yep and so is your charger (shouldn't be giving 40v to charge a 12v battery)
Well, you probably need a better charger.
One of more of the series connected 2-V cell(s) have developed a high
Hello Mr Chung,
On Sun, 16 May 2004 20:49:49 GMT, eric@chunglim.freeserve.co.uk (L
Chung) wrote:
On Sat, 15 May 2004 16:19:54 +1200, "Darren" <no@email.com> wrote:
I have pulled an old 7ah 12v sealed led acid battery out of a UPS
When I put it on the charger the volts jump up to 40v, why is this? is
the
battery stuffed?
One of more of the series connected 2-V cell(s) have developed a high
impedance. No charging can return the battery to normal.
Before you bin it, see what I have done to such a battery to get some
of its life back.
A
href="http://www.chunglim.freeserve.co.uk/c/sealedbat.htm">http://www.chung
lim.freeserve.co.uk/c/sealedbat.htm</a
L.Chung
Hello Mr Chung,
you are a man after my own heart
Darrren,
on some of my old sealed batteries, sonnenshien brand,
like the ones shown in Mr Chung's web page, you can
see the outline of the connecting link between the cells.
It is very easy to drill and separate the link between the
cells. Turning a 12V battery into a larger capacity 6 V
battery was easy. I have successfully hack sawed away
one complete side where there were two dud cells to make
a slim 6volt battery.
Darren,
about charging. Bypass the dud cells first as Mr Chung
described. Drilling and soldering is easy.
Try your charger with some series resistors to limit the
current.
I like the constant current method. Fixed current for 12 to
14 hours or whenever I remember days later.
Here is a simple circuit for a constant current charger.
http://wlan.sdvanime.com/wireless-leeuwarden/img/zelfbouw/LM317_datasheet.pdf
Look at figure 7 on page 5.
Resistor R1 sets the maximum current.
For 1 amp, find a resistor around 1.2 ohms 2W or slightly more
in your junk box. Parrallel up whatever you have in your junk.
If you want to make your charger even nicer, you can add
a normal voltage regulator after the constant current regulator.
Build up Figure 5 on page 5.
That way your charger would be set and forget ( almost.)
Constant current of around say 1 amp when the battery
is dead flat and then the current drops to a trickle later on. So
you can float charge at whatever voltage is recommended.
You will need two LM317s one for the constant current section
and one for the constant voltage section. You could probably
use your existing charger as the supply to the two additional
current and voltage regulators.
Have Fun,
John Crighton
Hornsby
The Super Nova is a constant-current charger, so in an attempt to get the
fThanks Chung I will take a look at your site.
Darren
"John Crighton" <john_c@tpg.com.au> wrote in message
news:40a8040b.3783606@News.individual.net...
On Sun, 16 May 2004 20:49:49 GMT, eric@chunglim.freeserve.co.uk (L
Chung) wrote:
On Sat, 15 May 2004 16:19:54 +1200, "Darren" <no@email.com> wrote:
I have pulled an old 7ah 12v sealed led acid battery out of a UPS
When I put it on the charger the volts jump up to 40v, why is this? is
the
battery stuffed?
One of more of the series connected 2-V cell(s) have developed a high
impedance. No charging can return the battery to normal.
Before you bin it, see what I have done to such a battery to get some
of its life back.
A
href="http://www.chunglim.freeserve.co.uk/c/sealedbat.htm">http://www.chung
lim.freeserve.co.uk/c/sealedbat.htm</a
L.Chung
Hello Mr Chung,
you are a man after my own heart
Darrren,
on some of my old sealed batteries, sonnenshien brand,
like the ones shown in Mr Chung's web page, you can
see the outline of the connecting link between the cells.
It is very easy to drill and separate the link between the
cells. Turning a 12V battery into a larger capacity 6 V
battery was easy. I have successfully hack sawed away
one complete side where there were two dud cells to make
a slim 6volt battery.
Darren,
about charging. Bypass the dud cells first as Mr Chung
described. Drilling and soldering is easy.
Try your charger with some series resistors to limit the
current.
I like the constant current method. Fixed current for 12 to
14 hours or whenever I remember days later.
Here is a simple circuit for a constant current charger.
http://wlan.sdvanime.com/wireless-leeuwarden/img/zelfbouw/LM317_datasheet.pd
You can set the nova to charge at any current.
Thanks Chung I will take a look at your site.
Darren
"John Crighton" <john_c@tpg.com.au> wrote in message
news:40a8040b.3783606@News.individual.net...
On Sun, 16 May 2004 20:49:49 GMT, eric@chunglim.freeserve.co.uk (L
Chung) wrote:
On Sat, 15 May 2004 16:19:54 +1200, "Darren" <no@email.com> wrote:
I have pulled an old 7ah 12v sealed led acid battery out of a UPS
When I put it on the charger the volts jump up to 40v, why is this?
is
the
battery stuffed?
One of more of the series connected 2-V cell(s) have developed a high
impedance. No charging can return the battery to normal.
Before you bin it, see what I have done to such a battery to get some
of its life back.
A
href="http://www.chunglim.freeserve.co.uk/c/sealedbat.htm">http://www.chung
lim.freeserve.co.uk/c/sealedbat.htm</a
L.Chung
Hello Mr Chung,
you are a man after my own heart
Darrren,
on some of my old sealed batteries, sonnenshien brand,
like the ones shown in Mr Chung's web page, you can
see the outline of the connecting link between the cells.
It is very easy to drill and separate the link between the
cells. Turning a 12V battery into a larger capacity 6 V
battery was easy. I have successfully hack sawed away
one complete side where there were two dud cells to make
a slim 6volt battery.
Darren,
about charging. Bypass the dud cells first as Mr Chung
described. Drilling and soldering is easy.
Try your charger with some series resistors to limit the
current.
I like the constant current method. Fixed current for 12 to
14 hours or whenever I remember days later.
Here is a simple circuit for a constant current charger.
http://wlan.sdvanime.com/wireless-leeuwarden/img/zelfbouw/LM317_datasheet.pd
f
Look at figure 7 on page 5.
Resistor R1 sets the maximum current.
For 1 amp, find a resistor around 1.2 ohms 2W or slightly more
in your junk box. Parrallel up whatever you have in your junk.
If you want to make your charger even nicer, you can add
a normal voltage regulator after the constant current regulator.
Build up Figure 5 on page 5.
That way your charger would be set and forget ( almost.)
Constant current of around say 1 amp when the battery
is dead flat and then the current drops to a trickle later on. So
you can float charge at whatever voltage is recommended.
You will need two LM317s one for the constant current section
and one for the constant voltage section. You could probably
use your existing charger as the supply to the two additional
current and voltage regulators.
Have Fun,
John Crighton
Hornsby
Sure, that's kind of what I meant - you specify a fixed charging current,
Which means, as others have said, that the battery, or at least one of the