---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Thu 08/30/12: 10 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:54 AM - Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III) 2. 06:20 AM - Re: 1948 Cartoon (Robert L. Nuckolls, III) 3. 10:18 AM - Re: Charger needed to revive 18 aH Lead Acid Batteries (rparigoris) 4. 10:21 AM - "Pulled Low to Ground"........(Huh?) (stearman456) 5. 10:45 AM - Re: "Pulled Low to Ground"........(Huh?) (Bill Watson) 6. 11:19 AM - Re: "Pulled Low to Ground"........(Huh?) (Bill Watson) 7. 12:45 PM - Re: "Pulled Low to Ground"........(Huh?) (Robert L. Nuckolls, III) 8. 01:23 PM - Re: "Pulled Low to Ground"........(Huh?) (stearman456) 9. 01:32 PM - Re: Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III) 10. 02:06 PM - Re: Re: Charger needed to revive 18 aH Lead Acid Batteries (Robert L. Nuckolls, III) ________________________________ Message 1 _____________________________________ Time: 05:54:11 AM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Charger needed to revive 18 aH Lead Acid Batteries At 06:22 PM 8/29/2012, you wrote: Hi Group I have a task to try and revive some 18 aH 12 volt sealed AGM batteries that weigh in at ~ 14.5 pounds. The charger that was being used on them begins at a 3.5aH charger, then slows down a bit and peaks ~ 14.2/3 then goes to 13.7 float. After a while, I don't know if from letting discharge too much or for too long, or the 3.5 aH is a bit too fast, but what happens is the batteries although they peak and go to float, they really don't take too much of a charge and have a very low capacity. How long does the charger stay in a top-off mode? 3.5 amps charge is okay. But the absorption charge should sustain at 14.7 or so until the charge acceptance current of the battery is 100 mA or less. http://tinyurl.com/9s7kpww I have a 900mA Yuasa motorcycle charger, that does a little better. Now what I did find works really well, is using the fool cheapest of cheap battery chargers I gave away with the 9aH batteries I sold on AeroElectric. Do you have a way to measure and plot the performance of your charger. Also a way to measure real capacity as a result of that charging protocol? One of these West Mountain Radio analyzers can be used to both plot charger performance -AND- confirm the battery's acceptance of charge. That charger is nothing more than a 500mA transformer that supplies a constant 500mA current, then the circuit just looks for 15.4/5 and turns off. Now mind you it can take not hours, but days to reach that magic 15.4/5 number, and some batteries can not be revived, but most can. Then I found that if I take two of these batteries and parallel them and let the poor 500mA charger reach 15.4/5, it gets about as good as it gets so far. Yes, the higher trip point is well into the range recommended for absorption charging . . . perhaps a bit high but certainly high enough. I think that the longer elevated voltage is perhaps desulfating?? Don't know if it's a sulfation problem at all, just a quirk of the chemistry. Those two batteries I bought from you have been subjected to a couple of charge/discharge cycles using just a Battery Tender and they seem to be taking on a full load of watt-seconds. Just for grins, I'll do a cap-check on one and then do a manual, constant current charge that guarantees sufficient dwell at absorption voltages and repeat the cap-check. There's a number of exemplar smart-charger profiles at: http://tinyurl.com/9t6t8x8 in particular, take a look at this curve plotted on a Schumacher 1562A http://tinyurl.com/945zdog it seems to be doing the right things in accordance with contemporary wisdom The Battery Tender Jr has the right moves too, but not as defined. That's what I use to charge and maintain a stack of test batteries here in my shop. Battery Minders behaved like this when I tested them http://tinyurl.com/9paguuy Little or no absorption dwell, very low end of charge trip point. I used to have a couple but after doing these tests, I relegated them to maintaining a fully charged battery only. Gave them away to family members for keep batteries in garden tractors and seldom used vehicles topped off . . . but cautioned against expectations for getting the battery up to 100%. It would probably pump it up to a value that would start the engine. Once the lawn was mowed, the machine's normal recharging protocols would probably top off the battery where the Battery Minder would be useful for maintaining that condition. I have a constant current 2 aH charger, and if I let it go much over 14.4 the batteries make a minor bubbling noise that I don't like too much and figure if I let it go it will begin venting? I let it go 2 hours but the 500mA charge brought back more capacity. Sorry for the long winded explain, what I need: I need a consistent source for a fairly inexpensive charger that can help revive these batteries. I looked at Walmart, they have a 1.5 amp charger that peaks too low. Is this the 1562 or it's offspring? I'm surprised that it wouldn't behave much as the version I tested some years ago. Schumacher is the BigDaddy of battery charging tools. If anyone should know how to do it right, it should be them. I'll do a looksee to find out if the Battery Tender falls short of top-off when used as a stand-alone charger-maintainer. I thought the short answer to your question would be to pick up a Schumacher 1562 or current replacement at Walmart. Do you have one of these in hand? You could mail it to me and I can run some plots on it. Bob . . . ________________________________ Message 2 _____________________________________ Time: 06:20:22 AM PST US From: "Robert L. Nuckolls, III" Subject: AeroElectric-List: Re: 1948 Cartoon At 09:25 PM 8/29/2012, you wrote: >A little thin-skinned are we, Joe? Let us allow this thread to die. The posting was inadvertent but in no instance does it warrant a stirring of the pot of perception for personal shortcomings. The truth, whether in physics or honorable government lies in metrics derived from repeatable experiments. To be sure, the present experiment in Washington is demonstrating many examples of how NOT to go about it. We can fix experiments gone wrong on airplanes here on the list. Experiments in Washington are another matter. I'd hoped to spool up a forum for those discussions but I'm still too busy with plumbing and wires for the bathroom remod. In mean time, let us not loose our grip on the mission for this List . . . nor the decorum that promotes accurate and useful exchange of knowledge. Bob . . . ________________________________ Message 3 _____________________________________ Time: 10:18:13 AM PST US Subject: AeroElectric-List: Re: Charger needed to revive 18 aH Lead Acid Batteries From: "rparigoris" Hi Bob Thx. for the reply. The chargers being used are Chargetek 3 stage chargers: http://www.chargetek.com/resources/battery-charger-basics/ I didn't measure it, but the link says it turns off at between 1/100C and 1/50C, so on a 17aH battery that is between 170 and 340mAs. What is the amp draw that you need to drop below for the Schumacher 1562A to drop out of absorption rate and go to float with a 17aH battery? If it's 100mAs or less that may just be the ticket to success. Is there a way to adjust this point to allow it to stay in absorb for a longer time? Thx. Ron Parigoris Read this topic online here: http://forums.matronics.com/viewtopic.php?p=382141#382141 ________________________________ Message 4 _____________________________________ Time: 10:21:37 AM PST US Subject: AeroElectric-List: "Pulled Low to Ground"........(Huh?) From: "stearman456" In the Garmin SL-40 installation guide it says that both the transmit and intercomm push-to-talks need to be "pulled low to ground". I'm asuming they just mean the other wire of the switch goes to ground? I'm also asuming they mean radio/contact ground, not airframe ground? Or am I missing something? Wish I could post the schematic but I'm working from my Ipad and haven't figured out how to do that yet! Dan Read this topic online here: http://forums.matronics.com/viewtopic.php?p=382142#382142 ________________________________ Message 5 _____________________________________ Time: 10:45:12 AM PST US From: Bill Watson Subject: Re: AeroElectric-List: "Pulled Low to Ground"........(Huh?) Yes, "pull to ground" still doesn't sound right for this electronic amateur but yes, that's what it means. It means the other wire of the switch is connected to ground. Either one will work because they are the same but... don't know. Bill On 8/30/2012 1:21 PM, stearman456 wrote: > > In the Garmin SL-40 installation guide it says that both the transmit and intercomm push-to-talks need to be "pulled low to ground". I'm asuming they just mean the other wire of the switch goes to ground? I'm also asuming they mean radio/contact ground, not airframe ground? Or am I missing something? Wish I could post the schematic but I'm working from my Ipad and haven't figured out how to do that yet! > > Dan > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=382142#382142 > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > > ________________________________ Message 6 _____________________________________ Time: 11:19:46 AM PST US From: Bill Watson Subject: Re: AeroElectric-List: "Pulled Low to Ground"........(Huh?) On 8/30/2012 1:44 PM, Bill Watson wrote: > > > Yes, "pull to ground" still doesn't sound right for this electronic > amateur but yes, that's what it means. It means the other wire of > the switch is connected to ground. Either one will work because they > are the "same" but there may be a distinction that makes the radio ground optimal... but I don't really know. The way I understand it, I have all my avionic grounds run to a single point and all my "pull to grounds" therefore are grounded to the same point. > > Bill > > On 8/30/2012 1:21 PM, stearman456 wrote: >> >> >> In the Garmin SL-40 installation guide it says that both the transmit >> and intercomm push-to-talks need to be "pulled low to ground". I'm >> asuming they just mean the other wire of the switch goes to ground? >> I'm also asuming they mean radio/contact ground, not airframe >> ground? Or am I missing something? Wish I could post the schematic >> but I'm working from my Ipad and haven't figured out how to do that yet! >> >> Dan >> >> >> >> >> Read this topic online here: >> >> http://forums.matronics.com/viewtopic.php?p=382142#382142 >> >> >> >> >> >> >> >> >> >> >> >> >> ----- >> No virus found in this message. >> Checked by AVG - www.avg.com >> >> > > > ----- > No virus found in this message. > Checked by AVG - www.avg.com > > ________________________________ Message 7 _____________________________________ Time: 12:45:13 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: "Pulled Low to Ground"........(Huh?) At 12:21 PM 8/30/2012, you wrote: > >In the Garmin SL-40 installation guide it says that both the >transmit and intercomm push-to-talks need to be "pulled low to >ground". I'm asuming they just mean the other wire of the switch >goes to ground? I'm also asuming they mean radio/contact ground, >not airframe ground? Or am I missing something? Wish I could post >the schematic but I'm working from my Ipad and haven't figured out >how to do that yet! This is an unfortunate scrambling of vernacular. The function of a discrete CONTROL or SIGNAL path is often described using these terms. For example, the legacy control philosophy for closing the battery contactor may be described as "pull to ground", "active low", "pulled down", "low side switched" or simply "switched ground". All of these phrases will bring the same image to mind for someone who works across several disciplines in electronics. The other side of the coin describes the control of something like your landing light where the author might say "active hi", "pull up to bus", "high side switched", etc. Discrete levels in both the power and digital worlds are not subject to interference from small noises that might exist on the selected ground for a pull-to- ground push-to-talk line. Many thousands of radios have produced performance as advertised when their mic jacks were simply grounded to airframe at the jack's mounting. Of course, in our legacy 3-wire microphone architecture this does put transmit audio at-risk for picking small noises that may exist in currents that flow on the airframe . . . hence a potential ground loop that manifests in noise heard on transmitted audio while those same noises had no effect on getting the transmitter to become active with the PTT button. I have often advised builders to "follow the manufacturer's instructions' when it comes to dissecting the designer's intent for installations. In the SL-40 wiring excerpt Emacs! We see that microphone and headset jack grounds are brought back to the radio on their own wires . . . good practice. This also means that the "pull down" on TxKey line by PTT buttons on wired into these jacks will share that ground line wiht the mic. This same drawing also shows "yolk mounted transmit buttons" with an undefined ground. This is because the discrete control line is not subject to the ground loop contamination and MAY be grounded anywhere . . . which includes the option of taking the wire all the way back to share a ground with the radio. Same condition exists for the Intercom Selector Switch. Bob . . . ________________________________ Message 8 _____________________________________ Time: 01:23:59 PM PST US Subject: AeroElectric-List: Re: "Pulled Low to Ground"........(Huh?) From: "stearman456" Thanks, guys! Read this topic online here: http://forums.matronics.com/viewtopic.php?p=382152#382152 ________________________________ Message 9 _____________________________________ Time: 01:32:09 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Charger needed to revive 18 aH Lead Acid Batteries At 12:16 PM 8/30/2012, you wrote: Hi Bob Thx. for the reply. The chargers being used are Chargetek 3 stage chargers: http://www.chargetek.com/resources/battery-charger-basics/ I didn't measure it, but the link says it turns off at between 1/100C and 1/50C, so on a 17aH battery that is between 170 and 340mAs. Hmmmm . . . okay. I seem to recall that Skip Koss talked about recharge currents below 100 mA for terminating an absorption cycle on really big batteries like the 30-50 a.h. aircraft batteries we used at HBC. Kicking off that high seems a bit 'light'. What is the amp draw that you need to drop below for the Schumacher 1562A to drop out of absorption rate and go to float with a 17aH battery? Have no idea. Never measured it. Don't know how critical it is. Given that the Schumacher product stayed in a absorption mode for a significant time suggested that a righteous absorption charge was being delivered. I don't have any 1562's around to measure. I could put one of your Chargetek machines on a DAS and find out where they are calibrated. If it's 100mAs or less that may just be the ticket to success. Yes. Just for grins, I took one of the 12a.h. batteries I bought from you that has been on a Battery Tender for the last several days (green light on, in maintenance mode. Fooey, didn't read the float voltage first) and hooked it to a 14.6v power supply. Charge current jumped to 300mA and over the next 12 minutes it fell to 100mA. Putting a crayon to the numbers suggests that the battery is 12 a.h. x 12v x 3600 s/hr ~ 500,000 watt-seconds at full charge. The little boost on the bench put in 200 mA average for 12 min for 0.2 x 14 x 720 ~ 2000 watt-seconds or less than 0.5% of capacity. Hence I deduce (1) that the Battery Tender did indeed return and support this battery to 100% of rated capacity and (2) an end of absorption cycle value of 100mA is not an unreasonable calibration point. It would be interesting to plot an absorption cycle for energy the battery takes on after recharge current drops below 300mA . . . I'm guessing that it's probably less than 1% of rated capacity . . . but don't know without measuring. Is there a way to adjust this point to allow it to stay in absorb for a longer time? Haven't had a 1562 (or replacement) apart to find out. But even if the EOAC termination value is higher, I'm not convinced that you're going to loose much. We could set up the experiment and find out. Bob . . . ________________________________ Message 10 ____________________________________ Time: 02:06:46 PM PST US From: "Robert L. Nuckolls, III" Subject: Re: AeroElectric-List: Re: Charger needed to revive 18 aH Lead Acid Batteries If it's 100mAs or less that may just be the ticket to success. Yes. Just for grins, I took one of the 12a.h. batteries I bought from you that has been on a Battery Tender for the last several days (green light on, in maintenance mode. Fooey, didn't read the float voltage first) and hooked it to a 14.6v power supply. Charge current jumped to 300mA and over the next 12 minutes it fell to 100mA. Another data point. After one hour at 14.6 volts, current going into the battery is still about 90mA. This suggests to me that the battery has stopped converting incoming energy into changes in chemistry and that 100mA may indeed be too large a value for marking end-of-absorption- charge cycle. The values you deduced for the Chargtek device of 200-300 mA may indeed be more practical. 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.