Charging?

[PaulaJay1]

I have a voltmeter plugin in the cig lighter socket. It reads about 11.5 when
I trun on the master. Reads about 12.8 after engine start and after an hour
flight has worked up to maybe 13.7 or so. I plan on taking a known accurate
meter out Sat to check these reading.
My A&P says maybe the alternator needs rebuilt (at about $250). He says that
the voltage reg is solid state and either works or not - ie no adjustment.
I've had a couple of times when the bat needed a boost, so something is wrong.
Any comments before I start throwing money at the problem.

Chuck
Archer 2185B

[[email protected]]

PaulaJay1 wrote:
> I have a voltmeter plugin in the cig lighter socket. It reads about
11.5 when
> I trun on the master. Reads about 12.8 after engine start and after
an hour
> flight has worked up to maybe 13.7 or so. I plan on taking a known
accurate
> meter out Sat to check these reading.
> My A&P says maybe the alternator needs rebuilt (at about $250). He
says that
> the voltage reg is solid state and either works or not - ie no
adjustment.
> I've had a couple of times when the bat needed a boost, so something
is wrong.
> Any comments before I start throwing money at the problem.
>

Put a voltmeter on the battery with the master off. It should be
reading above 12 volts (mine reads ~12.4V) if it's fully charged. I
always see at least 12 volts on the bus and cigarette lighter before I
start. The fact that your voltage is slowly working its way up to
normal (should be around 14V), would lead me to think that the problem
may be that the battery is slow to take a charge.

Before tearing into the alternator, which appears to be generating
some electricity, I'd pull the battery, put it on a charger, then see
if it will hold itself above 12V. If not, it's time for a new battery.
John Galban=====>N4BQ (PA28-180)

[[email protected]]

On 27-Jan-2005, (PaulaJay1) wrote:

> Any comments before I start throwing money at the problem.


Pardon if this sounds overly obvious, but have you verified that the
alternator belt is nice and tight (and not deteriorated)? A worn and/or
slipping belt could easily give you these symptoms.

Speaking of alternator belts, our mechanic did something very clever for us
that might be of interest to others. When he installed our new engine some
months ago, he tie-wrapped a spare belt up against the engine, around but
well behind the flywheel. The idea is that if we suffer a broken alternator
belt the spare can be put on in a matter of minutes, with no special tools,
and without having to take off the prop. Anybody else use this trick?

--
-Elliott Drucker

[BTIZ]

I would think the heat from the engine would raise a havoc with the belt..
and it might smell pretty bad it gets hot
BT

> wrote in message
news:U7gKd.1200$Pr4.896@trnddc03...
>
> On 27-Jan-2005, (PaulaJay1) wrote:
>
>> Any comments before I start throwing money at the problem.
>
>
> Pardon if this sounds overly obvious, but have you verified that the
> alternator belt is nice and tight (and not deteriorated)? A worn and/or
> slipping belt could easily give you these symptoms.
>
> Speaking of alternator belts, our mechanic did something very clever for
> us
> that might be of interest to others. When he installed our new engine
> some
> months ago, he tie-wrapped a spare belt up against the engine, around but
> well behind the flywheel. The idea is that if we suffer a broken
> alternator
> belt the spare can be put on in a matter of minutes, with no special
> tools,
> and without having to take off the prop. Anybody else use this trick?
>
> --
> -Elliott Drucker

[Michelle P]

Chuck,
You need to also measure the current the alternator is putting out at
the same time. The voltage alone will not tell the whole story.
If the alternator is putting out and the voltage is still low then there
is a big draw on the system. Likely the battery. Once it is satisfied
then the buss voltage will rise. The comment about the regulator is BS.
Likely from someone who does not understand them. They are adjustable.
13.7 is only slightly low for a 14V system. it should be 13.8-14.2.
If you can get a recording meter like a Fluke that would be best. If you
can get one that will do both AC and DC at the same time, this would be
good as well. This will tell you if a diode or two has or is dying.
Michelle

PaulaJay1 wrote:

>I have a voltmeter plugin in the cig lighter socket. It reads about 11.5 when
>I trun on the master. Reads about 12.8 after engine start and after an hour
>flight has worked up to maybe 13.7 or so. I plan on taking a known accurate
>meter out Sat to check these reading.
>My A&P says maybe the alternator needs rebuilt (at about $250). He says that
>the voltage reg is solid state and either works or not - ie no adjustment.
>I've had a couple of times when the bat needed a boost, so something is wrong.
>Any comments before I start throwing money at the problem.
>
>Chuck
>Archer 2185B
>
>

[David Lesher]

Michelle P > writes:

>Chuck,
>You need to also measure the current the alternator is putting out at
>the same time. The voltage alone will not tell the whole story.
>If the alternator is putting out and the voltage is still low then there
>is a big draw on the system. Likely the battery. Once it is satisfied
>then the buss voltage will rise. The comment about the regulator is BS.
>Likely from someone who does not understand them. They are adjustable.
>13.7 is only slightly low for a 14V system. it should be 13.8-14.2.
>If you can get a recording meter like a Fluke that would be best. If you
>can get one that will do both AC and DC at the same time, this would be
>good as well. This will tell you if a diode or two has or is dying.
>Michelle

I second the line of thinking. Make more measurements. Use a scope
to look for bad diodes. Use a good DVM to measure the alternator
OUTPUT at the alternator. Big issue here is keeping body parts out
of the way of the people-chopper up front as you must be well above
idle.

Bad diodes are about the only {alternator} thing that keeps an
alternator+regulator+installation from making full output. Most of
the time, it's regulator or loose wiring issues that bite you on
the [banned by Mikey Powell]... err tailwheel.

GM auto alternators have a "full-field" tab. It lets you bypass
the regulator so you can see the alternator working full tilt.
This typically gets you 15+ volts DC, so if such can be done,
pull all the avionics feeds first......

In a car, I think the best belt test is your ears. Load the alternator
with headlights/blowers/heated seats etc. The belt should talk to
you but not howl/sing. I don't know if you can hear as well w/
aircraft.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

[[email protected]]

On 27-Jan-2005, "BTIZ" > wrote:

> I would think the heat from the engine would raise a havoc with the belt..
> and it might smell pretty bad it gets hot


The "spare" belt is positioned in a way that it is well clear of the
cylinders and heads. Actually, the belt doesn't even contact the crankcase
that much, and the case doesn't get particularly hot. The mechanic says his
shop has been doing this for a while now with no problems.
--
-Elliott Drucker

[RST Engineering]

Mostly anybody who has worked on a Lycoming in the last thirty years.

Jim



The idea is that if we suffer a broken alternator
> belt the spare can be put on in a matter of minutes, with no special
> tools,
> and without having to take off the prop. Anybody else use this trick?
>
> --
> -Elliott Drucker

[Jay Honeck]

> The "spare" belt is positioned in a way that it is well clear of the
> cylinders and heads. Actually, the belt doesn't even contact the
> crankcase
> that much, and the case doesn't get particularly hot. The mechanic says
> his
> shop has been doing this for a while now with no problems.

I, for one, think it's a fabulous idea.

I wish more shops would think proactively like this.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Ross Richardson]

Hmmm, My solid state regulator has an adjustment under a screw that is
removed. I believe it even has arrows to show increase/decrease
direction.

PaulaJay1 wrote:
>
> I have a voltmeter plugin in the cig lighter socket. It reads about 11.5 when
> I trun on the master. Reads about 12.8 after engine start and after an hour
> flight has worked up to maybe 13.7 or so. I plan on taking a known accurate
> meter out Sat to check these reading.
> My A&P says maybe the alternator needs rebuilt (at about $250). He says that
> the voltage reg is solid state and either works or not - ie no adjustment.
> I've had a couple of times when the bat needed a boost, so something is wrong.
> Any comments before I start throwing money at the problem.
>
> Chuck
> Archer 2185B

[[email protected]]

PaulaJay1 > wrote:
: I have a voltmeter plugin in the cig lighter socket. It reads about 11.5 when
: I trun on the master. Reads about 12.8 after engine start and after an hour
: flight has worked up to maybe 13.7 or so. I plan on taking a known accurate
: meter out Sat to check these reading.
: My A&P says maybe the alternator needs rebuilt (at about $250). He says that
: the voltage reg is solid state and either works or not - ie no adjustment.
: I've had a couple of times when the bat needed a boost, so something is wrong.
: Any comments before I start throwing money at the problem.

The only way for voltage to drop is if there's current in the measurement
chain. There are also a number of reasons that could cause these symptoms, and having
a bad alternator isn't very high on the list.

Since it's difficult for most people to measure current, it's worth measuring
battery voltage with a number of load conditions to narrow down the search. To reduce
the number of variables, measure the voltage *AT* the battery with master off, on (no
engine), on (above idle some), on (cruise RPM). Do this with and without heavy loads
on (pitot heat, nav, and landing light on/off together make for a good 25-40A
transient). It would also be good to measure the DC and AC output of the alternator
*AT* the alternator post during these tests. Possibly even the voltage at the
regulator input to the alternator.

Not all those measurements would likely be completely necessary, but with all
of them the problem can almost certainly be found. Possible reasons:

- Bad diode(s) in alternator
- Bad connection on field to alternator (it will get a bit hot)
- Bad connection on output of alternator (it will get a lot hot)
- Bad connection with current draw between bus and cig lighter
- Bad regulator (either adjustment or replacement if fixed)
- Bad alternator (unlikely, since if it's turning and the windings aren't faulted,
there's nothing else to be wrong)
- Bad battery (unlikely since if it's dead it won't draw enough current to keep the
voltage down for a long time)

Lots of reasons... not quite enough info to determine the cause.

-Cory
--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Gene Seibel]

Pretty good idea. I'd imagine the spare belt would suffer some
deterioation over time, but should be good enough to get you home from
some far away place.
--
Gene Seibel
Hangar 131 - http://pad39a.com/gene/plane.html
Because I fly, I envy no one.

[Nathan Young]

On Fri, 28 Jan 2005 10:46:10 -0600, Ross Richardson
> wrote:

>Hmmm, My solid state regulator has an adjustment under a screw that is
>removed. I believe it even has arrows to show increase/decrease
>direction.

Yep, mine too. And amazingly it adjusts the bus voltage when the
screw is turned! I suspect the OP's A&P is not that familiar with
aircraft electrical systems. Very common. It is also explains the
'shotgun' replacement methodology that many owners have to go through
to fix their electrical systems.

-Nathan

[nrp]

> - Bad battery (unlikely since if it's dead it won't draw enough
current to keep the
> voltage down for a long time)

Don't excuse the battery too quickly, although more accurate voltage
and voltage drop measurements are certainly in order. Check also that
the engine/alternator is grounded with respect to the battery negative,
and do it under heavy load. Check also that the regulator is
adequately grounded with respect to the battery negative. Remember
that the airframe isn't necessarily a good conductor.

Wires are used to carry current. The airframe only might do so.

>From reading these and other posts, Pipers seem to have an inordinate
amount of electrical problems. Is it because of the aluminum wiring on
the main cables?
>

[zatatime]

On 27 Jan 2005 23:44:49 GMT, (PaulaJay1) wrote:

>I have a voltmeter plugin in the cig lighter socket. It reads about 11.5 when
>I trun on the master. Reads about 12.8 after engine start and after an hour
>flight has worked up to maybe 13.7 or so. I plan on taking a known accurate
>meter out Sat to check these reading.
>My A&P says maybe the alternator needs rebuilt (at about $250). He says that
>the voltage reg is solid state and either works or not - ie no adjustment.
>I've had a couple of times when the bat needed a boost, so something is wrong.
>Any comments before I start throwing money at the problem.
>
>Chuck
>Archer 2185B


Sounds like what I just went through a few months ago. Turned out
that some of my windings were burnt (and maybe a bad diode). Got a
rebuild, charged the battery, and the starter spun the prop like I
hadn't seen in a long time!

HTH.
z

[BTIZ]

well.. your original post did say "strapped up against the engine"..
is part of the preflight to make sure the zip ties have not broken or gotten
brittle?
BT

> wrote in message
news:UMkKd.262$by2.128@trnddc03...
>
> On 27-Jan-2005, "BTIZ" > wrote:
>
>> I would think the heat from the engine would raise a havoc with the
>> belt..
>> and it might smell pretty bad it gets hot
>
>
> The "spare" belt is positioned in a way that it is well clear of the
> cylinders and heads. Actually, the belt doesn't even contact the
> crankcase
> that much, and the case doesn't get particularly hot. The mechanic says
> his
> shop has been doing this for a while now with no problems.
> --
> -Elliott Drucker

[Matt Whiting]

BTIZ wrote:

> well.. your original post did say "strapped up against the engine"..
> is part of the preflight to make sure the zip ties have not broken or gotten
> brittle?
> BT

Yes, I'd be worried about carrying it in the engine compartment. Why
not just carry it in baggage compartment?


Matt

[Tyler]

Matt Whiting wrote:
> BTIZ wrote:
>
>> well.. your original post did say "strapped up against the engine"..
>> is part of the preflight to make sure the zip ties have not broken or
>> gotten brittle?
>> BT
>
>
> Yes, I'd be worried about carrying it in the engine compartment. Why
> not just carry it in baggage compartment?
>
>
> Matt

Because from the baggage compartment you have to stretch it over the
propeller to get it on (not likely!) - or remove the propeller :-)
whereas if it's already between the engine and the propeller you just put
it over the engine pulley, loosen the alternator, and put it over the
alternator pulley.

Tyler

[[email protected]]

nrp > wrote:
: Don't excuse the battery too quickly, although more accurate voltage

Actually, the battery is quite likely screwed if the charging system is broken
somehow. If a flooded lead-acid battery sits dead for even a short period of time
(like overnight), it can be considerably damaged. If you replace the battery without
fixing the charging system (a *very* common practice, BTW), you'll only succeed in
destroying a brand new battery in a short period of time.

When a battery goes bad, it almost always has a weak cell. In that case, It
won't absorb any current without easily floating up to the max voltage. The
"time-dependent" voltage rise he mentioned isn't consistent with that. If the battery
is somehow taking lots of current but not charging, the energy is going somewhere else
(read: heat)... badness will ensue in this unlikely failure mode.

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Roger]

On Fri, 28 Jan 2005 13:07:05 GMT, "Jay Honeck"
> wrote:

>> The "spare" belt is positioned in a way that it is well clear of the
>> cylinders and heads. Actually, the belt doesn't even contact the
>> crankcase
>> that much, and the case doesn't get particularly hot. The mechanic says
>> his
>> shop has been doing this for a while now with no problems.
>
>I, for one, think it's a fabulous idea.
>
>I wish more shops would think proactively like this.

I wonder what the FAA would have to say about a non standard
attachment to the engine?

Although this sounds really handy, I'd bet they would require it to be
removed.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

[PaulaJay1]

I flew today and got more info - good and bad. First, I took a good volt meter
out and found that the I get 12.6 or so with main turned on (light load) and
13.25 with engine running. Seems the plugin cig lighter volt meter is also
part thermometer :-). The 13.25 is reasonably constant when I vary the load.
eg I turned on the landing lights( about 20 amps) and still 13.25v. So I look
for the regulator to see if there is an adjustment and I CAN'T FIND THE
REGULATOR. I was looking for a rectangular two inch by three inch by two inch
metal box. Nothing. Sure thought it would be on the engine side of the
firewall. Do you suppose that it is built in to the alternator? You can't get
to the alternator very easily on my Archer so I didn't check it very well.

Chuck
Archer 2185B

By the way, the flying today was GREAT. Smooth and clear. Flew over central
Ohio where there was flooding a week or two ago and there is still water (and
ice) all over.


>Hmmm, My solid state regulator has an adjustment under a screw that is
>removed. I believe it even has arrows to show increase/decrease
>direction.
>
>PaulaJay1 wrote:
>>
>> I have a voltmeter plugin in the cig lighter socket. It reads about 11.5
>when
>> I trun on the master. Reads about 12.8 after engine start and after an
>hour
>> flight has worked up to maybe 13.7 or so. I plan on taking a known
>accurate
>> meter out Sat to check these reading.
>> My A&P says maybe the alternator needs rebuilt (at about $250). He says
>that
>> the voltage reg is solid state and either works or not - ie no adjustment.
>> I've had a couple of times when the bat needed a boost, so something is
>wrong.
>> Any comments before I start throwing money at the problem.
>>
>> Chuck
>> Archer 2185B

[[email protected]]

On 29 Jan 2005 19:31:11 GMT, (PaulaJay1) wrote:

>
>
>I flew today and got more info - good and bad. First, I took a good volt meter
>out and found that the I get 12.6 or so with main turned on (light load) and
>13.25 with engine running. Seems the plugin cig lighter volt meter is also
>part thermometer :-). The 13.25 is reasonably constant when I vary the load.
>eg I turned on the landing lights( about 20 amps) and still 13.25v. So I look
>for the regulator to see if there is an adjustment and I CAN'T FIND THE
>REGULATOR. I was looking for a rectangular two inch by three inch by two inch
>metal box. Nothing. Sure thought it would be on the engine side of the
>firewall. Do you suppose that it is built in to the alternator? You can't get
>to the alternator very easily on my Archer so I didn't check it very well.

try looking under the instrument panel (between the panel and the
firewall) on the pilot's side toward the left (outboard) side of the
fuselage.

TC

[Bill J]

It has saved me a couple of times. Fully approved by two AIs.

Tyler wrote:

> Matt Whiting wrote:
>
>> BTIZ wrote:
>>
>>> well.. your original post did say "strapped up against the engine"..
>>> is part of the preflight to make sure the zip ties have not broken or
>>> gotten brittle?
>>> BT
>>
>>
>>
>> Yes, I'd be worried about carrying it in the engine compartment. Why
>> not just carry it in baggage compartment?
>>
>>
>> Matt
>
>
> Because from the baggage compartment you have to stretch it over the
> propeller to get it on (not likely!) - or remove the propeller :-)
> whereas if it's already between the engine and the propeller you just
> put it over the engine pulley, loosen the alternator, and put it over
> the alternator pulley.
>
> Tyler

[Mike W.]

Those voltages you are measuring are normal, the output voltage of the
alternator (13v-14v) is slightly higher than the battery voltage (12v±) so
that it charges.

BTW, what airport do you fly out of, Chuck?
>
> I flew today and got more info - good and bad. First, I took a good volt
meter
> out and found that the I get 12.6 or so with main turned on (light load)
and
> 13.25 with engine running. Seems the plugin cig lighter volt meter is
also
> part thermometer :-). The 13.25 is reasonably constant when I vary the
load.
> eg I turned on the landing lights( about 20 amps) and still 13.25v. So I
look
> for the regulator to see if there is an adjustment and I CAN'T FIND THE
> REGULATOR. I was looking for a rectangular two inch by three inch by two
inch
> metal box. Nothing. Sure thought it would be on the engine side of the
> firewall. Do you suppose that it is built in to the alternator? You
can't get
> to the alternator very easily on my Archer so I didn't check it very well.
>
> Chuck
> Archer 2185B
>
> By the way, the flying today was GREAT. Smooth and clear. Flew over
central
> Ohio where there was flooding a week or two ago and there is still water
(and
> ice) all over.

[PaulaJay1]

In article >, "Mike W."
> writes:

>BTW, what airport do you fly out of, Chuck?
>>

I64

[David Lesher]

Good background page on batteries:

http://www.windsun.com/Batteries/Battery_FAQ.htm


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433