Voltage Regulator Failed

[Red]

6 hours ago, facthunter said:

I have a pile of Battery chargers and none of them are suitable for Lithium Batteries. Why would the standard Rotax voltage regulator just cope?   Nev

Thing is these batteries arent just a pack of cells they all have built in Battery Management Systems that are designed to be compatible with regular Lead acid Reg/Recs.

I have used them on my motorcycles for years now with no other change made, they just are a straight swap.

 

I just think the Ducati unit that Rotax use is not as robust as some others, lets face it Italian Electrics have never been top of the pile

[facthunter]

Not everything Italian is junk though. Nev

[skippydiesel]

From Rotax Owners Forum, Mike Miller

 

"It’s been my experience the 965349 regulator fail from vibration. The potting compound is not rigid, think of the PCB as floating in jello (not sure if jello is a thing in Australia,) the PCB is held to the case by the eight wire leads of the rectifier and SCRs. The typical failure mode is a low voltage alarm at low and moderate RPMs (half wave operation) or no output at all. Typically it starts as an intermittent problem that worsens over time.

Usually these regulators are easily repairable. The potting compound can be removed cleanly with simple tools and minimal effort. The picture of potting compound removal sequence spanned less that 10 minutes from start to finish, but I’ve had a little practice. Inspect the eight locations in the second photo for broken connections and re-solder as needed. The SCR leads may look ok, inspect them carefully, often they can be lifted off the board with your finger nail. The rectifier leads should have a cone of solder up from the board to the cut lead, what you usually find is a crater of solder with the disconnected lead coming through the center. If a lead falls off as you solder it, that’s an indication the failure point was at the body of the component and it won’t be repairable without replacing that component, I’ve only seen this happen once. If you we’re successful and removed the potting compound in one one piece, you can resecure it with RTV,  after confirming it’s fixed." 😈

[danny_galaga]

6 hours ago, skippydiesel said:

"No need for capacitor ........"

 

Does this mean that the capacitor is redundant?😈

I would think so, if you mean that were you to install the Carmo, you won't need it anymore. But it can't hurt to leave it, if that's easier for you. My plane only has about 3 hours flying time now, but all good so far. Radio did have some sort of problem, but that was occuring whether the engine was running or not.

[aro]

22 hours ago, skippydiesel said:

No one else has mentioned the high current/Earth X possibility.

All the more reason to go with a more recent VR, that specifically claims compatibility with LiFePo4 battery's😈

Rotax do allow Lithium batteries and even sell them under the Rotax brand - so in theory it should be OK.

But Rotax specify max 22 amps from the regulator, and the batteries list charging current as 5-15A recommended 60A max so I'm not sure how that works together.

Is there something that reduces charging current to keep the maximum load under 22 amps?

[danny_galaga]

2 hours ago, aro said:

Rotax do allow Lithium batteries and even sell them under the Rotax brand - so in theory it should be OK.

But Rotax specify max 22 amps from the regulator, and the batteries list charging current as 5-15A recommended 60A max so I'm not sure how that works together.

Is there something that reduces charging current to keep the maximum load under 22 amps?

The battery will only be able to draw the maximum 22 amps I think. That's theoretically, as presumably there are other loads on. Radio, lights etc. it will only the draw heavily for a few minutes after starting, since it will be charging up. The current draw between the battery and alternator is governed purely by the difference in voltage between the two. If there's nothing wrong with the battery it will charge up and the batteries voltage increases. If you have an ammeter you should see the amps drop down pretty quickly after a start. Longer if the battery was flat 

Edited yesterday at 12:59 AM by danny_galaga

[Geoff_H]

If I understand it correctly the way a permanent magnet generator works is the same as a switch mode power supply.  The AC voltage from the generator that will be speed dependent.  This voltage is rectified and a large capacitor charged.  A control circuit will turn a power transistor on and off through a transformer at a rate that will give an output at the aircraft system charging voltage the rectify this ac voltage and connect the rectified output to the system.  Well in a similar way to this.

[skippydiesel]

1 hour ago, danny_galaga said:

The battery will only be able to draw the maximum 22 amps I think. That's theoretically, as presumably there are other loads on. Radio, lights etc. it will only the draw heavily for a few minutes after starting, since it will be charging up. The current draw between the battery and alternator is governed purely by the difference in voltage between the two. If there's nothing wrong with the battery it will charge up and the batteries voltage increases. If you have an ammeter you should see the amps drop down pretty quickly after a start. Longer if the battery was flat 

In my aircraft system, at start up, there is only two small additional loads, my Dynon & iPad both come on with the Master Switch. Further electrical loads are all post start, these are transceiver, transponder (Ground). I don't have lights, which traditionally are a significant load. So whatever the battery is drawing to recharge, is only slightly reduced by additional loads.😈 

[danny_galaga]

14 minutes ago, skippydiesel said:

In my aircraft system, at start up, there is only two small additional loads, my Dynon & iPad both come on with the Master Switch. Further electrical loads are all post start, these are transceiver, transponder (Ground). I don't have lights, which traditionally are a significant load. So whatever the battery is drawing to recharge, is only slightly reduced by additional loads.😈 

In any case, max 22 amps for a few minutes. Well below the 60 amp peak mentioned before 😇 

[danny_galaga]

46 minutes ago, Geoff_H said:

If I understand it correctly the way a permanent magnet generator works is the same as a switch mode power supply.  The AC voltage from the generator that will be speed dependent.  This voltage is rectified and a large capacitor charged.  A control circuit will turn a power transistor on and off through a transformer at a rate that will give an output at the aircraft system charging voltage the rectify this ac voltage and connect the rectified output to the system.  Well in a similar way to this.

Sorta. A switch mode power supply ramps up the frequency several thousand hertz before then converting that to the required voltage. There isn't a need here. You aren't converting a voltage, just regulating it. 

Edited yesterday at 03:51 AM by danny_galaga

[skippydiesel]

To all -  VECTRIQ (Australian agents for CARMO, maker of CARR5115 MOSFET) are coming across as somewhat lacking in professionalism;

• Take two days to respond to enquiries - phone contact not available.
• Do not have any product - want payment before back ordering.
• Do not answer my technical questions.
• Have at least two advertised prices ($52 Au difference).
• Would seem to be asking somewhere in the region of  + $164 Au above makers advertised price

B & C  (USA - PMR1C-14 regulator) took less than 12 hrs to respond to my enquiry. They have replaced the AVC1 with the PRM1C-14. Looking good!😈

[Geoff_H]

36 minutes ago, danny_galaga said:

Sorta. A switch mode power supply ramps up the frequency several thousand hertz before then converting that to the required voltage. There isn't a need here. You aren't converting a voltage, just regulating it. 

Doesn't it depend upon whether the output from the alternator is below or above 14V?.  I think that you are right but if you use straight resistance you may have a heat dissipation problem.  Yes I agree that the oscillation frequency is high, that way only a small transformer is needed.  In the 1970's I had a job that needed 5volts from a 24Volt supply.  Two racks of many 2n3055's tied together, then switch mode became available,  one small package 1/10 the panel space and no heat issues.

[skippydiesel]

FYI - Silent Hektik do not sell outside the EU. 

 

However some determined  RV 12/USA pilots have found ways around this; https://vansairforce.net/threads/silent-hektik-voltage-regulator-install.130921/

 

[danny_galaga]

2 hours ago, Geoff_H said:

Doesn't it depend upon whether the output from the alternator is below or above 14V?.  I think that you are right but if you use straight resistance you may have a heat dissipation problem.  Yes I agree that the oscillation frequency is high, that way only a small transformer is needed.  In the 1970's I had a job that needed 5volts from a 24Volt supply.  Two racks of many 2n3055's tied together, then switch mode became available,  one small package 1/10 the panel space and no heat issues.

Except maybe at the very lowest rpm, the alternator will be putting out more than 14V. Not sure of exact figures but I would guess easily over 20V if no load. I think on a 3 phase car alternator it's over 50V. In the olden days (say 40 or so years ago) the regulator consisted of a relay. Below a certain voltage it was closed and above a certain voltage it would open. In this way it would vary it's rate of vibration, depending on the load, which had the effect of varying the voltage. Of course now it's done with a transistor. Same principle though. 

[danny_galaga]

9 minutes ago, skippydiesel said:

FYI - Silent Hektik do not sell outside the EU. 

 

However some determined  RV 12/USA pilots have found ways around this; https://vansairforce.net/threads/silent-hektik-voltage-regulator-install.130921/

 

I can't remember if I bought my Carmo from the Aussie distributor or not. I guess I did. Maybe different manager now? I didn't have any dramas, but that was several years ago 

 

Incidentally, my Carmo runs at a solid 14.3V

Edited yesterday at 06:58 AM by danny_galaga

[skippydiesel]

20 hours ago, skippydiesel said:

To all -  VECTRIQ (Australian agents for CARMO, maker of CARR5115 MOSFET) are coming across as somewhat lacking in professionalism;

• Take two days to respond to enquiries - phone contact not available.
• Do not have any product - want payment before back ordering.
• Do not answer my technical questions.
• Have at least two advertised prices ($52 Au difference).
• Would seem to be asking somewhere in the region of  + $164 Au above makers advertised price

B & C  (USA - PMR1C-14 regulator) took less than 12 hrs to respond to my enquiry. They have replaced the AVC1 with the PRM1C-14. Looking good!😈

Update;

 

VECTRIQ have:

• Suddenly found they have the product in stock????
• Still have not answered my questions.

 

I am in error with the $164 above price - it is a much more reasonable + $83.

 

I find I am a little uncomfortable with VECTRIQ"s service style - I may be better paying whatever extra and going with one of the overseas suppliers😈

 

[IBob]

I wouldn't conflate the service style with the product. My position would be that you're wanting to buy a good product to do the job reliably: if that comes via a less polished sales outlet, yes that's pesky, but does that effect the product?

[Geoff_H]

18 hours ago, danny_galaga said:

Except maybe at the very lowest rpm, the alternator will be putting out more than 14V. Not sure of exact figures but I would guess easily over 20V if no load. I think on a 3 phase car alternator it's over 50V. In the olden days (say 40 or so years ago) the regulator consisted of a relay. Below a certain voltage it was closed and above a certain voltage it would open. In this way it would vary it's rate of vibration, depending on the load, which had the effect of varying the voltage. Of course now it's done with a transistor. Same principle though. 

Not exactly the same.  The non permanent magnet alternator/generators alternator the magnetic current of the rotating field.  The stator voltage is then a function of rotating flux density and velocity.  The relay was altering the field current.   With a permanent magnet rotor the field flux is fixed, the velocity varies so the output voltage varies with rpm, so you have to  convert the output  voltage to 14volts (or 28volts depending on system).  It is just the same as a phone charger that converts 110 or 240volts to 5/12volts automatically. 

[Geoff_H]

Second sentence should read:

The  non permanent magnet alternator/ generators regulate the magnetic field strength of the rotating field to give a stator voltage of 12volt

[skippydiesel]

Another Option- https://www.trispark.com.au/products/mosfet-20-amp-voltage-rectifier-regulator

 

Competitively priced at $199.65 Au (before delivery cost

 

[skippydiesel]

1 hour ago, IBob said:

I wouldn't conflate the service style with the product. My position would be that you're wanting to buy a good product to do the job reliably: if that comes via a less polished sales outlet, yes that's pesky, but does that effect the product?

Hi IBob,

 

This is very much in the perception of the customer. Australian service providers, have improved markedly over the last 40 years or so, however remnants of the  "take it or leave it" approach, still persist. I would like to think that market pressures will eventually result in unprofessional service becoming a rarity. Due to the small (undemanding?) Au market, this is unlikly in my lifetime.

 

If COMO CARR5115 was the only option, I would be more inclined to put up with unprofessional service, however, by my count, there are now 7 alternatives to the Ducati VR.

 

At least 4 of these are the current MOSFET standard.

 

Some are cheaper some are more expensive - the range is approximately $200 -$735 Au (plus delivery cost)  with the CARR5115 being sort of mid range.

 

It should be noted that only a very few are "drop" in replacements. Most  will require wiring changes, some fabrication of a new/adapter mounting bracket.😈

[skippydiesel]

FYI - Very Useful Article On Rotax Electrical Power System curtesy of Vans Air Force forum

 

https://pointsforpilots.blogspot.com/2012/12/testing-rotax-912914-generator-and.html

 

Also;

 

https://vansairforce.net/threads/yet-another-voltage-regulator-failure.123402/

 

 

😈

[facthunter]

ALL because you use a Permanent magnet..  Nev

[danny_galaga]

1 hour ago, Geoff_H said:

Not exactly the same.  The non permanent magnet alternator/generators alternator the magnetic current of the rotating field.  The stator voltage is then a function of rotating flux density and velocity.  The relay was altering the field current.   With a permanent magnet rotor the field flux is fixed, the velocity varies so the output voltage varies with rpm, so you have to  convert the output  voltage to 14volts (or 28volts depending on system).  It is just the same as a phone charger that converts 110 or 240volts to 5/12volts automatically. 

Right you are. I think we talked about this before. My point is I don't think there is a need for a switch mode system, particularly since we've had this type of 'alternator' from before there was such a thing. With these low current alternators, the output amperage isn't that great. 22 amps total output for instance compared to about 5 to 10 amps for a rotor field. Totally doable with the same hardware, whether that was relays or now with transistors

[facthunter]

They don't use just a simple relay. It includes windings reacting to the voltage as well as Current flow, all spring tension adjusted, and it  modulates  by opening and closing the Points . Some times a  resistor is also across the Point  to minimize the current change. A cut out was used as well to prevent reverse current on shut down. Later Diodes do the same thing. They need cooling.  Nev