Today's Message Index:
----------------------
1. 03:38 AM - Re: charging system (FLYaDIVE)
2. 09:42 AM - Re: charging system (Noel Loveys)
3. 12:57 PM - Re: charging system (rampil)
4. 02:30 PM - Re: Re: charging system (FLYaDIVE)
5. 02:47 PM - Re: Re: charging system (Gilles Thesee)
6. 02:55 PM - Re: Re: charging system (Craig Payne)
7. 03:01 PM - Re: Re: charging system (Craig Payne)
8. 03:10 PM - Re: Re: charging system (Gilles Thesee)
9. 04:10 PM - Re: charging system (rampil)
10. 04:27 PM - Re: Re: charging system (Pete Christensen)
11. 05:20 PM - Re: Re: charging system (steve feigley)
Message 1
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| Subject: | Re: charging system |
Steve:
The "18 Amps" is not correct.
Here are the rules:
1. Charger for NORMAL charge should be 10% of the rated AH ratting.
2. So if the battery is 20 AH the charger should be MAX 2 Amps (20 *
0.10 = 2 Amps)
3. The time to charge is AH divided by Charger Amperage AND that is from
zero charge.
4. So 20 / 2 = 10 Hours.
5. Trickle Charge is 25% of Charger 2 * 0.25 = 0.5 Amps (500 mA)
6. Get a GOOD charger that is designed for LITHIUM ION BATTERIES.
7. Keep the battery COOL. Li batteries get VERY warm - HOT when charging.
That is all there is too it.. Other than don't over charge... Use a timer.
Barry
On Sun, Nov 27, 2011 at 5:40 PM, steve feigley <fygdog@yahoo.com> wrote:
> hey guys'
> this is for the electronics types listening . I'm thinking of trying a
> lithium ion type battery for my 912s for the considerable weight savings.
> the battery calls for a charge rate of no more than 18 amps the 912 specs
> its elec. output at 20 amps. does this nessesarally mean that it charges at
> that rate? also have any of you tried one of theese batt, if so which brand
> from where?
>
> *
>
> *
>
>
Message 2
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I would be careful there... A simple resistor could lower your charge rate
inside the prescribed 18 A but the extreme current necessary to turn the
starting motor could cause your LI Ion battery to go into thermal runaway a
condition that could cause a fire.
Cloth covered planes are not good places to play with fire!
Noel
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of steve
feigley
Sent: November 27, 2011 7:11 PM
Subject: RotaxEngines-List: charging system
hey guys'
this is for the electronics types listening . I'm thinking of trying a
lithium ion type battery for my 912s for the considerable weight savings.
the battery calls for a charge rate of no more than 18 amps the 912 specs
its elec. output at 20 amps. does this nessesarally mean that it charges at
that rate? also have any of you tried one of theese batt, if so which brand
from where?
Message 3
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| Subject: | Re: charging system |
And..
BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit,
like a "real" purpose designed battery charger.
18 A is simply and approximately the max current output capacity for
the stated voltage threshold of about 12 volts. You can pull more
current at a lower voltage but the $900 regulator may blow up.
An airplane's battery charging circuit is not microprocessor controlled like
the charger for an Apple laptop battery, airplanes do not either time the
charge or do they internally monitor the state of the state of the battery to
control shutdown of charging.
Overall, and not knowing the specifics of the specific vendor's product,
it does not sound like the best match to the Rotax.
What was the weight loss you calculated?
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=359569#359569
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| Subject: | Re: charging system |
Ira:
Someone is feeding you a bucket of misnomers.
Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to call
them ] DO monitor the state of the battery. If they did not you would
constantly OVERCHARGE the battery and the life of the battery would be
brought down to zero.
Even the Very OLD mechanical voltage regulators control the charge into the
battery.
They DO NOT monitor the internal resistance of the battery. Though some
battery test units do calculate the value.
The ACU applies voltage to the FIELD of the alternator which turns the
alternator ON this usually takes place around 12.5 to 13.5 VDC. The FIELD
voltage is removed when the voltage across the battery reads 14.2 to 14.5
VDC. Then the alternator is turned OFF.
The AMPERAGE of the alternator is a factor of wire size, diodes and slip
rings. The higher the amperage usually the bigger and heavier the
alternator. Of course there are differences between manufactures.
Advertising and sales spume not withholding.
IF the current draw was to exceed the rated amperage of the alternator say
18 Amps... The fuse would pop. If not - Someone did a poor job of design
or install. In most aircraft there are two fuses... Alternator FIELD and
Alternator OUTPUT.
If the voltage was to drop below 12 V as you stated the ACU would be OFF
LINE - Something is Broke - And you would be drawing from the battery.
Barry
On Mon, Nov 28, 2011 at 3:54 PM, rampil <ira.rampil@gmail.com> wrote:
>
> And..
> BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit,
> like a "real" purpose designed battery charger.
>
> 18 A is simply and approximately the max current output capacity for
> the stated voltage threshold of about 12 volts. You can pull more
> current at a lower voltage but the $900 regulator may blow up.
>
>
> An airplane's battery charging circuit is not microprocessor controlled
> like
> the charger for an Apple laptop battery, airplanes do not either time the
> charge or do they internally monitor the state of the state of the battery
> to
> control shutdown of charging.
>
>
> Overall, and not knowing the specifics of the specific vendor's product,
> it does not sound like the best match to the Rotax.
>
> What was the weight loss you calculated?
>
> --------
> Ira N224XS
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=359569#359569
>
>
Message 5
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| Subject: | Re: charging system |
FLYaDIVE a crit :
> Someone is feeding you a bucket of misnomers.
>
> Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to
> call them ] DO monitor the state of the battery. If they did not you
> would constantly OVERCHARGE the battery and the life of the battery
> would be brought down to zero.
> Even the Very OLD mechanical voltage regulators control the charge
> into the battery.
> They DO NOT monitor the internal resistance of the battery. Though
> some battery test units do calculate the value.
>
> The ACU applies voltage to the FIELD of the alternator which turns the
> alternator ON this usually takes place around 12.5 to 13.5 VDC. The
> FIELD voltage is removed when the voltage across the battery reads
> 14.2 to 14.5 VDC. Then the alternator is turned OFF.
>
> The AMPERAGE of the alternator is a factor of wire size, diodes and
> slip rings. The higher the amperage usually the bigger and heavier
> the alternator. Of course there are differences between manufactures.
> Advertising and sales spume not withholding.
>
> IF the current draw was to exceed the rated amperage of the alternator
> say 18 Amps... The fuse would pop. If not - Someone did a poor job
> of design or install. In most aircraft there are two fuses...
> Alternator FIELD and Alternator OUTPUT.
Barry,
The Rotax alternator is a permanent magnet device, so no field circuit.
Anytime it is rotating it generates *voltage*. Alternators are
inherently current limited, so you just can't draw too much current, as
the voltage drops when current gets higher.
With a Rotax alternator and voltage regulator, we found it was safer not
to draw more than about 12 amps permanently, otherwise the regulator may
overheat if no special cooling is provided.
Some info on the study we did at
http://contrails.free.fr/elec_ducati_en.php.
Please note that the regulator schematic is provided as is, some time
ago some readers advised they had a more accurate drawing.
Best regards,
--
Gilles
http://contrails.free.fr
Message 6
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| Subject: | Re: charging system |
At least for the Rotax 912/914 the alternator is a permanent magnet
alternator. Although it has a regulator it has no field windings or brushes.
The schematic of the Ducati regulator is attached.
-- Craig
From: owner-rotaxengines-list-server@matronics.com
[mailto:owner-rotaxengines-list-server@matronics.com] On Behalf Of FLYaDIVE
Sent: Monday, November 28, 2011 2:27 PM
Subject: Re: RotaxEngines-List: Re: charging system
Ira:
Someone is feeding you a bucket of misnomers.
Alternator Regulators [APC, VCU, ACU, etc. or what ever you wish to call
them ] DO monitor the state of the battery. If they did not you would
constantly OVERCHARGE the battery and the life of the battery would be
brought down to zero.
Even the Very OLD mechanical voltage regulators control the charge into the
battery.
They DO NOT monitor the internal resistance of the battery. Though some
battery test units do calculate the value.
The ACU applies voltage to the FIELD of the alternator which turns the
alternator ON this usually takes place around 12.5 to 13.5 VDC. The FIELD
voltage is removed when the voltage across the battery reads 14.2 to 14.5
VDC. Then the alternator is turned OFF.
The AMPERAGE of the alternator is a factor of wire size, diodes and slip
rings. The higher the amperage usually the bigger and heavier the
alternator. Of course there are differences between manufactures.
Advertising and sales spume not withholding.
IF the current draw was to exceed the rated amperage of the alternator say
18 Amps... The fuse would pop. If not - Someone did a poor job of design
or install. In most aircraft there are two fuses... Alternator FIELD and
Alternator OUTPUT.
If the voltage was to drop below 12 V as you stated the ACU would be OFF
LINE - Something is Broke - And you would be drawing from the battery.
Barry
On Mon, Nov 28, 2011 at 3:54 PM, rampil <ira.rampil@gmail.com> wrote:
And..
BTW, the 18 Amp limit on the Rotax 912 is by no means a hard limit,
like a "real" purpose designed battery charger.
18 A is simply and approximately the max current output capacity for
the stated voltage threshold of about 12 volts. You can pull more
current at a lower voltage but the $900 regulator may blow up.
An airplane's battery charging circuit is not microprocessor controlled like
the charger for an Apple laptop battery, airplanes do not either time the
charge or do they internally monitor the state of the state of the battery
to
control shutdown of charging.
Overall, and not knowing the specifics of the specific vendor's product,
it does not sound like the best match to the Rotax.
What was the weight loss you calculated?
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=359569#359569
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Message 7
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| Subject: | Re: charging system |
Oh please don't confuse us with actual facts and direct observations. This
is the Internet where we thrive on speculation and rumors. ;-)
-- Craig
> "The Rotax alternator is a permanent magnet device, so no field circuit.
Anytime it is rotating it generates *voltage*. Alternators are
inherently current limited, so you just can't draw too much current, as
the voltage drops when current gets higher.
With a Rotax alternator and voltage regulator, we found it was safer not
to draw more than about 12 amps permanently, otherwise the regulator may
overheat if no special cooling is provided.
Some info on the study we did at
http://contrails.free.fr/elec_ducati_en.php.
Please note that the regulator schematic is provided as is, some time
ago some readers advised they had a more accurate drawing.
Best regards,
--
Gilles
http://contrails.free.fr"
-- Craig
Message 8
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| Subject: | Re: charging system |
Craig Payne a crit :
>
> Oh please don't confuse us with actual facts and direct observations. This
> is the Internet where we thrive on speculation and rumors. ;-)
>
;-D
Best regards,
--
Gilles
http://contrails.free.fr
Message 9
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| Subject: | Re: charging system |
Thanks Gilles,
For $900 the Ducati just isn't that great a regulator!
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=359583#359583
Message 10
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| Subject: | Re: charging system |
$900? It was more like $160. When I replaced mine a couple years ago.
Pete
Sent from my iPad
On Nov 28, 2011, at 6:06 PM, "rampil" <ira.rampil@gmail.com> wrote:
>
> Thanks Gilles,
>
> For $900 the Ducati just isn't that great a regulator!
>
> --------
> Ira N224XS
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=359583#359583
>
>
>
>
>
>
>
>
>
>
Message 11
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| Subject: | Re: charging system |
--- On Sun, 11/27/11, rampil <ira.rampil@gmail.com> wrote:
From: rampil <ira.rampil@gmail.com>
Subject: RotaxEngines-List: Re: charging system
I also agree that the incentive to use an "exotic" battery for
a Rotax starter must be minimal.
The Rotax requires only a small lead-based battery, not much weight
saved compared with what's required for spinning up a TIO550!
The reference articles provided note that LiPo batteries don't overheat
(the old Halt & Catch Fire command) like LiCo, but do they just die
quietly when overcharged like LiCo?
If you're not expert enough to completely understand the engineering
considerations in switching, I'd leave to someone else to be first.
Ira
(EE in a former life)
--------
Ira N224XS
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=359512#359512
le, List Admin.
le, List Admin.
the battery I am considering is sold at shoraipower.com and is of the lithi
um iron type, the current battery I use is a lead acid type weighing 13.3 l
bs. the shorai battery with the same amp/hr rating and comperable cranking
amps wieghs approx. 3 lbs.-- this is considerable but with the unknowns
maybe not worth the risk
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