J
JosephKK
Guest
On Thu, 20 Mar 2008 15:29:57 -0500, John Fields
<jfields@austininstruments.com> wrote:
<jfields@austininstruments.com> wrote:
R
Robert Baer
Guest
Michael A. Terrell wrote:
Been this way from at least 2001.
not know what you are talking about; not even the stupidvisers.
Been this way from at least 2001.
A
Allodoxaphobia
Guest
On Thu, 03 Apr 2008 09:10:10 GMT, Arfa Daily wrote:
Jonesy
And, where do these pin-heads think the lead came from, in the first place?
Jonesy
C
CWatters
Guest
Na, can't be that. Otherwise well just try searching for "dumb terminal
engineer" see who's number 3 on the list
http://www.google.com/search?hl=en&q=terminal+dumb+engineer
Only joking!
B
Bennett Price
Guest
You might find the publications here of help:
http://www.bodine-electric.com/Asp/Literature.asp
Basics of Fractional Horsepower Motors and Repair
by Gerald Schweitzer (I believe this is out of print but available
through Amazon, isbn.nu, etc.
Ditto Smeaton Motor Application and Maintenance Handbook.
Lots of books at http://books.mcgraw-hill.com/index.php Search
under engineering.
I'm not sure you can find one book that will cover clock motors,
100 hp polyphase motors, and servo disk drive motors.
lucasjensen@gmail.com wrote:
http://www.bodine-electric.com/Asp/Literature.asp
Basics of Fractional Horsepower Motors and Repair
by Gerald Schweitzer (I believe this is out of print but available
through Amazon, isbn.nu, etc.
Ditto Smeaton Motor Application and Maintenance Handbook.
Lots of books at http://books.mcgraw-hill.com/index.php Search
under engineering.
I'm not sure you can find one book that will cover clock motors,
100 hp polyphase motors, and servo disk drive motors.
lucasjensen@gmail.com wrote:
N
No Spam
Guest
SQLit wrote:
<snip>
<snip>
Huh??
K
Kryten
Guest
Charging Li-Ion cells is non-trivial - they can overcharge and die
catastrophically.
Possible - yes, simple - no.
You'd need a gadget to get a decent steady supply from the dynamo/windmill,
and then you need a charger smart enough to manage Li-Ion cells.
Guest
Hi Dave,
I've been searching the internet for suitable AA battery cameras, but
they are all too bulky. I understand that you want to stabilize the
voltage my means of a battery pack in between. But this is not a
working solution, because the entire system has to be really
lightweight. I know of some chips called something like 7805. They are
designed to give a constant output voltage as long as the input voltage
stays above a certain value. The 7805 would give a 5 V output. Frankly,
I hate the bike generator solution the most because it gives more
friction which I personally hate. I would rather stay with the mini
wind mill or the solar cell. As for the solar cells, they readily
produce DC current at a defined voltage. As I remember a solar cell
will always produce the same voltage if exposed to the same light
soruce (for instance the sun) and only the intensity will determine the
current. This means that you should have a fairly stable voltage but
alternating current (due to clouds etc).
Lucas
I've been searching the internet for suitable AA battery cameras, but
they are all too bulky. I understand that you want to stabilize the
voltage my means of a battery pack in between. But this is not a
working solution, because the entire system has to be really
lightweight. I know of some chips called something like 7805. They are
designed to give a constant output voltage as long as the input voltage
stays above a certain value. The 7805 would give a 5 V output. Frankly,
I hate the bike generator solution the most because it gives more
friction which I personally hate. I would rather stay with the mini
wind mill or the solar cell. As for the solar cells, they readily
produce DC current at a defined voltage. As I remember a solar cell
will always produce the same voltage if exposed to the same light
soruce (for instance the sun) and only the intensity will determine the
current. This means that you should have a fairly stable voltage but
alternating current (due to clouds etc).
Lucas
J
James Sweet
Guest
lucasjensen@gmail.com wrote:
Sure it can be done, have a look at www.maximic.com, they make a whole
range of Li-Ion charger IC's, and you can even get free samples to play
with. As for the generator, you could regulate the output with a small
high efficiency switchmode regulator, National Semiconductor makes a
line of those which are very easy to work with, and again samples are
available.
Sure it can be done, have a look at www.maximic.com, they make a whole
range of Li-Ion charger IC's, and you can even get free samples to play
with. As for the generator, you could regulate the output with a small
high efficiency switchmode regulator, National Semiconductor makes a
line of those which are very easy to work with, and again samples are
available.
Guest
Jim Thompson schreef:
Don't worry. Your Li-Ion battery is NOT managed.
Adhere to Funfly3.
Charging your battery is like charging a lead-acid battery: Constant
voltage with current limiting. Correction for temeprature might be
required. That is where the third connection is for. As far as I know
there is no standard for a temperature sensing element in Li-Ion
battery packs, so you have to find out!
Take care, but don't be afraid for explosions etc. Li-Ion battery packs
are internally protected by means of
(1) discharge valve. prevents pressure build-up inside the cell
(2) thermal fuse
(3) semiconductor fuse
So, if you do something wrong, the battery pack will be defective, but
will not explode.
Reason for "managing" Li-Ion battery packs (the ones with 4 or 5
connections) is
a) For "fuel gauging". As the discharge characteristic of a Li-Ion
battery is almost flat, it is almost impossible to determine the
state-of-charge from the battery voltage
b) For faster charging. Using appropriate algorithm can charge
batteries faster
c) Universal battery chargers. The battery charger can obtain battery
pack data from the battery pack.
The "managed"battery packs have a serial interface (normally the Smart
Battery Bus) for communication between battery and camera or charger.
Don't worry. Your Li-Ion battery is NOT managed.
Adhere to Funfly3.
Charging your battery is like charging a lead-acid battery: Constant
voltage with current limiting. Correction for temeprature might be
required. That is where the third connection is for. As far as I know
there is no standard for a temperature sensing element in Li-Ion
battery packs, so you have to find out!
Take care, but don't be afraid for explosions etc. Li-Ion battery packs
are internally protected by means of
(1) discharge valve. prevents pressure build-up inside the cell
(2) thermal fuse
(3) semiconductor fuse
So, if you do something wrong, the battery pack will be defective, but
will not explode.
Reason for "managing" Li-Ion battery packs (the ones with 4 or 5
connections) is
a) For "fuel gauging". As the discharge characteristic of a Li-Ion
battery is almost flat, it is almost impossible to determine the
state-of-charge from the battery voltage
b) For faster charging. Using appropriate algorithm can charge
batteries faster
c) Universal battery chargers. The battery charger can obtain battery
pack data from the battery pack.
The "managed"battery packs have a serial interface (normally the Smart
Battery Bus) for communication between battery and camera or charger.
F
Funfly3
Guest
"mike" <spamme0@netscape.net> wrote in message
news:4361FB43.4040106@netscape.net...
chargers for the model industry and all these just limit the current and
voltage even a school boy could design one, ask on one of the radio control
groups as we are big users of Li-Ion and Li-Po batteries from 3.6 volts to
40+ volts and current ratings from MAh to tens of amp hours I have a $10
charger that will charge 1 to 3 cells at various current
news:4361FB43.4040106@netscape.net...
charged and the current will have dropped to zero, there are plenty of 12v
chargers for the model industry and all these just limit the current and
voltage even a school boy could design one, ask on one of the radio control
groups as we are big users of Li-Ion and Li-Po batteries from 3.6 volts to
40+ volts and current ratings from MAh to tens of amp hours I have a $10
charger that will charge 1 to 3 cells at various current
R
Rich Grise
Guest
On Fri, 28 Oct 2005 02:11:55 -0700, lucasjensen wrote:
maybe even with a telescoping shaft, but then you'd need guy wires
or something...
Have Fun!
Rich
just gear it suitably. I'm also thinking some kind of vertical windmill,
maybe even with a telescoping shaft, but then you'd need guy wires
or something...
Have Fun!
Rich
P
PeteS
Guest
Sandra wrote:
<<Charging your battery is like charging a lead-acid battery: Constant
voltage with current limiting.>>
Bzzt. You missed an important point.
A Li+ battery *can* be constant voltage charged (if you can live with
the loss of life - figure 60% vs. constant current / constant voltage),
but what you forgot is the voltage limiting. Never charge a Li+ to more
than 4.2V per cell unless you want to see interesting light and nasal
effects (I know this to be a fact - I have a charger where the voltage
management failed).
Cheers
PeteS
<<Charging your battery is like charging a lead-acid battery: Constant
voltage with current limiting.>>
Bzzt. You missed an important point.
A Li+ battery *can* be constant voltage charged (if you can live with
the loss of life - figure 60% vs. constant current / constant voltage),
but what you forgot is the voltage limiting. Never charge a Li+ to more
than 4.2V per cell unless you want to see interesting light and nasal
effects (I know this to be a fact - I have a charger where the voltage
management failed).
Cheers
PeteS
F
Funfly3
Guest
"PeteS" <ps@fleetwoodmobile.com> wrote in message
news:1130532448.631162.18160@g44g2000cwa.googlegroups.com...
factor at the end voltage is the limiting factor?
news:1130532448.631162.18160@g44g2000cwa.googlegroups.com...
current limiting ,at the beginning of the charge the current is the limiting
factor at the end voltage is the limiting factor?
C
Chris Jones
Guest
Dave D wrote:
following information might be of use:
It looks like your battery is a single cell.
Some information on charging lithium batteries is here:
http://www.energyplus.com/articles/Panasonic_LiIon_Charging.pdf
Most lithium packs have built-in MOSFETs and protection circuitry to
disconnect the battery from the terminals if any cell is charged over some
very accurate threshold which (according to Panasonic) is 4.30V +/- 0.05V.
The safety circuit will probably also disconnect if you try to discharge
the cell to too low a voltage, i.e. it disconnects at 2.3V +/-0.1V, but you
shouldn't discharge it below 3V. Don't rely on the safety circuit to
control your charging, it is meant as a backup, and I wouldn't be surprised
if once it disconnects, it's time to buy a new battery pack.
If you are charging single cells, then the important things are:
Never exceed 4.2 Volts/cell, regardless of current or anything else. For
some cells this should even be 4.1 Volts, depending on the cell chemistry.
This needs to be an accurate regulator (1% accuracy will do).
Never exceed the current limit specified for the cell (which is usually
about 0.7C, i.e. the current you would have to draw to flatten the cell in
one hour). For your battery it would be about 0.45 Amps
Never flatten the battery below about 3V or so, nor allow it to
self-discharge below about 2.5V, the battery will undergo permanent damage
and some people say it becomes dangerous. Basically don't store them
completely flat for long periods. I have seen it suggested that optimum
life results from storing with 40% charge in the battery.
If the battery happens to have a voltage below 2.9V, the charger is supposed
to reduce the charging current to 0.1C (the amount of current that would
flatten a charged battery in 10 hours). This would be 68mA for your
battery. If you can manually verify that you haven't flattened it this far
then that ought to suffice.
So you need to limit the current to 0.45Amps and you need to limit the
voltage very accurately to 4.1 or 4.2V. If the voltage has reached 4.2V
and the current dies down to 0.1C (68mA for you) then the battery is full
and you should disconnect it for best life, though I don't think it is
dangerous to continue charging it at 4.2 Volts.
There are 'intelligent' charging chips available from several manufacturers
that will manage the whole charging cycle, but these chips would probably
expect a steady and constant supply voltage from start to finish which you
will not have unless you use the second battery route when you might as
well use the camera's internal charging circuit.
Since you require opportunistic charging, I would suggest rectifying the
generator output and filtering it with a big electrolytic capacitor, and
limiting the peak voltage with a zener diode of perhaps 8.2V, 5 Watt or
whatever power rating you find necessary. This can then be applied to a
non-intelligent charging IC such as the ADP3820.
http://www.analog.com/UploadedFiles/Data_Sheets/490002128ADP3820_a.pdf
Chris
to work. If you want to charge the battery outside the camera then the
following information might be of use:
It looks like your battery is a single cell.
Some information on charging lithium batteries is here:
http://www.energyplus.com/articles/Panasonic_LiIon_Charging.pdf
Most lithium packs have built-in MOSFETs and protection circuitry to
disconnect the battery from the terminals if any cell is charged over some
very accurate threshold which (according to Panasonic) is 4.30V +/- 0.05V.
The safety circuit will probably also disconnect if you try to discharge
the cell to too low a voltage, i.e. it disconnects at 2.3V +/-0.1V, but you
shouldn't discharge it below 3V. Don't rely on the safety circuit to
control your charging, it is meant as a backup, and I wouldn't be surprised
if once it disconnects, it's time to buy a new battery pack.
If you are charging single cells, then the important things are:
Never exceed 4.2 Volts/cell, regardless of current or anything else. For
some cells this should even be 4.1 Volts, depending on the cell chemistry.
This needs to be an accurate regulator (1% accuracy will do).
Never exceed the current limit specified for the cell (which is usually
about 0.7C, i.e. the current you would have to draw to flatten the cell in
one hour). For your battery it would be about 0.45 Amps
Never flatten the battery below about 3V or so, nor allow it to
self-discharge below about 2.5V, the battery will undergo permanent damage
and some people say it becomes dangerous. Basically don't store them
completely flat for long periods. I have seen it suggested that optimum
life results from storing with 40% charge in the battery.
If the battery happens to have a voltage below 2.9V, the charger is supposed
to reduce the charging current to 0.1C (the amount of current that would
flatten a charged battery in 10 hours). This would be 68mA for your
battery. If you can manually verify that you haven't flattened it this far
then that ought to suffice.
So you need to limit the current to 0.45Amps and you need to limit the
voltage very accurately to 4.1 or 4.2V. If the voltage has reached 4.2V
and the current dies down to 0.1C (68mA for you) then the battery is full
and you should disconnect it for best life, though I don't think it is
dangerous to continue charging it at 4.2 Volts.
There are 'intelligent' charging chips available from several manufacturers
that will manage the whole charging cycle, but these chips would probably
expect a steady and constant supply voltage from start to finish which you
will not have unless you use the second battery route when you might as
well use the camera's internal charging circuit.
Since you require opportunistic charging, I would suggest rectifying the
generator output and filtering it with a big electrolytic capacitor, and
limiting the peak voltage with a zener diode of perhaps 8.2V, 5 Watt or
whatever power rating you find necessary. This can then be applied to a
non-intelligent charging IC such as the ADP3820.
http://www.analog.com/UploadedFiles/Data_Sheets/490002128ADP3820_a.pdf
Chris
P
przemek klosowski
Guest
On Fri, 28 Oct 2005 08:56:08 -0700, Jim Thompson wrote:
actual test showing that they are surprisingly robust. I was surprised to
learn that discharging dead short didn't kill the pack. On the other hand,
long-term short (over a day) and overcharging tend to do Li-ions in.
http://www.stensat.org/Docs/battery_test_results.pdf describes an
actual test showing that they are surprisingly robust. I was surprised to
learn that discharging dead short didn't kill the pack. On the other hand,
long-term short (over a day) and overcharging tend to do Li-ions in.
N
Nick.
Guest
On Fri, 28 Oct 2005 16:53:06 +0000, James Sweet wrote:
overvoltage protection! My bike gen will quite happily produce 50V RMS
given enough speed (~30mph) and a light or no load.
If using a bike gen to power electronics, make sure you cater for input
overvoltage protection! My bike gen will quite happily produce 50V RMS
given enough speed (~30mph) and a light or no load.
M
Mike W.
Guest
'Generic PC boards' I think you mean perf. board, just a rectangular PC
board, with rows of holes pre-drilled and pads/traces on the back.
You might want to go to a junkyard and see if you can get your hands on a
late-model Cadillac taillight assembly, they use LED's just as you are
wanting to do. Maybe it will help you with the engineering.
"Steve TR" <noemail@all.com> wrote in message
news:RuS8f.529$qk4.46@bgtnsc05-news.ops.worldnet.att.net...
board, with rows of holes pre-drilled and pads/traces on the back.
You might want to go to a junkyard and see if you can get your hands on a
late-model Cadillac taillight assembly, they use LED's just as you are
wanting to do. Maybe it will help you with the engineering.
"Steve TR" <noemail@all.com> wrote in message
news:RuS8f.529$qk4.46@bgtnsc05-news.ops.worldnet.att.net...
B
Bob
Guest
"Steve TR" <noemail@all.com> wrote in message
news:RuS8f.529$qk4.46@bgtnsc05-news.ops.worldnet.att.net...
The arrow is already rectangular.
This http://www.alltronics.com/images/23L002.jpg has 18 real bright leds in
a pattern..
news:RuS8f.529$qk4.46@bgtnsc05-news.ops.worldnet.att.net...
http://www.alltronics.com/Light_Sources.htm
The arrow is already rectangular.
This http://www.alltronics.com/images/23L002.jpg has 18 real bright leds in
a pattern..
S
Steve TR
Guest
I knew your name would pop up eventually with loads of flawless advice.
THANK YOU!
Looking at the websites you provided, I think I can easily adapt some of the
products listed to fit my needs. And as far as a diffuser goes, each tail
lamp already has a full width clear fresnel (?) lens in there behind the
outer red lens. I found that by sticking a single LED flashlight in the
center on the lens, it would illuminate the entire lens evenly. Dim, but it
was fully lit. So one of these round or rectagular complete LED lamp
assemblies in each tail light section would work great. I could get away
with four of them I believe, maybe six, or even if I have to use eight, the
current draw would still be less than what I'm having with eight 1157's all
lit up.
And yep, thermal flasher won't work. I've already switched to an electronic
"heavy duty" flasher just for the shear loudness of it. It's a convertible
and so there is wind noise... It's nice to be able to hear the flasher
ticking.
THANKS AGAIN!
-Steve
"Daniel J. Stern" <dastern@127.0.0.1> wrote in message
newsine.GSO.4.63.0510292109080.3172@alumni.engin.umich.edu...
THANK YOU!
Looking at the websites you provided, I think I can easily adapt some of the
products listed to fit my needs. And as far as a diffuser goes, each tail
lamp already has a full width clear fresnel (?) lens in there behind the
outer red lens. I found that by sticking a single LED flashlight in the
center on the lens, it would illuminate the entire lens evenly. Dim, but it
was fully lit. So one of these round or rectagular complete LED lamp
assemblies in each tail light section would work great. I could get away
with four of them I believe, maybe six, or even if I have to use eight, the
current draw would still be less than what I'm having with eight 1157's all
lit up.
And yep, thermal flasher won't work. I've already switched to an electronic
"heavy duty" flasher just for the shear loudness of it. It's a convertible
and so there is wind noise... It's nice to be able to hear the flasher
ticking.
THANKS AGAIN!
-Steve
"Daniel J. Stern" <dastern@127.0.0.1> wrote in message
news
ine.GSO.4.63.0510292109080.3172@alumni.engin.umich.edu...