savannah s wiring question

[Bodie]

Hi all.  I got what I think should be a simple question, but can't find a logical solution.  After the 50 amp fuse in the engine compartment, there are three wires.  One goes to the "Bat" on the regulator.  The other two wires are the ones that I don't k now where they connect to.  Can someone tell me where item #1 and item #2 are supposed to connect to?  Thanks!  -steve

[Lucky01]

Sorry mate, this is from a Automotive background.

 

But Bat normally means power supply from Battery. 50 Amp fuse would be correct if you have a 40 - 50 amp Alternator. That splice would be just a power supply to another busbar / fuse panel

 

Definitely wouldnt trust a spade terminal with 50 amps. Thats how those shitty white connectors turn brown. 

 

With that wire disconnected and the motor running what does your battery voltage read? 

[IBob]

The fuse sits between:

terminal B on the voltage regulator and

the starter relay, where it is attached to the same terminal as the heavy + cable coming from the battery: that is item 4 on page 3/9.

 

So, one side should have a spade terminal to go onto the voltage regulator, the other side a lug to go onto the starter terminal bolt.
That much is clear.
I don't know about any third wire.

[IBob]

Marty_d who is building a 701 but using some savannah parts including wiring, raised the same question here on 11 August:

https://www.recreationalflying.com/topic/28196-marty-ds-ch-701-build-log/?do=findComment&comment=512650&_rid=6547

 

It's not clear what the other wires are intended for. But it would be nice to know!

 

[nomadpete]

I'm no expert on Savanna wiring looms, but the schematic diagram should tell all. It looks like a Rotax regulator in the pic, so I'd expect one wire to be going to the electrolytic capacitor.

[Bodie]

Thanks guys.  I'm tracking what you're saying Ibob.  I have the one end of the 50 amp fuse connected to the battery wire on the solenoid.  I stuck the white paper in for a clearer picture.  So then the other side of the 50 amp fuse goes to the battery terminal of the voltage regulator.  That's good so far.  The picture you sent of Marty_d's is the same as my dilemma, where are the other two wires supposed to go?  And namadpete, I too would have expected the schematic to explain things, but apparently there are just things that the Italians like to leave to chance in their manual.  They have a great schematic of the cabin side, but no schematic of the other side of the firewall....  so are you suggesting that the 22mF capacitor should be connected to one of the spare wires? 

 

I've attached another pic with the detail the first pic lacked.  One side of the 50 amp fuse connects to battery terminal of starter solenoid.  On the other side of the 50 amp fuse one leg goes to the battery terminal of the voltage regulator, and the other two have no obvious place to go.....

 

Also,  not wanting to encourage thread drift by any means since I would like the electrical issue solved 😉, have attached a few current pics of my 6 year project!

[IBob]

Looking really good there!

Just PM'd you.....

[APenNameAndThatA]

Hats off to anyone who builds their aircraft. High school physics and maths is a fine basis for learning about navigation, weather, force vectors, acceleration, ideal gas laws, energy vs momentum and force vs mass and etc. Chemistry was good with the latent energy of evaporation and clouds rising. 

But the capacitors and resistors and volts and amps and induced magnetic fields we learnt about were *completely* inadequate as a base for learning about electronics and aircraft electrical systems. I have no clue.  

Edited October 15, 2021 by APenNameAndThatA

[perrynz]

Hi Steve. Had a look at my wiring. My 50amp fuse has only 2 wires. As Bob says, the one with the ring to the battery side of the solenoid, and the one with the spade connector to “bat” on the regulator. On that particular connection there is also a wire that connects to the +ve on the capacitor. (I fitted a new spade connector with both wires crimped into it) So, my guess would be that the white coloured connector in your picture goes directly to the capacitor.

[Bodie]

Thanks guys!  Here's my best guess.  The 50 amp fuse and wires are a part that is bought from another supplier, hence Marty_d's 701 and the Savannah are the same.  I re-read Mark Kyle's response and I will use one wire for the resistor and clip the other then terminate it in heat shrink!  

[Marty_d]

20 hours ago, Bodie said:

Thanks guys!  Here's my best guess.  The 50 amp fuse and wires are a part that is bought from another supplier, hence Marty_d's 701 and the Savannah are the same.  I re-read Mark Kyle's response and I will use one wire for the resistor and clip the other then terminate it in heat shrink!  

Although mine's a 701, it's scratch built and I use a lot of Sav parts.  My fuse came as part of the wiring harness with a set of Sav instruments (the bloke selling them had a kit but wanted a glass cockpit).

 

So for some reason Savannah has changed the fuse from having one wire coming off that side to three.  I think I'll do the same as you and use one for the resistor, if that's how it's meant to be wired.