On Wed, 21 Nov 2007 13:48:30 -0800 (PST), Tim
wrote:



Steve wrote:
dh@. wrote in message ...
Someone told me it's possible to charge an inverter
system's batteries using a battery charger plugged
into the inverter that's being run by the batteries
you want to charge. Is there any truth to that, and
if so, how does it work?

If you have 2 half dead batteries it is possible to use them to juice up one
battery completely and leave the other dead.

I dont' even see how you could do that. with jumper cables? no.

with a power inverter and battery charger? no, (not really)

your "half dead" battery won't produce enough power to keep the
inverter AND battery charger up (ona 12v. system) 14v DC [+/-], at
least for any real length of time to charge the other "half dead"
battery. especially fully charged.


Hmmm...these days, there are boost regulators (step up) and buck
regulators (step down) and even buck/boost regulators, that can
produce a set voltage from a source that goes from higher to lower
than the target voltage.
And this leads to high efficiencies too.
I imagine an inverter system could have similar qualities.

Brian Whatcott Altus OK

Brian Whatcott wrote:
On Wed, 21 Nov 2007 13:48:30 -0800 (PST), Tim
wrote:


Steve wrote:
dh@. wrote in message ...
Someone told me it's possible to charge an inverter
system's batteries using a battery charger plugged
into the inverter that's being run by the batteries
you want to charge. Is there any truth to that, and
if so, how does it work?
If you have 2 half dead batteries it is possible to use them to juice up one
battery completely and leave the other dead.
I dont' even see how you could do that. with jumper cables? no.

with a power inverter and battery charger? no, (not really)

your "half dead" battery won't produce enough power to keep the
inverter AND battery charger up (ona 12v. system) 14v DC [+/-], at
least for any real length of time to charge the other "half dead"
battery. especially fully charged.


Hmmm...these days, there are boost regulators (step up) and buck
regulators (step down) and even buck/boost regulators, that can
produce a set voltage from a source that goes from higher to lower
than the target voltage.
And this leads to high efficiencies too.
I imagine an inverter system could have similar qualities.

Brian Whatcott Altus OK
Brian, I was stationed at Altus AFB back in the 50s and 60s. Helped Hoyt
Shaded mayor build a mobile home park out close to the base. Spent about
eight years there.

--
BILL P.
&
DOG

"Brian Whatcott" wrote in message
...


Hmmm...these days, there are boost regulators (step up) and buck
regulators (step down) and even buck/boost regulators, that can
produce a set voltage from a source that goes from higher to lower
than the target voltage.
And this leads to high efficiencies too.
I imagine an inverter system could have similar qualities.

Brian Whatcott Altus OK

I've never heard of a buck, boost, or buck/boost regulator. There are
bucking, boosting and buck/boost transformers, but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss of
available current, plus transformer loss.

Eisboch

dh@. wrote in message ...
Someone told me it's possible to charge an inverter
system's batteries using a battery charger plugged
into the inverter that's being run by the batteries
you want to charge. Is there any truth to that, and
if so, how does it work?

Yes you will find the plans for that in your local public library in the
perpetual motion machine section.

"Eisboch" wrote in message
...

I've never heard of a buck, boost, or buck/boost regulator.

Now you have:

http://www.national.com/pf/LM/LM2698.html




There are
bucking, boosting and buck/boost transformers,

No transformer in the above link.

but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss of
available current, plus transformer loss.

Only applies to transformers. Power (voltage and current over a given time
period) is conserved.



Eisboch

"Steve" wrote in message
...

"Eisboch" wrote in message
...

I've never heard of a buck, boost, or buck/boost regulator.

Now you have:

http://www.national.com/pf/LM/LM2698.html




There are
bucking, boosting and buck/boost transformers,

No transformer in the above link.

but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss of
available current, plus transformer loss.

Only applies to transformers. Power (voltage and current over a given time
period) is conserved.



Eisboch



Interesting. If the power source is a 12 volt DC battery, what does this
regulator boost and how does it do it?

Eisboch

On Thu, 22 Nov 2007 20:50:03 -0600, williamboyd
wrote:


Brian, I was stationed at Altus AFB back in the 50s and 60s. Helped Hoyt
Shaded mayor build a mobile home park out close to the base. Spent about
eight years there.

There is a little park on one side of the city lake (formerly a city
water reservoir) named for Hoyt. Unusual name. Kids can pull 12 inch
fish out of that lake, if they can get past the geese and ducks -
though the recent bird flu issue has led the city to start scaring off
the birds there. There are surprizingly few military folks on base -
mostly aircrew students, served by a largely civilian staff.

Brian Whatcott Altus OK

"Eisboch" wrote in message
...

"Steve" wrote in message
...


I've never heard of a buck, boost, or buck/boost regulator.

Now you have:

http://www.national.com/pf/LM/LM2698.html




There are
bucking, boosting and buck/boost transformers,

No transformer in the above link.

but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss of
available current, plus transformer loss.

Only applies to transformers. Power (voltage and current over a given
time period) is conserved.



Eisboch



Interesting. If the power source is a 12 volt DC battery, what does this
regulator boost and how does it do it?

Eisboch


My apologies. I didn't notice the link you provided.
It appears to be an inverter circuit and indeed can provide a DC boost.
However, it's not a perpetual power system and will still use more power
from a battery that it is trying to charge.

Eisboch

On Fri, 23 Nov 2007 00:15:42 -0500, "Eisboch" wrote:


"Brian Whatcott" wrote in message
.. .


Hmmm...these days, there are boost regulators (step up) and buck
regulators (step down) and even buck/boost regulators, that can
produce a set voltage from a source that goes from higher to lower
than the target voltage.
And this leads to high efficiencies too.
I imagine an inverter system could have similar qualities.

Brian Whatcott Altus OK

I've never heard of a buck, boost, or buck/boost regulator. There are
bucking, boosting and buck/boost transformers, but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss of
available current, plus transformer loss.

Eisboch


Yep, there are many many topics that *I've* never heard of either!
As usual, Google is your friend - with keywords: buck/boost
regulator.
Here's an old article that gives the flavor....
http://www.edn.com/article/CA318719.html

And, it goes without saying, you don't get more power out than the
power you put in, but you don't throw away power as heat so much
as older methods, so the volt times amp product of the output can be
85% or 90% of the volt amps input over a fair voltage input range.

Brian Whatcott Altus OK

Brian Whatcott Altus OK

"Eisboch" wrote in message
...

"Eisboch" wrote in message
...

"Steve" wrote in message
...


I've never heard of a buck, boost, or buck/boost regulator.

Now you have:

http://www.national.com/pf/LM/LM2698.html




There are
bucking, boosting and buck/boost transformers,

No transformer in the above link.

but if the voltage is
boosted, it is at the expense of a corresponding same percentage loss
of available current, plus transformer loss.

Only applies to transformers. Power (voltage and current over a given
time period) is conserved.



Eisboch



Interesting. If the power source is a 12 volt DC battery, what does this
regulator boost and how does it do it?

Eisboch


My apologies. I didn't notice the link you provided.
It appears to be an inverter circuit and indeed can provide a DC boost.
However, it's not a perpetual power system and will still use more power
from a battery that it is trying to charge.

Eisboch


DC-DC converter. I see there are references to Buck Regulators on the
I-net. But Buck just means reducing voltage.