Today's Message Index:
----------------------
1. 05:44 AM - Fusing (Eric M. Jones)
2. 06:38 AM - Z-11 I think (Mark Wesson)
3. 09:09 AM - Re: Z-11 I think (Robert L. Nuckolls, III)
4. 09:37 AM - Re: Battery Tender performance (Bill Watson)
5. 12:22 PM - Re: Z-11 I think (Mark Wesson)
6. 12:22 PM - 19v laptop power in vehicles (Robert L. Nuckolls, III)
7. 01:45 PM - Re: Z-11 I think (Ed Holyoke)
Message 1
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Much has been written about fusing, and yes, the approach is to "fuse to protect
the wire and not the end equipment. But there is room for what is called "Intrinsically
Safe Wiring" that requires no fuse by definition.
A circuit can be "Intrinsically Safe" if that circuit can never provide enough
short-circuit current, or even spark energy to ignite the hazard of interest (ethylene
for most of us).
Now this is not so esoteric, since in many circuits, including sensors, memories
small devices and motors, very bright LEDs, the "intrinsically-safe" current
levels are quite usable. For simple LEDs the current limiting means would typically
be at the bus.
See this for some background:
http://www.mtl-inst.com/images/uploads/datasheets/App_Notes/AN9003.pdf
For your boy's science project:
How these standard were developed might be of interest (old manuals showed this):
Make a tiny grounded container (like a metal bottle cap) with a few drops of
gasoline (or whatever material is of interest). Then at a range of temperatures,
at a range of voltages and currents, touch the + lead to spark on the rim
of the tiny container. Below certain limits, The intrinsically safe limits, nothing
happens.
--------
Eric M. Jones
www.PerihelionDesign.com
113 Brentwood Drive
Southbridge, MA 01550
(508) 764-2072
emjones(at)charter.net
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=382439#382439
Message 2
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I am in the process of designing the electrical for my RV-9 build and have a
few questions. I think I started with the Z-11 drawing but have made so many
small changes using a little of each that I don't know what to call it at
this point. However I am using a single alt. with an E-Bus.
Would I be better off with a E-Bus relay rather than a switch only? Seems
better to have the wire running all the way to the swith as a ground only
rather than a hot there and back.
During normal flight operation is the E-Bus switch left on so that power is
direct rather than through the diode. The diode seems inefficient since it
generates heat.
Why are all the drawings showing the simple on-off switches as on-on
S700-1-3 rather than the 1-2?
I am sure I will have additional questions as I progress.
Mark Wesson
Message 3
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| Subject: | Re: Z-11 I think |
>However I am using a single alt. with an E-Bus.
>Would I be better off with a E-Bus relay rather than a switch only?
>Seems better to have the wire running all the way to the swith as a
>ground only rather than a hot there and back.
If your total e-bus loads can be supported through
the 7A fuse, then that size of always-hot feeder from
the battery bus does not violate legacy design goals
for crash safety.
Adding the relay is fine too . . . except that it
adds a parasitic load on the order of .15 A . . .
and one of the goals for the e-bus was to minimize
if not eliminate such loads. But it's your choice
commensurate with your own design goals.
>During normal flight operation is the E-Bus switch left on so that
>power is direct rather than through the diode. The diode seems
>inefficient since it generates heat.
No. Consider the operating requirements for power
in every device qualified for commercial aircraft.
The device must perform down pass battery-dead voltage
levels (9V in a 14v system). When the alternator is
running, main bus is 14.2 or better which puts the e-
bus at 13.6 or so . . . nice source. When the alternator
is off, the MAX voltage available to anything in the
airplane is what ever the battery will provide . . . 12.5
volts and DOWN.
Hence the suggestion that a slightly depressed e-bus
is not an operational concern. Now, if your e-bus
is configured for HOURS of operations battery only
(hopefully equal to or greater than duration of
fuel aboard) then the e-bus loads are small . . . 3-6
amps. 6 amps droped across a diode is about 4 watts
of heat . . . insignificant when a 40-60 amp alternator
is providing a 500 to 750 watt source of operating
power.
>Why are all the drawings showing the simple on-off switches as on-on
>S700-1-3 rather than the 1-2?
You can go buy 1-2 if you like. I used to stock the 1-3
which serviced both purposes and to keep line-items
of inventory low, I suggested that the 1-3 was a good
choice for BOTH slots both in terms of my inventory
and your spares.
Bob . . .
Message 4
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| Subject: | Re: Battery Tender performance |
The charger from Walmart is a Shumacher:
https://dl.dropbox.com/u/60509998/DSC04046.JPG
There were several models but this one seemed to be the right one for my
Odyssey 680s
Here is a blurry shot of my Battery Tender Plus:
https://dl.dropbox.com/u/60509998/DSC04048.JPG
Bill
On 9/4/2012 10:00 PM, Jared Yates wrote:
>
> Bill, next time you are out at the hangar and think about it, could
> you see what the manufacturer and model are of your successful Walmart
> charger?
>
> On Tue, Sep 4, 2012 at 9:20 PM, Bill Watson <Mauledriver@nc.rr.com> wrote:
>> Bob, your previous posts on this topic of using a "Battery Tender" as a
>> "charger" was the key to helping me unravel a set of problems I was having
>> with my Odyssey 680s. Just wanted to say thanks and to share my experience
>> if others may find it useful.
>>
>> I have a Z-14 with 2 680s. Very early in my build I bought 2 680s (which
>> really weren't needed at the time) to ease design of the battery box but
>> they were actually used very little. They were charged a few times and
>> occasionally maintained (hooked up overnight even though they had not been
>> discharged) with the brand name "Battery Tender". A few years later when I
>> was 90% done with 90% to go, I decided to get fresh batteries (not quite at
>> the same time and these weren't needed at the time either). These batteries
>> were used quite a bit in panel testing and such. These were also charged
>> and maintained with the battery tender (many cycles).
>>
>> When I finally got to first flight, I found that neither of the new
>> batteries would turn over the IO540 on my RV10. When both batteries were
>> cross fed, no problem but alone, neither battery could quite turn the cold
>> engine over. Per Bob's posts, I suspected that use of the "Tender" was my
>> problem. A trip to Walmart turned up a suitable charger with settings for
>> Gel vs Lead vs (glass mat?). One charge and now one of the new batteries
>> was a tiger and the other got a lot better.
>>
>> The way I intended to use my 2 batteries was to normally use one to power
>> the EFISs and most of the rest of the avionics. The other was for starting.
>> After start, the batteries would be cross fed. This now worked but my
>> avionics panel would start to go dim after 5 minutes or so unless the engine
>> was started and the alternators were online. I was hoping for more.
>>
>> After much data collection, a carbon pile tester, and some additional field
>> experience it turned out that the batteries I bought some 4 or 5 years ago
>> were still in great shape once charged with the new charger. Furthermore, 1
>> of the new batteries seemed ruined in the sense that the other 3 batteries
>> consistently outperformed it and I found it unsuitable for either position
>> in the aircraft.
>>
>> It appeared that repeated discharge and charge with only the Battery Tender
>> permanently reduced the capacity of 1 of my new batteries. It also
>> appeared that 4 or 5 years of aging on the shelf in a more or less fully
>> charged state was not as bad as repeated use and undercharging with a
>> Battery Tender/maintainer.
>>
>> Further reinforcing these observations, at my first condition inspection I
>> decided to swap in the better of my 2 newer batteries. for the first year,
>> I had been flying with my 2 older batteries. Thought my carbon pile tester
>> had bellied up, I found that my 2 older batteries and one of my new
>> batteries all had the same voltage when fully charged with no load. When
>> I swapped out my oldest battery for my best new battery it turns out it
>> didn't perform quite as well (the engine would not always turn over on it).
>> I went back to the 2 older batteries and everything works as intended.
>>
>> I've since set aside the battery tender knowing that if I have a charged
>> battery on the shelf, I could probably use it to maintain the full charge.
>> But the Walmart charger is my main charging tool. Now that I'm flying
>> regularly there is little need for charging and my Z-14 is performing
>> exactly as desired (though I haven't had any kind of electrical component
>> failure to test its failure tolerance). I'm quite confident behind my 100%
>> electrical panel in IFR operations.
>>
>> (I do have 2 mags which are refreshingly retro in this microprocessor world
>> - they are electromagnetic mechanical wonders!)
>>
>> Thanks again Bob,
>> Bill Watson
>> N215TG
>>
Message 5
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The bis question now is what should I put on the E-Buss.
I think I can survive without a GPS or Xpndr.
I do think I want my Coms and NAV and since that is a SL-30 I will leave the
430W off.
Then my back-up Dynon D-6 draws very little.
I can power up the audio as is is cheap power. This leaves me with
E-Buss
Garmin GMA 240 540 MA @ 13.8v = 7.5 watts 1A Fuse
Garmin SL-30 Com 5A Fuse
Nav 3A Fuse
Dynon D-6 1A @ 13.8v = 13 watts 1A Fuse
Total max 10 Amps which seems like smaller than the 7A for the E-Buss
without relay.
Am I missing anything essential on the E-buss?
I am not sure I would want this on a 7a fuse though.
??
Mark Wesson
President / Owner
mark@wessonair.com
Ph # 407-831-5061
Fax # 407-831-2570
http://www.wessonair.com
-----Original Message-----
From: owner-aeroelectric-list-server@matronics.com
[mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
Nuckolls, III
Sent: Wednesday, September 05, 2012 12:08 PM
Subject: Re: AeroElectric-List: Z-11 I think
--> <nuckolls.bob@aeroelectric.com>
>However I am using a single alt. with an E-Bus.
>Would I be better off with a E-Bus relay rather than a switch only?
>Seems better to have the wire running all the way to the swith as a
>ground only rather than a hot there and back.
If your total e-bus loads can be supported through
the 7A fuse, then that size of always-hot feeder from
the battery bus does not violate legacy design goals
for crash safety.
Adding the relay is fine too . . . except that it
adds a parasitic load on the order of .15 A . . .
and one of the goals for the e-bus was to minimize
if not eliminate such loads. But it's your choice
commensurate with your own design goals.
>During normal flight operation is the E-Bus switch left on so that
>power is direct rather than through the diode. The diode seems
>inefficient since it generates heat.
No. Consider the operating requirements for power
in every device qualified for commercial aircraft.
The device must perform down pass battery-dead voltage
levels (9V in a 14v system). When the alternator is
running, main bus is 14.2 or better which puts the e-
bus at 13.6 or so . . . nice source. When the alternator
is off, the MAX voltage available to anything in the
airplane is what ever the battery will provide . . . 12.5
volts and DOWN.
Hence the suggestion that a slightly depressed e-bus
is not an operational concern. Now, if your e-bus
is configured for HOURS of operations battery only
(hopefully equal to or greater than duration of
fuel aboard) then the e-bus loads are small . . . 3-6
amps. 6 amps droped across a diode is about 4 watts
of heat . . . insignificant when a 40-60 amp alternator
is providing a 500 to 750 watt source of operating
power.
>Why are all the drawings showing the simple on-off switches as on-on
>S700-1-3 rather than the 1-2?
You can go buy 1-2 if you like. I used to stock the 1-3
which serviced both purposes and to keep line-items
of inventory low, I suggested that the 1-3 was a good
choice for BOTH slots both in terms of my inventory
and your spares.
Bob . . .
Message 6
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| Subject: | 19v laptop power in vehicles |
We've had some discussions on the List about powering
lap-tops without a great mish-mash of inverters,
ac mains power supplies and their attendant cables.
Here's a gizmo I bought these two offers off eBay:
http://tinyurl.com/bn3nkw9
http://tinyurl.com/7vwr4ur
at very reasonable prices. I mounted the fan
to the up-converter heatsink thusly.
http://tinyurl.com/c7jc92s
http://tinyurl.com/bqqxhy8
http://tinyurl.com/c4kzeh4
E6000 or JB Weld gets a good grip on the
mounting surface. I'm going to us this in
my van up behind the glove-box. I don't KNOW
that it will benefit from forced cooling . . .
but heat-sink performance jumps up by quantum
values when subject to the smallest flow of
air.
This will allow me to put a 19V outlet on
the panel that needs only a short jumper
cord to the computer. This would no doubt
work in you airplane as well.
Bob . . .
Message 7
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| Subject: | Re: Z-11 I think |
Or you can leave that stuff on the E-bus and turn any of them off with
their own power switches if you think you need to save power. That gives
you the flexibility to choose what you want to use when the alternator
is down. I lost the alternator once, turned off the master, and flew on
with two portable gps (powered from E-bus), transponder, Dynon D10, and
an electronic ignition for a total of about 4 amps. Landed at a towered
airport (with com turned back on), gassed up, started the engine, turned
off the main bus, took off, turned off the radio, and flew on for a
total of about 3 1/2 hrs and an engine start after the alternator
failure. The next day still I had enough juice for an engine start after
I had replaced the alternator. This was on a Concorde RG25.
As far as E-bus switch position goes, I take Bob's point that the diode
voltage drop is insignificant for the electronics, but I like to have
the E-bus on so that I don't have to worry about which switch goes first
when the alternator fails. If I happen to turn off the main bus before I
turn on the E-bus, my electronics will re-boot. The feed path from the
diode should of course be checked regularly so an E-bus switch failure
can't ruin an otherwise groovy day.I also don't have to do any math to
see the true bus voltage.
Pax,
Ed Holyoke
On 9/5/2012 12:21 PM, Mark Wesson wrote:
> --> AeroElectric-List message posted by: "Mark Wesson"<Mark@wessonair.com>
>
> The bis question now is what should I put on the E-Buss.
> I think I can survive without a GPS or Xpndr.
> I do think I want my Coms and NAV and since that is a SL-30 I will leave the
> 430W off.
> Then my back-up Dynon D-6 draws very little.
> I can power up the audio as is is cheap power. This leaves me with
>
> E-Buss
> Garmin GMA 240 540 MA @ 13.8v = 7.5 watts 1A Fuse
>
> Garmin SL-30 Com 5A Fuse
> Nav 3A Fuse
>
> Dynon D-6 1A @ 13.8v = 13 watts 1A Fuse
> Total max 10 Amps which seems like smaller than the 7A for the E-Buss
> without relay.
> Am I missing anything essential on the E-buss?
> I am not sure I would want this on a 7a fuse though.
>
> ??
>
>
>
> Mark Wesson
> President / Owner
>
> mark@wessonair.com
> Ph # 407-831-5061
> Fax # 407-831-2570
> http://www.wessonair.com
>
>
> -----Original Message-----
> From: owner-aeroelectric-list-server@matronics.com
> [mailto:owner-aeroelectric-list-server@matronics.com] On Behalf Of Robert L.
> Nuckolls, III
> Sent: Wednesday, September 05, 2012 12:08 PM
> To: aeroelectric-list@matronics.com
> Subject: Re: AeroElectric-List: Z-11 I think
>
> --> AeroElectric-List message posted by: "Robert L. Nuckolls, III"
> --> <nuckolls.bob@aeroelectric.com>
>
>
>> However I am using a single alt. with an E-Bus.
>> Would I be better off with a E-Bus relay rather than a switch only?
>> Seems better to have the wire running all the way to the swith as a
>> ground only rather than a hot there and back.
> If your total e-bus loads can be supported through
> the 7A fuse, then that size of always-hot feeder from
> the battery bus does not violate legacy design goals
> for crash safety.
>
> Adding the relay is fine too . . . except that it
> adds a parasitic load on the order of .15 A . . .
> and one of the goals for the e-bus was to minimize
> if not eliminate such loads. But it's your choice
> commensurate with your own design goals.
>
>> During normal flight operation is the E-Bus switch left on so that
>> power is direct rather than through the diode. The diode seems
>> inefficient since it generates heat.
> No. Consider the operating requirements for power
> in every device qualified for commercial aircraft.
> The device must perform down pass battery-dead voltage
> levels (9V in a 14v system). When the alternator is
> running, main bus is 14.2 or better which puts the e-
> bus at 13.6 or so . . . nice source. When the alternator
> is off, the MAX voltage available to anything in the
> airplane is what ever the battery will provide . . . 12.5
> volts and DOWN.
>
> Hence the suggestion that a slightly depressed e-bus
> is not an operational concern. Now, if your e-bus
> is configured for HOURS of operations battery only
> (hopefully equal to or greater than duration of
> fuel aboard) then the e-bus loads are small . . . 3-6
> amps. 6 amps droped across a diode is about 4 watts
> of heat . . . insignificant when a 40-60 amp alternator
> is providing a 500 to 750 watt source of operating
> power.
>
>> Why are all the drawings showing the simple on-off switches as on-on
>> S700-1-3 rather than the 1-2?
> You can go buy 1-2 if you like. I used to stock the 1-3
> which serviced both purposes and to keep line-items
> of inventory low, I suggested that the 1-3 was a good
> choice for BOTH slots both in terms of my inventory
> and your spares.
>
>
> Bob . . .
>
>
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