shajen Posted October 20, 2023 Author Share Posted October 20, 2023 This is photo taken a few weeks ago, doesn’t show the regulator. Note there is no yellow wire going to the battery. Is the thing on the firewall the main bus? Is that where the isolator should go? The red power wire from the regulator is where I’m guessing the 20 amp fuse should go. Does it matter where along the wire it needs to go? Ie close to battery, or close or regulator? Does it matter? 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 20, 2023 Share Posted October 20, 2023 Good. 5A fuse for the sense wire OK. The wire will pass 5A and blow the fuse if there is a fault. (remember- idea is that fuse blows before wire melts) In your photo, the starter V+ goes to the starter solenoid ..... I see a smaller red wire going to the battery V+ terminal to a connector off photo - I gather this is the regulator charge output (check). this needs to have a 20A fuse in it so that if the regulator fails it doesnt cause a fire. There needs to be THE alternator charger relay that we discussed in series with this 20A fuse. The alternator relay can have the negative of the coil to ground (anywhere) and the positive of the relay coil should go back through the firewall to your MASTER 12V bus. That is the minimum for modifications And regulator sense wire to battery termal. If you want to go further, you can see that there are UNFUSED battery white wires going through the firewall. This is bad in an crash- the battery master relay needs to be IN the engine bay and connected to the master switch. so that unfused and unswitched battery + does NOT go through the firewall ..... There is a master relay behind the instrument panel, that relay needs to be moved next to the battery and via a good sized fuse probably 30A is enough for a Jabiru. Link to comment Share on other sites More sharing options...
RFguy Posted October 20, 2023 Share Posted October 20, 2023 1 Link to comment Share on other sites More sharing options...
shajen Posted October 20, 2023 Author Share Posted October 20, 2023 You’re a good nan, Glen! THAT makes it much easier! Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 (edited) V1.1 Edited October 21, 2023 by RFguy Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 (edited) SAFE JABIRU - WITH BATTERY ISOLATION - METHOD 1 - ROUTING STARTER CURRENT THROUGH MAIN BATTERY ISOLATOR \ Edited October 21, 2023 by RFguy Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 (edited) SAFE JABIRU - WITH BATTERY ISOLATION - METHOD 2 - ROUTING STARTER CURRENT AROUND MAIN ISOLATOR (AND THUS CAN USE SAME 40 AMPS RELAY AS ALTERNATOR ) Edited October 21, 2023 by RFguy Link to comment Share on other sites More sharing options...
facthunter Posted October 21, 2023 Share Posted October 21, 2023 You limit what isolating you can do for In flight troubleshooting if you do that. ALL planes should have an electrical "crash Bar". Relays can stick (Points welding). How do I know this?? It started a fire. Nev Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 Nev, pls expain the 'crash bar' comment ? Do you mean some sort of method to short the bus and blow the battery fuse ? Link to comment Share on other sites More sharing options...
facthunter Posted October 21, 2023 Share Posted October 21, 2023 No just open circuit manually. Nev Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 so in that case, needs a shaft through the firewall to the battery isolator location. Yes, I do like that ! Link to comment Share on other sites More sharing options...
facthunter Posted October 21, 2023 Share Posted October 21, 2023 It has to work. Nev. Link to comment Share on other sites More sharing options...
skippydiesel Posted October 21, 2023 Share Posted October 21, 2023 You may have mentioned the following elsewhere ; The ground (-) should be to a ground buss, airframe (where appropriate) & engine via a dedicated ground circuit. Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 NO ground 'circuit'. Ground location - yes. But regulator CANNOT go to the busy ground say on the firewall that a bunch of things front side and back get connected to. The reason for connecting the regulator direct to battery ground (or - the engine block is pretty well battery ground because of the 50mm2 cable to the battery negative) , is that high pulsing current from the regulator needs NOT to crosstalk with other signals. If the alternator regulator negative goes to some 'ground bus' then that whole ground bus will be noisy unless there is another (short) 50mm2 cable to the bat negative. it is no longer ground if you connect the noisy charging current into it. ground is supposed to be quiet. 2 1 Link to comment Share on other sites More sharing options...
Thruster88 Posted October 21, 2023 Share Posted October 21, 2023 Being able to remove all electricity from aircraft circuits is not just for impending forced landings or crashes, smoke in the cockpit rates right up there. 2 Link to comment Share on other sites More sharing options...
shajen Posted October 21, 2023 Author Share Posted October 21, 2023 Funny how this all started by a radio issue that has been stumping us for a month. Along the way we’ve found and fixed quite a few other possible wiring problems. Earth wires not connected, intercom not connected, pilots headphone Jack needed replacing, no earthing on either headphone jacks, pins missing and in incorrect places on radio install, no fuse on radio. These were all on the inside of the firewall (cabin side). They all needed fixing, or would still be possible causes of interference and noise. Hopefully once we fix wiring and earthing issues in front of the firewall I will have a safe and functional aircraft and a radio that works. The help and suggestions and advice that I’ve got from everyone here has been phenomenal! Everyone’s busy , but so many people have spent the time to help me get this radio issue sorted. Can’t thank you all enough! if any of you ever fly to Mansfield, lunch is on me! 2 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 (edited) Hi Jenny. WHat's the aircraft type and SN ? Yeah if you do " improved jabiru with switched and fuses alternator" circuit that will go a long way to removing the chance that that is a problem. (Ideally you do method 1 or method 2 diagrams but this is a fair bit more work but ensures you can disconnect the battery) When the voltage goes sky-high- the device called a crowbar in the Jabiru bus wiring may begin to 'arcing over' and causes ALOT of noise. ALSO many electrical devices will have their own 'crowbar' - a type of high voltage transient suppressor - will begin to conduct to try and clip off the high voltage peaks and make alot of noise. Edited October 21, 2023 by RFguy 1 Link to comment Share on other sites More sharing options...
shajen Posted October 21, 2023 Author Share Posted October 21, 2023 It’s a SP500, 19-3346. We intend using diagram 1. We can do the fuses and check earthing. There is a guy who is good at avionics who is willing to check our work and put in the relay, but he’s on holidays till Nov. He’s the guy who had the VSWR meter and checked the voltages against his machine. The radio sounds great on the ground, but in the air under power, you just get noise and no radio. Initially when I first flew it home to Benalla, there was SO much static and screeching in my ears that I took the headphones off! Had such a headache when I got home. Found out a cheap USB plug causing a lot of that, and since then we just keep finding other faults. 1 Link to comment Share on other sites More sharing options...
shajen Posted October 21, 2023 Author Share Posted October 21, 2023 So do you think the damage might already be done with the voltages being so high? Is it likely this crowbar effect will continue even once earthing and fuses are fixed? 1 Link to comment Share on other sites More sharing options...
RFguy Posted October 21, 2023 Share Posted October 21, 2023 SP500 OK. wiring varies ! "So do you think the damage might already be done with the voltages being so high?" ---anyone's guess. See how you go. Usually, protection devices clip the peaks, but if the battery gets that high, the peak limiting devices are usually cooked and may require replacement (if it has any) Get it all wired up. See how it goes. if it all works, then good. 2 Link to comment Share on other sites More sharing options...
shajen Posted October 27, 2023 Author Share Posted October 27, 2023 I’m really happy today!! The wiring we did actually works! It was as you said, incorrect wire going to instrument bus bar instead of battery. We changed that around and put in the inline fuse. Went for a fly yesterday and about 80% fixed. We can both hear each other, hear transmissions and others can hear us. There is still a slight problem , when I transmit I can’t hear myself speaking and my passenger also can’t hear the transmission. When he makes a call it’s the same for me, I can’t hear what he’s transmitting. I’ve still got to get the relay put in, too. But basically my radio problem is sorted, I can live with the rest for a while. Just wanted to say thankyou to everyone who gave advice and supported me. RFGuy, I’d still love to drop in to Cowra sometime and meet you. Happy flying everyone😀 1 1 2 Link to comment Share on other sites More sharing options...
RFguy Posted October 28, 2023 Share Posted October 28, 2023 good stuff. Sounds like the SIDETONE etc in the intercom setup is not right. You are using the TRIG internal intercom, yes ? Link to comment Share on other sites More sharing options...
shajen Posted October 28, 2023 Author Share Posted October 28, 2023 Yes, using the Trig. I’ve got the sidetone set in the middle, perhaps I’ll play around with it a bit and see if it makes a difference. Didn’t think of that Link to comment Share on other sites More sharing options...
RFguy Posted October 28, 2023 Share Posted October 28, 2023 (edited) yeah if you are both connected to the radio and you can both talk OK on the radio, then all the connections are OK, seems odd, will have to read the manual later. I have one to install in the next week or so. Edited October 28, 2023 by RFguy Link to comment Share on other sites More sharing options...
shajen Posted October 28, 2023 Author Share Posted October 28, 2023 Check it out before you give it back to the owner. 🤣🤣🫢 Link to comment Share on other sites More sharing options...
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