Today's Message Index:
----------------------
1. 07:58 AM - Dual Batteries (user9253)
2. 09:08 AM - Re: Dual Batteries (Jeff Luckey)
3. 09:56 AM - Re: Dual Batteries (Tim Andres)
4. 12:06 PM - Re: Radio interference (Builder_Bill)
5. 05:08 PM - Re: Failed contactor (Roger & Jean)
6. 07:34 PM - Re: Failed contactor (nuckollsr)
7. 08:20 PM - Re: Dual Batteries (Ed Holyoke)
Message 1
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> If you have dual, battery powered, electronic ignition
> and single alternator, a second battery will improve system
> reliability numbers.
Bob,
The above quote is from yesterday's AeroElectric daily digest. Did you inadvertently
leave the word "NOT" out? Or are you recommending that aircraft with electrically
dependent engines with single alternators have dual batteries?
Modern AGM batteries are very unlikely to short out. Good workmanship will minimize
the danger of an open circuit. In the event of an open battery circuit,
the alternator is capable of providing power without the battery. I think that
a second battery adds unnecessary weight, cost, and complexity.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399486#399486
Message 2
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Subject: | Re: Dual Batteries |
Joe,
I disagree.- When you add the second battery, you add redundancy to the w
hole power train [battery, master solenoid, shunt, wiring, etc].- If any
one of those components fails, the associated battery is off-line.
Another consideration is how long you can run after an alternator failure.
- IIRC, the Odessy-type batteries have about a 20 amp-hour rating which,
depending on your buss load, is probably 45-60 minutes of flight time after
alt failure.- My personal preference is to have 100% reserve for emergen
cy situations.
Jeff Luckey
--- On Sat, 4/27/13, user9253 <fransew@gmail.com> wrote:
From: user9253 <fransew@gmail.com>
Subject: AeroElectric-List: Dual Batteries
>- ---If you have dual, battery powered, electronic ignition
>- ---and single alternator, a second battery will improve system
>- ---reliability numbers.
Bob,
The above quote is from yesterday's AeroElectric daily digest.- Did you i
nadvertently leave the word "NOT" out?- Or are you recommending that airc
raft with electrically dependent engines with single alternators have dual
batteries?
Modern AGM batteries are very unlikely to short out.- Good workmanship w
ill minimize the danger of an open circuit.- In the event of an open batt
ery circuit, the alternator is capable of providing power without the batte
ry.- I think that a second battery adds unnecessary weight, cost, and com
plexity.
Joe
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399486#399486
le, List Admin.
Message 3
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Subject: | Re: Dual Batteries |
I think a lot of us, me included tend to over engineer these systems to some
extent. Unless you really are going to follow C-130s into hurricanes or similar,
Id suggest adding one layer of protection over what your Cessna/Piper had and
call it good. Ebus, second alternator OR battery, PMAG or any one thing to add
a
layer over a bare bones system. If you lose both of those you're one un-lucky
guy.
Tim
________________________________
From: Jeff Luckey <jluckey@pacbell.net>
Sent: Sat, April 27, 2013 9:20:40 AM
Subject: Re: AeroElectric-List: Dual Batteries
Joe,
I disagree. When you add the second battery, you add redundancy to the whole
power train [battery, master solenoid, shunt, wiring, etc]. If any one of those
components fails, the associated battery is off-line.
Another consideration is how long you can run after an alternator failure.
IIRC, the Odessy-type batteries have about a 20 amp-hour rating which, depending
on your buss load, is probably 45-60 minutes of flight time after alt failure.
My personal preference is to have 100% reserve for emergency situations.
Jeff Luckey
--- On Sat, 4/27/13, user9253 <fransew@gmail.com> wrote:
>From: user9253 <fransew@gmail.com>
>Subject: AeroElectric-List: Dual Batteries
>To: aeroelectric-list@matronics.com
>Date: Saturday, April 27, 2013, 7:57 AM
>
>
>
>
>> If you have dual, battery powered, electronic ignition
>> and single alternator, a second battery will improve system
>> reliability numbers.
>
>Bob,
>The above quote is from yesterday's AeroElectric daily digest. Did you
>inadvertently leave the word "NOT" out? Or are you recommending that aircraft
>with electrically dependent engines with single alternators have dual batteries?
>Modern AGM batteries are very unlikely to short out. Good workmanship will
>minimize the danger of an open circuit. In the event of an open battery
>circuit, the alternator is capable of providing power without the battery. I
>think that a second battery adds unnecessary weight, cost, and complexity.
>Joe
>
>--------
>Joe Gores
>
>
>Read this topic online here:
>
>http://forums.matronics.com/viewtopic.php?p=399486#399486
>
>http://www.matronics.com/Navigator?AeroElectric-List -->
>
>
>
Message 4
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Subject: | Re: Radio interference |
Hey Bob, if the noise gets worst at higher alt output, does that implicate a rectifier
diode exclusively? I was trying to think if there was another source of
noise that would follow the alt load.
Bill
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399493#399493
Message 5
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Subject: | Re: Failed contactor |
Hi Bob,
Just checking to see if you had a chance to open up that failed Main
contactor that I sent to you a few weeks back. No urgency, just checking.
Thanks,
Roger
Message 6
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Subject: | Re: Failed contactor |
Yes I did. Lots of moisture damage. I've got it on my list of things to do when
I get back to the office on Monday. Will take some pictures and report to the
List
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=399510#399510
Message 7
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Subject: | Re: Dual Batteries |
I'm doing dual Lightspeed Plasma 3 on my RV. I chose to run each
directly off a separate PC680 with a fuselink. Either battery can be run
on the main buss, or on the ebuss which also has a diode feed from the
main. The 680 is rated at 17ah and my ebuss minimum comfortable load
will be about 4 amps plus 2 more amps for the ignitions. Assuming day
VFR, if I turn off one both battery contactors and have one battery
supporting the ebuss, I should be able to run for about 3 plus hours
while keeping the second battery in reserve except for the one amp I was
drawing for the other ignition. That should leave me about 13 -14ah with
which to run out my fuel with at least one ignition assured. This also
assumes that I have tested the batteries recently and know how much they
will really do at low draw rate. Putting a backup alternator on top of
all that seems a little over the top, but maybe I'll add it before I
undertake a Bahamas trip or something like that.
The option I didn't select was for one battery and two alternators.
Seems viable, and is lighter, but I just liked the separate feeds to the
ignitions and being able to start from one battery and have no brownout
problems with EFIS run from the other one. I will need to remember to
close the contactor on the non starting battery after engine start so it
will charge. I don't see that as a problem, just a post start checklist
item. Push comes to shove, I can use both batteries for starting, too.
If I do need both to start, it's time to do another capacity check and
maybe replace one or both batteries.
Ed Holyoke
On 4/27/2013 9:56 AM, Tim Andres wrote:
> I think a lot of us, me included tend to over engineer these systems
> to some extent. Unless you really are going to follow C-130s into
> hurricanes or similar, Id suggest adding one layer of protection over
> what your Cessna/Piper had and call it good. Ebus, second alternator
> OR battery, PMAG or any one thing to add a layer over a bare bones
> system. If you lose both of those you're one un-lucky guy.
> Tim
>
>
> ------------------------------------------------------------------------
> *From:* Jeff Luckey <jluckey@pacbell.net>
> *To:* aeroelectric-list@matronics.com
> *Sent:* Sat, April 27, 2013 9:20:40 AM
> *Subject:* Re: AeroElectric-List: Dual Batteries
>
> Joe,
>
> I disagree. When you add the second battery, you add redundancy to
> the whole power train [battery, master solenoid, shunt, wiring, etc].
> If any one of those components fails, the associated battery is off-line.
>
> Another consideration is how long you can run after an alternator
> failure. IIRC, the Odessy-type batteries have about a 20 amp-hour
> rating which, depending on your buss load, is probably 45-60 minutes
> of flight time after alt failure. My personal preference is to have
> 100% reserve for emergency situations.
>
> Jeff Luckey
>
> --- On *Sat, 4/27/13, user9253 /<fransew@gmail.com>/* wrote:
>
>
> From: user9253 <fransew@gmail.com>
> Subject: AeroElectric-List: Dual Batteries
> To: aeroelectric-list@matronics.com
> Date: Saturday, April 27, 2013, 7:57 AM
>
> <fransew@gmail.com>
>
>
> > If you have dual, battery powered, electronic ignition
> > and single alternator, a second battery will improve system
> > reliability numbers.
>
> Bob,
> The above quote is from yesterday's AeroElectric daily digest.
> Did you inadvertently leave the word "NOT" out? Or are you
> recommending that aircraft with electrically dependent engines
> with single alternators have dual batteries?
> Modern AGM batteries are very unlikely to short out. Good
> workmanship will minimize the danger of an open circuit. In the
> event of an open battery circuit, the alternator is capable of
> providing power without the battery. I think that a second
> battery adds unnecessary weight, cost, and complexity.
> Joe
>
> --------
> Joe Gores
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=399486#399486
>
> http://www.matronics.com/Navigator?AeroElectric-List -->
>
>
> <http://forums.matronics.com>
>
> *
>
>
> *
> *
>
>
> *
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