hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a week
or so , would be good....

any body have any or know of any links ?

mark krawczuk wrote:
hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a week
or so , would be good....

any body have any or know of any links ?




Trickle charge is very bad for a lead battery.

If you can get a computer equipped charger(~40-60 euro),
those do a much better job, they switch on automatically
at the right discharge level, and also stop in time.
That way the batteries live longest.

On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:

hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a week
or so , would be good....

any body have any or know of any links ?



http://electronicdesign.com/article/...gle-trans.aspx

http://archive.electronicdesign.com/.../figure_01.gif
--

One possible problem I see with this simple circuit is that it has no inbuilt
hysteresis or maximum voltage charge time. A battery will charge to its preset
maximum voltage and because there is no time limit placed on the charge current
at the maximum voltage, the relay will operate and stop the charge before it has
time for the battery charge capacity to be maximised. This will lead to
"hunting" where the relay will operate and release rapidly, ad-infinitum, as the
battery voltage fluctuates above and below the preset maximum.

On Mon, 14 Jun 2010 09:00:02 -0400, default wrote:

:On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:
:
:hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
:acid ) batteries.... basically dont need to charge them flat out , cause
:they dont get used much, something i can leave on trickle charge for a week
:or so , would be good....
:
:any body have any or know of any links ?
:
:
:
:http://electronicdesign.com/article/...gle-trans.aspx
:
:http://archive.electronicdesign.com/.../figure_01.gif

Ross Herbert wrote:
One possible problem I see with this simple circuit is that it has no inbuilt
hysteresis or maximum voltage charge time. A battery will charge to its preset
maximum voltage and because there is no time limit placed on the charge current
at the maximum voltage, the relay will operate and stop the charge before it has
time for the battery charge capacity to be maximised. This will lead to
"hunting" where the relay will operate and release rapidly, ad-infinitum, as the
battery voltage fluctuates above and below the preset maximum.


The difference between the relay pull in and drop out current
provides the hysteresis. Typical general purpose relays will
pull it at roughly 90% of nominal rated current, and drop out
at roughly 10% of nominal rated current.

Ed

On Thu, 17 Jun 2010 02:09:18 GMT, Ross Herbert
wrote:

One possible problem I see with this simple circuit is that it has no inbuilt
hysteresis or maximum voltage charge time. A battery will charge to its preset
maximum voltage and because there is no time limit placed on the charge current
at the maximum voltage, the relay will operate and stop the charge before it has
time for the battery charge capacity to be maximised. This will lead to
"hunting" where the relay will operate and release rapidly, ad-infinitum, as the
battery voltage fluctuates above and below the preset maximum.

On Mon, 14 Jun 2010 09:00:02 -0400, default wrote:

:On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:
:
:hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
:acid ) batteries.... basically dont need to charge them flat out , cause
:they dont get used much, something i can leave on trickle charge for a week
:or so , would be good....
:
:any body have any or know of any links ?
:
:
:
:http://electronicdesign.com/article/...gle-trans.aspx
:
:http://archive.electronicdesign.com/.../figure_01.gif

I think electronic design probably vetted the schematic before they
published.

Did you read the write-up? My only criticism might be setting turn on
point at 11.8 the way they suggest, that seems a bit low. AND it
needs an LED in there somewhere for a little glitz, or better still, a
bicolor LED.

A slight trickle could be provided around the relay contacts with a
resistor - it would also null the slight load the divider string
imposes on the battery.


Looks to me like the battery is charging while the relay is
de-energized, when the battery voltage is high enough to bias the
transistor "on," the relay energizes, at the same time the movable
contact switches VR1 out of the circuit (shorting around it) raising
the voltage on the base a little more, insuring it turns on harder,
and longer. (the hysteresis)
--

In article ,
default wrote:

On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:

hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a week
or so , would be good....

any body have any or know of any links ?



http://electronicdesign.com/article/...charger-using-
a-single-trans.aspx

http://archive.electronicdesign.com/.../figure_01.gif
--

Awesome circuit.

High battery drain: Check
Replace SRC with expensive relay: Check
Wildly unstable voltage sensing: Check
Capacitor to weld relay shut: Check
Wrong unit symbols: Check

OK, publish!
--
I won't see Google Groups replies because I must filter them as spam

On Thu, 17 Jun 2010 00:19:34 -0700, Kevin McMurtrie
wrote:

In article ,
default wrote:

On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:

hi, after some schematics to charge 6 volt and 12 volt sla ( sealed lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a week
or so , would be good....

any body have any or know of any links ?



http://electronicdesign.com/article/...charger-using-
a-single-trans.aspx

http://archive.electronicdesign.com/.../figure_01.gif
--

Awesome circuit.

High battery drain: Check
Replace SRC with expensive relay: Check
Wildly unstable voltage sensing: Check
Capacitor to weld relay shut: Check
Wrong unit symbols: Check

OK, publish!

Why do you suppose it is easier to find fault with other people's
efforts than one's own? Lack of the adoration one feels entitled to?
Some childhood psychological need that wasn't met? Easy to bolster
one's ego by denigrating others? In an overpopulated world
competition supplants cooperation as a survival strategy?

Perhaps you could just address the problems you see in this simple
circuit and show how you would do it differently? Without, of course,
letting the complexity, cost or need for custom parts destroy the easy
to build with parts on hand aspects of it.

It has drawbacks if perfection is the goal, but all engineering is
compromise.

The cap discharge is easily remedied with a steering diode. Unstable
voltage sensing - more like it may need some temperature compensation
if repeatability is a goal - that's assuming that the design doesn't
happen to coincide with the battery's optimal charge/temperature
tracking. The biggest flaw is the lack of some current limiting in my
opinion. This circuit would self destruct if it tried to charge a
shorted battery.

Do you have anything positive to add?
--

In article ,
default wrote:

On Thu, 17 Jun 2010 00:19:34 -0700, Kevin McMurtrie
wrote:

In article ,
default wrote:

On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:

hi, after some schematics to charge 6 volt and 12 volt sla ( sealed
lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a
week
or so , would be good....

any body have any or know of any links ?



http://electronicdesign.com/article/...ry-charger-usi
ng-
a-single-trans.aspx

http://archive.electronicdesign.com/.../figure_01.gif
--

Awesome circuit.

High battery drain: Check
Replace SRC with expensive relay: Check
Wildly unstable voltage sensing: Check
Capacitor to weld relay shut: Check
Wrong unit symbols: Check

OK, publish!

Why do you suppose it is easier to find fault with other people's
efforts than one's own? Lack of the adoration one feels entitled to?
Some childhood psychological need that wasn't met? Easy to bolster
one's ego by denigrating others? In an overpopulated world
competition supplants cooperation as a survival strategy?

Perhaps you could just address the problems you see in this simple
circuit and show how you would do it differently? Without, of course,
letting the complexity, cost or need for custom parts destroy the easy
to build with parts on hand aspects of it.

It has drawbacks if perfection is the goal, but all engineering is
compromise.

The cap discharge is easily remedied with a steering diode. Unstable
voltage sensing - more like it may need some temperature compensation
if repeatability is a goal - that's assuming that the design doesn't
happen to coincide with the battery's optimal charge/temperature
tracking. The biggest flaw is the lack of some current limiting in my
opinion. This circuit would self destruct if it tried to charge a
shorted battery.

Do you have anything positive to add?
--

Ooops. Meant to say "SCR" but it was late.

I think it's OK to criticize a circuit that's worse than what Google
search results provide.
--
I won't see Google Groups replies because I must filter them as spam

On Thu, 17 Jun 2010 08:50:48 -0700, Kevin McMurtrie
wrote:

In article ,
default wrote:

On Thu, 17 Jun 2010 00:19:34 -0700, Kevin McMurtrie
wrote:

In article ,
default wrote:

On Wed, 9 Jun 2010 13:13:46 +0930, "mark krawczuk"
wrote:

hi, after some schematics to charge 6 volt and 12 volt sla ( sealed
lead
acid ) batteries.... basically dont need to charge them flat out , cause
they dont get used much, something i can leave on trickle charge for a
week
or so , would be good....

any body have any or know of any links ?



http://electronicdesign.com/article/...ry-charger-usi
ng-
a-single-trans.aspx

http://archive.electronicdesign.com/.../figure_01.gif
--

Awesome circuit.

High battery drain: Check
Replace SRC with expensive relay: Check
Wildly unstable voltage sensing: Check
Capacitor to weld relay shut: Check
Wrong unit symbols: Check

OK, publish!

Why do you suppose it is easier to find fault with other people's
efforts than one's own? Lack of the adoration one feels entitled to?
Some childhood psychological need that wasn't met? Easy to bolster
one's ego by denigrating others? In an overpopulated world
competition supplants cooperation as a survival strategy?

Perhaps you could just address the problems you see in this simple
circuit and show how you would do it differently? Without, of course,
letting the complexity, cost or need for custom parts destroy the easy
to build with parts on hand aspects of it.

It has drawbacks if perfection is the goal, but all engineering is
compromise.

The cap discharge is easily remedied with a steering diode. Unstable
voltage sensing - more like it may need some temperature compensation
if repeatability is a goal - that's assuming that the design doesn't
happen to coincide with the battery's optimal charge/temperature
tracking. The biggest flaw is the lack of some current limiting in my
opinion. This circuit would self destruct if it tried to charge a
shorted battery.

Do you have anything positive to add?
--

Ooops. Meant to say "SCR" but it was late.

It's cool. I have one of the Heathkit lead acid chargers from years
ago. It died twice before I figured out lightening was killing it.
Ground the (floating) negative to the chassis seems to have fixed it
(10 years ago)

I think it's OK to criticize a circuit that's worse than what Google
search results provide.

Thing is, no one does any research for the beginning op. Sure he
should Google it first (and from the number of hits shouldn't ever
post a question) - in an ideal world.

The "basic group" should (to my way of thinking) answer and aid
beginners.

God knows a time or two my questions have been answered by no less
Walt Jung, Don Lancaster, and Bob Pease. Icons . . .

There has to be a free exchange of ideas (screw politics and ego). No
one has the insight you do - and you don't have the insight of others.

Carried to a logical conclusion . . .

The skid row bum, sitting in feces and vomit, will have a different
perspective than you or I. That doesn't mean we can't learn

Doesn't mean he isn't knowledgeable about his own world - he has more
knowledge than you or I, in that respect.

Learning is the active, teaching is the passive.

Critique the circuit, god knows it has flaws, but post the analysis
and corrections you would recommend, and why.

And here I sit - presuming to take on the mantle of wise peaceful
coexistence - when honest people liken my diplomatic skill to Attila
the Hun on steroids.

"Don't care who or how you **** someone off," That's their problem.
Worry about yourself.



--