Voltage regulator on engine side?

[Rodney]

Also had the Ducatti regulator inside the cockpit fail. No toxic fumes I was aware of.

In doing some research on the Vans RV-12 forum, ( they mount their regulators on the engine side of the firewall). I came to the conclusion that heat may be a factor contributing to failures.

I replaced my regulator with one from NAPA and mounted a 5 inch dia. 12 volt cooling fan about an inch away from the regulator. Fan wired into master switch.

That was a little over a year ago and so far, no problems

Rodney

[Esser]

I ended up putting my regulator right near the firewall but aft so it is in the cockpit.

[Av8r3400]

I replaced my regulator with one from NAPA and mounted a 5 inch dia. 12 volt cooling fan about an inch away from the regulator. Fan wired into master switch.

What type of regulator did you use from NAPA?

[Rodney]

The NAPA part number is SME 7068102

My store did not stock it, but ordered it in, in about three or four days.

The new regulator has five tabs instead of the six on the Ducatti.
Wiring sequence is as follows

Regulator. = Wire

B. = White
AC. = Yellow
AC = Yellow
L = Orange/Green
IGW = Orange/Blue

The extra white wire is tied off and not used

Voltage output at cruise is 14.7 volts

Regards
Rodney

[Floog]

Cost of NAPA reg?

[Av8r3400]

Looks like about $90 for the John Deere lawnmower (NAPA) regulator.

[Floog]

Thank you!

[Rodney]

Also, I believe the NAPA regulator has a lifetime warranty. It is rated at 20 amps.

Ok, I have a question for you electronic guys that understand this stuff.

I read on another forum, that: (Hope it's ok to post this - not sure I understand enough about this to repeat it accurately. My son is the electrical engineer - not me! )

'The Rotax alternator is a permanent magnet design meaning that the field is produced by permanent magnets moving past the coils. This differs from the typical automotive type with the method required to regulate voltage. With the automotive type, the regulator varies the field voltage to increase/decrease the output current. With the permanent magnet type the alternator is continuously producing maximum power. These systems require a regulator that can add resistance between the alternator and the battery. The resistor bank is designed so the resistance can be varied and essentially is burning off the excess power that would otherwise overcharge the battery.
So, to reduce the work that the regulator is required to do it would actually be better to have all current consuming devices powered up (lights, radios, iPad charger and so on). The more power you are using, the less the regulator has to dump into the resistor bank, therefore the less heat the regulator has to get rid of. It becomes obvious that typically the regulator will be producing heat and will most certainly last longer with a supply of cooling air passing through/over the heat sink fins. Running with your landing lights on will take a load off the regulator, not add to it. Adding cooling air flow will extend the life of the resistors in the regulator.
I hope this helps understand some of the differences of the Rotax electrical system."

Is this right??? So it's better for the regulator to have all the electrical load one can put on it - and that will reduce the internal heat, or the heat that the regulator has to dissipate?

Maybe jrevens who seems to really know this electrical stuff can jump in here and educate me - well maybe all of us. Anything we can do to prolong the life of these regulators would be advantageous.

We know the "what" - and that is the Ducatti regulators are failing. I believe the consensus opinion seems that these are heat related failures.

Maybe this explains the "why." Not enough load on the regulators.

Thanks
Rodney