---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Mon 03/27/17: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:11 AM - Re: Re: Lightweight rechargeable battery backup unit (Robert L. Nuckolls, III) 2. 09:16 AM - Re: Klixon Circuit Breaker (William Hunter) 3. 09:18 AM - Re: Re: Lightweight rechargeable battery backup unit (The Kuffels) 4. 02:04 PM - Re: Klixon Circuit Breaker (Robert L. Nuckolls, III) 5. 03:32 PM - Re: Re: Lightweight rechargeable battery backup unit (Robert L. Nuckolls, III) 6. 03:34 PM - Re: Klixon Circuit Breaker (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 06:11:54 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight rechargeable battery backup unit At 05:32 PM 3/26/2017, you wrote: > >Bob, > >As far as I can see , the instrument itself has no facility for >battery backup input, just the normal power feed >http://www.mglavionics.co.za/Infinitec/Manuals/ASX1.pdf neat gizmo . . . does lots of interesting things. >I therefore think the options are > >1) go with a commercial device that has been suggested on the Europa Forum >http://www.mini-box.com/picoUPS-120-12V-DC-micro-UPS-battery-backup >with a small backup battery such as this >http://www.zbattery.com/Batteries/List-of-All-12Vs >2) build my own unit, as suggested in the post by user9253 (Joe >Gores) in the original thread >3) Buy one of the more expensive units from either Funkework or LX >Navigation with the battery backups built in >4) stick with the steam driven ASI and Altimeter. A standby battery is more a bureaucratic philosophy than a strong mitigation of risk . . . as an OBAM aircraft operator, it's pretty much a given that you're going to fly with an artfully maintained electrical system . . . especially the battery. You will KNOW what your battery-only endurance values are for a pre-determined load which would, of course, included the 50mA max demand of the ASX1. It seems the practical need is to comply with requirements and demonstrate a 'back up battery' and offer an analysis of its performance and a rational plan for insuring continued airworthiness. I note that the ASX1 doesn't have a power switch built in, so you not only need to provide a little bundle of watt-seconds, you also need to manage isolation that source when the ship is powered down. Consider this: Emacs! >I guess my priorities are accuracy, minimum weight, and cost in that order > >I would value your opinion. The legacy, alkaline 9v battery has a nominal energy rating on the order of 500mAH. Suggest two such batteries in series for a nominal operating output of 16v falling to 12v at end of life. The reason for suggesting these devices is their WIRING. You can purchase snap-clips that make good connection with the batteries. The 'ideal' cell for a tiny DIY standby battery is the alkaline AA. But battery trays for cylindrical cells are rather flakey under environmental stress and you can't routinely buy AA cells with welded tabs for low risk soldering. The schematic above shows two steering diodes that insure power to the ASX1 from EITHER source when the switch is closed. You need the switch to (1) eliminate drain on the standby battery when parked and (2) facilitate pre-and-post flight testing of the installed batteries. Your check-list would turn the ASX-1 on FIRST to show that the device comes alive on the standby battery. Then bring ship's power up and proceed as you normally would. The ASX-1 would be turned off last . . . again showing that the battery is at least capable of powering the instrument. Requirements for continued air-worthiness would simply call for replacing the batteries every year. The alkaline cell will loose about 15% of capacity in first year if stored at about 120F. I stuck one of these batteries on the WestMountain Radio Battery-runner-downer and it tells me that when the fresh battery is loaded at 40mA (I de-rated from the 13.8V/50mA value in the manual . . . we're battery operating at a slightly higher voltage into a constant power demand). Emacs! The fresh Duracell 9v delivered a solid 2 watt-hours at the 40mA rate. A pair of cells would be 4 watt-hours. At 14v the specified demand of the ASX1 with the display illuminated is 14v x 0.05A or 0.7W. Hence, the pair of Duracell 9v batteries can be expected to carry the instrument solidly for 6 hours . . . for 4+ hours at end of year assuming storage at elevated temperatures. The installed weight of this system would be under 0.3 pounds. The bill of materials cost would be on the order of $10 which includes the first year's compliment of batteries. Continued air worthiness burden would be on the order of $4/year assuming Sam's club prices for the 9v batteries. Best yet, there is no burden of labor to verify the capacity of a rechargeable back up system. The FMEA looks good . . . the system gets pre and post-flight tested. This would seem to be the minimalist approach to meeting the regulatory demand for a back up system that is, like a circuit breaker, exceedingly unlikely to ever see real service. Bob . . . ________________________________ Message 2 _____________________________________ Time: 09:16:08 AM PST US From: William Hunter Subject: Re: AeroElectric-List: Klixon Circuit Breaker Hi Bob, thanks (as always) for your advice! I already have two circuit breaker holes (one labeled "gear control" and the other one labeled "gear hydraulic" and therefore I was trying to figure out some way to salvage this mess and make it look like it it's supposed to be that way. So it looks like what I should do is simply remove this 30 amp circuit breaker and cover up its laser etched label with some sort of black paint or happy face sticker or something to make it look like it wasn't there. I know you stated "current limiter" in your reply however is an automotive automatically reseting inline circuit breaker sufficient for airplane use or should it be a real slow blow one shot for real current limiter? Bill Hunter On Mar 26, 2017 08:46, "Robert L. Nuckolls, III" < nuckolls.bob@aeroelectric.com> wrote: At 07:31 PM 3/25/2017, you wrote: Hi all,=C3=82 I have a slight spacial conflict problem with the instrument panel design and I need a smaller circuit breaker.=C3=82 I designed my instrument panel with a row of circuit breakers and I have already had the instrument panel holes drilled and the silk screening done for the circuit breaker labels. My landing gear hydraulic motor requires a 30 amp circuit breaker and I placed it's 30 amp Potter and Brumfield W23-x1a1g-30 circuit breaker on the end of the row however I discovered that I have a slight space conflict to the point where the Potter and Brumfield circuit breaker will not fit in its hole.=C3=82 I wouldn't bring this kind of high current feeder up to the panel. I'd use a current limiter at the battery contactor thus keeping all the fat-wires of the panel. If there's already a spot for a breaker marked 'landing gear', put a 5a breaker there to power the control system. Bob . . . ________________________________ Message 3 _____________________________________ Time: 09:18:40 AM PST US From: "The Kuffels" Subject: Re: AeroElectric-List: Re: Lightweight rechargeable battery backup unit Bob, Hesitate to display my ignorance but with the schematic you drew won't the ASX-1 draw power from the higher voltage source, the batteries, until they are depleted to below the E-bus voltage? Won't replacing the diodes and SP ST switch with a SPDT (even an on - off - on) with the center contact going to the ASX-1 solve the issue and provide the same functionality? Tom Kuffel --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ________________________________ Message 4 _____________________________________ Time: 02:04:33 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Klixon Circuit Breaker At 11:13 AM 3/27/2017, you wrote: >Hi Bob, thanks (as always) for your advice!=C2 > >I already have two circuit breaker holes =C2 (one >labeled "gear control" and the other one labeled >"gear hydraulic" and therefore I was trying to >figure out some way to salvage this mess and >make it look like it it's supposed to be that way.=C2 > >So it looks like what I should do is simply >remove this 30 amp circuit breaker and cover up >its laser etched label with some sort of black >paint or happy face sticker or something to make >it look like it wasn't there.=C2 You could put a 5A breaker in there and use it to POWER the coil on the hydraulic pump contactor . . . >I know you stated "current limiter" =C2 in your >reply however is an automotive automatically >reseting inline circuit breaker sufficient for >airplane use or should it be a real slow blow >one shot for real current limiter? > >Bill Hunter I recommend the mini-ANL devices now available all over the 'net . . . and showing up in some auto parts stores. Here one example: http://tinyurl.com/k4x4bua Off the shelf holders for these fuses come in TWO varieties (1) uses 'set screws' to mash down on the fat-wires, ostensibly capturing them in the end of the fuse holder . . . AVOID THESE. (2) uses two threaded posts over which the fuse is dropped along with the terminals that bring fat-wires up to the fuse holder. Here's one example . . Emacs! Obviously, you could make something like this yourself. Get a piece of phenolic, delrin, lexan, etc, and cut out a base. Drill 10-32 fuse mounting holes (counter bore back side for electrical clearance to ground). A couple more 6-32 attach holes. The cover is more cosmetic than utilitarian. Bob . . . ________________________________ Message 5 _____________________________________ Time: 03:32:03 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Lightweight rechargeable battery backup unit At 11:16 AM 3/27/2017, you wrote: >Bob, > >Hesitate to display my ignorance but with the schematic you drew >won't the ASX-1 draw power from the higher voltage source, the >batteries, until they are depleted to below the E-bus >voltage? Won't replacing the diodes and SPST switch with a SPDT >(even an on - off - on) with the center contact going to the ASX-1 >solve the issue and provide the same functionality? > >Tom Kuffel Nothing ignorant about your observation my friend . . . good eye! Your suggestion eliminates the conflict you noted. Here's another alternative. The diodes prevent back-feeding of either source to the opposite source. The switch isolates the standby batteries. Preflight would be modified to close the sb battery switch first to see that the ASX-1 lights up. Then turn it back off for remainder of that flight op. Thanks for the catch! Emacs! Bob . . . ________________________________ Message 6 _____________________________________ Time: 03:34:43 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Klixon Circuit Breaker > > Obviously, you could make something like this yourself. > Get a piece of phenolic, delrin, lexan, etc, and cut > out a base. Drill 10-32 fuse mounting holes (counter bore > back side for electrical clearance to ground). A couple > more 6-32 attach holes. The cover is more cosmetic than > utilitarian . . . P.S. Dug around and found some pix I'd taken of an exemplar DIY Mini-ANL holder some years ago . . . http://tinyurl.com/mv2dq98 http://tinyurl.com/lvununh http://tinyurl.com/m2tj9ux http://tinyurl.com/mbmjoev 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.