Re: 12 volt power source?

Ray Haddad wrote:

On Wed, 26 Dec 2007 10:13:33 +1300, I said, "Pick a card, any card"
and Greg Procter <procter@xxxxxxxxxx> instead replied:

Ray Haddad wrote:

On Wed, 26 Dec 2007 07:30:19 +1300, I said, "Pick a card, any card"
and Greg Procter <procter@xxxxxxxxxx> instead replied:

Ray Haddad wrote:

On Mon, 24 Dec 2007 09:36:14 +1300, I said, "Pick a card, any card"
and Greg Procter <procter@xxxxxxxxxx> instead replied:

Ray Haddad wrote:

On Mon, 24 Dec 2007 08:34:58 +1300, I said, "Pick a card, any card"
and Greg Procter <procter@xxxxxxxxxx> instead replied:

Here's a laboratory power supply from Jaycar Electronics:
<http://www1.jaycar.com.au/productView.asp?ID=MP3078&CATID=&keywords=Bench+power+supply&SPECIAL=&form=KEYWORD&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCATID=>

Here's a laboratory power supply from *** Smith Electronics:
<http://dseau.resultspage.com/search.php?sessionid=476eb5e50123fe3a273fc0a87f9c0718&w=Power+supply+13.8&site=&submit.x=11&submit.y=8>

Sorry the links are so long but that takes you to the specific product.

I've been involved with fitting ship, boat and truck radio/depth finding
etc gear (AWA NZ, a division of RCA USA) All our gear was rated at 13.8
volts because that's the operating voltage found on batteries in circuit
in those situations.

That's because they run from a generator or an alternator and not a
12 volt battery which is never, ever going to be at 13.8 volts.

LOL.

The battery is in circuit between the generator/alternator and the load,
it's an integral part of the voltage regulation circuit.
If the alternator and the load are at 13.8 volts then the battery _must_
be at ...?

No, Greg. The entire CIRCUIT is at 13.8 volts.

Exactly Ray - geeze, it really takes a _long_ time for you to not
understand the completely obvious!

Baloney. You've been spewing from the mountaintops that a 12 volt
battery will measure 13.8 volts and that's simply wrong. Don't try
to weasel out of it now. Everyone here has been trying to convince
you that the CHARGING circuit is 13.8 volts and now you pretend you
knew it all along.

A 12 volt battery will not ever measure 13.8 volts as you stated.

That battery company I cited is going to be very disappointed!

They're on the same page as me, Greg. Why would you believe
otherwise?

Not the battery. When
you turn off the motor, the battery drops to 12 volts just like
always.

Why do you keep stating that which is only correct when the battery is
at 12 volts?

Because a 12 volt battery will never, ever measure 13.8 volts. Ever.

In that case the car electric connected to said battery will never
measure 13.8 volts. Ever.

Exactly. Not without external potential added. A battery circuit,
including the battery, can be driven to a higher voltage but that
process is known as charging. When used as a source of power, a
battery will never be at 13.8 volts. It's a physics thing.


Awww Ray, if the electrical circuitry of the car is at 13.8 volts then
the battery is at 13.8 volts - it's a physics thing.


The information that voltages above 13.8 volts will cause gassing is
sort of wasted really.

That's what the float limit is all about. Gassing causes the
electrolyte's hydrogen to leave the battery. It's a serious issue.
If you charge at too high a voltage, the electrolyte outgasses and
you get spidering between the cells which can cause cell failure.
Water vapor also escapes during gassing which lowers the levels.


I do hope you mean _to_ too high a level? If you charge a battery it has
to rise through every voltage point from start to ...


Gel
batteries don't suffer that same fate but an overcharge voltage on
them can cause swelling and cell failure from heat.

It's best not to overcharge those either - however, they still have to
be charged from their starting point through every voltage point to
overcharge.


You really don't understand batteries. Just leave it at
that. Otherwise you'll keep on making a fool of yourself.

This one bears repeating. You simply don't understand batteries,
Greg.

Fair point - care to design my current electric car design for me?

No thanks, mate. I'm converting one now. A Dihatsu Mira-J. I'm so
pleased about how clean the car has become since the engine is gone.
I've got 3 years invested in it and don't expect to finish for at
least another 3. Batteries (huge power sources) are getting cheaper
and different every day.

I've just put aside the idea of building a car from scratch and am
looking for something like the Daihatsu Mira.
There's not enough years left!


Have you looked at the commercially available fuel cells? Brilliant!
http://www.batterybook.com/default.asp

Look in the middle column, third one down. The best part? They're
literally a few miles away from me.

Now, Greg, I'm offering you a Boxing Day olive branch. Can we end
this seemingly endless debate and get back to trains?
--
Ray
.