---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Fri 06/22/07: 12 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 04:25 AM - Internal reg failed. Everything fried (Bob Barrow) 2. 06:28 AM - Re: Question about Aux battery contactor on Z30 (Robert L. Nuckolls, III) 3. 06:51 AM - Re: Internal reg failed. Everything fried (Robert L. Nuckolls, III) 4. 08:25 AM - Re: Radios squawk ...literally (W Meier) 5. 08:56 AM - Digital Ampmeter (Carlos Trigo) 6. 01:08 PM - Re: Digital Ampmeter (Robert L. Nuckolls, III) 7. 01:26 PM - Digital Ampmeter (P.S.) (Robert L. Nuckolls, III) 8. 02:47 PM - Re: Digital Ampmeter (Carlos Trigo) 9. 07:23 PM - Cutting off battery posts (Terry Miles) 10. 07:40 PM - Re: Digital Ampmeter (Richard E. Tasker) 11. 07:46 PM - Re: Digital Ampmeter (Robert L. Nuckolls, III) 12. 09:08 PM - Re: Cutting off battery posts (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 04:25:24 AM PST US From: "Bob Barrow" Subject: AeroElectric-List: Internal reg failed. Everything fried The following copy of a post on the Yahoo GRT_EFIS group site is most interesting. It seems the internal regulator on a Vans supplied alternator failed on an RV and the resultant overvoltage fried all of the avionics. FOR THE WHAT ITS WORTH COLUMN. WE HAVE HAD THE GRT EFIS AND EIS INSTALLED IN AN RV9A AND HAVE NOTHING BUT GOOD THINGS TO SAY ABOUT THE COMPANY, THE PEOPLE AND THE EQUIPMENT. WE HAD OVER 300 HRS ON THE GRT EQUIP AND WE WERE FLYING FROM TYLER TEXAS TO VICKSBURG MISSISSIPPI WHEN OUR ALT (FROM VANS FIREWALL FORWARD PACKAGE) TOSSED ITS INTERNAL VOLTAGE REGULATOR INTO THE ARMATURE. THE RESULT WAS THAT EVERTYING FRIED. AS YOU ALL PROBABLY KNOW , AN OVERVOLTAGE IS NOT PROTECTED BY BREAKERS. OUR SL30, 327 AUTO PILOTS AND .....EVERYTHING FRIED. WE SENT OUR COOKED EFIS, AND EIS TO GRT AND TOLD THEM THAT IT WAS NOT THEIR EQUIPMENT THAT FAILED BUT RATHER THE ABOVE,,,, THEIR RESPONSE.... THEY SENT US NEW ONES ? IT IS RARE TO FIND A COMPANY WITH THAT MUCH EXPERTISE AND ... HOW DO YOU DESCRIBE THAT KIND OF SERVICE? GOOD WILL? FRED HOLLOWAY _________________________________________________________________ Advertisement: ninemsn Travel - Hot deals, travel ideas & Lonely Planet guides. http://ninemsn.com.au/share/redir/adTrack.asp?mode=click&clientID=799&referral=hotmailtagline&URL=http://travel.ninemsn.com.au/compIntro.aspx?compId=2404 ________________________________ Message 2 _____________________________________ Time: 06:28:27 AM PST US From: "Robert L. Nuckolls, III" Subject: RE: AeroElectric-List: Question about Aux battery contactor on Z30 At 08:50 PM 6/21/2007 -0600, you wrote: >Bob, > >Thank you for the quick response and the multiply options. In building an >airplane, so far, the electrical is by far the most intriguing to me. >Thanks again, I'm pleased that you find value in the $time$ you spend here . . . Bob . . . ________________________________ Message 3 _____________________________________ Time: 06:51:43 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Internal reg failed. Everything fried . . . any student of the assemblage of simple-ideas that form a useful invention ultimately comes to understand that the risk for such events is never zero . . . and the $time$ to achieve 1x10^-6 reliability is great. So, the cost effective approach hangs a hat on a parallel concept . . . failure tolerance. Assuming we know nothing about the pedigree of the simple- ideas and cooks that crafted any particular alternator, the prudent system designer simply assumes that the alternator can and will fail in ugly ways at some point in time. The traditional approach to making that failure tolerable is to (1) fit the system with a means by which the pilot exercises absolute control, (2) fit the system with active notification of malfunction and (3) install an automatic, milliseconds fast responder to the OV event that exercises feature (1) which causes feature (2) to announce that the alternator is off line . . . for whatever reason. In terms of SYSTEM reliability, one can easily deduce that the likelihood of a failure in the alternator and in either (1), (2) or (3) happening together on the same tank full of fuel is exceedingly small. Now if one has a well considered plan-b for the unexpected alternator shut-down event, then the builder has crafted great SYSTEM reliability from a collection of components for which there is little or no data as to the reliability of any one component. The anecdote cited has no "hard evidence" by virtue of an autopsy of the alleged failure but the byproducts of that failure are inarguable and the source of the energy that caused the damage is not debatable. This is an expensive lesson that has taxed the $time$ of someone else . . . who has seen fit to make us beneficiaries of his/her experience and observations. It would be foolish of us not to exploit that information and apply the best-we-know-how-to-do as a prophylactic against sharing the writer's experience. This ladies and gentlemen is not a dark-n-stormy-night story that yields little data for refining a recipe for success. It's a bright-light- of-day-illumination of how a particular recipe failed in expensive ways but fortunately without injury to the "cooks". Thank you Mr. Barrow for sharing this with us. Bob . . . At 09:23 PM 6/22/2007 +1000, you wrote: > > >The following copy of a post on the Yahoo GRT_EFIS group site is most >interesting. It seems the internal regulator on a Vans supplied alternator >failed on an RV and the resultant overvoltage fried all of the avionics. > >FOR THE WHAT ITS WORTH COLUMN. WE HAVE HAD THE GRT EFIS AND EIS >INSTALLED IN AN RV9A AND HAVE NOTHING BUT GOOD THINGS TO SAY ABOUT >THE COMPANY, THE PEOPLE AND THE EQUIPMENT. > >WE HAD OVER 300 HRS ON THE GRT EQUIP AND WE WERE FLYING FROM TYLER >TEXAS TO VICKSBURG MISSISSIPPI WHEN OUR ALT (FROM VANS FIREWALL >FORWARD PACKAGE) TOSSED ITS INTERNAL VOLTAGE REGULATOR INTO THE >ARMATURE. THE RESULT WAS THAT EVERTYING FRIED. > >AS YOU ALL PROBABLY KNOW , AN OVERVOLTAGE IS NOT PROTECTED BY >BREAKERS. OUR SL30, 327 AUTO PILOTS AND .....EVERYTHING FRIED. > >WE SENT OUR COOKED EFIS, AND EIS TO GRT AND TOLD THEM THAT IT WAS >NOT THEIR EQUIPMENT THAT FAILED BUT RATHER THE ABOVE,,,, THEIR >RESPONSE.... THEY SENT US NEW ONES ? IT IS RARE TO FIND A COMPANY >WITH THAT MUCH EXPERTISE AND ... HOW DO YOU DESCRIBE THAT KIND OF >SERVICE? GOOD WILL? > >FRED HOLLOWAY ________________________________ Message 4 _____________________________________ Time: 08:25:43 AM PST US From: W Meier Subject: Re: AeroElectric-List: Radios squawk ...literally Try turning one of the transmitters off. If both are transmitting at the same time (not by design, but for some unknown reason), the frequencies "beat" against each other and the resultant squeal is the difference between them. Wayne Jerry2DT@aol.com wrote: > Folks, > > Away from home with very annoying problem... Dual Icom's, dual > antennas,same problem either one. Hit transmit and I send out a squeal > with voice. other pilots say it is LOUD!! Before I borrow tools and > tear things apart, any suggestions? Only one PTT switch wired in at > present. Sound like a bad ground somewheres? > > Any and all help very appreciated. > > Jerry Cochran > > > ------------------------------------------------------------------------ > See what's free at AOL.com > . > * > > > * ________________________________ Message 5 _____________________________________ Time: 08:56:21 AM PST US From: "Carlos Trigo" Subject: AeroElectric-List: Digital Ampmeter I installed a 50 mV shunt in the AWG 6 wire coming from the alternator, to measure Amps "produced" by it, and I don't want to put an analog Ampmeter in my pannel. Can someone please indicate me a source and a model of digital ampmeter to connect to my shunt. TIA Carlos ________________________________ Message 6 _____________________________________ Time: 01:08:04 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Digital Ampmeter At 04:48 PM 6/22/2007 +0100, you wrote: > > >I installed a 50 mV shunt in the AWG 6 wire coming from the alternator, to >measure Amps "produced" by it, and I don't want to put an analog Ampmeter >in my pannel. >Can someone please indicate me a source and a model of digital ampmeter to >connect to my shunt. > >TIA >Carlos It's not a simple answer. Unlike the ordinary analog instrument, a digital instrument cares about how much voltage is on the shunt with respect to ground. The instrument is trying to deduce and display a voltage on the order of millivolts while shunt is riding above ground by about 14,000 millivolts and has a lot of 'noise' on it. The ability to ignore the big picture while staying accurately focused on the little picture is not a trivial task. Most manufacturers get around it by using the hall effect sensor which doesn't care how much voltage is on the sensed wire . . . it cares only about the magnetic field around the wire that results from the flow of the current to be measured. If you're dead set against an analog (pretty cheap at $50) like https://matronics.com/aeroelectric/Catalog/AEC/9007/9007.html then in order to use a digital instrument, you'll need to find one that can either run from your 14v bus and resolve a millivolt signal riding on 14v common mode or select an LCD instrument that runs from a 9v battery (just leave it on all the time. Battery lasts for months!) and doesn't worry about the 14v common mode thing. An example of the later instrument can be seen at: http://www.mpja.com/download/12205me.pdf These are inexpensive but you'll note that the input signal must lie within plus or minus 1.0 volts of the instrument's ground (Com Mode Voltage). Now, there ARE ways that one can craft a shunt signal processing amplifier using a device with a very high common mode capability. And example of such a part is the Analog Devices AD628 http://www.analog.com/UploadedFiles/Data_Sheets/AD628.pdf Note that this puppy is designed to live in a very large common mode range of over plus/minus 100 volts. This is the type of device employed by folks to choose to offer digital displays driven by shunts. However, most digital suppliers no probably use hall-sensors and step over the common mode limits. I thought JPI or Electronics International had stand alone ammeters and voltmeters but a quick check of their websites didn't turn anything up. Perhaps someone else on the list will have some suggestions. It seems the trends are toward multifunction instrument packages that include volts and amps. Stand alone instruments are going to be increasingly difficult to find. The easiest thing to do is bite the bullet and go the stone-simple analog instrument. You can spend a lot of time and a lot more money getting to the digital solution. Bob . . . ________________________________ Message 7 _____________________________________ Time: 01:26:34 PM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Digital Ampmeter (P.S.) At 03:05 PM 6/22/2007 -0600, you wrote: At 04:48 PM 6/22/2007 +0100, you wrote: I installed a 50 mV shunt in the AWG 6 wire coming from the alternator, to measure Amps "produced" by it, and I don't want to put an analog Ampmeter in my pannel. Can someone please indicate me a source and a model of digital ampmeter to connect to my shunt. TIA Carlos It's not a simple answer. Unlike the ordinary analog instrument, a digital instrument cares about how much voltage is on the shunt with respect to ground. The instrument is trying to deduce and display a voltage on the order of millivolts while shunt is riding above ground by about 14,000 millivolts and has a lot of 'noise' on it. The ability to ignore the big picture while staying accurately focused on the little picture is not a trivial task. Most manufacturers get around it by using the hall effect sensor which doesn't care how much voltage is on the sensed wire . . . it cares only about the magnetic field around the wire that results from the flow of the current to be measured. If you're dead set against an analog (pretty cheap at $50) like https://matronics.com/aeroelectric/Catalog/AEC/9007/9007.html then in order to use a digital instrument, you'll need to find one that can either run from your 14v bus and resolve a millivolt signal riding on 14v common mode or select an LCD instrument that runs from a 9v battery (just leave it on all the time. Battery lasts for months!) and doesn't worry about the 14v common mode thing. An example of the later instrument can be seen at: http://www.mpja.com/download/12205me.pdf These are inexpensive but you'll note that the input signal must lie within plus or minus 1.0 volts of the instrument's ground (Com Mode Voltage). Now, there ARE ways that one can craft a shunt signal processing amplifier using a device with a very high common mode capability. And example of such a part is the Analog Devices AD628 http://www.analog.com/UploadedFiles/Data_Sheets/AD628.pdf Note that this puppy is designed to live in a very large common mode range of over plus/minus 100 volts. This is the type of device employed by folks to choose to offer digital displays driven by shunts. However, most digital suppliers no probably use hall-sensors and step over the common mode limits. I thought JPI or Electronics International had stand alone ammeters and voltmeters but a quick check of their websites didn't turn anything up. Perhaps someone else on the list will have some suggestions. It seems the trends are toward multifunction instrument packages that include volts and amps. Stand alone instruments are going to be increasingly difficult to find. The easiest thing to do is bite the bullet and go the stone-simple analog instrument. You can spend a lot of time and a lot more money getting to the digital solution. P.S. If you wanted to shed the shunt and roll your own hall-effect loadmeter, consider the parts from AmpLoc at: http://amploc.com/PRO%20Series.pdf You could combine one of these sensors with an inexpensive DPM . . . http://mpja.com/productview.asp?product=16179+ME . . . and probably craft a loadmeter for under $40 in materials and take care of the common mode problem at the same time. Bob . . . ________________________________ Message 8 _____________________________________ Time: 02:47:46 PM PST US From: "Carlos Trigo" Subject: Re: AeroElectric-List: Digital Ampmeter Bob Thanks for your quick and complete response. I have a couple of (electric instruments challenged guy) questions: If I use the first digital panel meter you suggested (http://www.mpja.com/download/12205me.pdf) do I simply connect power (9V and -) and the 2 wires from the shunt, and it will indicate Amps? The "Full scale range" of 200mV indicated in the specifications, has it anything to do with the 50mV characteristic of my shunt ? Carlos ----- Original Message ----- From: "Robert L. Nuckolls, III" Sent: Friday, June 22, 2007 10:26 PM Subject: AeroElectric-List: Digital Ampmeter (P.S.) > > > At 03:05 PM 6/22/2007 -0600, you wrote: > > > > At 04:48 PM 6/22/2007 +0100, you wrote: > > > > I installed a 50 mV shunt in the AWG 6 wire coming from the > alternator, to measure Amps "produced" by it, and I don't want > to put an analog Ampmeter in my pannel. Can someone please indicate > me a source and a model of digital ampmeter to connect to my shunt. > > TIA > Carlos > > It's not a simple answer. Unlike the ordinary analog instrument, > a digital instrument cares about how much voltage is on the shunt > with respect to ground. The instrument is trying to deduce and display > a voltage on the order of millivolts while shunt is riding above ground > by about 14,000 millivolts and has a lot of 'noise' on it. The ability > to ignore the big picture while staying accurately focused on the little > picture is not a trivial task. > > Most manufacturers get around it by using the hall effect sensor > which doesn't care how much voltage is on the sensed wire . . . it > cares only about the magnetic field around the wire that results > from the flow of the current to be measured. > > If you're dead set against an analog (pretty cheap at $50) like > > https://matronics.com/aeroelectric/Catalog/AEC/9007/9007.html > > then in order to use a digital instrument, you'll need to > find one that can either run from your 14v bus and resolve > a millivolt signal riding on 14v common mode or select an > LCD instrument that runs from a 9v battery (just leave it on > all the time. Battery lasts for months!) and doesn't worry > about the 14v common mode thing. An example of the later > instrument can be seen at: > > http://www.mpja.com/download/12205me.pdf > > These are inexpensive but you'll note that the input > signal must lie within plus or minus 1.0 volts of > the instrument's ground (Com Mode Voltage). > > Now, there ARE ways that one can craft a shunt signal > processing amplifier using a device with a very high > common mode capability. And example of such a part is > the Analog Devices AD628 > > http://www.analog.com/UploadedFiles/Data_Sheets/AD628.pdf > > Note that this puppy is designed to live in a very > large common mode range of over plus/minus 100 volts. > This is the type of device employed by folks to choose to > offer digital displays driven by shunts. However, most > digital suppliers no probably use hall-sensors and step > over the common mode limits. > > I thought JPI or Electronics International had stand > alone ammeters and voltmeters but a quick check of their > websites didn't turn anything up. Perhaps someone else on > the list will have some suggestions. It seems the trends > are toward multifunction instrument packages that include > volts and amps. Stand alone instruments are going to be > increasingly difficult to find. > > The easiest thing to do is bite the bullet and > go the stone-simple analog instrument. You can spend > a lot of time and a lot more money getting to the > digital solution. > > P.S. > > If you wanted to shed the shunt and roll your own hall-effect > loadmeter, consider the parts from AmpLoc at: > > http://amploc.com/PRO%20Series.pdf > > You could combine one of these sensors with an inexpensive > DPM . . . > > http://mpja.com/productview.asp?product=16179+ME > > . . . and probably craft a loadmeter for under $40 in materials > and take care of the common mode problem at the same time. > > > Bob . . . > > > ________________________________ Message 9 _____________________________________ Time: 07:23:21 PM PST US From: "Terry Miles" Subject: AeroElectric-List: Cutting off battery posts Hi all, I bought a pair of Yellow Top Optima batteries. They are the absorbed gas matt type. They are located in the nose area and stacked one on top of the other in my Velocity XL. I cut the top posts off the bottom battery due to height limitations and planned to use the side posts. That turned out to be a mistake. Even though I have good continuity between the top post nub and the side posts, the battery will not accept an external charge. It shows 12.1 v or so, but collapses under any kind of load. Without being all that clear despite my best efforts to learn more of the mechanical connections involved...the tech service arm of Optima said cutting off the posts somehow compromises the top-post-to-side-post physical connection. He also said removing the posts opens the battery's controlled venting system to outside air. I was surprised at both of these discoveries...and out $200 to boot. Anybody out there running side post batteries w/ the top posts removed? Likely I am back to the drawing boards for a complete redesign now of battery size and hold downs, but I am considering one alternative and that is mounting a new Optima upside down with the top posts still in place by drilling holes in my mounting floor for the posts to protrude into. Risks there would be if I ever overcharged it, electrolyte would leak on the base surface. Any thoughts? Suggestions? Thanks Terry ________________________________ Message 10 ____________________________________ Time: 07:40:54 PM PST US From: "Richard E. Tasker" Subject: Re: AeroElectric-List: Digital Ampmeter Since Bob has not answered yet, I will. The 50mV shunt will drop 50mV at it's rated amperage. You didn't specify what one you have, but let's assume that it is a 50mV shunt at 50 Amps. The voltage drop across the shunt will vary from 0V to 50 mV as the current goes from 0A to 50 A. The digital voltmeter has a 200 mV full scale readout so it will read 0 to 50 mV. If you indeed have the shunt in the example above, then the meter will read 0-50mV which you can interpret to be 0-50A. If you have some other range shunt, the you will have to interpret the reading. For example, if you have a 100 A shunt then it will have a 50 mV drop at 100 amps and the digital meter will read 50 mV when you have 100 amps flowing. Dick Tasker Carlos Trigo wrote: > > > Bob > > Thanks for your quick and complete response. > > I have a couple of (electric instruments challenged guy) questions: > > If I use the first digital panel meter you suggested > (http://www.mpja.com/download/12205me.pdf) > do I simply connect power (9V and -) and the 2 wires from the shunt, > and it will indicate Amps? > > The "Full scale range" of 200mV indicated in the specifications, has > it anything to do with the 50mV characteristic of my shunt ? > > Carlos > > > ----- Original Message ----- From: "Robert L. Nuckolls, III" > > To: > Sent: Friday, June 22, 2007 10:26 PM > Subject: AeroElectric-List: Digital Ampmeter (P.S.) > > >> >> >> At 03:05 PM 6/22/2007 -0600, you wrote: >> >> >> >> At 04:48 PM 6/22/2007 +0100, you wrote: >> >> >> >> I installed a 50 mV shunt in the AWG 6 wire coming from the >> alternator, to measure Amps "produced" by it, and I don't want >> to put an analog Ampmeter in my pannel. Can someone please indicate >> me a source and a model of digital ampmeter to connect to my shunt. >> >> TIA >> Carlos >> >> It's not a simple answer. Unlike the ordinary analog instrument, >> a digital instrument cares about how much voltage is on the shunt >> with respect to ground. The instrument is trying to deduce and display >> a voltage on the order of millivolts while shunt is riding above >> ground >> by about 14,000 millivolts and has a lot of 'noise' on it. The ability >> to ignore the big picture while staying accurately focused on the >> little >> picture is not a trivial task. >> >> Most manufacturers get around it by using the hall effect sensor >> which doesn't care how much voltage is on the sensed wire . . . it >> cares only about the magnetic field around the wire that results >> from the flow of the current to be measured. >> >> If you're dead set against an analog (pretty cheap at $50) like >> >> https://matronics.com/aeroelectric/Catalog/AEC/9007/9007.html >> >> then in order to use a digital instrument, you'll need to >> find one that can either run from your 14v bus and resolve >> a millivolt signal riding on 14v common mode or select an >> LCD instrument that runs from a 9v battery (just leave it on >> all the time. Battery lasts for months!) and doesn't worry >> about the 14v common mode thing. An example of the later >> instrument can be seen at: >> >> http://www.mpja.com/download/12205me.pdf >> >> These are inexpensive but you'll note that the input >> signal must lie within plus or minus 1.0 volts of >> the instrument's ground (Com Mode Voltage). >> >> Now, there ARE ways that one can craft a shunt signal >> processing amplifier using a device with a very high >> common mode capability. And example of such a part is >> the Analog Devices AD628 >> >> http://www.analog.com/UploadedFiles/Data_Sheets/AD628.pdf >> >> Note that this puppy is designed to live in a very >> large common mode range of over plus/minus 100 volts. >> This is the type of device employed by folks to choose to >> offer digital displays driven by shunts. However, most >> digital suppliers no probably use hall-sensors and step >> over the common mode limits. >> >> I thought JPI or Electronics International had stand >> alone ammeters and voltmeters but a quick check of their >> websites didn't turn anything up. Perhaps someone else on >> the list will have some suggestions. It seems the trends >> are toward multifunction instrument packages that include >> volts and amps. Stand alone instruments are going to be >> increasingly difficult to find. >> >> The easiest thing to do is bite the bullet and >> go the stone-simple analog instrument. You can spend >> a lot of time and a lot more money getting to the >> digital solution. >> >> P.S. >> >> If you wanted to shed the shunt and roll your own hall-effect >> loadmeter, consider the parts from AmpLoc at: >> >> http://amploc.com/PRO%20Series.pdf >> >> You could combine one of these sensors with an inexpensive >> DPM . . . >> >> http://mpja.com/productview.asp?product=16179+ME >> >> . . . and probably craft a loadmeter for under $40 in materials >> and take care of the common mode problem at the same time. >> >> >> >> Bob . . . >> >> >> >> >> >> >> > > -- Please Note: No trees were destroyed in the sending of this message. We do concede, however, that a significant number of electrons may have been temporarily inconvenienced. -- ________________________________ Message 11 ____________________________________ Time: 07:46:48 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Digital Ampmeter At 10:42 PM 6/22/2007 +0100, you wrote: > > >Bob > >Thanks for your quick and complete response. > >I have a couple of (electric instruments challenged guy) questions: > >If I use the first digital panel meter you suggested >(http://www.mpja.com/download/12205me.pdf) >do I simply connect power (9V and -) and the 2 wires from the shunt, and >it will indicate Amps? > >The "Full scale range" of 200mV indicated in the specifications, has it >anything to do with the 50mV characteristic of my shunt ? No, the instrument cited doesn't have sufficient common mode range to use with your shunt. You would either have to convert from a shunt to a hall-effect sensor . . . -OR- build the signal conditioning amplifier I suggested using the AD628 chip -OR- you could use a 9v battery to power the instrument, leave it hooked up all the time (but easy to replace) and set the instrument to read 200.0 Mv full-scale. Now, if your shunt is a 50A shunt (50 mv = 50A) then the instrument will now read correctly in amps to the nearest 0.1 amps. Bob . . . ________________________________ Message 12 ____________________________________ Time: 09:08:05 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Cutting off battery posts At 10:21 PM 6/22/2007 -0400, you wrote: > > >Hi all, > >I bought a pair of Yellow Top Optima batteries. They are the absorbed gas >matt type. They are located in the nose area and stacked one on top of the >other in my Velocity XL. I cut the top posts off the bottom battery due to >height limitations and planned to use the side posts. > >That turned out to be a mistake. Even though I have good continuity between >the top post nub and the side posts, the battery will not accept an external >charge. It shows 12.1 v or so, but collapses under any kind of load. >Without being all that clear despite my best efforts to learn more of the >mechanical connections involved...the tech service arm of Optima said >cutting off the posts somehow compromises the top-post-to-side-post physical >connection. He also said removing the posts opens the battery's controlled >venting system to outside air. > >I was surprised at both of these discoveries...and out $200 to boot. > >Anybody out there running side post batteries w/ the top posts removed? Without knowing the details of how the post is molded and retained in the battery housing, the experiment is not without risk . . . when you cut the posts off, were they not solid? I.e., a smooth lead alloy surface with no holes? I'm mystified as to how this would have compromised the seal if they were smooth, contiguous surfaces after cutting. >Likely I am back to the drawing boards for a complete redesign now of >battery size and hold downs, but I am considering one alternative and that >is mounting a new Optima upside down with the top posts still in place by >drilling holes in my mounting floor for the posts to protrude into. Risks >there would be if I ever overcharged it, electrolyte would leak on the base >surface. Any thoughts? Suggestions? Those are real "pig" batteries. Do you NEED the capacity? Or the weight? As I recall, the smallest of the yellow-top batteries are something on the order of 50 a.h. batteries at a 2-hour rate and weighs about 44 pounds. Is this the battery we're talking about? http://tinyurl.com/2z8xgu Unless you need the weight, surely there are smaller batteries that meet your electrical needs that don't cost so much and will fit into the space allotted? 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.