Today's Message Index:
----------------------
1. 06:45 AM - Re: Rotax install (meat_ball)
2. 06:59 AM - Re: Re: Rotax install (Charlie England)
3. 07:05 AM - Re: Rotax install (meat_ball)
4. 07:50 AM - Re: Rotax install (meat_ball)
5. 07:57 AM - Re: Re: Rotax install (Charlie England)
6. 08:06 AM - Re: Rotax install (meat_ball)
7. 08:50 AM - Re: Rotax install (user9253)
8. 11:11 AM - Re: Rotax install (meat_ball)
9. 05:56 PM - Revmaster engine with EarthX battery (Paul Eckenroth)
10. 07:36 PM - Re: Revmaster engine with EarthX battery (user9253)
11. 07:46 PM - Re: Revmaster engine with EarthX battery (Robert L. Nuckolls, III)
12. 07:47 PM - The new email firewall is up and running . . . (Robert L. Nuckolls, III)
Message 1
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| Subject: | Re: Rotax install |
I've done a bit of homework. The strobes are average 0.8 Amps and comm radio comes
down to about .5 amps. The engine components work out like this (I've used
a guesstimate for the Fuel pumps as I haven't heard back from manufacturer yet):
Fuel pump 3amps
fuel pump 3amps
TCU .3 amps
Servomotor 1 amp
two indicating lamps .25 amps each
extra ~8 amps.
using the averages of the other high draw components, it comes out to 17.86 amps
(which is using the draw for the backup battery as well). From my understanding,
the 18 amp internal alternator can handle that, but you want a bit of buffer.
It appears I will indeed need the external...do you agree? Am I thinking
correctly?
Thanks,
Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497527#497527
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| Subject: | Re: Rotax install |
On Thu, Aug 6, 2020 at 8:49 AM meat_ball <arjayefem@fastmail.net> wrote:
> arjayefem@fastmail.net>
>
> I've done a bit of homework. The strobes are average 0.8 Amps and comm
> radio comes down to about .5 amps. The engine components work out like this
> (I've used a guesstimate for the Fuel pumps as I haven't heard back from
> manufacturer yet):
>
> Fuel pump 3amps
> fuel pump 3amps
> TCU .3 amps
> Servomotor 1 amp
> two indicating lamps .25 amps each
>
> extra ~8 amps.
>
> using the averages of the other high draw components, it comes out to
> 17.86 amps (which is using the draw for the backup battery as well). From
> my understanding, the 18 amp internal alternator can handle that, but you
> want a bit of buffer. It appears I will indeed need the external...do you
> agree? Am I thinking correctly?
>
> Thanks,
>
> Rob
>
You only need one fuel pump at a time (except takeoff & landing), but have
you told us whether it's carb'd or electronic injection? Electronic
injection pumps will use an absolute minimum of 4A each; likely more like
6A each. On the other hand, a little Facet cube pump for a carb only draws
around 2.5A.
But bottom line is, you need a decent margin between constant draw and
alternator capacity. Otherwise, you can't recharge the battery after engine
start and idle operation ('dynamo' style permanent magnet alternators don't
have much if any output when the engine is running near idle).
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| Subject: | Re: Rotax install |
ceengland7(at)gmail.com wrote:
> On Thu, Aug 6, 2020 at 8:49 AM meat_ball wrote:
>
>
> >
> > I've done a bit of homework. The strobes are average 0.8 Amps and comm radio
comes down to about .5 amps. The engine components work out like this (I've
used a guesstimate for the Fuel pumps as I haven't heard back from manufacturer
yet):
> >
> > Fuel pump 3amps
> > fuel pump 3amps
> > TCU .3 amps
> > Servomotor 1 amp
> > two indicating lamps .25 amps each
> >
> > extra ~8 amps.
> >
> > using the averages of the other high draw components, it comes out to 17.86
amps (which is using the draw for the backup battery as well). From my understanding,
the 18 amp internal alternator can handle that, but you want a bit of
buffer. It appears I will indeed need the external...do you agree? Am I thinking
correctly?
> >
> > Thanks,
> >
> > Rob
> >
> You only need one fuel pump at a time (except takeoff & landing), but have you
told us whether it's carb'd or electronic injection? Electronic injection pumps
will use an absolute minimum of 4A each; likely more like 6A each. On the
other hand, a little Facet cube pump for a carb only draws around 2.5A.
>
>
> But bottom line is, you need a decent margin between constant draw and alternator
capacity. Otherwise, you can't recharge the battery after engine start and
idle operation ('dynamo' style permanent magnet alternators don't have much
if any output when the engine is running near idle).
Sorry, I thought I mentioned that at the top of this thread. It is electronic
ignition and fuel injected.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497529#497529
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| Subject: | Re: Rotax install |
Attached is the Rotax 914 Electrical Diagram (hopefully you can make sense of it).
It shows just what kenryan suggests as far as the fuel pumps. What about
the master switch? From what I see when you turn it on, the battery gets connected
to the bus, but that also gives a ground to the master relay which allows
the Internal and External Alternators to connect to the bus/battery. Now turning
off the Master Switch will kill all power to the Bus Bar and battery from
the Alternators. Am I missing something? That seems like a bad thing...
Is this where I would wire in the s700-2-10, 3 position ON-ON-ON switch? the positions
would be off, battery on, and battery/alternators on. Or would it be
better to have a separate switch for the external alternator just after the field
output and before the master switch?
Again, I sincerely appreciate all the help!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497530#497530
Attachments:
http://forums.matronics.com//files/scannable_document_on_aug_6_2020_at_9_27_03_am_991.pdf
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| Subject: | Re: Rotax install |
On 8/6/2020 9:04 AM, meat_ball wrote:
>
>
> ceengland7(at)gmail.com wrote:
>> On Thu, Aug 6, 2020 at 8:49 AM meat_ball wrote:
>>
>>
>>>
>>> I've done a bit of homework. The strobes are average 0.8 Amps and comm radio
comes down to about .5 amps. The engine components work out like this (I've
used a guesstimate for the Fuel pumps as I haven't heard back from manufacturer
yet):
>>>
>>> Fuel pump 3amps
>>> fuel pump 3amps
>>> TCU .3 amps
>>> Servomotor 1 amp
>>> two indicating lamps .25 amps each
>>>
>>> extra ~8 amps.
>>>
>>> using the averages of the other high draw components, it comes out to 17.86
amps (which is using the draw for the backup battery as well). From my understanding,
the 18 amp internal alternator can handle that, but you want a bit
of buffer. It appears I will indeed need the external...do you agree? Am I thinking
correctly?
>>>
>>> Thanks,
>>>
>>> Rob
>>>
>> You only need one fuel pump at a time (except takeoff & landing), but have you
told us whether it's carb'd or electronic injection? Electronic injection pumps
will use an absolute minimum of 4A each; likely more like 6A each. On the
other hand, a little Facet cube pump for a carb only draws around 2.5A.
>>
>>
>> But bottom line is, you need a decent margin between constant draw and alternator
capacity. Otherwise, you can't recharge the battery after engine start and
idle operation ('dynamo' style permanent magnet alternators don't have much
if any output when the engine is running near idle).
>
> Sorry, I thought I mentioned that at the top of this thread. It is electronic
ignition and fuel injected.
You probably did and I missed it. I was probably confused by the
reference to it being a 912, and the 145 HP reference; didn't know what
mods were made. In that case, you need to budget at least 4A per pump.
Do you have the brand/model number of the pump you intend to use? As an
example, the Walbro GSL393, likely the most common pump being used in
aircraft electronic injection systems, is recommended to be fused at 15A
and average current consumption is 5 A-6 A.
Charlie
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Message 6
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| Subject: | Re: Rotax install |
ceengland7(at)gmail.com wrote:
> On 8/6/2020 9:04 AM, meat_ball wrote:
>
> >
> >
> >
> > ceengland7(at)gmail.com wrote:
> > > On Thu, Aug 6, 2020 at 8:49 AM meat_ball wrote:
> > >
> > >
> > >>
> > >>
> > >> I've done a bit of homework. The strobes are average 0.8 Amps and comm
radio comes down to about .5 amps. The engine components work out like this (I've
used a guesstimate for the Fuel pumps as I haven't heard back from manufacturer
yet):
> > >>
> > >> Fuel pump 3amps
> > >> fuel pump 3amps
> > >> TCU .3 amps
> > >> Servomotor 1 amp
> > >> two indicating lamps .25 amps each
> > >>
> > >> extra ~8 amps.
> > >>
> > >> using the averages of the other high draw components, it comes out to
17.86 amps (which is using the draw for the backup battery as well). From my understanding,
the 18 amp internal alternator can handle that, but you want a bit
of buffer. It appears I will indeed need the external...do you agree? Am I
thinking correctly?
> > >>
> > >> Thanks,
> > >>
> > >> Rob
> > >>
> > > You only need one fuel pump at a time (except takeoff & landing), but have
you told us whether it's carb'd or electronic injection? Electronic injection
pumps will use an absolute minimum of 4A each; likely more like 6A each. On
the other hand, a little Facet cube pump for a carb only draws around 2.5A.
> > >
> > >
> > > But bottom line is, you need a decent margin between constant draw and alternator
capacity. Otherwise, you can't recharge the battery after engine start
and idle operation ('dynamo' style permanent magnet alternators don't have much
if any output when the engine is running near idle).
> >
> > Sorry, I thought I mentioned that at the top of this thread. It is electronic
ignition and fuel injected.
> > You probably did and I missed it. I was probably confused by the
> >
>
> reference to it being a 912, and the 145 HP reference; didn't know what
> mods were made. In that case, you need to budget at least 4A per pump.
> Do you have the brand/model number of the pump you intend to use? As an
> example, the Walbro GSL393, likely the most common pump being used in
> aircraft electronic injection systems, is recommended to be fused at 15A
> and average current consumption is 5 A-6 A.
>
> Charlie
>
> --
> This email has been checked for viruses by Avast antivirus software.
> https://www.avast.com/antivirus
I just got a reply. He said pumps draw 5-7 amps but only one pump used at a time.
I'm clarifying whether or not they will EVER be used at the same time such
as t/o and landing.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497532#497532
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| Subject: | Re: Rotax install |
I would NOT buy an external alternator now, but wait until you determine that
it is actually needed. I added up your loads and the total came to 13 amps. I
did not include intermittent loads: landing - taxi lights, or charging two
batteries. Run the engine and measure the actual alternator output with all
continuous loads turned on. If the total current is 15 amps or less, an aux
alternator is not needed.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497533#497533
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| Subject: | Re: Rotax install |
user9253 wrote:
> I would NOT buy an external alternator now, but wait until you determine that
> it is actually needed. I added up your loads and the total came to 13 amps.
I
> did not include intermittent loads: landing - taxi lights, or charging two
> batteries. Run the engine and measure the actual alternator output with all
> continuous loads turned on. If the total current is 15 amps or less, an aux
> alternator is not needed.
Okay! I'll give that a shot. However, I will need to wire the plane to make it
easy to add the external alternator if needed. So I go back to my previous
question about the "master switch".
> Attached is the Rotax 914 Electrical Diagram (hopefully you can make sense of
it). It shows just what kenryan suggests as far as the fuel pumps. What about
the master switch toward the bottom? From what I see when you turn it on, the
battery gets connected to the bus, but that also gives a ground to the master
relay which allows the Internal and External Alternators to connect to the bus/battery.
Now turning off the Master Switch will kill all power to the Bus Bar
and battery from the Alternators. Am I missing something? That seems like a
bad thing...
>
> Is this where I would wire in the s700-2-10, 3 position ON-ON-ON switch?
>
How would I wire this switch to make it work for the single alternator, and also
in the case that I add an external?
Again, thank you for indulging my ignorance.
Rob
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497535#497535
Attachments:
http://forums.matronics.com//files/scannable_document_on_aug_6_2020_at_9_27_03_am_149.pdf
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| Subject: | Revmaster engine with EarthX battery |
I have a Revmaster engine in my Onex which is not dealing well with my EarthX battery.
The engine has a total of 12 coils arranged on the stator which consists
of 2 each of 5 coils making up the dual generator and 2 coils powering the
ignition. It all sounded good on paper with much redundancy but apparently
the generator coils produce too much heat at full output which can cause them
to short out. When used with the old fashioned lead acid battery the charge rate
is less and therefore less heat. Is there any proper method to throttle the
generator output or reduce the EarthX input to approach the charging rate of
the lead acid battery and not cause the generator to create the excessive heat.
I know the easy way is to just replace the battery but that would not be
good for my W&B. Thanks for any help and suggestions.
Paul
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497543#497543
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| Subject: | Re: Revmaster engine with EarthX battery |
All you have to do is put a diode between the alternator and battery. That will
drop the voltage that the battery sees and limit the current.
An EarthX battery has very low internal resistance. When the battery is low,
it will take the full output of an alternator. That is why the size of the battery
has to be matched to the alternator size.
--------
Joe Gores
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=497544#497544
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| Subject: | Re: Revmaster engine with EarthX battery |
At 07:52 PM 8/6/2020, you wrote:
>
>I have a Revmaster engine in my Onex which is not dealing well with
>my EarthX battery. The engine has a total of 12 coils arranged on
>the stator which consists of 2 each of 5 coils making up the dual
>generator and 2 coils powering the ignition. It all sounded good
>on paper with much redundancy but apparently the generator coils
>produce too much heat at full output which can cause them to short
>out. When used with the old fashioned lead acid battery the charge
>rate is less and therefore less heat. Is there any proper method to
>throttle the generator output or reduce the EarthX input to approach
>the charging rate of the lead acid battery and not cause the
>generator to create the excessive heat. I know the easy way is to
>just replace the battery but that would not be good for my
>W&B. Thanks for any help and suggestions.
I've been hearing/reading about shortfalls in
the design of that alternator for years.
The thing is thermally marginal at best.
If you can acquire an adjustable regulator
for PM alternators, you can set the charging
voltage down such that the alternator is
not working quite so hard at the LOWEST
voltage that will still charge the battery.
The attached plot show EarthX test data from
some years back. A bus voltage of 13.0 falls
far short of fully charging the battery . . . while
voltages of 13.5, 14.0 and 15.0 will all
fully charge the battery. The BMS takes
care of moderating any 'excess' voltage but
its design rules will allow the battery
to accept any safe level of replenishment . . .
safe for the battery. Unfortunately,
that current value is more than your
alternator/regulator combination is able
to grunt without smoking the windings.
B&C has a new product that MIGHT be a
solution . . . albeit an unfortunate
'band aid' on the Revmaster's shortcomings.
https://tinyurl.com/y6mr4x7e
You would want to set the bus voltage
to 13.6 +/- 0.1 volts. I'm thinking this
MIGHT do the trick.
Give B&C a call and talk with their
technowienies about this.
Bob . . .
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| Subject: | The new email firewall is up and running . . . |
Matt tells me that the new Barracuda server
is many times faster that the vintage hardware
that it replaced.
Bob . . .
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