Truncated match.
PICList
Thread
'Battery Isolators (Totally Unrelated to PIC)'
1997\02\05@185456
by
Brian Boles
Does anyone know what is in a battery isolator, the devices that let
one alternator charge 2 batteries on seperate circuits in a truck or
boat. Is it low forward drop diodes or some kind of relay???
I would go for a newsgroup but our IS dept. won't set us up for that.
Rgds, Brian. spam_OUTbbolesTakeThisOuT
microchip.com
1997\02\05@194133
by
bigb
Brian Boles wrote:
>
> Does anyone know what is in a battery isolator, the devices that let
> one alternator charge 2 batteries on seperate circuits in a truck or
> boat. Is it low forward drop diodes or some kind of relay???
>
> I would go for a newsgroup but our IS dept. won't set us up for that.
>
> Rgds, Brian. .....bbolesKILLspam
@spam@microchip.com
The only ones i've seen contain 2 low forward drop diodes.
Brian Hurst
1997\02\05@195346
by
Tony Matthews
Brian Boles wrote:
>
> Does anyone know what is in a battery isolator, the devices that let
> one alternator charge 2 batteries on seperate circuits in a truck or
> boat. Is it low forward drop diodes or some kind of relay???
>
> I would go for a newsgroup but our IS dept. won't set us up for that.
>
> Rgds, Brian. bboles
KILLspammicrochip.com
Two diodes is my experience in the maritime buis. Tony m.
1997\02\05@230517
by
Bob Blick
At 04:47 PM 2/5/97 -0700, you wrote:
> Does anyone know what is in a battery isolator, the devices that let
> one alternator charge 2 batteries on seperate circuits in a truck or
> boat. Is it low forward drop diodes or some kind of relay???
The diodes are not low drop. The voltage regulator monitors the actual
battery voltage and the alternator just produces a little more voltage. The
secondary battery is not directly regulated, just regulated because of its
similar connection.
-Bob
1997\02\06@090213
by
William Sadler
On 5 Feb 97 at 16:47, Brian Boles wrote:
> Does anyone know what is in a battery isolator, the devices that let
> one alternator charge 2 batteries on seperate circuits in a truck or
> boat. Is it low forward drop diodes or some kind of relay???
>
> I would go for a newsgroup but our IS dept. won't set us up for that.
>
> Rgds, Brian. .....bbolesKILLspam
.....microchip.com
>
In the UK for a second battery in a towed caravan a relay is usually
used. The relay is switched on when the ignition of the vehicle is
switched on, (ie. when the engine is running).
William Sadler
1997\02\06@105520
by
Martin McCormick
I privately wrote Bryan, but one of the replies to the group makes
me a bit curious. I told Bryan that one would need a voltage regulator
for each path since the batteries might be in different states of discharge.
If one battery sulphated or was, for some reason, discharged more than the
other, the one that was most charged would get an overcharge while the
deader battery was trying to catch up. Is this possible or am I just mistaken?
The battery with the highest voltage will totally carry the system since the
diodes won't let current flow any other direction.
Martin McCormick
1997\02\06@112229
by
Bradley, Larry
|
Except that in a lot of standard marine alternators, the voltage
regulator is built into the alternator directly, and only can monitor
the alternator output voltage, not the battery voltage.
West Marine sells a device (which would be easy to build) that is a
relay that parallels the two batteries when the voltage is "high",
indicating that the alternator is charging the batteries. When the
voltage drops to a level that suggests discharge, the relay opens and
the two batteries are disconnected form one another.
Larry
{Quote hidden}>----------
>From: Bob Blick[SMTP:
EraseMEbblickspam_OUT
TakeThisOuTTELIS.ORG]
>Sent: Wednesday, February 05, 1997 10:59 PM
>To: Multiple recipients of list PICLIST
>Subject: Re: Battery Isolators (Totally Unrelated to PIC)
>
>At 04:47 PM 2/5/97 -0700, you wrote:
>> Does anyone know what is in a battery isolator, the devices that let
>> one alternator charge 2 batteries on seperate circuits in a truck or
>> boat. Is it low forward drop diodes or some kind of relay???
>
>The diodes are not low drop. The voltage regulator monitors the actual
>battery voltage and the alternator just produces a little more voltage. The
>secondary battery is not directly regulated, just regulated because of its
>similar connection.
>
>-Bob
>
1997\02\06@182736
by
William Chops Westfield
I privately wrote Bryan, but one of the replies to the group makes me a
bit curious. I told Bryan that one would need a voltage regulator for
each path since the batteries might be in different states of discharge.
Lead acid batteries, unlike NiCd's/etc, are usually charged from a
constant-volatge supply (ie same voltage regardless of charge state.)
BillW
1997\02\06@201600
by
Bob Blick
|
At 11:21 AM 2/6/97 -0500, you wrote:
>Except that in a lot of standard marine alternators, the voltage
>regulator is built into the alternator directly, and only can monitor
>the alternator output voltage, not the battery voltage.
>
Yes and no. The regulator is built into many alternators, but that does not
mean it can't monitor the battery voltage.
I don't want to contradict you, but if you check with alternator
manufacturers, you will find that the alternator output wire is "never"
used for sensing the battery voltage. There is always another wire used to
sense the battery voltage, even if it does not appear that way, ie the
"idiot light" wire serves two purposes, both sensing(input) and
indicating(output)(Mercury Capri among others).
Alternators can be incorrectly connected, and monitor their output voltage
rather than the battery voltage, but no boat or automobile manufacturer
will do it that way. Mechanics and do-it-yourselfers, on the other hand,
will do whatever they want, whether it's right or not, and it might "work"
sort of.
Cheers, Bob
1997\02\06@215204
by
Tony Matthews
|
Bradley, Larry wrote:
{Quote hidden}>
> Except that in a lot of standard marine alternators, the voltage
> regulator is built into the alternator directly, and only can monitor
> the alternator output voltage, not the battery voltage.
>
> West Marine sells a device (which would be easy to build) that is a
> relay that parallels the two batteries when the voltage is "high",
> indicating that the alternator is charging the batteries. When the
> voltage drops to a level that suggests discharge, the relay opens and
> the two batteries are disconnected form one another.
>
> Larry
>
> >----------
> >From: Bob Blick[SMTP:
bblick
spam_OUTTELIS.ORG]
> >Sent: Wednesday, February 05, 1997 10:59 PM
> >To: Multiple recipients of list PICLIST
> >Subject: Re: Battery Isolators (Totally Unrelated to PIC)
> >
> >At 04:47 PM 2/5/97 -0700, you wrote:
> >> Does anyone know what is in a battery isolator, the devices that let
> >> one alternator charge 2 batteries on seperate circuits in a truck or
> >> boat. Is it low forward drop diodes or some kind of relay???
> >
> >The diodes are not low drop. The voltage regulator monitors the actual
> >battery voltage and the alternator just produces a little more voltage. The
> >secondary battery is not directly regulated, just regulated because of its
> >similar connection.
> >
> >-Bob
> >
It's only .7 volt and I have used the two diode method to charge and
maintain starter motor battery /lighting electronics battery many times
in commercial enviroments.
1997\02\07@001539
by
*optoeng
|
Bob Blick wrote:
>
> At 11:21 AM 2/6/97 -0500, you wrote:
> >Except that in a lot of standard marine alternators, the voltage
> >regulator is built into the alternator directly, and only can monitor
> >the alternator output voltage, not the battery voltage.
> >
>
> Yes and no. The regulator is built into many alternators, but that does not
> mean it can't monitor the battery voltage.
>
> I don't want to contradict you, but if you check with alternator
> manufacturers, you will find that the alternator output wire is "never"
> used for sensing the battery voltage. There is always another wire used to
> sense the battery voltage, even if it does not appear that way, ie the
> "idiot light" wire serves two purposes, both sensing(input) and
> indicating(output)(Mercury Capri among others).
Never say 'never'. There are definitely alternators that have only 2
external electrical connections.
>
> Alternators can be incorrectly connected, and monitor their output voltage
> rather than the battery voltage, but no boat or automobile manufacturer
> will do it that way. Mechanics and do-it-yourselfers, on the other hand,
> will do whatever they want, whether it's right or not, and it might "work"
> sort of.
>
> Cheers, Bob
--
NOTE: remove asterisks from email address to reply directly
Paul Mathews, consulting engineer
AEngineering Co.
email: @spam@optoengKILLspam
whidbey.com
non-contact sensing and optoelectronics specialists
1997\02\07@035433
by
Bob Blick
At 09:06 PM 2/6/97 -0800, you wrote:
>Never say 'never'.
I didn't. I intentionally said "never" :-)
Cheers, Bob
1997\02\07@150259
by
peter
|
Anyone interested in alternators read on
if not delete
Before I start I would like to say that I am talking
about the type of alternator found on most European cars
and I'm sure there are exceptions
The alternator is a three phase AC generator
the three windings are connected in delta( triangle )
The three corners each go to two diodes (one to earth called D-
the other to 12V called D+ )
Now we come to the first variation
some alternators have three more diodes
which are connected to each corner to give a second
+ V. These diodes are small (5amps)
This second + V. source powers, via the regulator,
the field ( also called DF )
This source is also connected to the ignition + via a
charge warning light, this has a double function,
first it powers the field (lamp lit) when the engine first starts
and indicates that the alternator is not charging
Regulators are normaly combinded with the brushes
but some are external normaly connected to the alternator
via a three pin plug, similar to a headlight bulb,
marked D-, D+ and DF
Regulators normaly use two transistors a Zener diode
one small cap (22n) and a few resistors
and the output is set to 13.8V
though a few are made for 14 or 14.2
Anyone want a circuit for a car regulator
email me direct and I'll send it to you
--
Peter Cousens
email: KILLspampeterKILLspam
cousens.her.forthnet.gr
snailmail: Peter Cousens, karteros, Heraklion, Crete, 75100, Greece,
phone: + 3081 380534, +3081 324450 voice/fax
After Bill Gates announced to the world that he was Microsoft,
his wife was asked to comment. She said that as his wife, she
had been the first to notice this problem
1997\02\10@131527
by
Bradley, Larry
The regulator on the Motorola alternator on my boat (>25 years old)
appears to use pulse width modulation to control the field current ...
at least, that's what it looks like on a 'scope
Larry
{Quote hidden}
1997\02\10@164903
by
peter
|
Bradley, Larry wrote:
>
> The regulator on the Motorola alternator on my boat (>25 years old)
> appears to use pulse width modulation to control the field current ...
> at least, that's what it looks like on a 'scope
> Larry
> >----------
> >From: Peter Cousens[SMTP:TakeThisOuTpeterEraseME
spam_OUTcousens.her.forthnet.gr]
> >Sent: Saturday, February 08, 1997 12:56 AM
> >To: RemoveMEPICLIST
TakeThisOuTMITVMA.MIT.EDU
> >Subject: Re: Battery Isolators (Totally Unrelated to PIC)
> >
> >(SNIP)
> >Regulators normaly use two transistors a Zener diode
> >one small cap (22n) and a few resistors
> >and the output is set to 13.8V
> >though a few are made for 14 or 14.2
Yes they do work in switchmode
thats what the 22n cap is for
--
Peter Cousens
email: peterEraseME
.....cousens.her.forthnet.gr
snailmail: Peter Cousens, karteros, Heraklion, Crete, 75100, Greece,
phone: + 3081 380534, +3081 324450 voice/fax
After Bill Gates announced to the world that he was Microsoft,
his wife was asked to comment. She said that as his wife, she
had been the first to notice this problem
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