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Jacques

13,2 volts

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

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

any idea ?

thanks

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The Dynon usually reads a.5 volt low so it's probably 13.7V. Amps usually fluctuate between 0-5 amps which is normal. If it turns to only a negative draw then there is an issue.

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.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 ?

 

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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.

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

still 13.2 V (indicated ) 

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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.

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Since the voltage fell like that and you replaced the VR and battery I would start checking wires. I believe you have a bad connection. Start at the VR with the AC voltage input from the trigger coils, then measure the VR output and so on through the system. I think you have a bad connection somewhere, but you won't know for sure until you check some voltage outputs.

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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. 

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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. 

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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

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You changed the VR and battery so it shouldn't be them. The 13.2 doesn't bother me, but the continued drop in battery voltage does. If you have a shunt unscrew the 4 wires and use a scotchbrite pad on each terminal and surface to clean and then ere-assemble with a tad of dielectric grease on each connection. Just has to be a wire or bad connection. Tighten all the grounds inside the engine compartment and instrument panel. Measure the two yellow wires going into the VR for AC voltage and the white wires coming out of the VR for 12 volts.

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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

 

 

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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.

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I did do this to my CTSW and it did raise the voltage. Flew it like that for about 1200 hrs.

Did you guys test the voltage with the engine running at about 3K rpm at the yellow wires and out of the VR on the white wires?

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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

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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.

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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.

 

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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.

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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?

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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.

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