Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :
http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz

On Sat, 21 Apr 2007 21:49:14 +1000, "marcus" wrote:

Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :
http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz


Of course. (Most of my early patents were automotive products.)

Early next week... I'm buried with work this weekend.

Flat voltage or do you need temperature compensation?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

On Sat, 21 Apr 2007 07:22:35 -0700, Jim Thompson
wrote:

On Sat, 21 Apr 2007 21:49:14 +1000, "marcus" wrote:

Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :
http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz


Of course. (Most of my early patents were automotive products.)

Early next week... I'm buried with work this weekend.

Flat voltage or do you need temperature compensation?

...Jim Thompson

Also, Is field tied to A+ end or ground end of alternator?

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

America: Land of the Free, Because of the Brave

On Sat, 21 Apr 2007 21:49:14 +1000, "marcus" wrote:

Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :
http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz

I couldn't see the file you reference.
but
12 volt alternators can put out 14 volts at idle so with just a pulley
adjustment or running them faster the voltage goes up proportionately.
From that point on it is just a matter of a regulator.

I have a two transistor regulator that I scrounged from a Chilton's
manual back in '72. They didn't show component values, but I put what
I thought would work and it did in a BMW motorcycle and Toyota Land
Cruiser. Doesn't do anything fancy like float at a lower voltage, but
I could post the schematic if you want or email it.

Very simple device - NPN pass transistor is biased "on" with a
resistor (turning on the rotor) and a second transistor turns it off
when the Zener/ and potentiometer-setting voltage is exceeded. The
Chilton's manual showed fixed resistors - I used a military spec wire
wound pot to set the voltage.

The BMW reg was in the bike for 10 years (in the weather) and I had no
problems with it other than painting the transistors so the TO66 cases
wouldn't rust through - on the land cruiser I used a 2N3055 and it
never rusted in the engine compartment. No heatsink was needed - the
rotor would pull about 3 amps maximum.
--

----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==----
http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups
----= East and West-Coast Server Farms - Total Privacy via Encryption =----

On Apr 21, 4:49 am, "marcus" wrote:
Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz


I agree with Jim about going analog. I've built more than one voltage
regulator for old vehicles I've owned. Building a simple analog
voltage regulator and getting it to work is relatively easy.
I got the basic idea from this website:
http://homepage.sunrise.ch/mysunrise...ot/voltreg.htm
The voltage regulator on that web page is for a grounded field
alternator. If you want to use the kind of alternator Jim suggested,
flip the diagram upside down and reverse the polarities. GM (Delco)
alternators for example have the kind of field Jim is talking about.
Field is tied to the high end, and you do the switching at ground.
The guy that designed the voltage regulator on the website suggests
jumpers (you could use switches) across diodes in the string to set
the voltage. If you want finer resolution in the voltage setpoint you
could put a shottky in the series.
Or you could work it out a little differently with a potentiometer/
voltage divider scenario, for continuous voltage adjustment.
I used a mosfet instead of the darlington in the diagram. The
hysteresis in Joerg's circuit minimizes heat in the switching element
by making it switch on and off in a narrow band around the setpoint
instead of going into linear operation.

Final note. A great website for RE stuff is
www.fieldlines.com

marcus inscribed in red ink for all to know:
Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?
Application is deep-cycle solar battery charging using 3-5HP small petrol
motor coupled to 24V alternator.
Need to tweak the voltage up to about 29-30V to equalise the batteries.
Solar batteries like a 3-stage charging regime - boost, bulk & float. These
voltages are all diff. and also depend on battery type (chemistry), so the
field needs to have these adjustable set-points.
Would be nice to be able to sense battery voltage and feedback into
alternator field voltage, to make a set-and-forget circuit.

Here's some background (12V, and no feedback) :
http://www.homepower.com/files/mark8.pdf

Thanks to everyone in aus.electronics who had a look at this.

Jim Thompson : I notice from your web pages that you have designed some car
alternator regulation projects - wondering if you have any thoughts?

Thanks all

Marcus in outback Oz




You can buy one for less than $20.

Are you talking about converting a 12V nominal automotive alternator to
24V? You won't need to make any changes to the pulley to make the
alternator deliver 24 V, but the the diodes and the diode trio will need
to be replaced with 24V versions.

And the new regulator, of course.

bob
s/v Eolian
Seattle

RW Salnick wrote:
(snip) You won't need to make any changes to the pulley to
make the
alternator deliver 24 V, but the the diodes and the diode trio will need
to be replaced with 24V versions.
(snip)

Are you seriously suggesting that a 12 volt alternator is
made with a diode trio that cannot handle 24 volts? I was
under the impression that few silicon rectifiers are made
with a breakdown voltage less than 50 volts.

John Popelish wrote:

RW Salnick wrote:
(snip) You won't need to make any changes to the pulley to
make the
alternator deliver 24 V, but the the diodes and the diode trio will need
to be replaced with 24V versions.
(snip)

Are you seriously suggesting that a 12 volt alternator is
made with a diode trio that cannot handle 24 volts? I was
under the impression that few silicon rectifiers are made
with a breakdown voltage less than 50 volts.


What PIV diodes do you think you need for 24 volts?


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Has anyone come across a circuit for a manually-adjustable, or even
automatic regulator circuit
to control a 24V car alternator?

The crude way is to use a voltage divider on the sense input. For the
GM 12 V 120 A alternators used on the 86-87 turbo V6 Regals, an example
diagram is at: http://www.gnttype.org/techarea/projects/gnalt.html The
idea is to use a throttle or boost actuated switch to kick up the output
voltage to give the ignition and fuel pump a boost at wide open
throttle. On these alternators the dash volts light is a 194 and it
goes from battery to the L pin on the 4 pin connector, to provide both
sensing input and idiot light. The internal resistance of this bulb is
crucial, you will blow things up if it is shorted and make things very
unhappy if it is open. The S terminal, on the other hand, is for
sensing only and can be connected directly to the battery. I don't know
the limits on output voltage but 16 V is what is commonly used in
racing - enough to make a real difference in ignition and fueling but
not quite start popping lightbulbs during a sub-12 second quarter mile
blast :-). This works on all the GM alternators I've seen from the 70's
and 80's. Somewhere in the 90's the engine computer started controlling
the alternator and I'm not familiar with the details on those. A
commercial external regulator (I think; it may just be a divider too) is
available from Precision Turbo & Engine in Indiana, USA.

--
Regards,
Carl Ijames carl dott ijames aat verizon dott net
(remove nospm or make the obvious changes before replying)

John Popelish inscribed in red ink for all to know:
RW Salnick wrote:
(snip) You won't need to make any changes to the pulley to make the

alternator deliver 24 V, but the the diodes and the diode trio will
need to be replaced with 24V versions.

(snip)

Are you seriously suggesting that a 12 volt alternator is made with a
diode trio that cannot handle 24 volts? I was under the impression that
few silicon rectifiers are made with a breakdown voltage less than 50
volts.

They need to be able to handle *at least* double the intended voltage
delivery. A 24 V alternator will probably actually deliver 28V (just as
today's 12 V alternators are delivering as much as 16V).

bob