13,2 volts

[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.

[Roger Lee]

If you know they read .5V low then it isn't a problem because you know whaever it reads is .5V higher. It's just the system that's installed they we have to live with.. 

[GrassStripFlyBoy]

Corey - good points, and then take a USB charger and stab in the cig plug and power an Ipad and cell phone and...  I'm not running Dynon, or dual screens, but was seeing a hefty drop with powering USB to Ipad.  I've since stopped keeping the Ipad plugged in 100% of the time, volts running much higher.