with

more permits, more paperwork, more bureaucracy. And don't plan on

moving. Ahead of this week's G20 summit in London, Timothy Geithner,

America's beloved Toxic Asset, called for 'global regulation.' 'Our

hope,' said Toxic Tim, 'is that we can work with Europe on a global

framework, a global infrastructure which has appropriate global

oversight.' 'Global oversight': Hmm. There's a phrase to savor. 'We

can't,' he continued, 'allow institutions to cherry pick among

competing regulators and ship risk to where it faces the lowest

standards and weakest constraints.' Just as a matter of interest, why

not? If you don't want to be subject to the punitive 'oversight' of

economically illiterate, demagogic legislators-for-life like Barney

Frank, why shouldn't you be 'allowed' to move your business to some

jurisdiction with a lighter regulatory touch?"

-- columnist Mark Steyn



In general, the art of government consists of taking as much money as possible from

one party of the citizens to give to the other.

-- Voltaire (1764)

_________________
Paul A. Franz, P.E.
Registration/Aircraft - N14UW/Merlin GT
Engine/Prop - Rotax 914/NSI CAP
Bellevue WA
425.241.1618 Cell
425.440.9505 Office

WurlyBird

Joined: 16 May 2008
Posts: 207
Location: North Pole, Alaska

Posted: Sun Apr 26, 2009 12:04 pm Post subject: Re: Charging system trouble shooting

I charge my battery in between flights and have about 2-3 hours before incoming transmissions are unintelligible.  The strobes operation can be seen on the voltmeter in flight as an undulation in voltage, which again, never indicates any higher then before starting 12.5-13 v.  I can say pretty definitively at this point that there is no charging going on.



So if the red wire is going to the battery, does there need to be an interrupt that can be turned off during start or can it just be wired directly the whole time?

_________________
James
Kitfox 3 / 582 / 70" IVO 2 blade GA
50 hrs on the 582 swapping for HKS 700E and Avid Cowl.

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Sun Apr 26, 2009 12:35 pm Post subject: Charging system trouble shooting

I've never seen an aircraft ignition switch with an ACC position so you've 

got me there. The big error I can spot is the one Noel Loveys already 

pointed out, The Mag terminals are grounded when the switch is set to off, 

the left ign. trigger  is grounded when set to right and the right trigger 

when set to left. The output of the Key West should never go near these 

terminals. If you have an ACC terminal, and the switch can handle 16 amps 

then you put it there assuming it is actually energized  when the switch is 

on. I'd put it through a 20 amp fuse and straight into the battery. In fact 

I did on my own. I can reach the fuse and remove it if desired.

So I would wire my switch :

MAG: one of the P pleads

MAG: the other P lead

ACC:  no advice.

GND: to a good reliable GND

BAT to + lead, it's used to energize the solenoid. should be dead when 

master is off in my opinion.

SOL to Solenoid actuator coil.



If you have separate left and right mag switches then nothing should be 

wired to the MAG terminals, and you could likely disregard the GND.





---

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Sun Apr 26, 2009 12:43 pm Post subject: Charging system trouble shooting

I've never seen an ACC position on an aircraft ignition switch, but it was 

common on a lot of other switches that did have ACC positions for that 

position to go dead as you moved the switch to start. You could check if 

it's something you desire.

---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Apr 26, 2009 2:17 pm Post subject: Charging system trouble shooting

I go along completely with what Dave has said here with one very minor

exception I would connect the output of your regulator to the bat lead

preferably through a switch.  In the unlikely event of a diode fusing in the

rectifier there then would be no chance of draining your battery through the

regulator.



Noel



--

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Kitfox III-A
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Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Sun Apr 26, 2009 2:21 pm Post subject: Charging system trouble shooting

That feature is supposed to give you full current for the start.  



Sometimes designers will put a dirt big diode in reverse polarity across the

lead to the starter and ground.  Then any reverse spikes generated when the

starter is released will be shunted to ground through the diode.



Noel



--

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Kitfox III-A
Aerocet 1100 Floats

WurlyBird

Joined: 16 May 2008
Posts: 207
Location: North Pole, Alaska

Posted: Fri Jun 19, 2009 6:37 pm Post subject: Re: Charging system trouble shooting

Well it has been a while but I have an update.  I took the RED wire off of the ignition switch and ran it to a spare switch on the panel, through a fuse.  When the switch is on the charging function reaches the battery.  when the switch is off the charging function dies at the regulator.  When the switch is on I am observing about 14-15V on the panel, so the charging system is now working.  Freakin awesome.



But now the "charging" is coming through to the radio and making noise.  I would not even notice but the intercom has an Ipod interface and the music mutes when the radio makes noise and it is not even worth playing music at this point.  Any ideas on this one?



James

_________________
James
Kitfox 3 / 582 / 70" IVO 2 blade GA
50 hrs on the 582 swapping for HKS 700E and Avid Cowl.

kerrjohna(at)comcast.net
Guest

Posted: Fri Jun 19, 2009 6:58 pm Post subject: Charging system trouble shooting

is the 22000 mf capacitor installed in the circuitry?  it will suppress the alternator noise.

---

WurlyBird

Joined: 16 May 2008
Posts: 207
Location: North Pole, Alaska

Posted: Sat Jun 20, 2009 10:42 am Post subject: Re: Charging system trouble shooting

Ummm. Where would it be and what does it look like? My guess is NO.

_________________
James
Kitfox 3 / 582 / 70" IVO 2 blade GA
50 hrs on the 582 swapping for HKS 700E and Avid Cowl.

occom

Joined: 26 Aug 2006
Posts: 404

Posted: Sat Jun 20, 2009 1:08 pm Post subject: Charging system trouble shooting

There are two ways to go in terms of silencing the noise if your radio is 

one affected. The first is a large capacitor wired between the battery 

positive (or anywhere on that red wire will do) to ground which will help to 

smooth out the ripple caused when the voltage spikes from the alternator are 

shunted to ground. It must be at least 2200 MFD and 25 volts rated, most 

dealers should be able to help you. The other is a noise filter in the line 

to the 12 feed and ground for the radio. Mine came from Radio Shack.  A 

larger battery of at least 16AH will also work as a reasonable filter but 

the capacitor is much lighter.



Please keep in mind that if you are using a Rotax/Tympanium single phase 

rectifier-regulator you should have at least 1 amp of load to allow it to 

regulate properly and it should not be disconnected while the engine is 

running.



---

dave

Joined: 22 Sep 2006
Posts: 1382

Posted: Sat Jun 20, 2009 6:51 pm Post subject: Re: Charging system trouble shooting

Don't think a capacitor will cure your problem. Might be a slight band aid but your battery will act as  a  capacitor. 



Just started since the charging system  got cured? 



Could be a plentitude of things.   Fix the little things first before you start adding band aid fixes that might not solve the problem at all.  

Noise comes from somewhere, could be a power wire running next to something it should not be. 



DAve

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Guest

Posted: Sun Jun 21, 2009 5:24 am Post subject: Charging system trouble shooting

The 22000 mf capacitor looks like a d battery in size and shape.  its wiring is included in the wiring diagram of the VI and later.  Check with John Mcbean or I can scan and send a diagram.  It is wired in parallel off the voltage regulator as I recall and acts as a noise sink.  In wiring the Hatz I took a lead off the output of the alternator to the capacitor then to ground.  The Hatz alternator was internally regulated.



John Kerr

Classic IV, 912ul, GSC prop, 900 hrs



---

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