What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Electric puzzle, no game - real troubleshoot

Daida

Well Known Member
Sum-up: Electric puzzle, no game - real troubleshoot

Hi Folks,
this is gonna be a longer one, but help is much appreciated.

I equipped my plane with a complete Dynon SV (Display, COM, XPDR, GPS, ADHRS, EMS, INTERCOM and a D6 as Backup). B&C light weight starter and Plane Power Alternator (AL12-EI60/V internal Voltage Regulator) and Concord Battery RG-25XC.

I am deep in Phase 1, adjusting the EFIS (IAS, HDG,.....).
On the last flight i had the CAUTION ALERT of HIGH AMPS of the Alternator.
Readout was +54 Amps positiv charge.

One thing i learned so far is that the Audio alert is only coming through when the INTERCOM is switched on. When i fly solo, i usually switch the INTERCOM OFF because the COM is working anyways. In the future i will switch the INTERCOM ON at all times!

Due to the issue above and my distraction on other things (calibrating the EFIS) i flew around with this high Amp charge for approximatly 20 minutes before i noticed it.
I immediately re-cycled the Alternator with no change of the Situation.
i switched off the Alternator and directly returned home, which took another 5 minutes. After i switched off the Alternator, i reduced the electrical load by switching off all unnecessary consumers and the ampermeter showed -2 Amps, which i consider a normal reading when only the SV is running.

On the Ground i shut down, waited 3 minutes and tried to restart to look if the Situation would be the same or not.
Battery Voltage was 12.7V, i engaged the starter, the prop did half of a turn and came to a stop. Battery voltage dropped down to 8V while the starter was engaged.

i de-cowled the front and started investigating.

i checked my battery with a battery tester, indication was normal, charge 50%.
i charged my battery and tried again, no change. Voltage drop down to 8V, half turn of the prop.

i disconnected the battery and jump-wired a car battery to the System. The car battery was tested as well, indication was good.
i engaged the starter, voltage drop to 8V. half turn of the prop.
i disconnected the car battery.

i got the jump-starter kit from my flying club, hooked it up to the plane, no additional battery connected, engaged the starter, half turn of the prop, voltage drop to 8V.

The AWG#2 wire from the battery to the master relay was warm after all the starting attempts. The AWG#2 wire from the master relay to the starter relay was not as warm but still warm.
The AWG#2 wire from the starter relay to the starter was Cold.

i figured that a bad contact in the starter relay was the probable cause and replaced it with a new master relay that i still had. (master relay insead of starter relay should work, right?)

Tried again, prop turned 2 rotations (now back on the re-charged, hooked up Aircraft battery), voltage drop to 8V.

I am running out of ideas what the Problem might be.

next steps are:
1. powering the starter directly to see what happens
2. replacing the master relay (bad contacts in there??)
3.checking the whole System for bad Connections, loose nuts (especially on the shunt)

I still don´t know what caused the high Amp charge of the Alternator.
As the Alternator is rated up to 60 Amps and the max value was 54 Amps, i don´t think that the Alternator is broken.

Questions are:
-did i fry my battery due to monumental discharge? (i know that they don´t like that but the battery tester indicates different)
-did i fry my battery with the high Amp charge from the Alternator for 20 minutes?
-might the Alternator be the cause?
-might the starter be the cause?

The Alternator switch is a 5 Amp braeker-switch as recommended by the manufacturer.
The 50A Fuse from the Alternator to the main bus as depicted in the scheme is a 60A Fuse
 

Attachments

  • Elec System D-EXLP.JPG
    Elec System D-EXLP.JPG
    87.7 KB · Views: 278
Last edited:
additional information

i described the Problem as good as i remebered.
Electronics and me are not the best Friends.
If i missed someting important, please ask and i will try to provide the best Information i have.

I have a 12V System and do not remember what the voltage was during the high amp Situation.
I try to get this info from the Dynon data-log.
however, i don´t think that i had a over-voltage as None of the curcuit breaker tripped and the Alternator was operating within specs at all times.
 
There are 2 sides to every electrical circuit. You don’t mention checking ground wires. Do you have a dedicated ground from engine block to where your battery ground is? Is it still good if you do have it?

Jay
 
additional information DATA LOG

i have the Dynon data.

The flight started out quite normal.
Voltage is steady during initial power up. Upon engine start, voltage drop, amps Show discharge (starter engaged).
Alternator switched on.
Voltage solid at 14.4 V. Amps initially Show charge of +28 A, rapidly decreasing to +1.8A.
Ops normal for 20 minutes.

During a 4G Pullup (i don´t know if this has something to do with it, but you can see it in the data-log), Voltage Drops 12.4V and the Amps go up to a maximum of +63,7A within 2 seconds. (coincidence???)
During the next Minute, the voltage creeps back up to 14.3V and the Amps coming gradually down to +8.6A.

(I did not switch the Alternator off, not yet.)

all of a sudden, Amps go up again (+55.4A) and voltage drops to 12.5V.

This is the moment when i saw the CAUTION ALERT and switched of the Alternator field.
Immediate voltage drop to 11.9V and Amps Show discharge -4.3A

I figure this as normal behaviour, as the SV Display, COM, XPDR, D& and Sttrobe Lights were drawing power.
11.9V for the battery is probably a bit low, but Maybe the high Amps have already deepfried the battery???

When i switched the Alternator back on, Voltage Comes up to 12.6V and Amps go up to +56A.

Alternator switched off.

i tried a second time with the same indications and values.

Alternator switched of again, remained off for the rest of the flight.
As i switched off the strobes, XPDR, D6 and the COM, the discharge was at -2.1A which i consider to be normal. Voltage however stayed below 12V. slowly but steady decreasing to values around 10.5V within those 5 minutes that the immediate return flight lasted.
From the first Amp rise till engine shutdown was 7 minutes and 43 seconds.

So i conclude:
-no overvoltage during the whole Event --> voltage Regulator of the Alternator should be working fine

-the Battery seems to be a bit weak, showing fairly huge voltage drop when only the SV was drawing -2A for 5 minutes.
Even so the battery tester on Ground say everything is okay.
But what About the other battteries i tried??? slight Chance that all of them are not the best anymore???

Questions:
-where ended all those Amps at??? who or what took the load???
-did the 4 G pullup caused a shortcut anywhere in the electrical system??
-did the 4G Pullup caused something within the battery to break (shortcutting two cells??) and all the load ended up there???
-were the other batteries i tested really as good as the tester said they were?

any other opinions??
missing data??
 
Last edited:
Ground

This has all the characteristics of a ground problem. Make SURE the engine is grounded to the airframe with large wire, same size or larger than the positive lead to the starter. If this is not done, you will be pulling the ground current through your control cables and wiring and this is NOT good and could cause a fire in the engine compartment as well as destroy avionics.
Ed
 
There are 2 sides to every electrical circuit. You don’t mention checking ground wires. Do you have a dedicated ground from engine block to where your battery ground is? Is it still good if you do have it?

Jay

Hi Jay,
i have a dedicated Ground wire from the engíne block to the Firewall, a big stud combined with a forrest of tabs.
The negative pole from the battery is also terminated at this stud.

I´ll check every nut (but especially this one) next time when i am at the Airport.

Thanks!!
 
Likely created an intermittent short at or near the battery. Something loose that created an external connection between the positive terminal and an airframe ground. The warm cable from the master to the batt is the clue that the issue is toward the batt and likely at the batt. The 4G pull points to an external source of the short, being pulled in by force or vibration. Also possible the battery is not secured well.

It would appear that your short is between the shunt and the batt, as you show a positive current flow to the batt (look for external sources near the + battery connection and the mating terminal at that shunt),. This assumes that you have the shunt between the battery and the master solenoid, as is implied in your post above. Don't forget to look for an area where the metal airframe slcided through the insulation on that cable.

Larry
 
Last edited:
This has all the characteristics of a ground problem. Make SURE the engine is grounded to the airframe with large wire, same size or larger than the positive lead to the starter. If this is not done, you will be pulling the ground current through your control cables and wiring and this is NOT good and could cause a fire in the engine compartment as well as destroy avionics.
Ed

Hi Ed,

from then battery to master relay to starter relay to starter is AWG#2.
The starter is bolted to the engine case Bottom (of course).
I ran a AWG#2 cable from the top of the engine to the Ground stud,with the forrest of tabs, where the Ground from the battery is also connected to.

i will check the Ground Connection thoroughly.

Thanks!!
 
Likely created an intermittent short at or near the battery. Something loose that created an external connection between the positive terminal and an airframe ground. The warm cable from the master to the batt is the clue that the issue is toward the batt and likely at the batt. The 4G pull points to an external source of the short, being pulled in by force or vibration. Also possible the battery is not secured well.

It would appear that your short is between the master solenoid and the shunt, as you show a positive discharge from the batt. This assumes that you have the shunt between the battery and the master solenoid, as is implied in your post above.

Larry

Hi Larry,

battery is mounted at the Firewall, Held in place with the Van´s battery tray and the crossbar on top. To countermeasure the G-loads i support the tray with a thick aluminum angle, mounted on the tray and the Firewall at a 45 degree angle.
i will double check for movement there and re-check the cable from the positive battery terminal to the master relay for possible shortcuts.

Question:
is it possible that the 4 G pullup made the starter relay engage???
i think that EXTRA´s have them mounted sideways or upside-down to prevent this during high G maneuvers……
but at 4 G..???????????

i don´t have a starter engaged light, so i cannot tell.
 
Hi Larry,
on:
is it possible that the 4 G pullup made the starter relay engage???
i think that EXTRA´s have them mounted sideways or upside-down to prevent this during high G maneuvers……
but at 4 G..???????????

i don´t have a starter engaged light, so i cannot tell.

Something downstream from your shunt was drawing at least 63 amps, and likely a LOT more, given th state of discharge on the battery after the flight.. accourding to your diagram, amps provided from the alternator to the starter will not register on your ammeter and if any current was provided by the battery, they would show as negative not positive.
 
.

Need more details on where your shunt is located.

Larry

Larry,
in my first post at the Bottom is my electrical System scheme.

(or am i the only one seeing it??, Posting Pictures gone wrong #7887378, sorry)

My shunt ist behind the master relay and the main bus.
(if you can sée my drawing, the box where the Ammeter ist wired to)
starter relay is powered directly from the master relay, not via the shunt.
Alternator powers the main bus.
 
Larry,
in my first post at the Bottom is my electrical System scheme.

(or am i the only one seeing it??, Posting Pictures gone wrong #7887378, sorry)

My shunt ist behind the master relay and the main bus.
(if you can sée my drawing, the box where the Ammeter ist wired to)
starter relay is powered directly from the master relay, not via the shunt.
Alternator powers the main bus.

I viewed it and re[wrote my post based upon that.
 
i re-looked my Dynon data.
the second Amp raise was also lead by a pull up maneuver with 4G.

most probably creating a shortcut somewhere.

i will drive to the Airport immediatly and disconnect the battery and look thorougly for anything to proof it Right.

Thanks everyone so far.
Keep coming with your thoughts.
 
Since the voltage drops when the current rises, that indicates that there is a
very heavy load or short circuit. That current was NOT going into the battery.
Is it possible that the 4G Pull up caused the starter contactor to close?
Maybe the high current was going into the starter and damaged it.
That would explain why starter is not working now.
No, the starter contactor should NOT be replaced with a battery contactor.
A battery contactor is designed to carry starter current, but not switch it on or off.
Install a new starter contactor and maybe a new battery contactor too.
Have the starter tested.
 
On a slightly different subject, looking at your wiring diagram, I don’t believe your pmags are connected properly. I don’t think you should be routing power thru your switch. Nothing to do with your original problem, just want you to be safe.


Jay
 
Is it possible that the 4G Pull up caused the starter contactor to close?
Maybe the high current was going into the starter and damaged it.
That would explain why starter is not working now.
No, the starter contactor should NOT be replaced with a battery contactor.
A battery contactor is designed to carry starter current, but not switch it on or off.
Install a new starter contactor and maybe a new battery contactor too.
Have the starter tested.

Wilco!

Thanks!!
 
On a slightly different subject, looking at your wiring diagram, I don’t believe your pmags are connected properly. I don’t think you should be routing power thru your switch. Nothing to do with your original problem, just want you to be safe.


Jay

will re-check as well.

Thanks!!
 
I should add that in addition to the possible short, the fact that you are getting an excessive voltage drop and low starter performance on a fully charged battery indicates that you have excessive resistance between the starter and the battery. It is possible that this is related to the mystery power consumption that we are speculating to be a short. Or possibly it is separate and coincidental.

Larry
 
Last edited:
Considering you jumped your battery and had the same problem, I’d assume your battery has an internal short and it is toast. Replace your battery. If you still have a problem then move forward from there.

BTW - I strongly recommend never jump starting any RV. If your battery is that bad, charge it on the ground. If you have abused your battery (e.g. left the master on) replace it before next flight. You might breath some life into a flat battery but it will never have the reserve capacity you need.

Carl
 
Probable cause found

I checked the starter relay which i took out yesterday.
(I still will change the master relay, Which i put in as a substitute, with a new starter relay.

When you shake it back and forth ever so slightly you can hear the contacts close and open.

I jumpwired a new battery directly to the starter. The starter turned but got slower after 2 full rotations of the prop.

I took the starter out and bench tested. Voltage drop on a 12V battery was coming down to 9 without the Load of the engine.
The manual says: voltage drop around 9V and poor starter performance is a good indication that the starter needs inspection/repair.

I will contact the guys from B&C tonight.

So i conclude the following:
During the 4G Pullups, the starter relays closed, engaging the starter.
Starter gear engaged in the starter ring. Engine was running at 2400 rpm. Trying to match the engine speed the starter needed a whole Lot of energy, or was not engaged but rubbing and spinning freely, drawing a whole lot of current as well.

Sounds realistic??

At least the starter ring gear on the engine seem to agree as there are quite sharp and protruding little edges on the rear end where the starter gear engages.

The story probably will go like this:
The 15$ starter contactor that cost me 719$ for a new starter.

Thanks for all your help!!! Big time!!!

It is good to know that you are not alone with your problem!!

I keep u posted.

Mit Fliegergruss

Peter
 
I checked the starter relay which i took out yesterday.
(I still will change the master relay, Which i put in as a substitute, with a new starter relay.

When you shake it back and forth ever so slightly you can hear the contacts close and open.

I jumpwired a new battery directly to the starter. The starter turned but got slower after 2 full rotations of the prop.

I took the starter out and bench tested. Voltage drop on a 12V battery was coming down to 9 without the Load of the engine.
The manual says: voltage drop around 9V and poor starter performance is a good indication that the starter needs inspection/repair.

I will contact the guys from B&C tonight.

So i conclude the following:
During the 4G Pullups, the starter relays closed, engaging the starter.
Starter gear engaged in the starter ring. Engine was running at 2400 rpm. Trying to match the engine speed the starter needed a whole Lot of energy, or was not engaged but rubbing and spinning freely, drawing a whole lot of current as well.

Sounds realistic??

Peter

No.

Please explain how activating the starter would show as a 63 amp charging of the battery with a 12.5 buss voltage. I have never seen a starter drop that little of voltage, even if it was free wheeling, as it would have in you case.

If your wiring diagram is accurate, I don't see how that can explain your data logs. Further, you were able to stop the event by opening that alt field. How can that be related to a starter solenoid?

Something downstream of your shunt was drawing an awefull lot of power and if your shcematic is correct, it cannot be the starter. Strongly suggest you find something down that path.

Not saying you don't have an issue with your starter or solenoid. Just saying that they don't explain the problem you outlined in you first two posts.
Larry
 
Last edited:
Not done yet?!?!?

Larry,
thanks for your help.
Like said, electronics and me are not the very best friends.
I will look into it, re-read some books and try to understand.

I will get back to you.

Thanks!
 
Simple check

Seems to me a quick inspection of the ring gear and starter clutch/head would solve the "starter engage" dilemma ...
 
Just a quick look at your diagram and io don't see any blocking diodes in your circuits. Maybe on further examination, you may want to be sure you only have DC voltage traveling one direction. You should also consider installing a diode across the coil on each contactor. Either way, be sure to let us know what you find.
 
No.

Please explain how activating the starter would show as a 63 amp charging of the battery with a 12.5 buss voltage. I have never seen a starter drop that little of voltage, even if it was free wheeling, as it would have in you case.

Not saying definitively that this is what happened, but it's possible for a starter thats stuck engaged with the engine running to shove a lot of juice back into the system.
 
Daida,
Please be aware that the Vans RV7 drawings - specifically 31A shows an orientation of the starter solenoid that per "Note 3" is not subject to accidental inadvertent actuation due to excessive positive G forces. I do not know if the RV8 drawing are similar or if you followed the suggested orientation of your solenoid. A starter that is inadvertently engaged CAN stay engaged & an over-run clutch typically protects the starter from running at full engine speed (but it still draws a fair amount of current). Sounds to me that if you have a "cold" #2awg wire from starter solenoid to starter it's because either the contractor is not making a connection or the starter itself has gone open circuit. That said - if you are still getting a huge voltage drop & current flow from the battery with the master solenoid engaged - you have some other short somewhere to find. And you very well may have injured the battery as well. Place a volt meter on output terminal of starter solenoid & also look at input terminal of starter.
Best of luck finding this issue.
Steve N7453C in AZ.
 
Daida:

A couple of comments on your relays:

First, there are two kinds of contactors (relays). "Intermittent" and "Continuous". They are designed differently. The Starter Contactor is an "Intermittent" type where the contacts are designed for an instantaneous high load for a short duration. They can take quite the hit all at once but are not designed to sustain load for long. Meanwhile the master contactor is a "Continuous" type where the contacts are designed to switch a normal load and continuously keep it on. So the master contactor is not designed to switch a huge instant load hit like a starter. The internal design of each type is not compatible to be used as the other type. They will work short term in each other's place but they will burn out quickly with short longevity.

That is the reason there are two kinds. Using the wrong type will burn out the contacts prematurely.

Secondly, try to steer away from cheap automotive relays. When you say you have a $15 relay that is a red flag. Most quality aircraft relays start at $65 and go up from there. However, since we are experimental aircraft we can take advantage of more modern type relays. You live in a perfect location for some of the most reliable of these. I might suggest the Bosch relays. Specifically, for master relay the Bosch / Tyco 332002150 continuous type. For the starter relay the Bosch / Tyco 0332002168 high-current type. Less than $50 each.

Jim
 
Last edited:
Just a quick look at your diagram and io don't see any blocking diodes in your circuits. Maybe on further examination, you may want to be sure you only have DC voltage traveling one direction. You should also consider installing a diode across the coil on each contactor. Either way, be sure to let us know what you find.

Diodes on master-relay and starter-relay are istalled but not shown in the circuit-scheme.
I will adapt the drawing.
 
No shortcuts found

A really thorough check of all connections showed no evidence of a shortcut during the 4G maneuvers. Cables showed no sign of rubbing, splicing, cutting or anything else.
Attached is a picture of my battery assembly to the firewall with the 45 degree support bar. I almost hung myself (200lbs) on that battery tray, not moving it significantly!
So i think i can exclude a shortcut in the wiring/cable.

Picture is rotatet 90 degree counter-clockwise
 

Attachments

  • 2BF80A86-B543-447E-A7C2-3ED7A64EA3C2.jpeg
    2BF80A86-B543-447E-A7C2-3ED7A64EA3C2.jpeg
    22.9 KB · Views: 183
Last edited:
Positive Amp Indication?

Not saying definitively that this is what happened, but it's possible for a starter thats stuck engaged with the engine running to shove a lot of juice back into the system.

Larry, maybe i am wrong, but wouldn’t it show as positive Amps thru the shunt when the starter is engaged whilst engine running, alternator providig power. The demand of the starter is greater than the (already weakend) battery can provide and the alternator jumps in to provide more power (Amps that is)?

I see electricity almost as fluid flowing.
The attached picture shows my way of thinking.
Green is the Flow from the battery. Red is the flow from the Alternator.
Blue is the flow across the shunt.
As of my understanding, the flow is the same as if the battery would be charged after startup and the alternator provides power. (Therefore the reading is positive and no discharge)
Just in this case, the starter draws all power available.

Yes/no??

Please comment!
 

Attachments

  • 08B8D871-CC00-4AE8-A818-61C1883B7F2E.jpeg
    08B8D871-CC00-4AE8-A818-61C1883B7F2E.jpeg
    296.2 KB · Views: 258
Last edited:
Is the problem solved

Is the problem solved?

I've read through the thread, and my suggestion is that your battery has a shorted cell.

The rationale is:
1. If as cell is shorted the output voltage will drop approx 2.x volt. The alternator regulator will respond by increasing field current and commanding the alternator to put out more current to get the voltage back to 14.4V. That will not happen, so the alternator will continue at max current.
2. When you jumpwire an external battery it doesn't help because the the damaged battery will effectively keep the voltage low.

This is just my idea.
 
probably not

The rationale is:
1. If as cell is shorted the output voltage will drop approx 2.x volt. The alternator regulator will respond by increasing field current and commanding the alternator to put out more current to get the voltage back to 14.4V. That will not happen, so the alternator will continue at max current.
2. When you jumpwire an external battery it doesn't help because the the damaged battery will effectively keep the voltage low.

I totally agree with you on Point 1, period. But i doubt that this is my case.

For your Point 2 i have some additional Information.
During the Troubleshooting i did jumpwire my battery once. But on following tgrials i took the battery terminals off, so the battery was not part of the System anymore. Additional tests with 2 different, external batteries without changing results. Massive voltage drop, half Rotation of the prop.
Both external batteries, as well as my Aircraft battery, are indicated as "healthy" if you put a battery tester on them.
So i doubt that i have a battery cell Fusion, because all 3 battteries Show the same behaviour. And it´s fairly unlikely that all 3 batteries suffer from the same Problem, isn´t it?
Furterhmore, yesterday a took the battery terminals off (Aircraft battery that is), took the starter cable off the starter. i took the jump-starter-kit from my flying club and put the negative clamp on the engine hoist hook on top of the crankcase. Then i crawled under the engine, clear of the prop and put the positice clamp direct to the starter stud.
2 rotations (way slower than used to, i compared Rotation Speed with the Video i made upon first engine start, Speed was barely one third as fast), slowing down noticeable during further rotations.
i took the starter out and bench tested it. Voltage dropped from 12V to 9V
without the load from the engine.
Manual says it should be send in for inspection/repair.

I contacted B&C yesterday via their homepage-contact form.
Answer will probably come in today.

i Keep u posted!
 
starter gear was not engaged in the starter ring, was it?

i doubt that the small starter gear was coupled with the starter ring gear.
first of all, the starter ring Shows Little nooks on the aft end that seem to be proof that the starter gear was trying to get in but did not due to the engine Spinning at 2400rpm.
second of all, if the starter would have matched the rpm from the engine, the starter Motor itself would have become a Generator, wouldn´t it???
That would have meant that the starter would have produced electricity. But then, due to the fact that the starter is not voltage regulated, the voltage due to the high rpm would have been extremly high, tripping some circuit breakers.
But None of that happend.
Everything is still working (Strobes, NAV Lights, EFIS, ….). And they all were switched on during the high amp Situation untill i switched them off to reduce consumers.

The SV Data Shows a maximum voltage during the whole event of 14.4V.

i still believe that the battery is good and has no cell Fusion (Maybe got whacked a bit. Battery is fully charged now and Shows 12.8V, voltage drop when i switch on the SV, COM,XPDR and D6 is minor).
I still believe that the G-induced closure of the starter relays fried some of the windings in the starter Motor, thus beeing the shortcut we are talking About.
Fried windings in the starter Motor leave the starter with less power to turn the prop and, as the starter still wants do do its Job, draw current like crazy, comparable to a short cut.

fixture i plan:

new starter relay, put in with a 90 Degree angle.
Starter repair or Exchange.

(re-check the wiring of the P-MAGS)


plausible???
 
Last edited:
Larry, maybe i am wrong, but wouldn’t it show as positive Amps thru the shunt when the starter is engaged whilst engine running, alternator providig power. The demand of the starter is greater than the (already weakend) battery can provide and the alternator jumps in to provide more power (Amps that is)?

I see electricity almost as fluid flowing.
The attached picture shows my way of thinking.
Green is the Flow from the battery. Red is the flow from the Alternator.
Blue is the flow across the shunt.
As of my understanding, the flow is the same as if the battery would be charged after startup and the alternator provides power. (Therefore the reading is positive and no discharge)
Just in this case, the starter draws all power available.

Yes/no??

Please comment!

You are correct. I did not pay close enough attention to the schematic. A draw at the starter would show as positive on the ammeter in your case. I would agree that a weak starter solenoid is a likely cause of your symptoms. My apologies for missing that on the first review.

larry
 
You are correct. I did not pay close enough attention to the schematic. A draw at the starter would show as positive on the ammeter in your case. I would agree that a weak starter solenoid is a likely cause of your symptoms. My apologies for missing that on the first review.

larry

no apologies, please!
you were trying to help, i appreciate this BIG TIME!!

you made me going on close contact with my "not-so-best-friend-electronics", you got me thinking and i learned something!!

Thank you for that!

infact, i thank all of you supporting me on this issue.

i keep you posted.
 
root cause found, puzzle completed, problem solved,

Hi community!

the title says it all. Well, not quite.

Root Cause: the builder!

The builder (me, that is!) did not pay good enough attention when initially wiring up the electrical System. He put a master relays where a starter relays was supposed to be when he wired up his electrical System.
The main diffference between those to relays is, that a master relays engages when the Connection to Ground/airframe is closed by a switch (Master switch). A starter relays engages when the coil of the solenoid gets positive System voltage (12V in my case) thru the starter switch.
In Addition to that, the spring, helping the contactor to disengage is much stronger in a starter relays than it is in a master relays. One can tell the difference by shaking the relays back and forth. If you hear the contacts closing, it is most definetly a master relays. If you hear nothing (unless shaking really, really hard) it should be a starter relays in your hands.

i know now!

How this could happen? i don´t know, but it did! Bad enough.
I even draw the electric scheme wrong in a way i cannot explain either, as it was not showing what i really did with the routing of the wires.

Please don´t give me a hard time about this, it is hard enough to confess and the shame is on me anyways.

It is solely me to blame, period.


puzzle completed:
The coil of an inadvertent used master relays as starter relays closed upon a 4G pullup during envelope expansion flights in Phase 1. Thus engaging the starter whilst the engine was running at 2400rpm, allowing the starter to wind up to infinite rpm internally, drawing infinite amount of Energy, resulting in approx 100 A (40 A from the battery, 60 A from the Alternator)for roughly 90 seconds to the starter, welding the relays contactor bridge in place and finally burning the starter Motor.

Situation ended when the Pilot (me, again!) switched of the master switch.

i took both (relays and starter) apart inspecting the interior. i did not like what i saw. You wouldn´t either, believe me.

At least the situation did not evolve into a electric fire or a even worse situation where i easily could have lost my plane.

My stupidity (only) cost me a new starter relays and a new starter.

So after all, i am lucky (but ashamed) to tell my story that others don´t have to go thru all this.


Problem solved:
i put in a new starter relays (on a 90 Degree angle), re-wired my starter switch, re-draw my Electric scheme, ordered a new starter, will put it in when it arrives, go fly again.

i re-checked my wiring of the P-Mags and discovered that i wired them up correctly, but did the drawing on the electric scheme wrong (again!!).
Re-draw the scheme for the P-Mag wiring.

Lessons learned:
Numerous, but the most important is probably that even if you build a plane all by yourself, get help on things you know you´re not good at (electronics in my case). The shame to admit that you need help (wiring things up) is nothing compared to the shame when things gone wrong due to the fact you did not ask for help!!

Don´t do it like i did!

Sooo, here i am...……

Thanks for all your Inputs!!
Stay well out there.
 

Attachments

  • Electric scheme new.JPG
    Electric scheme new.JPG
    89.2 KB · Views: 238
Last edited:
Glad you got it sorted out, with minimal expense and drama. No need to be ashamed. I can't imagine anyone building an airplane can have a mistake rate of Zero. We all do it, though to different levels. I applaud you for sharing the details so that all can learn from it.

Larry
 
Hi community!


The main diffference between those to relays is, that a master relays engages when the Connection to Ground/airframe is closed by a switch (Master switch). A starter relays engages when the coil of the solenoid gets positive System voltage (12V in my case) thru the starter switch.
In Addition to that, the spring, helping the contactor to disengage is much stronger in a starter relays than it is in a master relays. One can tell the difference by shaking the relays back and forth. If you hear the contacts closing, it is most definetly a master relays. If you hear nothing (unless shaking really, really hard) it should be a starter relays in your hands.

Thanks for posting the problem and the solution. This will help a lot of new builders, including myself.
 
Back
Top