---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 06/09/16: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 10:25 AM - Re: 24V replacement batteries? (RV7builder) 2. 11:50 AM - Size of battery cables (Sebastien) 3. 12:50 PM - Re: Size of battery cables (Ron Burnett) 4. 03:08 PM - Re: Size of battery cables (RV7builder) 5. 04:35 PM - Re: Multiple wires/ring terminals on the contactor? (Robert L. Nuckolls, III) 6. 07:34 PM - Re: Saggy bus voltage on Cessna 182 (Robert L. Nuckolls, III) 7. 07:38 PM - Re: 24V replacement batteries? (Robert L. Nuckolls, III) 8. 07:48 PM - Re: Antenna grounding (Robert L. Nuckolls, III) 9. 07:57 PM - Re: Saggy bus voltage on Cessna 182 (Alec Myers) 10. 08:05 PM - Re: Saggy bus voltage on Cessna 182 (Alec Myers) ________________________________ Message 1 _____________________________________ Time: 10:25:15 AM PST US Subject: Re: AeroElectric-List: 24V replacement batteries? From: RV7builder On June 8, 2016 6:38:19 PM CDT, "Robert L. Nuckolls, III" wrote: > >> >> >>Heads-up; not universally true. Commonly available agm quit starting >>my rv4 after about a year of use. Pulled top cowl & found a pinhole >>in side of case, & acid stain on the firewall 'shelf'. Obvious >>acid trail from pinhole. Furtunately, it didn't eat through the >>stainless firewall. >> >>I still use open hold downs like the pic, but a rubber 'tray liner' >>now seems advisable. >> >>Charlie > > > Interesting. What kind of battery was this? Was there > a 'goose egg' under the pin hole? I'm mystified as > to how this might happen. The AGM is valve regulated > to vent at 1-2 psi so that any swelling of the case > is associated with expanding plates material in their > death throes. I've not heard of a cell getting opened > to atmosphere on the sides without first suffering > gross chemical and electrical energy releases within > the cell. This has the smell of a manufacturing > defect. > > Did you go back in with the same brand and part > number? > > Bob . . . Don't know if this went through on the 1st attempt. Response was to the 'poke a hole; can't leak' statement. Hard to edit a quote on a phone/tablet screen keyboard. Pinhole likely happened in shipping. Worked for almost a year, but was slowly losing acid out the pinhole and on to the stainless firewall. Charlie -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ________________________________ Message 2 _____________________________________ Time: 11:50:25 AM PST US From: Sebastien Subject: AeroElectric-List: Size of battery cables Planning on moving my battery from the tail to the firewall. Current wiring is 2 gauge and so far all the homebuilders I have talked to say minimum 4 gauge but when I go on Aircraft Spruce the only battery cable they sell is 6 gauge. Does anyone use this stuff? I'm going to reuse the 2 gauge for the starter cable but has anyone used 6 gauge wire on a low current, short run install? Longest cable would be 3 feet and while the alternator is 50 A, load is never above 10 A for more than a couple minutes and that's only the initial battery charge after a hard start. Thank you, Sebastien ________________________________ Message 3 _____________________________________ Time: 12:50:20 PM PST US Subject: Re: AeroElectric-List: Size of battery cables From: Ron Burnett I used it for my RV-6A with Subaru and now going Lycoming Ron Burnett Sent from my iPhone > 9, 2016, at 1:49 PM, Sebastien wrote: > > Planning on moving my battery from the tail to the firewall. Current wiring is 2 gauge and so far all the homebuilders I have talked to say minimum 4 gauge but when I go on Aircraft Spruce the only battery cable they sell is 6 gauge. Does anyone use this stuff? I'm going to reuse the 2 gauge for the starter cable but has anyone used 6 gauge wire on a low current, short run install? Longest cable would be 3 feet and while the alternator is 50 A, load is never above 10 A for more than a couple minutes and that's only the initial battery charge after a hard start. > > Thank you, > > Sebastien ________________________________ Message 4 _____________________________________ Time: 03:08:35 PM PST US Subject: Re: AeroElectric-List: Size of battery cables From: RV7builder On June 9, 2016 1:49:03 PM CDT, Sebastien wrote: >Planning on moving my battery from the tail to the firewall. Current >wiring >is 2 gauge and so far all the homebuilders I have talked to say minimum >4 >gauge but when I go on Aircraft Spruce the only battery cable they sell >is >6 gauge. Does anyone use this stuff? I'm going to reuse the 2 gauge for >the >starter cable but has anyone used 6 gauge wire on a low current, short >run >install? Longest cable would be 3 feet and while the alternator is 50 >A, >load is never above 10 A for more than a couple minutes and that's only >the >initial battery charge after a hard start. > >Thank you, > >Sebastien Conventional wisdom is to size the alt wire to handle max alt output, and protect the wire on the battery end. I'm using 4 for bat & starter; 8 for alt & runs to the buses. But a really short jump of 6 from bat to master contactor (inches, not feet) should be fine. Charlie -- Sent from my Android device with K-9 Mail. Please excuse my brevity. ________________________________ Message 5 _____________________________________ Time: 04:35:53 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Multiple wires/ring terminals on the contactor? At 08:23 PM 6/5/2016, you wrote: >Le 05/06/2016 =E0 14:39, donjohnston a =E9crit : >> >> >> >>I thought about combining the 10 and 18 gauge >>wire into a single ring terminal which would clean things up a bit. >Hi Don and all, Just realized that I'd put my foot in the tar bucket on this one . . . didn't read the problem closely. Given that the small wires are tapping a major feeder, both wires are candidates for protection at the source end . . . consider installing two, ATC fuse holders http://tinyurl.com/jjel6e6 into a single un-insulated terminal then having that terminal install on the contactor stud back-to-back with the fat wire terminal and all wires parallel to each other. I think you'll find that most silicon rubber boots will stretch over this combination. Then butt-splice extensions on the free ends to continue on toward their assigned tasks. Install fuses size to the extension wires . . . 30A or less for the 10AWG, 10A or less for the 18AWG. Bob . . . ________________________________ Message 6 _____________________________________ Time: 07:34:10 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Saggy bus voltage on Cessna 182 At 10:29 PM 6/8/2016, you wrote: >There is an adjustment inside the regulator. The newer regulator has >the lid riveted on, but the older one (same part code) has the lid >secured by screws, so the trim pot can be reached. Set to maximum, I >now get a bus voltage of 14.2V under no load, and 13.8 with >everything energized. Which is a big improvement. But still too low . . . it shouldn't sag that much under load. Bob . . . ________________________________ Message 7 _____________________________________ Time: 07:38:07 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: 24V replacement batteries? > >Don't know if this went through on the 1st attempt. > >Response was to the 'poke a hole; can't leak' statement. Hard to >edit a quote on a phone/tablet screen keyboard. Pinhole likely >happened in shipping. Worked for almost a year, but was slowly >losing acid out the pinhole and on to the stainless firewall. that makes more sense. internal pressure excursions . . .while small . . . are not zero. So it makes sense that over time, such excursions could cause small amounts of moisture to get loose on each cycle and over time, the effects may well become observable. Good data . . . thanks. Bob . . . ________________________________ Message 8 _____________________________________ Time: 07:48:55 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Antenna grounding I have a weird one for you Bob. I have been struggling to mount my antennas the proper distance from each other and comply with other Garmin restrictions . After a lot of back and forth with Garmin I made sure my transponder antenna was three feet from the transponder as required in their installation manual. Which transponder are we talking about? I sent them a picture of where everything was and their tec guy said he was " concerned" about how close my transponder antenna is to the magnatomiter . The antenna in question is on the belly and is about 11 inches below the manotomiter. There are no restrictions in the magnatomiter installation that says it has to be any specific distance from the transponder antenna. I know they are concerned about magnetism near the unit. Why would they care about the antenna? A transponder's output is not 'magnetic' in the sense that it would upset the calibration of a compass. However, the peak power output is on the order of 100 to 150 watts which CAN disturb the electronics associated with a magnetometer. If you're already installed, leave it and do flight tests to see if a transponder making replies to ground stations has any observable effect on displayed magnetic heading values. I suspect it will not but it's easy to check. Bob . . . ________________________________ Message 9 _____________________________________ Time: 07:57:25 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Saggy bus voltage on Cessna 182 Tyco quote a resistance of 20mOhms for their 50A breaker. I just put the new 60A (not Tyco) breaker on the bench for a four terminal resistance check, a nd measure about 30mOhms - at 50A that's a 0.15 volt drop (and 7 watts of he at, which should warm it up). I'm seeing not much more than that on the exis ting installed original breaker, so I'm not sure how much better the new bre aker will be. On Jun 9, 2016, at 22:32, Robert L. Nuckolls, III wrote: At 10:29 PM 6/8/2016, you wrote: > There is an adjustment inside the regulator. The newer regulator has the l id riveted on, but the older one (same part code) has the lid secured by scr ews, so the trim pot can be reached. Set to maximum, I now get a bus voltage of 14.2V under no load, and 13.8 with everything energized. Which is a big i mprovement. But still too low . . . it shouldn't sag that much under load. Bob . . . ________________________________ Message 10 ____________________________________ Time: 08:05:40 PM PST US From: Alec Myers Subject: Re: AeroElectric-List: Saggy bus voltage on Cessna 182 Oops... my bad. The breaker resistance is 2 milliohms (measured on the bench at 3) but the voltage drop calculation is correct - 150mV. Plus another 2 m illiohm for 3 feet of 8ga wire from the B terminal to the bus, so that's ano ther 150mV drop. That's about half the voltage loss accounted for. On Jun 9, 2016, at 22:56, Alec Myers wrote: Tyco quote a resistance of 20mOhms for their 50A breaker. I just put the new 60A (not Tyco) breaker on the bench for a four terminal resistance check, a nd measure about 30mOhms - at 50A that's a 0.15 volt drop (and 7 watts of he at, which should warm it up). I'm seeing not much more than that on the exis ting installed original breaker, so I'm not sure how much better the new bre aker will be. On Jun 9, 2016, at 22:32, Robert L. Nuckolls, III wrote: At 10:29 PM 6/8/2016, you wrote: > There is an adjustment inside the regulator. The newer regulator has the l id riveted on, but the older one (same part code) has the lid secured by scr ews, so the trim pot can be reached. Set to maximum, I now get a bus voltage of 14.2V under no load, and 13.8 with everything energized. Which is a big i mprovement. But still too low . . . it shouldn't sag that much under load. Bob . . . ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.