---------------------------------------------------------- Avionics-List Digest Archive --- Total Messages Posted Mon 10/02/06: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:14 PM - Backup Power supply for GNS-430? (Andrew Olech) 2. 03:27 PM - Re: Backup Power supply for GNS-430? (Gilles Thesee) 3. 03:54 PM - Re: Backup Power supply for GNS-430? (Carlos Trigo) 4. 06:27 PM - Re: Backup Power supply for GNS-430? (Noel Loveys) 5. 06:36 PM - Re: Backup Power supply for GNS-430? (Bob C.) 6. 07:25 PM - Re: Backup Power supply for GNS-430? (Noel Loveys) ________________________________ Message 1 _____________________________________ Time: 03:14:56 PM PST US From: "Andrew Olech" Subject: Avionics-List: Backup Power supply for GNS-430? Hey guys, I posted this question to a Yahoo forum and someone suggested I post it here as well. For those in both forums, sorry for repeats! I would like to know if anyone out there has wired up a home-made backup power supply (rechargable/UPS variety) that, in my case, would feed something like a GNS-430? I prefer not spending an arm/leg on a COTS (commercial off-the-shelf) rig. Actually, let me tell you what I want to do and maybe there's a simpler solution... please read on. I want to be able to fire up Com & GPS prior to engine start in order to talk to the tower, get my clearance and program in the routing/waypoints. However, I am afraid of start-up spikes in the system, so I'd prefer to either cut the power to it or IDEALLY I'd isolate the 430 to its own battery momentarily so it can stay alive and be ready to roll. Hopefully some of you guys can relate and chime in: 1. Is it a long shutdown/recycle process for the 430? 2. Should I not worry about the startup spike and keep it on? 3. Is there a startup procedure that will minimize any power fluctuations (ie. waiting to turn on the alternator field until engine stabilizes) 4. Are there any special filters that I can use (I'm thinking no) 5. Wiring diagrams available / small rechargeable battery availability? 6. If I put it on a manual isolate switch, might I see enough of a spike/voltage drop during switching to trip the 430? 7. Is COTS the only way to go? Apologies for the lengthy email. Thoughts and comments will be much appreciated! -Andy RV-7, Finish ________________________________ Message 2 _____________________________________ Time: 03:27:44 PM PST US From: Gilles Thesee Subject: Re: Avionics-List: Backup Power supply for GNS-430? --> Avionics-List message posted by: Gilles Thesee Andrew, I installed a Garmin Series 400 in our four seater project. > > > I want to be able to fire up Com & GPS prior to engine start in order > to talk to the tower, get my clearance and program in the > routing/waypoints. However, I am afraid of start-up spikes in the > system, so I'd prefer to either cut the power to it or IDEALLY I'd > isolate the 430 to its own battery momentarily so it can stay alive > and be ready to roll. > Why not just switch your master switch on ? Just do what you want, and then start your engine. You afraid of start-up spikes ? Fear not, no one ever caught one with a scope or so. Hangar tales. Besides, modern avionics is totally immune to any transient the on-board circuit may throw at it. Still not convinced ? Turn off your radios before start-up, that's all. Why would you need your GPS during engine startup and pretaxi checks. Be careful with the "avionics master" some are still fond of : if the switch fails, you loose all your avionics. That's a single point failure. I usually turn the radios on just after startup. Regards, Gilles Thesee Grenoble, France http://contrails.free.fr ________________________________ Message 3 _____________________________________ Time: 03:54:50 PM PST US From: "Carlos Trigo" Subject: Re: Avionics-List: Backup Power supply for GNS-430? Hi Andrew Good questions, to which I would like to know the answers as well. Have you posted this in the AeroElectric list? Carlos ----- Original Message ----- From: Andrew Olech To: avionics-list@matronics.com Sent: Monday, October 02, 2006 11:14 PM Subject: Avionics-List: Backup Power supply for GNS-430? Hey guys, I posted this question to a Yahoo forum and someone suggested I post it here as well. For those in both forums, sorry for repeats! I would like to know if anyone out there has wired up a home-made backup power supply (rechargable/UPS variety) that, in my case, would feed something like a GNS-430? I prefer not spending an arm/leg on a COTS (commercial off-the-shelf) rig. Actually, let me tell you what I want to do and maybe there's a simpler solution... please read on. I want to be able to fire up Com & GPS prior to engine start in order to talk to the tower, get my clearance and program in the routing/waypoints. However, I am afraid of start-up spikes in the system, so I'd prefer to either cut the power to it or IDEALLY I'd isolate the 430 to its own battery momentarily so it can stay alive and be ready to roll. Hopefully some of you guys can relate and chime in: 1. Is it a long shutdown/recycle process for the 430? 2. Should I not worry about the startup spike and keep it on? 3. Is there a startup procedure that will minimize any power fluctuations (ie. waiting to turn on the alternator field until engine stabilizes) 4. Are there any special filters that I can use (I'm thinking no) 5. Wiring diagrams available / small rechargeable battery availability? 6. If I put it on a manual isolate switch, might I see enough of a spike/voltage drop during switching to trip the 430? 7. Is COTS the only way to go? Apologies for the lengthy email. Thoughts and comments will be much appreciated! -Andy RV-7, Finish ________________________________ Message 4 _____________________________________ Time: 06:27:08 PM PST US From: "Noel Loveys" Subject: RE: Avionics-List: Backup Power supply for GNS-430? As far as I know starting spikes are always reverse voltage caused when disengaging the starter. Most radios and even the power distribution systems of larger turbine starter/generators have a healthy diode installed to shunt reverse voltage away from avionics equipment. This shouldn't be necessary on your RV7 unless you have been busy shoe horning a turbine in it. You can check your schematic for a reverse polarity diode where the positive terminal enters a unit. With such a diode installed any reverse voltage will be grounded. One thing to be careful about these diodes is if you wire your unit with reverse polarity it will cause a big spark without damaging sensitive components. Most units wired in this way have the diode in the circuit after a fuse. Wire it up in reverse and you will have to replace the fuse. In smaller piston engines where the starter and charging system are separate the battery itself should be able to filter out a pretty big spike, forward or reverse. The only thing I would avoid is trying to transmit and start the engine at the same time...not much chance of that happening. Noel -----Original Message----- From: owner-avionics-list-server@matronics.com [mailto:owner-avionics-list-server@matronics.com] On Behalf Of Andrew Olech Sent: Monday, October 02, 2006 7:44 PM Subject: Avionics-List: Backup Power supply for GNS-430? Hey guys, I posted this question to a Yahoo forum and someone suggested I post it here as well. For those in both forums, sorry for repeats! I would like to know if anyone out there has wired up a home-made backup power supply (rechargable/UPS variety) that, in my case, would feed something like a GNS-430? I prefer not spending an arm/leg on a COTS (commercial off-the-shelf) rig. Actually, let me tell you what I want to do and maybe there's a simpler solution... please read on. I want to be able to fire up Com & GPS prior to engine start in order to talk to the tower, get my clearance and program in the routing/waypoints. However, I am afraid of start-up spikes in the system, so I'd prefer to either cut the power to it or IDEALLY I'd isolate the 430 to its own battery momentarily so it can stay alive and be ready to roll. Hopefully some of you guys can relate and chime in: 1. Is it a long shutdown/recycle process for the 430? 2. Should I not worry about the startup spike and keep it on? 3. Is there a startup procedure that will minimize any power fluctuations (ie. waiting to turn on the alternator field until engine stabilizes) 4. Are there any special filters that I can use (I'm thinking no) 5. Wiring diagrams available / small rechargeable battery availability? 6. If I put it on a manual isolate switch, might I see enough of a spike/voltage drop during switching to trip the 430? 7. Is COTS the only way to go? Apologies for the lengthy email. Thoughts and comments will be much appreciated! -Andy RV-7, Finish ________________________________ Message 5 _____________________________________ Time: 06:36:02 PM PST US From: "Bob C. " Subject: Re: Avionics-List: Backup Power supply for GNS-430? --> Avionics-List message posted by: "Bob C. " Andy, I plan to add a second smaller battery to support my 430, BMA Lite, Engine Monitor and Elec AH . . . more for backup in the air but could and probably will be used the way you suggest. In IFR Conditions it will be isolated from the other battery in VFR I'll probably cross connect putting them in parallel. Good Luck, Bob RV-8 Finishing Slowly! On 10/2/06, Andrew Olech wrote: > > > Hey guys, > > I posted this question to a Yahoo forum and someone suggested I post it here > as well. For those in both forums, sorry for repeats! > > > I would like to know if anyone out there has wired up a home-made > backup power supply (rechargable/UPS variety) that, in my case, would > feed something like a GNS-430? I prefer not spending an arm/leg on a > COTS (commercial off-the-shelf) rig. Actually, let me tell you what I > want to do and maybe there's a simpler solution... please read on. > > I want to be able to fire up Com & GPS prior to engine start in order > to talk to the tower, get my clearance and program in the > routing/waypoints. However, I am afraid of start-up spikes in the > system, so I'd prefer to either cut the power to it or IDEALLY I'd > isolate the 430 to its own battery momentarily so it can stay alive > and be ready to roll. > > Hopefully some of you guys can relate and chime in: > 1. Is it a long shutdown/recycle process for the 430? > 2. Should I not worry about the startup spike and keep it on? > 3. Is there a startup procedure that will minimize any power > fluctuations (ie. waiting to turn on the alternator field until engine > stabilizes) > 4. Are there any special filters that I can use (I'm thinking no) > 5. Wiring diagrams available / small rechargeable battery availability? > 6. If I put it on a manual isolate switch, might I see enough of a > spike/voltage drop during switching to trip the 430? > 7. Is COTS the only way to go? > > Apologies for the lengthy email. Thoughts and comments will be much > appreciated! > > -Andy > RV-7, > Finish > - The Avionics-List Email Forum - > Navigator to browse > page, > Photoshare, and much much more: > http://www.matronics.com/Navigator?Avionics-List > - NEW MATRONICS WEB FORUMS - > the Web Forums! > http://forums.matronics.com > - NEW MATRONICS LIST WIKI - > Wiki! > http://wiki.matronics.com > - List Contribution Web Site - > -Matt Dralle, List Admin. > ________________________________ Message 6 _____________________________________ Time: 07:25:32 PM PST US From: "Noel Loveys" Subject: RE: Avionics-List: Backup Power supply for GNS-430? Item 6. Even better you could put a forward diode in the positive line to your GNS and then wire the second (stay alive) battery in parallel to the first that way if voltage from the main battery dropped below 12V. on start-up the second battery would keep the voltage up to the GNS 430 during starting. I'll attach a little thumb nail drawing. BTW this set up will keep the stay alive 12v battery charged while in normal operation. Both batteries would absorb forward spikes. I would suggest a small 12V gel pac cell or a battery pack of 9 or ten NiMh AAA batteries in series. There is a very slight voltage drop across the diode but not enough for the GNS 430 to notice it. just choose a diode to handle the current of the GNS. You'll be surprised how small these diodes are. For safety put a piece of heat shrink over the diode and its leads Noel -----Original Message----- From: owner-avionics-list-server@matronics.com [mailto:owner-avionics-list-server@matronics.com] On Behalf Of Carlos Trigo Sent: Monday, October 02, 2006 8:20 PM Subject: Re: Avionics-List: Backup Power supply for GNS-430? Hi Andrew Good questions, to which I would like to know the answers as well. Have you posted this in the AeroElectric list? Carlos ----- Original Message ----- From: Andrew Olech Sent: Monday, October 02, 2006 11:14 PM Subject: Avionics-List: Backup Power supply for GNS-430? Hey guys, I posted this question to a Yahoo forum and someone suggested I post it here as well. For those in both forums, sorry for repeats! I would like to know if anyone out there has wired up a home-made backup power supply (rechargable/UPS variety) that, in my case, would feed something like a GNS-430? I prefer not spending an arm/leg on a COTS (commercial off-the-shelf) rig. Actually, let me tell you what I want to do and maybe there's a simpler solution... please read on. I want to be able to fire up Com & GPS prior to engine start in order to talk to the tower, get my clearance and program in the routing/waypoints. However, I am afraid of start-up spikes in the system, so I'd prefer to either cut the power to it or IDEALLY I'd isolate the 430 to its own battery momentarily so it can stay alive and be ready to roll. Hopefully some of you guys can relate and chime in: 1. Is it a long shutdown/recycle process for the 430? 2. Should I not worry about the startup spike and keep it on? 3. Is there a startup procedure that will minimize any power fluctuations (ie. waiting to turn on the alternator field until engine stabilizes) 4. Are there any special filters that I can use (I'm thinking no) 5. Wiring diagrams available / small rechargeable battery availability? 6. If I put it on a manual isolate switch, might I see enough of a spike/voltage drop during switching to trip the 430? 7. Is COTS the only way to go? Apologies for the lengthy email. Thoughts and comments will be much appreciated! -Andy RV-7, Finish onics.com/Navigator?Avionics-List