X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.121] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5101157 for flyrotary@lancaironline.net; Tue, 23 Aug 2011 11:50:44 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.121; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=aeMH4JcVOnVr0LmJAzqEvfnmJyuaZufWdlng4HTRGCk= c=1 sm=0 a=Rjak6Qw-LC4A:10 a=SC71y0a/4S6V9vjVxUojGA==:17 a=g-ZOccbRAAAA:8 a=ayC55rCoAAAA:8 a=Ia-xEzejAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=o2QoyYduAAAA:8 a=7g1VtSJxAAAA:8 a=Wu2x2hkCOUnmcU99gdcA:9 a=KbBR0ttOVvObiYtqfeAA:7 a=wPNLvfGTeEIA:10 a=Rbd-iJhMrt8A:10 a=Qa1je4BO31QA:10 a=QX1TN2WjEnEA:10 a=EzXvWhQp4_cA:10 a=TlnOPt13aEMA:10 a=VgBAb4Hjeyzy61Wq:21 a=E_kfUDIig6n_nhNy:21 a=SaT-V5p6AAAA:8 a=HZJGGiqLAAAA:8 a=CjxXgO3LAAAA:8 a=Q-dpSA_HrkRq6Th86HcA:9 a=7U_-OcpgkFmsRU7JCXgA:7 a=tXsnliwV7b4A:10 a=HeoGohOdMD0A:10 a=rC2wZJ5BpNYA:10 a=TirP_Dok60lwbw-4:21 a=-iRqqEOx_nqGLzeh:21 a=SC71y0a/4S6V9vjVxUojGA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.175.135 Received: from [174.110.175.135] ([174.110.175.135:51436] helo=EdPC) by cdptpa-oedge02.mail.rr.com (envelope-from ) (ecelerity 2.2.3.46 r()) with ESMTP id 5D/2B-03893-03CC35E4; Tue, 23 Aug 2011 15:50:09 +0000 Message-ID: <2F735B98A0F649F4B4FD9DA433BB921C@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] The Case for Solid state Relays (SSR) Date: Tue, 23 Aug 2011 11:48:20 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002D_01CC618A.8DE10FE0" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_002D_01CC618A.8DE10FE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Kelly, Like all technology Solid state relays have advantages/disadvantages - = I did a quick search to see if I could find assessments of DC relays = using DC switching. Here is what I found which seem to sum up both. I = have no experience in using them. Ed Advantages over mechanical relays Most of the relative advantages of solid state and electromechanical = relays are common to all solid-state as against electromechanical = devices. a.. SSRs are faster than electromechanical relays; their switching = time is dependent on the time needed to power the LED on and off, of the = order of microseconds to milliseconds=20 b.. Lower (if any) minimum output current (latching current) required=20 c.. Increased lifetime, particularly if activated many times, as there = are no moving parts to wear=20 a.. Output resistance remains constant regardless of amount of use=20 d.. Clean, bounceless operation=20 e.. Decreased electrical noise when switching=20 f.. No sparking, allowing use in explosive environments where it is = critical that no spark is generated during switching=20 g.. Totally silent operation=20 h.. Inherently smaller than a mechanical relay of similar = specification (if desired may have the same "casing" form factor for = interchangeability).=20 i.. Much less sensitive to storage and operating environment. For = example much less sensitive to mechanical shock and vibration, humidity. = Disadvantages a.. Voltage/current characteristic of semiconductor rather than = mechanical contacts:=20 a.. When closed, higher resistance (generating heat), and increased = electrical noise=20 b.. When open, lower resistance, and reverse leakage current = (typically =B5A range)=20 c.. Voltage/current characteristic is not linear (not purely = resistive), distorting switched waveforms to some extent. An = electromechanical relay has the low ohmic (linear) resistance of the = associated mechanical switch when activated, and the exceedingly high = resistance of the air gap and insulating materials when open.=20 d.. DC load must observe polarity (- and + not interchangeable) to = avoid an undesirable "always conducting" state that does not depend on = switching input. Electromechanical relays do not depend on polarity.=20 b.. Possibility of spurious switching due to voltage transients (due = to much faster switching than mechanical relay)=20 c.. Isolated bias supply required for gate charge circuit=20 d.. Higher Transient Reverse Recovery time (Trr) due to the presence = of Body diode=20 Here is a note from one manufacture on their relays Transient Voltage Protection: When operating a solid state relay in an electrically noisy environment, = large voltage transients may damage the relay. To protect against this occurrence, it = is advisable to install appropriate MOVs across the respective supply and load terminals = of the relay output. The "5V" option is available for customers who want the MOVs to = be supplied internally with the solid state relay. Short-Circuit Protection: CII Continental recommends the use of an appropriately sized I2t fuse on = the supply side of the relay to protect the SCR devices. Although a semiconductor = relay is designed for virtually countless operation cycles, it can be destroyed = by an overvoltage or a short circuit, unless protected adequately by an I2t fuse. NOTE: = Overload protection should be provided by another slow acting fuse in series with = the short circuit protection fuse. (An overload being an over-current From: Kelly Troyer=20 Sent: Tuesday, August 23, 2011 11:12 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] The Case for Solid state Relays (SSR) Ed & Group, I brought up the question of possible use of Solid State Relays = (SSR) to replace the=20 electro-mechanical contactors most of us use in our flying electrical = systems but I need=20 to depend on the smarter "EE" (Electronic Engineer) types of our group = to tell me if this would be a good idea...........To the electrically challenged (Me) they = look good.......Light weight, small, low operating voltage (down to 3 volts), low current = draw, low voltage drop, high surge amp survival, etc..............They do require a heat sink to = utilize their maximum amp capibility............They do cost considerably more than the = contactors but do not wear or degrade and if used within their limits will probably last longer = than me........... I have included a link to the company that made the SSR that I = have purchased on blind faith that it would serve as my master relay........It is a = "Power-IO" model HDD-06V75 which has been upgraded since my purchase by the HDD-06V75E which will = operate at a lower voltage,lower drop and lower current draw............Both = versions will stay operated=20 at down to 1 volt..........Looking forward for a critique of this idea = pro or con...............<:) http://www.power-io.com/products/hdd.htm http://www.power-io.com/library/databulletin/hdd-family.pdf http://www.power-io.com/library/databulletin/hdd-e-family.pdf =20 Kelly Troyer "DYKE DELTA JD2" (Eventually) "13B ROTARY"_ Engine "RWS"_RD1C/EC2/EM2 "MISTRAL"_Backplate/Oil Manifold "TURBONETICS"_TO4E50 Turbo From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, August 22, 2011 8:37 PM Subject: [FlyRotary] Re: One Battery - Two Battery was [FlyRotary] Re: = Batteries Yes, Kelly, back a few years ago, I did look into them. The models I = looked at had some strange characteristics that I didn't fully = understand (and didn't take the time to), so I passed. Besides in my = case 3 volts would taken me a bit closer to the airport before the relay = let loose, but would have done nothing to provide a solution for my = problem - head up and locked {:>). I'm still waiting for the 16X before I start anything major new on my = aircraft - hope won't have to wait too much longer. Ed From: Kelly Troyer=20 Sent: Monday, August 22, 2011 8:48 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] One Battery - Two Battery was [FlyRotary] Re: = Batteries Ed, Have you ever considered "Solid State Relays" for = contactors..........The DC versions will operate=20 at down to 3 volts and draw a lot less amperage than the electro = mechanical versions...........=20 Kelly Troyer "DYKE DELTA JD2" (Eventually) "13B ROTARY"_ Engine "RWS"_RD1C/EC2/EM2 "MISTRAL"_Backplate/Oil Manifold "TURBONETICS"_TO4E50 Turbo From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, August 22, 2011 4:12 PM Subject: [FlyRotary] Re: One Battery - Two Battery was [FlyRotary] Re: = Batteries Yes, I have also found my GPS can get confused - especially in the inner = city (where you need it the most). So can my brain when tired and/or = under pressure - the old brain can do some not so funny things. I left out one important fact about why the switch in the wrong position = caused the engine out landing. =20 When I had designed that switch in to disengage the battery from the = alternator (in case of an over voltage condition), the switch not only = removed the battery from the alternator line - but also all my critical = systems (fuel, ignition) which were "smartly" tied to my battery bus. = So even though the alternator was putting out plenty of power - even if = the battery had been stone, cold dead, it could have powered all of = those power hungry devices. But having all of that on the battery bus = and the battery bus disconnected from alternator - that pulled that = battery down even quicker.=20 So the fact that it last 45 minutes including cranking drain for engine = start says a lot about the Odyssey PC 680. From: Tom Walter=20 Sent: Monday, August 22, 2011 2:44 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: One Battery - Two Battery was [FlyRotary] Re: = Batteries Ed, Thanks. I remembered you discussing it, but now it makes sense why you = didn't see the low voltage warning from the battery. I know that 'fixation' issue, all to well. On business I'm always = running between meetings in new cities, and got to the point where I = really loved (& blindly trusted) my Garmin GPS. Well in Phoenix there = was an "W.Shangri-La Rd" vs "E. Shangri-La Rd". Van full of hungry = people wanting dinner, and I kept following the GPS... despite a = passenger in the back telling me I was taking the wrong route. I just = figured the GPS was smarter as it rcd traffic information, and would get = us there faster! Had I thought to look at a map, or listened the my = passenger, but with a load of people, 5pm traffic, and overload after a = day in the sun.... my brain wasn't working. Live and learn!=20 Tom From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, August 22, 2011 12:27 PM Subject: [FlyRotary] One Battery - Two Battery was [FlyRotary] Re: = Batteries Actually, Tom, in that particular incident - a second battery would = have only enabled me to fly too far away from the only safe airport to = make a return and dead stick into. IF I had realized the root cause (a = switch accidently put in the wrong position) then one battery would have = worked just as well as two {:>). =20 Having said that, I certainly would not try to get anyone to change = their mind about using two batteries. . Some folks would not feel = comfortable even with two batteries - but, would add a second = alternator, etc. So, you have to think through your scenarios, the risk = involved and your personal risk tolerance. Yes, Bob now has several = good electrical designs - for just about any kind of power system you = could come up with. Back in 1992, I had never heard of Aeroelectric or = Bob. But, since my previous engine out almost 5 years previous had been fuel = related and the engine was sputtering in a similar manner - my = diagnostic side of the brain got locked in to searching for a fuel = problem (again) - but even switching tanks did no good - because, this = time the "fuel problem" was a decreasing electrical power. This = incident clearly pointed out the need for an emergency check list that = involved checking both fuel AND electrical systems. Coming up with one = in your head with the engine sputtering is not recommended {:>) Contributing factors were two early design decisions that on hindsight = revealed shortcomings. =20 One was an electrical system design that permitted my voltmeter to keep = showing me the 13.8 volts being generated by the alternator while the = battery voltage was steadly decreasing. Yes, I had a low-voltage light = right in front of my eyes - but, it was wired into the alternator = powered circuit - so never showed low voltage because the alternator = voltage was fine - up to the point the relay released. Now, had it occurred to me I might have an electrical problem - and = switched the volt meter to the battery (instead of alternator) AND had = thought to observe it, I would have seen the battery voltage decreasing = and that MIGHT have got me looking for an electrical problem rather than = a fuel problem. But, when you get your head locked into one focus - and = you truly have mental blinders on, NOT GOOD! The second design deficiency was that the relay holding the alternator = On-Line was provided current solely by the battery - so guess what = happened when the battery juice got too low to hold the alternator = on-line? Right "CLACK!!!!!" followed immediately by all lights, = radios, LEDS, panel going dark. It gets even lonelier when the lights = go out. Had I two batteries - all of this would have happened further = from my emergency airport in Salem, Al. No, I have not added the second battery back in after the incident - = because in my particular case, the incident had nothing to do with one = battery vs two battery - it was a case of a mis-positioned switch which = the pilot never recognized was the cause - until later on the ground, = cleaning off the seat cushion. The corrective action was to put a = switch guard over that particular switch so it could NOT be accidently = toggled incorrectly AND rewire my relay so that a dead battery would no = longer prevent my system from using the power of a perfectly good = alternator. But, this is just my perspective - provided for anyone to glean what = they wish from it - if that is two batteries, two alternators or what = have you, then as always in this hobby, that is up to individual choice. = Just don't make the same dumb mistakes I made, we know how those turned = out - advance the state of the art and make NEW mistakes {:>) Oh, yes, the switch I accidently activated (I think I probably hit it = with my foot getting out of the aircraft at the previous refueling stop) = was one that enabled me to detach my battery from the alternator. The = thought at design time was that if my alternator ran-away with high = voltage, I could isolate the battery from the alternator thereby = preventing the battery from overheating/boiling and get to an emergency = landing on battery power alone. Seemed like a good idea at the time. Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com From: Tom Walter=20 Sent: Monday, August 22, 2011 12:35 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: Batteries Joe, Which Bob Knuckles system? Z19? I realize Ed is happy with one battery, but I like two batteries. The = THUNK of relays all popping open and the realization of "I turned off = the alternator, and voltage dropped way too low.... followed with LAND = NOW!" would have convinced Ed to have put the second battery back in! It = sure got my attention on why two batteries is a good thing!(Great Story, = but I'll let Ed tell it!) So two batteries, and a BIG RED LIGHT with "low voltage" will go on my = panel. I did the spread sheet with 17AH batteries and flying time. Add in = Night, and no place to easily land.... two batties seem like a good = trade off. My biggest shock was the FORD style contactor needed 1Amp = draw to remain closed. Shutting down non essential, but leaving = contactors, PDF, ECU and coils.... System draw is around 15 Amps. 17AH = implies you'd have an hour, but at 15Amp draw... more like 30-40 = minutes, hence two batteries as 1 hour flying time makes finding a = landing strip a little easier. =20 Tom From: Ed Anderson To: Rotary motors in aircraft Sent: Monday, August 22, 2011 11:20 AM Subject: [FlyRotary] Re: Batteries Joe, I started out using two Concord 25AH RGB each weighing 22 lbs for a = total of over 44 lbs of battery (some joked I could get home by using = the start to crank the prop {:>)) ! I then transition to two Odyssey = PC-680 17AH batteries each weighing 14 lbs for a total of 28 lbs. Then = after 6 years of flying with two batteries and never using the second = one - except to help crank on a cold morning, I removed one of them. = Have now been flying for over 4-5 years with one Odyssey 14lbs. I swap = it out every two years. Ed -------------------------------------------------- From: Sent: Monday, August 22, 2011 11:59 AM To: "Rotary motors in aircraft" Subject: [FlyRotary] Batteries > What size an type of batteries are required for the rotary? I am = leaning toward using 2 batteries and use Bob Nuckols system. Thanks for = any help. >=20 > Joe Berki > Limo EZ >=20 > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html=20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_002D_01CC618A.8DE10FE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Kelly,
 
Like all technology Solid state relays have=20  advantages/disadvantages - I did a quick search to see if I could = find=20 assessments of DC relays using DC switching.  Here is what I found=20 which seem to sum up both.  I have no = experience in=20 using them.
 
Ed
 
 

Advantages over=20 mechanical relays

Most of the relative advantages of solid = state and=20 electromechanical relays are common to all solid-state as against=20 electromechanical devices.

  • SSRs are faster than electromechanical = relays;=20 their switching time is dependent on the time needed to power the LED = on and=20 off, of the order of microseconds to milliseconds
  • Lower (if any) minimum output current = (latching=20 current) required
  • Increased lifetime, particularly if = activated many=20 times, as there are no moving parts to wear
    • Output resistance remains constant = regardless of=20 amount of use
  • Clean, bounceless operation
  • Decreased electrical noise when = switching
  • No sparking, allowing use in explosive = environments where it is critical that no spark is generated during = switching=20
  • Totally silent operation
  • Inherently smaller than a mechanical = relay of=20 similar specification (if desired may have the same "casing" form = factor for=20 interchangeability).
  • Much less sensitive to storage and = operating = environment. For example much less sensitive to mechanical shock and vibration,=20 humidity.

Disadvantages

  • Voltage/current characteristic of semiconductor rather = than=20 mechanical contacts:
    • When closed, higher resistance (generating heat), and = increased=20 electrical noise
    • When open, lower resistance, and reverse leakage current = (typically =B5A range)
    • Voltage/current characteristic is not linear (not purely = resistive), distorting switched waveforms to some extent. An=20 electromechanical relay has the low ohmic (linear) resistance of the = associated mechanical switch when activated, and the exceedingly = high=20 resistance of the air gap and insulating materials when open. =
    • DC load must observe polarity (- and + not = interchangeable) to=20 avoid an undesirable "always conducting" state that does not depend = on=20 switching input. Electromechanical relays do not depend on polarity. =
  • Possibility of spurious switching due to voltage = transients (due=20 to much faster switching than mechanical relay)
  • Isolated bias supply required for gate charge circuit =
  • Higher Transient Reverse Recovery time (Trr) due to the = presence=20 of Body diode
 
Here is a = note from one=20 manufacture on their relays
 

Transient Voltage Protection:

When operating a solid state = relay in an=20 electrically noisy environment, large voltage

transients may damage the = relay. To=20 protect against this occurrence, it is advisable to

install appropriate MOVs = across the=20 respective supply and load terminals of the relay

output. The =935V=94 option = is available for=20 customers who want the MOVs to be supplied

internally with the solid = state=20 relay.

Short-Circuit Protection:

CII Continental recommends = the use of an=20 appropriately sized I2t = fuse on the=20 supply

side of the relay to protect the SCR = devices.=20 Although a semiconductor relay is

designed for virtually countless = operation=20 cycles, it can be destroyed by an overvoltage

or a short circuit, unless protected = adequately=20 by an I2t fuse. NOTE: Overload

protection should be provided by = another slow=20 acting fuse in series with the short

circuit protection fuse. (An overload being an=20 over-current


From: Kelly Troyer
Sent: Tuesday, August 23, 2011 11:12 AM
To: Rotary motors in = aircraft
Subject: [FlyRotary] The Case for Solid state Relays=20 (SSR)

Ed & Group,
    &n= bsp; =20 I brought up the question of possible use of Solid State Relays = (SSR) to replace the
electro-mechanical contactors most of us use in our flying = electrical systems=20 but I need 
to depend on the=20 smarter "EE" (Electronic Engineer) = types of our=20 group to tell me if this
would be a good=20 idea...........To the electrically challenged (Me) they look=20 good.......Light
weight, small, low = operating=20 voltage (down to 3 volts), low current draw, low voltage drop,
high=20 surge amp survival, etc..............They do require a heat sink to = utilize=20 their maximum
amp capibility............They do cost considerably = more than=20 the contactors but do not wear
or degrade and if = used within=20 their limits will probably last longer than me...........
    &= nbsp; =20 I have included a link to the company that made the SSR that I have purchased on
blind faith that it = would=20 serve as my master relay........It is a "Power-IO" model HDD-06V75
which has been = upgraded since=20 my purchase by the HDD-06V75E which will = operate=20 at
a lower=20 voltage,lower drop and lower current draw............Both versions will=20 stay operated
at down to 1 volt..........Looking forward = for a=20 critique of this idea pro or con...............<:)
 
 
http://www.power-io.com= /products/hdd.htm
 
 
ht= tp://www.power-io.com/library/databulletin/hdd-e-family.pdf
  
Kelly = Troyer
"DYKE DELTA JD2" (Eventually)
"13B ROTARY"_ = Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo

From: Ed Anderson=20 <eanderson@carolina.rr.com>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Monday, August 22, 2011 = 8:37=20 PM
Subject: = [FlyRotary] Re: One=20 Battery - Two Battery was [FlyRotary] Re: Batteries

Yes, Kelly, back a few years ago, I did look = into them.=20 The models I looked at had some strange characteristics that I didn't = fully=20 understand (and didn't take the time to), so I passed.  Besides in = my case=20 3 volts would taken me a bit closer to the airport before the relay let = loose,=20 but would have done nothing to provide a solution for my problem - head = up and=20 locked {:>).
 
I'm still waiting for the 16X before I start = anything=20 major new on my aircraft  - hope won't have to wait too much=20 longer.
 
Ed
 
 

From: Kelly = Troyer=20
Sent: Monday, August 22, 2011 8:48 PM
Subject: [FlyRotary] One Battery - Two Battery was = [FlyRotary] Re:=20 Batteries

Ed,
  Have you ever considered "Solid State Relays" = for  contactors..........The DC versions will operate =
at down to 3 volts and draw a lot less amperage than the = electro mechanical versions........... 
 
Kelly Troyer
"DYKE DELTA=20 JD2" (Eventually)
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Backplate/Oil Manifold
"TURBONETICS"_TO4E50 Turbo

From:=20 Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Monday, August 22, 2011 = 4:12=20 PM
Subject: = [FlyRotary] Re: One=20 Battery - Two Battery was [FlyRotary] Re: Batteries

Yes, I have also found my GPS=20 can get confused - especially in the inner city (where you need it the=20 most).  So can my brain when tired and/or under  pressure - = the old=20 brain can do some not so funny things.
 
I left out one important fact about why the = switch in the=20 wrong position caused the engine out landing. 
 
When I had designed that switch in to disengage = the=20 battery from the alternator (in case of an over voltage condition), the = switch=20 not only removed the battery from the alternator line - but also all my = critical=20 systems (fuel, ignition) which were "smartly" tied to my battery = bus.  So=20 even though the alternator was putting out plenty of power - even if the = battery=20 had been stone, cold dead, it could have powered all of those power = hungry=20 devices.  But having all of that on the battery bus and the battery = bus=20 disconnected from alternator - that pulled that battery down even=20 quicker. 
 
So the fact that it last 45 minutes including = cranking=20 drain for engine start says a lot about the Odyssey PC 680.
 
 

From: Tom Walter
Sent: Monday, August 22, 2011 2:44 PM
Subject: [FlyRotary] Re: One Battery - Two Battery was = [FlyRotary]=20 Re: Batteries

Ed,

Thanks.  I remembered you discussing it, = but now it=20 makes sense why you didn't see the low voltage warning from the=20 battery.

I know that 'fixation' issue, all to = well.   On=20 business I'm always running between meetings in new cities, and got to = the point=20 where I really loved (& blindly trusted) my Garmin GPS.  = Well in=20 Phoenix there was an "W.Shangri-La Rd" vs "E.  Shangri-La Rd". Van full=20 of hungry people wanting dinner, and I kept following the GPS... despite a passenger in the back telling = me I was=20 taking the wrong route.  I just figured the GPS=20 was smarter as it rcd traffic information, = and would=20 get us there faster!  Had I thought to look at a map, or listened = the my=20 passenger, but with a load of people, 5pm traffic, and overload after a = day in=20 the sun.... my brain wasn't working.  Live and = learn! 

Tom

From:=20 Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Monday, August 22, 2011 = 12:27=20 PM
Subject: = [FlyRotary] One=20 Battery - Two Battery was [FlyRotary] Re: Batteries

Actually, Tom,  in that particular incident = - a=20 second battery would have only enabled me to fly too far away from = the only=20 safe airport to make a return and dead stick into.  IF I had = realized the root cause (a switch accidently put in=20 the wrong position) then one battery would have worked just as well as = two=20 {:>). 
 
Having said that, I certainly would not try to = get anyone=20 to change their mind about using two batteries. . Some folks = would not=20 feel comfortable even with two batteries - but, would add a second = alternator,=20 etc.  So, you have to think through your scenarios, the risk = involved=20 and your personal risk tolerance.  Yes, Bob now has several good = electrical=20 designs - for just about any kind of power system you could come up = with. =20 Back in 1992, I had never heard of Aeroelectric or=20 Bob.
 
 
 
But, since my previous engine out almost 5 years = previous=20 had been fuel related and the engine was sputtering in a similar manner = - my=20 diagnostic side of the brain got locked in to searching  for a = fuel=20 problem (again) - but even switching tanks did no good - because, this = time the=20 "fuel problem" was a decreasing electrical power.  This incident = clearly=20 pointed out the need for an emergency check list that involved checking = both=20 fuel AND electrical systems.  Coming up with one in your head with = the=20 engine sputtering is not recommended {:>)
 
Contributing factors were two early design = decisions that=20 on hindsight revealed shortcomings.  
 
One was an electrical system design that = permitted my=20 voltmeter to keep showing me the 13.8 volts being generated by the = alternator=20 while the battery voltage was steadly=20 decreasing.  Yes, I had a low-voltage light right in front of my = eyes -=20 but, it was wired into the alternator powered circuit - so never showed = low=20 voltage because the alternator voltage was fine - up to the point the = relay=20 released.
 
   Now,  had  it = occurred to me I=20 might have an electrical problem - and switched the volt meter to the = battery=20 (instead of alternator) AND had thought to observe it, I would have seen = the=20 battery voltage decreasing and that MIGHT have got me looking for an = electrical=20 problem rather than a fuel problem.  But, when you get your head = locked=20 into one focus - and you truly have mental blinders on, NOT = GOOD!
 
The second design deficiency was that  the = relay=20 holding the alternator On-Line was provided current solely  by the = battery=20 - so guess what happened when the battery juice got too low to hold the=20 alternator on-line?  Right "CLACK!!!!!"  followed immediately = by all=20 lights, radios, LEDS, panel going = dark.  It=20 gets even lonelier when the lights go out.  Had I two batteries - = all of=20 this would have happened further from my emergency airport in Salem,=20 Al.
 
No, I have not added the second battery back in = after the=20 incident  - because in my particular case, the incident had nothing = to do=20 with one battery vs two battery  - it was a case of a mis-positioned switch which the pilot never = recognized was=20 the cause - until later on the ground, cleaning off the seat = cushion.  The=20 corrective action was to put a switch guard over that particular switch = so it=20 could NOT be accidently toggled = incorrectly AND=20 rewire my relay so that a dead battery would no longer prevent my system = from=20 using the power of a perfectly good alternator.
 
But, this is just my perspective - provided for = anyone to=20 glean what they wish from it - if that is two batteries, two alternators = or what=20 have you, then as always in this hobby, that is up to individual=20 choice. 
 
 Just don't make the same dumb mistakes = I made, we=20 know how those turned out - advance the state of the art and make = NEW=20 mistakes {:>)
 
Oh, yes, the switch I accidently activated (I think I probably hit it = with my=20 foot getting out of the aircraft at the previous refueling stop) was one = that=20 enabled me to detach my battery from the alternator.  The thought = at design=20 time was that if my alternator ran-away with high voltage, I could = isolate the=20 battery from the alternator thereby preventing the battery from=20 overheating/boiling and get to an emergency landing on battery power=20 alone.  Seemed like a good idea at the time.
 
Ed
 
Edward L. Anderson
Anderson Electronic = Enterprises=20 LLC
305 Reefton=20 Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com

From: Tom Walter
Sent: Monday, August 22, 2011 12:35 PM
Subject: [FlyRotary] Re: Batteries

Joe,

Which Bob Knuckles system?  Z19?

I realize Ed is happy with one battery, but I like two=20 batteries.  The THUNK of relays all popping open and = the=20 realization of "I turned off the alternator, and voltage = dropped=20 way too low.... followed with LAND NOW!" would have convinced Ed = to=20 have put the second battery back in! It sure got my attention on why two = batteries is a good thing!(Great Story, but I'll let Ed = tell=20 it!)

So two batteries, and a BIG RED LIGHT with "low voltage" will = go on=20 my panel.

I did the spread sheet with 17AH = batteries and=20 flying time. Add in Night, and no place to easily land.... = two=20 batties seem like a good trade off.  = My biggest=20 shock was the FORD style contactor=20 needed 1Amp draw to remain closed.  Shutting down non=20 essential, but leaving contactors, PDF, ECU and coils....   System draw = is around=20 15 Amps. 17AH implies you'd have an hour, but at 15Amp = draw... more=20 like 30-40 minutes, hence two batteries as 1 hour flying = time makes=20 finding a landing strip a little easier. 

Tom

From:=20 Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft=20 <flyrotary@lancaironline.net>
Sent: Monday, August 22, 2011 = 11:20=20 AM
Subject: = [FlyRotary] Re:=20 Batteries

Joe, I started out using two Concord 25AH RGB each weighing 22 lbs for a total of over 44 = lbs of=20 battery (some joked I could get home by using the start to crank the = prop=20 {:>)) !  I then transition to two Odyssey PC-680 17AH batteries = each=20 weighing 14 lbs for a total of 28 lbs.  Then after 6 years of = flying with=20 two batteries and never using the second one - except to help crank on a = cold=20 morning, I removed one of them.  Have now been flying for over 4-5 = years=20 with one Odyssey 14lbs.  I swap it out every two=20 years.

Ed

-------------------------------------------------= -
From:=20 <jskmberki@windstream.net&= gt;
Sent:=20 Monday, August 22, 2011 11:59 AM
To: "Rotary motors in aircraft" = <flyrotary@lancaironline.ne= t>
Subject:=20 [FlyRotary] Batteries

> What size an type of batteries are = required=20 for the rotary?  I am leaning toward using 2 batteries and use Bob = Nuckols system.  Thanks for any = help.
>=20
> Joe Berki
> Limo EZ
>
> --
> Homepage:  = http://www.flyrotary.com/
> Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.htm= l=20


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