13,2 volts

[Jacques]

what would cause a Ducati(rotax) regulator to only charge to 13.2 V ? 

while using only 5-8 amps .?.?.?.?

any idea ?

thanks

[Jacques]

.5V low  really    13.7 is still low though   

and then , in few hours went from  13.2  to 12.9.to 12. to 11 then 9.9  and kaput  all black no more dynons/COM/xpnder/intcom etc etc

any idea ?

 

[Tom Baker]

I would try cleaning the the terminals and plug. If that doesn’t fix it , then probably a regulator. If your regulations allow I have heard there is a John Deere regulator that works well.

[Jacques]

we installed another regulator (borrowed from another plane) and also changed the battery,,,,no result

still 13.2 V (indicated ) 

[Madhatter]

B&C makes a high quality plug and play regulator specifically for a 912.

[Jacques]

yep, I was told about it a couple days ago...  the owner is aware   surely better than the Ducati   but   it's cooling  under the CT cowl is deficient ..I think

but , that doesn't tell me where my problem is   unless the 2nd regulator was also bad.

[GlennM]

13.2 - 13.3 V is normal for me.  Measure at the battery terminals and you will see .5V higher as Roger mentioned.

 

My voltage regulator died the same way you mentioned; it never cut in the alternator to charge. 

[GrassStripFlyBoy]

10 hours ago, Jacques said:

13.7 is still low though 

My SW runs about 13.6 -13.7, and since my panel update I now have digital read out besides the UMA analog.  I've noticed it drop to 13.2 / 13.3 on occasion.  Is this weak?  I've not really had trouble with it, but connect the Odyessy charger on it all the time it's parked too, which could be masking things. 

[Jacques]

recharging/maintaining after flights might not show the problem...  charging is suppossed to be 13.8/ 14,2

our problem happenned after an 8 hrs day flight and 5 hrs the next day,,,,,,,story of the trip coming in an other post shortly

[Jacques]

I will be fowarding all this to Patrick, the new owner....which is 160 miles from me.  We did checked the yellow wires and zero resistance showned all good there.

I', ll ask him to clean everything dry and grease     we had a very small lost at the oil cooler connection nipple ,   and  suggested him to go for the B & C regulator

https://bandc.com/product/avc1-advanced-voltage-controller-14v-homebuilt/#installation-kit

 

 

[Anticept]

A user on this forum named Chanik would put regulators on a variac and test their output with an ocilliscope attached. As it turned out, almost every regulator was complete garbage, but the ducati one was the least garbage because it wouldn't vibrate the coils of the engine under load.

The only regulator that he found that actually worked well was from silent hektik, but they refuse to sell outside germany.

I haven't spoken to him in many years, but I know the method he used. If I get ahold of one of those regulators, I can maybe link up with the local university's EE dept to test it. I really do want a non-trash regulator.

[Jacques]

found this  from 10 years ago

interesting reading

 

 

[Jacques]

we did the test up to 5000 rpm static , I was on left seat and the guy holding the multimeter on the right

Dynon showing 13,2 ( sometimes up to 13,5 ) , his multimeter couple volts higher

but can't tell you where the connections were      not sure we tested the yellow wires while runnning,

we did test them , engine off,  all good no resistance

[Anticept]

You need to do voltage drop tests to actually determine the problem. Resistance measurements are only reliable on good clean wires, but poor grounds can fool it. Very low current tests, like ohmmeter tests, can pass, yet putting a couple amps across it can show it's actually a poor connection.

Only voltage drop tests tell with 100% certainty.

[Jacques]

Thanks Corey for chiming in,  '' voltage drop test'' , i'll have to google that...never done that.  and will forward the info to the plane owner.

 

[Anticept]

I'll give you an example.

A broken ring terminal will rub against the terminal, and a few miliamps will conduct just fine. This is an ohmmeter test.

But, if you attempted to use a starter across it, the starter won't even turn, now you are pushing 150 amps. That is too much for what effectively is a small gauge connection at that point, and so there will be a very high resistances while the amperage is attempting to move. By ohms law, now there will be a lot of voltage being dropped there, and thus very little available for the starter. Power is voltage * amps.

A voltage drop test is putting your meter in voltage mode, and testing across the connections, such as from one end of a leg of wire, to the other, while it is live. Not across the loads or across the supply like normal!

If the wire and connection is good, then the voltage potential at one end of the wire will be the same as the other, and nothing will flow through the meter, so it will still read appox 0 volts (there will always be a little drop, we just want this to be as minimal as possible in a 12v system, less than 0.1v is pretty good and obtainable, AC 43-13 lists 0.5v as the absolute minimum acceptable for continuous in a 14v circuit). This is a PASSED test.

If the wire or connection is bad, some voltage will drop across it. This means now there is a voltage difference from one end to the other, and putting your meter across it will show some voltage. This is a FAILED test.

[Runtoeat]

This wown't fix Jacques problem but how about installing the Schottky diode for those with the 13.2 level charge?  It has been a few years but I recall a good charging voltage increase when this was done.  I think it increased my charge voltage .5 volts to now be  13.7 to 13.9?

[Jacques]

35 minutes ago, Runtoeat said:

 installing the Schottky diode

https://en.wikipedia.org/wiki/Schottky_diode

Hi Dick      how (where) did you install it  ?   thanks

[Anticept]

There was a post on this forum about the shockey diode. Roger actually posted it though it was chanik who discovered it. You have to use the correct diode. It gives a part number. Sorry not near a machine to go searching for it right now.

[Jacques]

it's n my July 31st post above..

[Anticept]

Didn't know that was this topic, and I misread badly! Sorry was only using my phone

[Runtoeat]

11 hours ago, Jacques said:

https://en.wikipedia.org/wiki/Schottky_diode

Hi Dick      how (where) did you install it  ?   thanks

Hi Jacques.  I followed the directions that Roger gave in his post which you show above.  I installed the Schottky between the #3 post and the "charge" post on the Ducatti.  I put two female blade connectors on the Schottky diode wires and this replaces the small white wire that used to run between these two posts.  Does this answer your question?

[Jacques]

hum...  not sure  ... here is what Chanik wrote in his previous post

....'' You use a 1 amp 200V diode which is available at any electronics store if you read 13.1V - 13.2V at the battery while it is running. The number for the diode is 1N4001 thru 1N4007. If you only need a .4V increase then a 1N5817 SCHOTTKY 1 amp 20V (http://www.allelectronics.com/make-a-store/category/205/Diodes/1.html). Do not use any other brand as when I tested the others they were off by . 3V -.4V too high. This 1N5817 seems to be good for most Ducati regulators in a CT. The band on one end will face up. It goes between the Regulator Rectifier "R" slot and the "Charge" slot. There is a small white wire already between these two slots and this is what you are replacing and then that small wire needs to be clipped in half. This will raise your output charging voltage .4 volts with the 1N5817.

He specified the SCHOTTKY  brand   ..and  this is what Dick ( Runtoeat ) installed with success. 

I will go with that myself...

[Anticept]

Shottky is a type of diode.

[Anticept]

Hello all. For the first time I was able to take a really close look at the positive side of the electrical system while I was working on a battery retrofit. @Roger Lee this one is important for you too.

The reason Dynon units appear to read low is not really the Dynon unit's fault. It's a combination of things.

First, wires have a resistance. Usually it is so incredibly low that it's not worth considering. However, for voltmeters, it actually IS important. Flight Design chose to use 12 gauge wire (in my aircraft at least) to carry the positive load. 12 gauge wire is rated for 20 amps, which is the theoretical peak output of the alternator, so no real surprise that was chosen.

It is also quite a long way from the voltage regulator, through the inside to the master breaker, through the breakers on the right side, and out to the EMS unit (the ammeter shunt is in a different circuit). The EMS unit is going to be sensing the voltage *after* all of that. That tiny bit of resistance is going to add up. All that wiring and switching will be dropping tiny bits of voltage, leaving less for the EMS to sense.

The thing is, it's also not straight forward. In complex circuits, voltage drop is proportional to the amperage flow, as well as to the resistance in the rest of the circuit. It can get pretty complicated fast.

So when you only have your EMS on, it might read 13.5v or so. When you turn everything on, especially those with a halogen light, suddenly you're as low as 12 volts. If you take your voltmeter to the battery though, you might be surprised to still see above 13 volts! That's because once we consider our wire as a resistance, our systems in the aircraft are a *complex circuit*. As you turn on systems, you're lowering resistance overall, but only later in the circuit. The wire running TO the bus is still a single resistance, you're pumping a lot of amps through it now with everything on, and so now it is dropping tens of volts to even over a full volt! And since the EMS unit comes AFTER that wire, it's only going to sense what's left.

The fix? First, make sure your wiring is CLEAN. Connections need to be pristine. Every resistance eliminated is important!

However, the real fix would be to change all of the 12 gauge positive side supply wire to 10 or even 8 gauge wire from the power sources all the way to the breaker bus. That would dramatically lower the voltage drop on the wire while all your systems are on, but this is really unfeasible and labor intensive for something that is a relatively minor payoff. Just remember that the voltage you see in the aircraft is going to be a little bit lower than what the battery is going to be seeing, and that's important ESPECIALLY if you use the shottky diode trick, you can over-volt the battery, especially an earthx battery, and damage it if you are not checking voltage at the battery when you install it.

But, that said, that's why the positive wires in certified aircraft are so dang huge going to the busses. It's to counter some of this voltage drop issue.