---------------------------------------------------------- RotaxEngines-List Digest Archive --- Total Messages Posted Mon 11/28/11: 11 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:38 AM - Re: charging system (FLYaDIVE) 2. 09:42 AM - Re: charging system (Noel Loveys) 3. 12:57 PM - Re: charging system (rampil) 4. 02:30 PM - Re: Re: charging system (FLYaDIVE) 5. 02:47 PM - Re: Re: charging system (Gilles Thesee) 6. 02:55 PM - Re: Re: charging system (Craig Payne) 7. 03:01 PM - Re: Re: charging system (Craig Payne) 8. 03:10 PM - Re: Re: charging system (Gilles Thesee) 9. 04:10 PM - Re: charging system (rampil) 10. 04:27 PM - Re: Re: charging system (Pete Christensen) 11. 05:20 PM - Re: Re: charging system (steve feigley) ________________________________ Message 1 _____________________________________ Time: 03:38:04 AM PST US Subject: Re: RotaxEngines-List: charging system From: FLYaDIVE Steve: The "18 Amps" is not correct. Here are the rules: 1. Charger for NORMAL charge should be 10% of the rated AH ratting. 2. So if the battery is 20 AH the charger should be MAX 2 Amps (20 * 0.10 = 2 Amps) 3. The time to charge is AH divided by Charger Amperage AND that is from zero charge. 4. So 20 / 2 = 10 Hours. 5. Trickle Charge is 25% of Charger 2 * 0.25 = 0.5 Amps (500 mA) 6. Get a GOOD charger that is designed for LITHIUM ION BATTERIES. 7. Keep the battery COOL. Li batteries get VERY warm - HOT when charging. That is all there is too it.. Other than don't over charge... Use a timer. Barry On Sun, Nov 27, 2011 at 5:40 PM, steve feigley wrote: > hey guys' > this is for the electronics types listening . I'm thinking of trying a > lithium ion type battery for my 912s for the considerable weight savings. > the battery calls for a charge rate of no more than 18 amps the 912 specs > its elec. output at 20 amps. does this nessesarally mean that it charges at > that rate? also have any of you tried one of theese batt, if so which brand > from where? > > * > > * > > ________________________________ Message 2 _____________________________________ Time: 09:42:51 AM PST US From: "Noel Loveys" Subject: RE: RotaxEngines-List: charging system I would be careful there... A simple resistor could lower your charge rate inside the prescribed 18 A but the extreme current necessary to turn the starting motor could cause your LI Ion battery to go into thermal runaway a condition that could cause a fire. Cloth covered planes are not good places to play with fire! Noel From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of steve feigley Sent: November 27, 2011 7:11 PM Subject: RotaxEngines-List: charging system hey guys' this is for the electronics types listening . I'm thinking of trying a lithium ion type battery for my 912s for the considerable weight savings. the battery calls for a charge rate of no more than 18 amps the 912 specs its elec. output at 20 amps. does this nessesarally mean that it charges at that rate? also have any of you tried one of theese batt, if so which brand from where? ________________________________ Message 3 _____________________________________ Time: 12:57:18 PM PST US Subject: RotaxEngines-List: Re: charging system From: "rampil" And.. BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit, like a "real" purpose designed battery charger. 18 A is simply and approximately the max current output capacity for the stated voltage threshold of about 12 volts. You can pull more current at a lower voltage but the $900 regulator may blow up. An airplane's battery charging circuit is not microprocessor controlled like the charger for an Apple laptop battery, airplanes do not either time the charge or do they internally monitor the state of the state of the battery to control shutdown of charging. Overall, and not knowing the specifics of the specific vendor's product, it does not sound like the best match to the Rotax. What was the weight loss you calculated? -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=359569#359569 ________________________________ Message 4 _____________________________________ Time: 02:30:04 PM PST US Subject: Re: RotaxEngines-List: Re: charging system From: FLYaDIVE Ira: Someone is feeding you a bucket of misnomers. Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to call them ] DO monitor the state of the battery. If they did not you would constantly OVERCHARGE the battery and the life of the battery would be brought down to zero. Even the Very OLD mechanical voltage regulators control the charge into the battery. They DO NOT monitor the internal resistance of the battery. Though some battery test units do calculate the value. The ACU applies voltage to the FIELD of the alternator which turns the alternator ON this usually takes place around 12.5 to 13.5 VDC. The FIELD voltage is removed when the voltage across the battery reads 14.2 to 14.5 VDC. Then the alternator is turned OFF. The AMPERAGE of the alternator is a factor of wire size, diodes and slip rings. The higher the amperage usually the bigger and heavier the alternator. Of course there are differences between manufactures. Advertising and sales spume not withholding. IF the current draw was to exceed the rated amperage of the alternator say 18 Amps... The fuse would pop. If not - Someone did a poor job of design or install. In most aircraft there are two fuses... Alternator FIELD and Alternator OUTPUT. If the voltage was to drop below 12 V as you stated the ACU would be OFF LINE - Something is Broke - And you would be drawing from the battery. Barry On Mon, Nov 28, 2011 at 3:54 PM, rampil wrote: > > And.. > BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit, > like a "real" purpose designed battery charger. > > 18 A is simply and approximately the max current output capacity for > the stated voltage threshold of about 12 volts. You can pull more > current at a lower voltage but the $900 regulator may blow up. > > > An airplane's battery charging circuit is not microprocessor controlled > like > the charger for an Apple laptop battery, airplanes do not either time the > charge or do they internally monitor the state of the state of the battery > to > control shutdown of charging. > > > Overall, and not knowing the specifics of the specific vendor's product, > it does not sound like the best match to the Rotax. > > What was the weight loss you calculated? > > -------- > Ira N224XS > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=359569#359569 > > ________________________________ Message 5 _____________________________________ Time: 02:47:41 PM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Re: charging system FLYaDIVE a crit : > Someone is feeding you a bucket of misnomers. > > Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to > call them ] DO monitor the state of the battery. If they did not you > would constantly OVERCHARGE the battery and the life of the battery > would be brought down to zero. > Even the Very OLD mechanical voltage regulators control the charge > into the battery. > They DO NOT monitor the internal resistance of the battery. Though > some battery test units do calculate the value. > > The ACU applies voltage to the FIELD of the alternator which turns the > alternator ON this usually takes place around 12.5 to 13.5 VDC. The > FIELD voltage is removed when the voltage across the battery reads > 14.2 to 14.5 VDC. Then the alternator is turned OFF. > > The AMPERAGE of the alternator is a factor of wire size, diodes and > slip rings. The higher the amperage usually the bigger and heavier > the alternator. Of course there are differences between manufactures. > Advertising and sales spume not withholding. > > IF the current draw was to exceed the rated amperage of the alternator > say 18 Amps... The fuse would pop. If not - Someone did a poor job > of design or install. In most aircraft there are two fuses... > Alternator FIELD and Alternator OUTPUT. Barry, The Rotax alternator is a permanent magnet device, so no field circuit. Anytime it is rotating it generates *voltage*. Alternators are inherently current limited, so you just can't draw too much current, as the voltage drops when current gets higher. With a Rotax alternator and voltage regulator, we found it was safer not to draw more than about 12 amps permanently, otherwise the regulator may overheat if no special cooling is provided. Some info on the study we did at http://contrails.free.fr/elec_ducati_en.php. Please note that the regulator schematic is provided as is, some time ago some readers advised they had a more accurate drawing. Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 6 _____________________________________ Time: 02:55:55 PM PST US From: "Craig Payne" Subject: RE: RotaxEngines-List: Re: charging system At least for the Rotax 912/914 the alternator is a permanent magnet alternator. Although it has a regulator it has no field windings or brushes. The schematic of the Ducati regulator is attached. -- Craig From: owner-rotaxengines-list-server@matronics.com [mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of FLYaDIVE Sent: Monday, November 28, 2011 2:27 PM Subject: Re: RotaxEngines-List: Re: charging system Ira: Someone is feeding you a bucket of misnomers. Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to call them ] DO monitor the state of the battery. If they did not you would constantly OVERCHARGE the battery and the life of the battery would be brought down to zero. Even the Very OLD mechanical voltage regulators control the charge into the battery. They DO NOT monitor the internal resistance of the battery. Though some battery test units do calculate the value. The ACU applies voltage to the FIELD of the alternator which turns the alternator ON this usually takes place around 12.5 to 13.5 VDC. The FIELD voltage is removed when the voltage across the battery reads 14.2 to 14.5 VDC. Then the alternator is turned OFF. The AMPERAGE of the alternator is a factor of wire size, diodes and slip rings. The higher the amperage usually the bigger and heavier the alternator. Of course there are differences between manufactures. Advertising and sales spume not withholding. IF the current draw was to exceed the rated amperage of the alternator say 18 Amps... The fuse would pop. If not - Someone did a poor job of design or install. In most aircraft there are two fuses... Alternator FIELD and Alternator OUTPUT. If the voltage was to drop below 12 V as you stated the ACU would be OFF LINE - Something is Broke - And you would be drawing from the battery. Barry On Mon, Nov 28, 2011 at 3:54 PM, rampil wrote: And.. BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit, like a "real" purpose designed battery charger. 18 A is simply and approximately the max current output capacity for the stated voltage threshold of about 12 volts. You can pull more current at a lower voltage but the $900 regulator may blow up. An airplane's battery charging circuit is not microprocessor controlled like the charger for an Apple laptop battery, airplanes do not either time the charge or do they internally monitor the state of the state of the battery to control shutdown of charging. Overall, and not knowing the specifics of the specific vendor's product, it does not sound like the best match to the Rotax. What was the weight loss you calculated? -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=359569#359569 ========== ="_blank">www.aeroelectric.com ooks.com" target="_blank">www.buildersbooks.com et="_blank">www.homebuilthelp.com ="_blank">http://www.matronics.com/contribution le, List Admin. ========== -List" target="_blank">http://www.matronics.com/Navigator?RotaxEngines-List ========== http://forums.matronics.com ========== le, List Admin. ="_blank">http://www.matronics.com/contribution ========== ________________________________ Message 7 _____________________________________ Time: 03:01:00 PM PST US From: "Craig Payne" Subject: RE: RotaxEngines-List: Re: charging system Oh please don't confuse us with actual facts and direct observations. This is the Internet where we thrive on speculation and rumors. ;-) -- Craig > "The Rotax alternator is a permanent magnet device, so no field circuit. Anytime it is rotating it generates *voltage*. Alternators are inherently current limited, so you just can't draw too much current, as the voltage drops when current gets higher. With a Rotax alternator and voltage regulator, we found it was safer not to draw more than about 12 amps permanently, otherwise the regulator may overheat if no special cooling is provided. Some info on the study we did at http://contrails.free.fr/elec_ducati_en.php. Please note that the regulator schematic is provided as is, some time ago some readers advised they had a more accurate drawing. Best regards, -- Gilles http://contrails.free.fr" -- Craig ________________________________ Message 8 _____________________________________ Time: 03:10:54 PM PST US From: Gilles Thesee Subject: Re: RotaxEngines-List: Re: charging system Craig Payne a crit : > > Oh please don't confuse us with actual facts and direct observations. This > is the Internet where we thrive on speculation and rumors. ;-) > ;-D Best regards, -- Gilles http://contrails.free.fr ________________________________ Message 9 _____________________________________ Time: 04:10:20 PM PST US Subject: RotaxEngines-List: Re: charging system From: "rampil" Thanks Gilles, For $900 the Ducati just isn't that great a regulator! -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=359583#359583 ________________________________ Message 10 ____________________________________ Time: 04:27:16 PM PST US Subject: Re: RotaxEngines-List: Re: charging system From: Pete Christensen $900? It was more like $160. When I replaced mine a couple years ago. Pete Sent from my iPad On Nov 28, 2011, at 6:06 PM, "rampil" wrote: > > Thanks Gilles, > > For $900 the Ducati just isn't that great a regulator! > > -------- > Ira N224XS > > > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=359583#359583 > > > > > > > > > > ________________________________ Message 11 ____________________________________ Time: 05:20:56 PM PST US From: steve feigley Subject: Re: RotaxEngines-List: Re: charging system --- On Sun, 11/27/11, rampil wrote: From: rampil Subject: RotaxEngines-List: Re: charging system I also agree that the incentive to use an "exotic" battery for a Rotax starter must be minimal. The Rotax requires only a small lead-based battery, not much weight saved compared with what's required for spinning up a TIO550! The reference articles provided note that LiPo batteries don't overheat (the old Halt & Catch Fire command) like LiCo, but do they just die quietly when overcharged like LiCo? If you're not expert enough to completely understand the engineering considerations in switching, I'd leave to someone else to be first. Ira (EE in a former life) -------- Ira N224XS Read this topic online here: http://forums.matronics.com/viewtopic.php?p=359512#359512 le, List Admin. le, List Admin. the battery I am considering is sold at shoraipower.com and is of the lithi um iron type, the current battery I use is a lead acid type weighing 13.3 l bs. the shorai battery with the same amp/hr rating and comperable cranking amps wieghs approx. 3 lbs.-- this is considerable but with the unknowns maybe not worth the risk ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message rotaxengines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/RotaxEngines-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/rotaxengines-list Browse Digests http://www.matronics.com/digest/rotaxengines-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.