X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from asmtpout025.mac.com ([17.148.16.100] verified) by logan.com (CommuniGate Pro SMTP 5.4.1) with ESMTP id 5101177 for flyrotary@lancaironline.net; Tue, 23 Aug 2011 12:07:56 -0400 Received-SPF: pass receiver=logan.com; client-ip=17.148.16.100; envelope-from=glasair2@me.com MIME-version: 1.0 Content-type: multipart/alternative; boundary="Boundary_(ID_1aSkVWnRl1BgM4FlnrAi6w)" Received: from [192.168.2.201] (ip70-177-24-126.sb.sd.cox.net [70.177.24.126]) by asmtp025.mac.com (Oracle Communications Messaging Exchange Server 7u4-20.01 64bit (built Nov 21 2010)) with ESMTPSA id <0LQE007TJ23R4370@asmtp025.mac.com> for flyrotary@lancaironline.net; Tue, 23 Aug 2011 09:07:05 -0700 (PDT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.4.6813,1.0.211,0.0.0000 definitions=2011-08-23_07:2011-08-23,2011-08-23,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 ipscore=0 suspectscore=9 phishscore=0 bulkscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx engine=6.0.2-1012030000 definitions=main-1108230162 From: Steve Thomas Subject: Re: [FlyRotary] The Case for Solid state Relays (SSR) Date: Tue, 23 Aug 2011 09:07:03 -0700 In-reply-to: To: Rotary motors in aircraft References: Message-id: <2B3CD102-C46A-438B-AE18-709717046CD4@me.com> X-Mailer: Apple Mail (2.1244.3) --Boundary_(ID_1aSkVWnRl1BgM4FlnrAi6w) Content-type: text/plain; charset=windows-1252 Content-transfer-encoding: quoted-printable Here is an SSA you might want to consider. I've not used them, however. = =20 http://www.periheliondesign.com/powerlinkjr.htm Best Regards, Steve Thomas _______________________________________________________ On Aug 23, 2011, at 8:48 AM, Ed Anderson wrote: > Hi Kelly, > =20 > 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. > =20 > Ed > =20 > =20 >=20 > Advantages over mechanical relays >=20 > Most of the relative advantages of solid state and electromechanical = relays are common to all solid-state as against electromechanical = devices. >=20 > 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 > Lower (if any) minimum output current (latching current) required > Increased lifetime, particularly if activated many times, as there are = no moving parts to wear > Output resistance remains constant regardless of 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 > Totally silent operation > Inherently smaller than a mechanical relay of similar specification = (if desired may have the same "casing" form factor for = interchangeability). > Much less sensitive to storage and operating environment. For example = much less sensitive to mechanical shock and vibration, humidity. > Disadvantages >=20 > Voltage/current characteristic of semiconductor rather than mechanical = contacts: > When closed, higher resistance (generating heat), and increased = 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 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. > 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. > Possibility of spurious switching due to voltage transients (due 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 of = Body diode > =20 > Here is a note from one manufacture on their relays > =20 > Transient Voltage Protection: >=20 > When operating a solid state relay in an electrically noisy = environment, large voltage >=20 > transients may damage the relay. To protect against this occurrence, = it is advisable to >=20 > install appropriate MOVs across the respective supply and load = terminals of the relay >=20 > output. The =935V=94 option is available for customers who want the = MOVs to be supplied >=20 > internally with the solid state relay. >=20 > Short-Circuit Protection: >=20 > CII Continental recommends the use of an appropriately sized I2t fuse = on the supply >=20 > side of the relay to protect the SCR devices. Although a semiconductor = relay is >=20 > designed for virtually countless operation cycles, it can be destroyed = by an overvoltage >=20 > or a short circuit, unless protected adequately by an I2t fuse. NOTE: = Overload >=20 > protection should be provided by another slow acting fuse in series = with the short >=20 > circuit protection fuse. (An overload being an over-current >=20 >=20 > From: Kelly Troyer > Sent: Tuesday, August 23, 2011 11:12 AM > To: Rotary motors in aircraft > Subject: [FlyRotary] The Case for Solid state Relays (SSR) >=20 >=20 > Ed & Group, > 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 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 > at down to 1 volt..........Looking forward for a critique of this idea = pro or con...............<:) > =20 > =20 > http://www.power-io.com/products/hdd.htm > =20 > http://www.power-io.com/library/databulletin/hdd-family.pdf > =20 > 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 >=20 > 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 >=20 > 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 {:>). > =20 > 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. > =20 > Ed > =20 > =20 >=20 > From: Kelly Troyer > Sent: Monday, August 22, 2011 8:48 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] One Battery - Two Battery was [FlyRotary] Re: = Batteries >=20 > 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...........=20 > =20 > Kelly Troyer > "DYKE DELTA JD2" (Eventually) > "13B ROTARY"_ Engine > "RWS"_RD1C/EC2/EM2 > "MISTRAL"_Backplate/Oil Manifold > "TURBONETICS"_TO4E50 Turbo >=20 > 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 >=20 > 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. > =20 > I left out one important fact about why the switch in the wrong = position caused the engine out landing.=20 > =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 > =20 > So the fact that it last 45 minutes including cranking drain for = engine start says a lot about the Odyssey PC 680. > =20 > =20 >=20 > From: Tom Walter > Sent: Monday, August 22, 2011 2:44 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: One Battery - Two Battery was [FlyRotary] Re: = Batteries >=20 > Ed, >=20 > Thanks. I remembered you discussing it, but now it makes sense why = you didn't see the low voltage warning from the battery. >=20 > 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 >=20 > Tom >=20 > 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 >=20 > 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 > =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. > =20 > =20 > =20 > 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 {:>) > =20 > Contributing factors were two early design decisions that on hindsight = revealed shortcomings. =20 > =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. > =20 > 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! > =20 > 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. > =20 > 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. > =20 > 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.=20= > =20 > 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 {:>) > =20 > 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. > =20 > Ed > =20 > Edward L. Anderson > Anderson Electronic Enterprises LLC > 305 Reefton Road > Weddington, NC 28104 > http://www.andersonee.com > http://www.eicommander.com >=20 > From: Tom Walter > Sent: Monday, August 22, 2011 12:35 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: Batteries >=20 > Joe, >=20 > Which Bob Knuckles system? Z19? >=20 > 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!) >=20 > So two batteries, and a BIG RED LIGHT with "low voltage" will go on my = panel. >=20 > 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 >=20 > Tom >=20 > From: Ed Anderson > To: Rotary motors in aircraft > Sent: Monday, August 22, 2011 11:20 AM > Subject: [FlyRotary] Re: Batteries >=20 > 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. >=20 > Ed >=20 > -------------------------------------------------- > From: > Sent: Monday, August 22, 2011 11:59 AM > To: "Rotary motors in aircraft" > Subject: [FlyRotary] Batteries >=20 > > 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 >=20 >=20 > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html >=20 >=20 >=20 >=20 >=20 >=20 >=20 >=20 --Boundary_(ID_1aSkVWnRl1BgM4FlnrAi6w) Content-type: text/html; charset=windows-1252 Content-transfer-encoding: quoted-printable Here = is an SSA you might want to consider.  I've not used them, however. =  

http://www.perihe= liondesign.com/powerlinkjr.htm

Best Regards,

Steve = Thomas

______________________________________________________= _





On Aug 23, 2011, at 8:48 AM, Ed Anderson wrote:

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=20 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=20 (typically =B5A range)
    • Voltage/current characteristic is not linear (not = purely=20 resistive), distorting switched waveforms to some extent. An=20 electromechanical relay has the low ohmic (linear) resistance of the=20= 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.=20=
  • 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


Sent: Tuesday, August 23, 2011 11:12 AM
Subject: [FlyRotary] The Case for Solid state Relays=20 (SSR)


Ed & = Group,
    &= nbsp; =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...........
    =   =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...............<:)
 
 
 
 
  
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=20
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=20= 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=20= 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&g= t;
Sent:=20 Monday, August 22, 2011 11:59 AM
To: "Rotary motors in aircraft" = <flyrotary@lancaironline.net= >
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.ht= ml=20


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