This is a multi-part message in MIME format.
--===============8328741749708188139==
boundary="------------06C79A78B3447C24CA8FCEBB"
Content-Language: en-US
This is a multi-part message in MIME format.
--------------06C79A78B3447C24CA8FCEBB
Content-Transfer-Encoding: 8bit
Thanks for the info, Bill.
Bob
On 6/7/2019 9:30 PM, WILLIAM B LAWRENCE wrote:
> "I don't think a generator could behave like this..."
>
> Actually a generator will act exactly like this if the cutout circuit
> of the regulator (control box for the purists among us) fails in the
> closed position.
>
> Bill Lawrence
> BN1 #554
> ------------------------------------------------------------------------
> *From:* Healeys <healeys-bounces@autox.team.net> on behalf of Bob
> Spidell <bspidell@comcast.net>
> *Sent:* Saturday, June 8, 2019 3:34 AM
> *To:* healeys@autox.team.net
> *Subject:* Re: [Healeys] Electric Draw
>
> OK, folks, I gotta eat crow. I'd never heard of it before, but I got
> to thinking about it and realized that alternator diodes are a direct
> path to the battery, and I did some research:
>
> /"//A leaky diode also can allow current to drain out of the battery
> through the alternator when the vehicle is not being driven."/
>
> /-
> /https://www.knowyourparts.com/technical-resources/starting-and-charging/starters-and-alternators-common-misdiagnosis/
>
> In my experience, diodes fail open, sort of like fuses, but if one
> failed short--or 'leaked'--it could draw current from the battery.  I
> think the way to test for this would be to disconnect the
> alternator->battery lead and see if the current draw ceases (or charge
> the battery to a known voltage, disconnect the alternator, and see if
> the battery remains charged overnight). I don't think a generator
> could behave like this, but I'm gonna think about it before I press
> 'send' before I've had my second cup of coffee.
>
> My apologies to all (including the OP's mechanic).
>
> Bob
>
>
> On 6/7/2019 9:09 AM, Bob Spidell wrote:
>>
>> Uh, I'm not an electrical engineer--but I play one on email
>> lists--but it sounds like your mechanic isn't one either (not
>> uncommon). The diodes in an alternator perform the same function as
>> the brushes and commutator in a generator; i.e. they rectify the
>> alternating current--produced by rotating an electromagnet--into DC
>> current, which your battery requires for charging and all your
>> accessories require to, well, accessorize. Hence, they aren't doing
>> squat when the engine isn't running--when there should be no current
>> coming to the alternator to energize the rotor--and if you had a
>> short somewhere and your alternator was getting current with the
>> engine stopped it would likely heat up (see if your alternator feels
>> warm after sitting overnight). Diodes can fail by either shorting out
>> or opening up; most alternators have 6 of them and when one fails by
>> opening up you lose one-sixth of your charging ability (I'd have to
>> research it, but as solid state devices--sort of one-third of a
>> transistor--they probably mostly fail by opening up as the silicon
>> junctions are relatively fragile). I'm not sure if it's an open or
>> shorted diode that causes it--maybe both--but with a bad diode you
>> will get all kinds of radio noise, which varies with engine speed
>> (when I used to fly light aircraft you could tell when someone had a
>> bad diode with serious noise in radio transmissions).
>>
>> Others have offered good suggestions so I'll just add that it's
>> conceivable your ignition switch is worn allowing some current flow
>> when in the 'off' position (after all, it's Lucas ;)). See if it
>> feels warm after sitting for a while (in fact, if you can get to them
>> see if any of the electrical devices in your car feel warmer than
>> ambient after sitting in the shade). Your battery ground doesn't
>> pull a load--something has to draw current that the ground cable
>> returns to the battery--so it isn't the problem. A nearly half-amp
>> current draw in a 12V system will produce 6 watts of heat (nearly
>> half of what a 60W equivalent CFL light rated at 13W will generate).
>>
>> Bob
>>
>>
>> On 6/7/2019 6:13 AM, Michael Salter wrote:
>>> Real Healeys don't have alternators.����
>>>
>>> On Fri, Jun 7, 2019, 8:55 AM Per Schoerner, <per@schoerner.se
>>>
>>> It sounds more like your cutout switch is the culprit here.
>>>
>>> Per
>>>
>>> Skickat från min iPhone
>>>
>>> > 7 juni 2019 kl. 14:47 skrev R. Lindsay <050.rpl@gmail.com
>>> >
>>> > For the past few weeks I have been fighting a parasitic draw
>>> on my BJ8. It was running about .48 amps and would drain my
>>> battery in a day or so. I was told by a mechanic that a diode in
>>> my alternator must have blown therefore causing the draw. He
>>> also mentioned that my ground wires in the boot were loose which
>>> he tightened. I brought the car home, turned off the power in
>>> the boot and 2 days later the battery was dead.
>>> >
>>> > So, hereâ??s what Iâ??ve done. I jumped the battery and started
>>> the car and ran it for 10 minutes. I disconnected the charger
>>> and tested the battery - 12.48 volts. I then removed the cutoff
>>> switch and bolted the grounding wires together. I tested for a
>>> draw and got a zero reading. That was last night. I went out
>>> this morning (12 hours later) and the battery reads 12.33 volts.
>>> >
>>> > My questions are 1. Is .15 volts a reasonable drop in voltage
>>> for a sitting car in 90 degree heat and 2. Can a diode in an
>>> alternator work sometimes and not at others. If itâ??s either
>>> â??good or badâ?? all the time, I guess I need to presume the
>>> alternator is not the source of the draw. If a .15 volt loss
>>> over 12 hours is reasonable then removing the cut out switch in
>>> conjunction with presuming the alternator is good (as it works
>>> fine now) solved my problem.
>>> >
>>> > What does the wisdom of this great resource think?
>>> >
>>> > Price Lindsay
>>>
>>
--------------06C79A78B3447C24CA8FCEBB
Content-Transfer-Encoding: 8bit
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<p>Thanks for the info, Bill.</p>
<p><br>
</p>
<p>Bob</p>
<p><br>
</p>
<div class="moz-cite-prefix">On 6/7/2019 9:30 PM, WILLIAM B LAWRENCE
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:DM6PR07MB45383E76F3B671059B0CC2A7A5110@DM6PR07MB4538.namprd07.prod.outlook.com">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style type="text/css" style="display:none;"> P
{margin-top:0;margin-bottom:0;} </style>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
"<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important"><span>Â </span>I don't think
a generator could behave like this..."</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important"><br>
</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important">Actually a generator will
act exactly like this if the cutout circuit of the regulator
(control box for the purists among us) fails in the closed
position.</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important"><br>
</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important">Bill Lawrence</span></div>
<div style="font-family: Calibri, Helvetica, sans-serif;
font-size: 12pt; color: rgb(0, 0, 0);">
<span style="caret-color: rgb(32, 31, 30); color: rgb(32, 31,
30); font-family: "Segoe UI", "Segoe UI Web
(West European)", "Segoe UI", -apple-system,
BlinkMacSystemFont, Roboto, "Helvetica Neue",
sans-serif; font-size: 15px; background-color: rgb(255, 255,
255); display: inline !important">BN1 #554</span></div>
<hr style="display:inline-block;width:98%" tabindex="-1">
<div id="divRplyFwdMsg" dir="ltr"><font style="font-size:11pt"
face="Calibri, sans-serif" color="#000000"><b>From:</b>
Healeys <a class="moz-txt-link-rfc2396E"
href="mailto:healeys-bounces@autox.team.net";><healeys-bounces@autox.team.net></a>
on behalf of
Bob Spidell <a class="moz-txt-link-rfc2396E"
href="mailto:bspidell@comcast.net";><bspidell@comcast.net></a><br>
<b>Sent:</b> Saturday, June 8, 2019 3:34 AM<br>
<b>To:</b> <a class="moz-txt-link-abbreviated"
href="mailto:healeys@autox.team.net";>healeys@autox.team.net</a><br>
<b>Subject:</b> Re: [Healeys] Electric Draw</font>
<div>Â </div>
</div>
<div style="background-color:#FFFFFF">
<p>OK, folks, I gotta eat crow. I'd never heard of it before,
but I got to thinking about it and realized that alternator
diodes are a direct path to the battery, and I did some
research:</p>
<p><i>"</i><i> A leaky diode also can allow current to drain out
of the battery through the alternator when the vehicle is
not being driven."</i></p>
<p><i>- </i><a class="x_moz-txt-link-freetext"
href="https://www.knowyourparts.com/technical-resources/starting-and-charging/starters-and-alternators-common-misdiagnosis/";
moz-do-not-send="true">https://www.knowyourparts.com/technical-resources/starting-and-charging/starters-and-alternators-common-misdiagnosis/</a></p>
<p>In my experience, diodes fail open, sort of like fuses, but
if one failed short--or 'leaked'--it could draw current from
the battery.  I think the way to test for this would be to
disconnect the alternator->battery lead and see if the
current draw ceases (or charge the battery to a known voltage,
disconnect the alternator, and see if the battery remains
charged overnight). I don't think a generator could behave
like this, but I'm gonna think about it before I press 'send'
before I've had my second cup of coffee.<br>
</p>
<p>My apologies to all (including the OP's mechanic).</p>
<p>Bob</p>
<p><br>
</p>
<div class="x_moz-cite-prefix">On 6/7/2019 9:09 AM, Bob Spidell
wrote:<br>
</div>
<blockquote type="cite">
<p>Uh, I'm not an electrical engineer--but I play one on email
lists--but it sounds like your mechanic isn't one either
(not uncommon). The diodes in an alternator perform the
same function as the brushes and commutator in a generator;
i.e. they rectify the alternating current--produced by
rotating an electromagnet--into DC current, which your
battery requires for charging and all your accessories
require to, well, accessorize. Hence, they aren't doing
squat when the engine isn't running--when there should be no
current coming to the alternator to energize the rotor--and
if you had a short somewhere and your alternator was getting
current with the engine stopped it would likely heat up (see
if your alternator feels warm after sitting overnight).Â
Diodes can fail by either shorting out or opening up; most
alternators have 6 of them and when one fails by opening up
you lose one-sixth of your charging ability (I'd have to
research it, but as solid state devices--sort of one-third
of a transistor--they probably mostly fail by opening up as
the silicon junctions are relatively fragile). I'm not sure
if it's an open or shorted diode that causes it--maybe
both--but with a bad diode you will get all kinds of radio
noise, which varies with engine speed (when I used to fly
light aircraft you could tell when someone had a bad diode
with serious noise in radio transmissions).</p>
<p>Others have offered good suggestions so I'll just add that
it's conceivable your ignition switch is worn allowing some
current flow when in the 'off' position (after all, it's
Lucas ;)). See if it feels warm after sitting for a while
(in fact, if you can get to them see if any of the
electrical devices in your car feel warmer than ambient
after sitting in the shade). Your battery ground doesn't
pull a load--something has to draw current that the ground
cable returns to the battery--so it isn't the problem. A
nearly half-amp current draw in a 12V system will produce 6
watts of heat (nearly half of what a 60W equivalent CFL
light rated at 13W will generate).<br>
</p>
<p>Bob</p>
<p><br>
</p>
<div class="x_moz-cite-prefix">On 6/7/2019 6:13 AM, Michael
Salter wrote:<br>
</div>
<blockquote type="cite">
<div dir="auto">Real Healeys don't have
alternators.����</div>
<br>
<div class="x_gmail_quote">
<div dir="ltr" class="x_gmail_attr">On Fri, Jun 7, 2019,
8:55 AM Per Schoerner, <<a
href="mailto:per@schoerner.se";
moz-do-not-send="true">per@schoerner.se</a>>
wrote:<br>
</div>
<blockquote class="x_gmail_quote" style="margin:0 0 0
.8ex; border-left:1px #ccc solid; padding-left:1ex">
It sounds more like your cutout switch is the culprit
here.<br>
<br>
Per<br>
<br>
Skickat från min iPhone<br>
<br>
> 7 juni 2019 kl. 14:47 skrev R. Lindsay <<a
href="mailto:050.rpl@gmail.com"; target="_blank"
rel="noreferrer"
moz-do-not-send="true">050.rpl@gmail.com</a>>:<br>
> <br>
> For the past few weeks I have been fighting a
parasitic draw on my BJ8. It was running about .48 amps
and would drain my battery in a day or so. I was told by
a mechanic that a diode in my alternator must have blown
therefore causing the draw. He also mentioned that my
ground wires in the boot were loose which he tightened.
I brought the car home, turned off the power in the boot
and 2 days later the battery was dead.
<br>
> <br>
> So, hereâ??s what Iâ??ve done. I jumped the battery and
started the car and ran it for 10 minutes. I
disconnected the charger and tested the battery - 12.48
volts. I then removed the cutoff switch and bolted the
grounding wires together. I tested for a draw and got a
zero reading. That was last night. I went out this
morning (12 hours later) and the battery reads 12.33
volts.
<br>
> <br>
> My questions are 1. Is .15 volts a reasonable drop
in voltage for a sitting car in 90 degree heat and 2.
Can a diode in an alternator work sometimes and not at
others. If itâ??s either â??good or badâ?? all the time, I
guess I need to presume the alternator is not the source
of the draw. If a .15 volt loss over 12 hours is
reasonable then removing the cut out switch in
conjunction with presuming the alternator is good (as it
works fine now) solved my problem.
<br>
> <br>
> What does the wisdom of this great resource think?<br>
> <br>
> Price Lindsay<br>
<br>
</blockquote>
</div>
</blockquote>
<br>
</blockquote>
</div>
</blockquote>
</body>
</html>
--------------06C79A78B3447C24CA8FCEBB--
--===============8328741749708188139==
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
_______________________________________________
Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archive
Healeys@autox.team.net
http://autox.team.net/mailman/listinfo/healeys
--===============8328741749708188139==--
|