R
Robert Baer
Guest
John Larkin wrote:
Crap capacitor.
That curve shows milliamps, not microamps.
Crap capacitor.
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A
amdx
Guest
On 5/26/2017 2:57 AM, Robert Baer wrote:
John Larkin wrote:
On Thu, 25 May 2017 07:10:30 +0200, Helmut Wabnig<hwabnig@.- ---
-.dotat> wrote:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
w.
Nothing happens quickly on a 10F capacitor.
At the rated 2.7 volts, leakage is spec'd at 30 uA max. That's a
discharge rate of 3 microvolts per second.
The leakage is specified after 72 hours at voltage. I didn't wait that
long.
That curve shows milliamps, not microamps.
Crap capacitor.
To be fair it is 130ua at it's maximum rated voltage.
J
John Larkin
Guest
On Fri, 26 May 2017 07:55:27 -0500, amdx <nojunk@knology.net> wrote:
I kept increasing the voltage until I got a lot of leakage.
>> Crap capacitor.
I think it's a very good capacitor.
And declines with a time constant of days.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
On 5/26/2017 2:57 AM, Robert Baer wrote:
John Larkin wrote:
On Thu, 25 May 2017 07:10:30 +0200, Helmut Wabnig<hwabnig@.- ---
-.dotat> wrote:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
w.
Nothing happens quickly on a 10F capacitor.
At the rated 2.7 volts, leakage is spec'd at 30 uA max. That's a
discharge rate of 3 microvolts per second.
The leakage is specified after 72 hours at voltage. I didn't wait that
long.
That curve shows milliamps, not microamps.
I kept increasing the voltage until I got a lot of leakage.
>> Crap capacitor.
I think it's a very good capacitor.
To be fair it is 130ua at it's maximum rated voltage.
And declines with a time constant of days.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
D
default
Guest
On Thu, 25 May 2017 11:03:49 -0400, rickman <gnuarm@gmail.com> wrote:
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
default wrote on 5/25/2017 7:01 AM:
On Thu, 25 May 2017 01:30:22 -0400, rickman <gnuarm@gmail.com> wrote:
Helmut Wabnig wrote on 5/25/2017 1:10 AM:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
That isn't what the diagram shows.
Wow! That's enough leakage to make them useless for micropower energy
harvesting. Good to know.
They are excellent for micro power applications, they do not
self-discharge rapidly
Way more effective in some dawn to dusk solar powered lights where I
replaced the nicad or nmh batteries - especially when you take into
consideration that the batteries are often discharged well past their
safe levels in normal use.
That's not micropower. The issue is not if they self-discharge rapidly.
The issue is if they can be charged up at all given the low power
source they are being charged from. JL's diagram shows higher leakage
current than the application I would be using these in.
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
D
default
Guest
On Thu, 25 May 2017 08:23:31 -0700, John Larkin
<jjlarkin@highlandtechnology.com> wrote:
I'm a believer. Did you test any to destruction?
<jjlarkin@highlandtechnology.com> wrote:
In these caps, current increases nonlinearly, radically upward, with
voltage, so a series pair will tend to equalize. In fact, a series
pair that I tried did equalize nicely. And overvoltage makes them leak
a lot but doesn't appear to damage them.
I'm a believer. Did you test any to destruction?
J
John Larkin
Guest
On Sat, 27 May 2017 06:04:01 -0400, default <default@defaulter.net>
wrote:
That's exactly what I wanted to explore. The data sheets don't have a
v-i curve. That matters if you want to stack them in series.
Rick is not good with numbers. Or thinking before he types.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
wrote:
On Thu, 25 May 2017 11:03:49 -0400, rickman <gnuarm@gmail.com> wrote:
default wrote on 5/25/2017 7:01 AM:
On Thu, 25 May 2017 01:30:22 -0400, rickman <gnuarm@gmail.com> wrote:
Helmut Wabnig wrote on 5/25/2017 1:10 AM:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
That isn't what the diagram shows.
Wow! That's enough leakage to make them useless for micropower energy
harvesting. Good to know.
They are excellent for micro power applications, they do not
self-discharge rapidly
Way more effective in some dawn to dusk solar powered lights where I
replaced the nicad or nmh batteries - especially when you take into
consideration that the batteries are often discharged well past their
safe levels in normal use.
That's not micropower. The issue is not if they self-discharge rapidly.
The issue is if they can be charged up at all given the low power
source they are being charged from. JL's diagram shows higher leakage
current than the application I would be using these in.
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
That's exactly what I wanted to explore. The data sheets don't have a
v-i curve. That matters if you want to stack them in series.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
Rick is not good with numbers. Or thinking before he types.
--
John Larkin Highland Technology, Inc
lunatic fringe electronics
R
rickman
Guest
default wrote on 5/27/2017 6:04 AM:
The leakage at 2.5 volts is over 100 uA. That's still more than the
load I would be providing power to. It's also over three times the spec
sheet value with a 72 hour soak. Real world performance can require use
well before 72 hours of "soak".
--
Rick C
On Thu, 25 May 2017 11:03:49 -0400, rickman <gnuarm@gmail.com> wrote:
default wrote on 5/25/2017 7:01 AM:
On Thu, 25 May 2017 01:30:22 -0400, rickman <gnuarm@gmail.com> wrote:
Helmut Wabnig wrote on 5/25/2017 1:10 AM:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
That isn't what the diagram shows.
Wow! That's enough leakage to make them useless for micropower energy
harvesting. Good to know.
They are excellent for micro power applications, they do not
self-discharge rapidly
Way more effective in some dawn to dusk solar powered lights where I
replaced the nicad or nmh batteries - especially when you take into
consideration that the batteries are often discharged well past their
safe levels in normal use.
That's not micropower. The issue is not if they self-discharge rapidly.
The issue is if they can be charged up at all given the low power
source they are being charged from. JL's diagram shows higher leakage
current than the application I would be using these in.
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
The leakage at 2.5 volts is over 100 uA. That's still more than the
load I would be providing power to. It's also over three times the spec
sheet value with a 72 hour soak. Real world performance can require use
well before 72 hours of "soak".
--
Rick C
D
default
Guest
On Sat, 27 May 2017 11:46:52 -0400, rickman <gnuarm@gmail.com> wrote:
Which is the reason we breadboard, build engineering prototypes, and
such. Design based on the datasheets, but only accept what you can
produce empirically. AND when it comes to the book and the real
world, trust what reality shows.
Which... makes me an atheist.
default wrote on 5/27/2017 6:04 AM:
On Thu, 25 May 2017 11:03:49 -0400, rickman <gnuarm@gmail.com> wrote:
default wrote on 5/25/2017 7:01 AM:
On Thu, 25 May 2017 01:30:22 -0400, rickman <gnuarm@gmail.com> wrote:
Helmut Wabnig wrote on 5/25/2017 1:10 AM:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
That isn't what the diagram shows.
Wow! That's enough leakage to make them useless for micropower energy
harvesting. Good to know.
They are excellent for micro power applications, they do not
self-discharge rapidly
Way more effective in some dawn to dusk solar powered lights where I
replaced the nicad or nmh batteries - especially when you take into
consideration that the batteries are often discharged well past their
safe levels in normal use.
That's not micropower. The issue is not if they self-discharge rapidly.
The issue is if they can be charged up at all given the low power
source they are being charged from. JL's diagram shows higher leakage
current than the application I would be using these in.
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
The leakage at 2.5 volts is over 100 uA. That's still more than the
load I would be providing power to. It's also over three times the spec
sheet value with a 72 hour soak. Real world performance can require use
well before 72 hours of "soak".
Which is the reason we breadboard, build engineering prototypes, and
such. Design based on the datasheets, but only accept what you can
produce empirically. AND when it comes to the book and the real
world, trust what reality shows.
Which... makes me an atheist.
J
John Larkin
Guest
On Sat, 27 May 2017 15:28:40 -0400, default <default@defaulter.net>
wrote:
Rick doesn't understand dielectric absorption. If you charge one of
these caps, leakage initially appears high, but the leakage current
will drop over time, such that the cap only self-discharges a bit.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com
wrote:
On Sat, 27 May 2017 11:46:52 -0400, rickman <gnuarm@gmail.com> wrote:
default wrote on 5/27/2017 6:04 AM:
On Thu, 25 May 2017 11:03:49 -0400, rickman <gnuarm@gmail.com> wrote:
default wrote on 5/25/2017 7:01 AM:
On Thu, 25 May 2017 01:30:22 -0400, rickman <gnuarm@gmail.com> wrote:
Helmut Wabnig wrote on 5/25/2017 1:10 AM:
On Wed, 24 May 2017 14:34:23 -0700, John Larkin
jjlarkin@highland_snip_technology.com> wrote:
https://dl.dropboxusercontent.com/u/53724080/Parts/Caps/Supercap_Leakage.JPG
Looks like it would be fine to stack these in series without any
equalizing parts, like regular wet aluminum caps.
Measuring supercaps is an enormous pain; every step takes hours. The
equivalent dielectric absorption is huge.
Leakage tempco appears to be strongly negative, but that may be an
illusion.
They self-discharge quickly, as shown in the diagram?
That isn't what the diagram shows.
Wow! That's enough leakage to make them useless for micropower energy
harvesting. Good to know.
They are excellent for micro power applications, they do not
self-discharge rapidly
Way more effective in some dawn to dusk solar powered lights where I
replaced the nicad or nmh batteries - especially when you take into
consideration that the batteries are often discharged well past their
safe levels in normal use.
That's not micropower. The issue is not if they self-discharge rapidly.
The issue is if they can be charged up at all given the low power
source they are being charged from. JL's diagram shows higher leakage
current than the application I would be using these in.
Look at it again, these are 2.7 volt caps and he's applying over three
volts to them, where the leakage starts to increase exponentially.
Treat them with respect, don't overcharge, equalize the charge, and be
mindful of the ambient temperature and they are just like any low
leakage, low ESR, capacitor...
I have one, now doing duty as UPS for my modem, that I used to
cold-start my truck 3 months after I charged it.
I do consider a solar cell 1-1/4" square a very low power source. The
latest crop of super cheap solar walkway lights are like that. None
of them can make it from dusk to dawn with the supplied nicad battery
yet they all work with a 50 farad 2.7 V cap even when overcast in
winter.
The leakage at 2.5 volts is over 100 uA. That's still more than the
load I would be providing power to. It's also over three times the spec
sheet value with a 72 hour soak. Real world performance can require use
well before 72 hours of "soak".
Which is the reason we breadboard, build engineering prototypes, and
such. Design based on the datasheets, but only accept what you can
produce empirically. AND when it comes to the book and the real
world, trust what reality shows.
Which... makes me an atheist.
Rick doesn't understand dielectric absorption. If you charge one of
these caps, leakage initially appears high, but the leakage current
will drop over time, such that the cap only self-discharges a bit.
--
John Larkin Highland Technology, Inc
picosecond timing precision measurement
jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com