Driver to drive?

[Tim Wescott]

On Wed, 08 Jan 2014 23:14:49 -0800, uchethegenius1 wrote:

How do you derive the efficiency of a transformer from the first
principle of electric circuit.

With great difficulty.

There are a lot of factors at play, some of which are dependent on
characteristics of the materials involved that aren't always easy to pin
down. Moreover, how you use the transformer in your circuit matters.

Finally, for some applications the efficiency doesn't matter nearly as
much as other things; usually bandwidth or fidelity of reproduction.

Factors that I know of are:

The resistance of the windings,
the resistivity of the core material,
the thickness of the laminations (if any),
the nonlinear magnetic properties of the core material,
the overall shape of the core and windings

I'm sure there's more.

I suspect that even in this day and age of high-falutin' computerized
finite-element analysis, you'll still find that in practice anyone who
can build you a transformer and have it possess the correct efficiency by
design is someone who has designed and tested dozens or hundreds of
similar transformers and is leaning on a wealth of practical information,
rather than analysis from "first principles".

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Jon Elson]

David Eather wrote:

On Thu, 09 Jan 2014 18:43:53 +1000, Phil Allison <phil_a@tpg.com.au

Now YOU get to explain WFT you really want to know.




.... Phil




Gee Phil, for someone so bereft of notable achievements as you are, you
are still an arrogant, abusive turd.
Now you get to explain WTF you are better than everyone else.
On the other hand, the original question WAS very vague!

Jon

 

[David Eather]

On Fri, 10 Jan 2014 06:11:25 +1000, Jon Elson <jmelson@wustl.edu> wrote:

David Eather wrote:

On Thu, 09 Jan 2014 18:43:53 +1000, Phil Allison <phil_a@tpg.com.au

Now YOU get to explain WFT you really want to know.




.... Phil




Gee Phil, for someone so bereft of notable achievements as you are, you
are still an arrogant, abusive turd.
Now you get to explain WTF you are better than everyone else.
On the other hand, the original question WAS very vague!

Jon

Phil doesn't care what the question is or how vague it was - if he sees
someone he can abuse he does, because it makes him feel superior and that
is the only thing important to him. Pity the poor sod who asks a question
hesitantly and politely.

But this still applies for Phil:

Gee Phil, for someone so bereft of notable achievements as you are, you
are still an arrogant, abusive turd.
Now you get to explain WTF you are better than everyone else.

 

[John Fields]

On Fri, 10 Jan 2014 01:18:27 +1000, "David Eather"
<eather@tpg.com.au> wrote:

On Thu, 09 Jan 2014 18:43:53 +1000, Phil Allison <phil_a@tpg.com.au> wrote:


uchethegenius1@gmail.com

How do you derive the efficiency of a transformer from the first
principle
of electric circuit.


** Efficiency = power out / power in ( times 100 for percent ).

Now YOU get to explain WFT you really want to know.




.... Phil




Gee Phil, for someone so bereft of notable achievements as you are, you
are still an arrogant, abusive turd.

---
PKB???

Phil's abhorrence for, and often knee-jerk verbal reactions to
bullshit (real or perceived) doesn't negate the fact he's often
posted lucid technical explanations here, and is an important member
of these groups.

You, not so much...
---

>Now you get to explain WTF you are better than everyone else.

---
Instead of adding to the dissention here, why don't you take that
chip off your shoulder and take a crack at answering the OP's
question?

 

[Adrian Tuddenham]

Tim Wescott <tim@seemywebsite.really> wrote:

On Wed, 08 Jan 2014 23:14:49 -0800, uchethegenius1 wrote:

How do you derive the efficiency of a transformer from the first
principle of electric circuit.

With great difficulty.

There are a lot of factors at play, some of which are dependent on
characteristics of the materials involved that aren't always easy to pin
down. Moreover, how you use the transformer in your circuit matters.

Finally, for some applications the efficiency doesn't matter nearly as
much as other things; usually bandwidth or fidelity of reproduction.

Factors that I know of are:

The resistance of the windings,
the resistivity of the core material,
the thickness of the laminations (if any),
the nonlinear magnetic properties of the core material,
the overall shape of the core and windings

I'm sure there's more.

I suspect that even in this day and age of high-falutin' computerized
finite-element analysis, you'll still find that in practice anyone who
can build you a transformer and have it possess the correct efficiency by
design is someone who has designed and tested dozens or hundreds of
similar transformers and is leaning on a wealth of practical information,
rather than analysis from "first principles".

If you are really determined, you could try studying some of the heavy
electrical engineering textbooks from the 1940s and 50s. They will give
the sort of information you need, but mainly aimed at the design of
massive power-distribution transformers where you really do have to
calculate first and build later.

That will give you some idea of the factors at work and the ball-park
figures you can expect, then you will have to scale everything to suit
the size of transformer you are interested in.


--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

 

[dp]

On Thursday, January 9, 2014 5:14:05 PM UTC+2, Don Y wrote:

...
I can also imagine a power supply telling the laptop how much power
it is *actually* using (adding those monitoring components *outside*
the physical constraints of the laptop itself) so the laptop can
better calibrate its battery monitoring algorithms (instead of
just watching Vbat without any real idea as to how quickly it
*should* be falling -- when operating on battery).

Hi Don,
of course we can imagine lots of things but moving the charger
control part outside of the laptop would likely be impractical.
For the time being, that is . Wait until they get as thin as
a sheet of paper....

It does not take much, here is most of the charger circuitry
of a one-off thingie I did for a university lab not so long ago:
http://tgi-sci.com/misc/swgps3.gif . Not that much one can save
in terms of space - and I have been conservative (e.g. put a 3.3V
zener and don't think how ADC inputs on the MCU react to clamping
currents into on a neighbour input). (here is the whole
thing: http://tgi-sci.com/dsv/swg800.gif ,
http://tgi-sci.com/misc/PICT6999.avi , http://tgi-sci.com/dsv/swgboard.gif ).

OTOH I know what a pain it can be to connect to a power adapter you
have not tested. I went to lengths I still can't believe myself
on the netmca to protect against various power input events (it has
no battery to buffer things somewhat, the input feeds the convertors
directly). Things were even more complicated given that the processor
(an MPC5200B) needed certain rise times on its 1.5V power so its
PLL feedback amp would not go into saturation before the oscillator
would get to work OK.... In hindsight if I had made the power adaptor
identifiable and somehow simply not starting the whole thing unless
the ID has been seen things might have been easier (not so sure but it
could have been an alternative path).
Having a battery makes things easier to control but with li-ion things
also can get hazardous so it might be not such a bad idea to have the
charger identify itself, at least from a legal point of view.

Dimiter

------------------------------------------------------
Dimiter Popoff, TGI http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/

 

Mr. B1ack <nowhere@nada.net> wrote:

On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.

They died WAY before I'd gotten good mileage out of them and the
battery packs are so expensive it's better to just buy a whole new
drill/battery set.

There seems to be a constant (intentional?) churn of voltages and
connectors on cordless tool battery packs. New 12 V NiCds to fit my
drill were 1) hard to find and 2) a significant part of the price of a
new set, as you noted. The rebuilds were priced right for me; I may or
may not get them rebuilt a second time - depends on how well the drill
is doing in 5 years.

> I'll NEVER use NiCads again !

That low internal resistance is great for getting drill bits moving,
though.

NiMH (<500 recharge cycles, sometimes much less)

The NiMH AAs I've used seem to give me more than that. YMMV.

You've counted ? Betcha it's really under 100 cycles.

I still have some working NiMHs from the first batch I bought with my
first digital camera in 2000. I've used them with that camera, the
other pointy-shoot cameras that have replaced it, and some other
portable equipment. I guarantee I have more than 100 cycles on them.
The capacity is not what they were when new, but it's not ridiculously
low, either.

Some of the NiMH cells from that first batch *have* expired.

In 2011 I bought a set of Sanyo Eneloop NiMHs and they seem to do a
pretty nice job for "consumer" equipment. The low-self-discharge thing
seems to be true; they stay charged better than the previous NiMH cells
I have used.

NiMH batteries are also a pain to charge since you can't really use
voltage as an indicator of reaching a full charge but instead have to
measure the temperature ... they start to get hot once fully charged.

I just buy a charger with a 120 V plug on one end and battery holders
on the other. I realize this is different than *designing* equipment
to use and charge them.

I'd *rather* have an "affordable" off-the-shelf solution - mostly
because of the way bosses think - but I just can't find one
anywhere.

I understand about the boss thing. Maybe you should design such an
off-the-shelf solution and sell it to other people!

It kind of boils down to whether I trust lithiums or Pb to last longer
in the field given my power production/consumption profile.

For 12 V PbA "gel cell" batteries from about 4 to 10 Ah nominal ratings,
in UPS-type indoor service, I have found Panasonic and PowerSonic brand
batteries to work the best - to go for the most cycles. PowerSonics
used to be made in Mexico, but some recent ones I got were made in
China, so I'm not sure if they are still as good. I put a set of
Chinese PowerSonics in my computer UPS a few months ago; check back with
me in a couple of years.

If your gadgets also have to get serviced in the field, and they are
deployed in the US, one thing to recommend 6 or 12 V PbA is that every
Home Depot has a couple of sizes of these batteries on the shelf, for
use in emergency lights, EXIT lights, and similar. In extreme cases of
field service, it's not too hard to make a harness to plug your gadget
into a car (RV, boat, etc) battery.

One kink particular to the PbA 12 V 7 Ah nominal size: they exist in the
world with both 3/16" (0.1875", 4.76 mm) and 1/4" (0.25", 6.35 mm) male
push-on terminals. PowerSonic sells adapters that will make a battery
with 1/4" push-on male terminals fit a wire with 3/16" push-on female
terminals.

Standard disclaimers apply: I don't get money or other consideration
from any companies mentioned.

Matt Roberds

 

[Mr. B1ack]

On Wed, 8 Jan 2014 21:44:44 -0800 (PST), dakupoto@gmail.com wrote:

If I may suggest, why not use a sealed lead acid cell.
They are cheap, rugged, can be charged with a simple
shunt type charge controller and immune to over-
charging.
A Li-ion battery, on the other hand has to be charged
very carefully. There is some excellent documentation
at the Battery University regarding the the charging
cycle of the Li-ion battery, and how overcharging
must be strictly avoided.

Actually I'm leaning towards "old tech" Pb-A because
it's just plain tougher. Yep, Li-ion and NiMH and NiCads
are a royal PAIN to charge properly. I've seen some of
those "how to do it perfectly" documents and I can see
why no commercial outfit bothers to even try very hard
at doing it right.

Pb-A can be killed too by poor charging practices ... but
it's more tolerant. Most UPS devices seem to slay the
battery in about two years, likely they just charge it at
x-milliamps constantly. DOES encourage people to
just buy a new UPS every couple of years though,
doesn't it ?

Li-ion seems to just die of its own accord, even if you
just have the things in a drawer. Three years, maybe
four. You'll have a hard time buying such cells too
because you won't know when it was actually made
until you can put your eyes on it and read the data
stamped on the battery pack.

So ... I think my TI battery manager chip (which is
intended for Pb-A, ought to guarentee a very long
life for my battteries - and my tiny little DC/DC
converters do a great job creating tightly regulated
output for my devices.

I'd like to get my hands on some NiFe, nickel-iron,
batteries sometime just to check 'em out. They do
not have as much power density as any of the
more modern designs, but they're supposed to be
tough as nails and hold up almost forever ... most
commonly used in disaster/military equipment in
the past and now they've become popular with
the off-gridders in their solar houses.

 

[Greegor]

Resurrecting a 13 year old dead thread has to be some kind of record.

 

[Don Y]

Hi Dimiter,

On 1/9/2014 9:17 PM, dp wrote:

On Thursday, January 9, 2014 5:14:05 PM UTC+2, Don Y wrote:
...
I can also imagine a power supply telling the laptop how much power
it is *actually* using (adding those monitoring components *outside*
the physical constraints of the laptop itself) so the laptop can
better calibrate its battery monitoring algorithms (instead of
just watching Vbat without any real idea as to how quickly it
*should* be falling -- when operating on battery).

of course we can imagine lots of things but moving the charger
control part outside of the laptop would likely be impractical.
For the time being, that is . Wait until they get as thin as
a sheet of paper....

I don't know. I spent some time yesterday digging through a
barrel of laptop power adapters looking for similar units.
I noticed a variety of output voltages (presumably, there is
a reason for these decisions and consequences of them! :> )
The most noteworthy was one that listed *two* different
output voltages: one for "operation" and one for "charging".
So, *something* is telling *that* charger to switch between
"operating" mode and "charging" mode. While not conclusive,
it makes me more leary of naďvely *assuming* characteristics
of this particular adapter/laptop combination!

It does not take much, here is most of the charger circuitry
of a one-off thingie I did for a university lab not so long ago:
http://tgi-sci.com/misc/swgps3.gif . Not that much one can save
in terms of space - and I have been conservative (e.g. put a 3.3V
zener and don't think how ADC inputs on the MCU react to clamping
currents into on a neighbour input). (here is the whole
thing: http://tgi-sci.com/dsv/swg800.gif ,
http://tgi-sci.com/misc/PICT6999.avi , http://tgi-sci.com/dsv/swgboard.gif ).

I don't think delivering "charge current" is the issue. Rather,
I think instrumenting and/or tightly controlling the process is where
most of the value added lies (or, will likely lie).

E.g., a "smart" charger (for some definition of "smart") can look to
see *how* the battery is accepting charge under various conditions
and, presumably, deduce the condition of the battery (not just how
much charge it is holding but how close to replacement it is, etc.).

Consider the efforts that laptop makers already make to try to eek
a bit more performance out of a given battery pack. Anything they
can glean about the battery's performance could enable them to
boast of higher nominal run times. Or, downsize the battery for
a given runtime. E.g., I suspect it is only a matter of time
before these sorts of devices start "learning" their usage
patterns: "When MSOffice is running, the user will tend to have
longer sessions than when, for example, browsing Facebook."

OTOH I know what a pain it can be to connect to a power adapter you
have not tested. I went to lengths I still can't believe myself
on the netmca to protect against various power input events (it has
no battery to buffer things somewhat, the input feeds the convertors
directly). Things were even more complicated given that the processor
(an MPC5200B) needed certain rise times on its 1.5V power so its
PLL feedback amp would not go into saturation before the oscillator
would get to work OK.... In hindsight if I had made the power adaptor
identifiable and somehow simply not starting the whole thing unless
the ID has been seen things might have been easier (not so sure but it
could have been an alternative path).

There's always some "fundamental" level of protection you have to
apply to any input -- esp power. (unless you can galvanically
isolate the inputs until you know what's connected to them)

Having a battery makes things easier to control but with li-ion things
also can get hazardous so it might be not such a bad idea to have the
charger identify itself, at least from a legal point of view.

I'm opting for inductive coupling in current projects (best fits the
application domain). While it doesn't guarantee immunity from these
sorts of issues, I think its relative obscurity works in my favor.
Certainly enough to offset the risks of exposing "bare conductors" and
hoping nothing "crawls in" that way! :>

 

Mr. B1ack <nowhere@nada.net> wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for
it, at Home Depot in 2007. [...] By 2013 the batteries were pretty
much gone. In mid-2013 I got both of them rebuilt with new NiCd
cells at Batteries Plus for about $35 each, out the door.

I don't know where you're getting $35 replacement NiCad packs.

Batteries Plus is a chain of stores that sells batteries. And cells.
http://www.batteriesplus.com/

I took my worn-out DeWalt NiCd packs to the local Batteries Plus store,
and then left.

The guy at the store disassembled the packs.

He looked at how the existing cells were arranged.

He spot-welded new cells together in the same physical layout.

He transferred over the insulators and terminals from my old pack (I
think... he may have brand new ones he used).

He put the new cell assembly back in the original housing.

He gave the rebuilt pack a charge and discharge test.

He called me on the phone.

I went back there and gave him money.

He gave me my rebuilt packs back.

Simple.

Typical off-the-shelf price is more like $75 ... which is like half
of more the price of the original tool + batteries.

Yes, I found prices north of $50 when I was looking for *brand new* NiCd
packs to fit my drill. That helped make the decision toward
*rebuilding* for me.

I just buy a charger with a 120 V plug on one end and battery holders
on the other. I realize this is different than *designing* equipment
to use and charge them.

Um .............. what kind of Frankensteinian device are you trying
to describe here ........???

Um... a battery charger?

What I was trying to say, and apparently failing to say, was that I
haven't been in a position to *design charging circuitry into a
product*.

Most of my charging needs can be met by commercial chargers; I don't
have to design a charger, I just go buy one.

Most of my NiMH charging has been done by a Rayovac PS-12 charger. It
does have a "smart" controller chip in it - if I put in a lightly-
discharged cell, it finishes charging much faster than if I put in a
heavily-discharged cell. It refuses to charge at all if the cells or
the charger is too hot.

More recenly, I got a Maha/Powerex MH-C9000. It does all kinds of
tricks, like charging, discharging, repeated charge/discharge cycles,
etc. It tells you how many mAh it put in or took out.

Both the Rayovac and the Maha have a wall plug on one end, and holders
for AA and AAA cells on the other.

For my flooded PbA batteries, I use a Schumacher Battery Companion (6 or
12 V at about 1.5 A and "smart"), a Deltran Battery Tender (6 V, 1.25 A,
"smart"), and an ancient Western Auto (probably rebranded Schumacher)
charger (6 or 12 V at 6 A, very dumb).

The PbA chargers have a wall plug on one end, and big alligator clips
on the other.

For my sealed PbA batteries, if I need to charge them outside of the
equipment they live in, I use a regulated, adjustable benchtop DC power
supply.

Oh, I also have a very fancy NiMH charger (273.6 V nominal, dozens of
amps, very very "smart") that runs on unleaded gasoline. It has a few
other features as well.

Matt Roberds

 

[dp]

On Friday, January 10, 2014 11:13:40 PM UTC+2, Don Y wrote:

...

E.g., a "smart" charger (for some definition of "smart") can look to
see *how* the battery is accepting charge under various conditions
and, presumably, deduce the condition of the battery (not just how
much charge it is holding but how close to replacement it is, etc.).

Consider the efforts that laptop makers already make to try to eek
a bit more performance out of a given battery pack. Anything they
can glean about the battery's performance could enable them to
boast of higher nominal run times. Or, downsize the battery for
a given runtime.

Well I don't know how much of this they do in laptops nowadays.
I did practically all of it still on the first nukeman (20 years ago).
Used to measure battery resistance during charge/discharge etc., its
change is pretty indicative to its age.
Under the score it did not buy me much if anything, once the battery
needed replacement I had to replace it - and it is easy to see without
all the subtleties. I had (still have) even two charge currents,
one could set either of them to a signed value and both could
be set to different durations. Thought this might lengthen the battery
life; if it did I did not notice it.

And all of this is done in firmware, the hardware part it takes
is on the circuit I posted formerly. Well measuring the battery
temp is not shown there.

... E.g., I suspect it is only a matter of time
before these sorts of devices start "learning" their usage
patterns: "When MSOffice is running, the user will tend to have
longer sessions than when, for example, browsing Facebook."

May be but just measuring the battery current & voltage while knowing
its internal resistance (and its initial value when the battery was
new) is enough to give a precise enough assessment of the % charge
(i.e. time before shutdown) you have left (I would consider 10% for
that almost good enough, 5% would be quite OK; I don't remember how
precise I was doing on the nukeman, it's been a while since, then we
did not sell that many units to have a very broad view on that).

I'm opting for inductive coupling in current projects (best fits the
application domain). While it doesn't guarantee immunity from these
sorts of issues, I think its relative obscurity works in my favor.
Certainly enough to offset the risks of exposing "bare conductors" and
hoping nothing "crawls in" that way! :

This makes good sense for your current project. It will add some
complexity but once you get it right it will make your life a lot
easier with many related things I guess.

Dimiter

------------------------------------------------------
Dimiter Popoff, TGI http://www.tgi-sci.com
------------------------------------------------------
http://www.flickr.com/photos/didi_tgi/sets/72157600228621276/

 

[Mr. B1ack]

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.

I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

They died WAY before I'd gotten good mileage out of them and the
battery packs are so expensive it's better to just buy a whole new
drill/battery set.

There seems to be a constant (intentional?) churn of voltages and
connectors on cordless tool battery packs. New 12 V NiCds to fit my
drill were 1) hard to find and 2) a significant part of the price of a
new set, as you noted. The rebuilds were priced right for me; I may or
may not get them rebuilt a second time - depends on how well the drill
is doing in 5 years.

I'll NEVER use NiCads again !

That low internal resistance is great for getting drill bits moving,
though.

Yep ... it IS nice - however the fix is to just use
higher voltage Li-Ion packs instead. If you can't
get enough amps, use volts

NiMH (<500 recharge cycles, sometimes much less)

The NiMH AAs I've used seem to give me more than that. YMMV.

You've counted ? Betcha it's really under 100 cycles.

I still have some working NiMHs from the first batch I bought with my
first digital camera in 2000. I've used them with that camera, the
other pointy-shoot cameras that have replaced it, and some other
portable equipment. I guarantee I have more than 100 cycles on them.
The capacity is not what they were when new, but it's not ridiculously
low, either.

Some of the NiMH cells from that first batch *have* expired.

In 2011 I bought a set of Sanyo Eneloop NiMHs and they seem to do a
pretty nice job for "consumer" equipment. The low-self-discharge thing
seems to be true; they stay charged better than the previous NiMH cells
I have used.

NiMH batteries are also a pain to charge since you can't really use
voltage as an indicator of reaching a full charge but instead have to
measure the temperature ... they start to get hot once fully charged.

I just buy a charger with a 120 V plug on one end and battery holders
on the other. I realize this is different than *designing* equipment
to use and charge them.

Um .............. what kind of Frankensteinian device
are you trying to describe here ........???

"Design" is very important when it comes to battery
chargers. Google-up the detailed charging specs
the major battery manufacturers have and see ...
to really get best performance AND long life you
can't just blast 'em with amps for an hour or so.

Even my simple homebrew charger centers around
an actual programmed charge-manager chip that
will carefully profile the rate and amps. Alas most
of what you'll find at Wal-Mart are vastly stupider
devices ... you're lucky if they'll even stop charging
before yer cells are smokin'.

I'd *rather* have an "affordable" off-the-shelf solution - mostly
because of the way bosses think - but I just can't find one
anywhere.

I understand about the boss thing. Maybe you should design such an
off-the-shelf solution and sell it to other people!

Hmmm ... maybe I could send off the "perfect" design
to a manufacturer, have 'em put it into a nice looking
plastic case contained within a nice looking box with
snazzy graphics ... and then I could buy 'em back as
"off the shelf" solutions

It kind of boils down to whether I trust lithiums or Pb to last longer
in the field given my power production/consumption profile.

For 12 V PbA "gel cell" batteries from about 4 to 10 Ah nominal ratings,
in UPS-type indoor service, I have found Panasonic and PowerSonic brand
batteries to work the best - to go for the most cycles. PowerSonics
used to be made in Mexico, but some recent ones I got were made in
China, so I'm not sure if they are still as good. I put a set of
Chinese PowerSonics in my computer UPS a few months ago; check back with
me in a couple of years.

If your gadgets also have to get serviced in the field, and they are
deployed in the US, one thing to recommend 6 or 12 V PbA is that every
Home Depot has a couple of sizes of these batteries on the shelf, for
use in emergency lights, EXIT lights, and similar. In extreme cases of
field service, it's not too hard to make a harness to plug your gadget
into a car (RV, boat, etc) battery.

One kink particular to the PbA 12 V 7 Ah nominal size: they exist in the
world with both 3/16" (0.1875", 4.76 mm) and 1/4" (0.25", 6.35 mm) male
push-on terminals. PowerSonic sells adapters that will make a battery
with 1/4" push-on male terminals fit a wire with 3/16" push-on female
terminals.

As I said somewhere ... certain sizes of Pb-A batteries
are just plain "common" and found in all sorts of devices.
Those are both availiable and relatively cheap due to
the usual market factors. They ARE much bulkier than
Lithiums, but if properly charged and not abused they
can last for a LONG time - and replacements are as
close as yer local Home Depot store.

The devices I'm looking to power ... some of them are
going WAY out "in the field" ... nasty places it could
take a couple of difficult hours to get to. These both
warrant radio/cell data connections AND need to be
very robust so nobody will have to actually go replace
things very often.

So, while I'll experiment with Lithiums ... I've now decided
that Pb-A will be the preferred storage medium.

 

[Mr. B1ack]

On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...

I've had both
VOltman and PrimeCell rebuild NiCd tool batteries. PrimeCell was
significantly cheaper last time I looked. Both did good work. $35 is
about right. The last one I had rebuilt was for a tool that the
cordless versions are no longer sold and batteries are unobtanium.

I took one of my useless cordless drills, removed
the batteries and put in a plug cord with spring clamps.
I connect it to a live 12vdc battery. Not as handy as the
original, but OK around the shop.

In any case, NiCads are especially prone to the thing where
conductive crystal "fingers" creep across the plates and
short out the cell. Yes, they're better than they used to be,
but "better" doesn't always add-up to "good". Frankly I've
just come to hate NiCads.

Pb-A are clearly not suited for portable power tools, but to
power an environmental datalogger forr five years at a
stretch isn't anything to be sneezed at. An 18v solar panel,
a UPS battery, a charging-management chip and gettting
that five years becomes attainable.

Hey ... I distinctly remember Walter Cronkite promising
us atomic batterues for *everything* when he served as
the voice for Union Carbides "The 21st Century". I want
my damned atomic batteries ! The flying car would be
cool as well

He also promised us "home computers" that'd only be
the size of a writing desk .............

Some years later, I came across an IBM computer in
a science museum which actually was just the size of
a desk (not counting the external memory - a few K of
magnetic-core RAM inside a meter-square box. Looked
neat-o and I wanted one.

Probably had 1/10th the computing power of your iPhone.

 

[Jasen Betts]

On 2014-01-11, Mr B1ack <nowhere@nada.net> wrote:

On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...

last time I had a pack rebuilt I watched the guy spot-welding the
strip to brand new cells.



--
For a good time: install ntp

--- news://freenews.netfront.net/ - complaints: news@netfront.net ---

 

On Sat, 11 Jan 2014 02:37:04 -0500, Mr. B1ack <nowhere@nada.net>
wrote:

On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...

Oh, good grief. They're new cells. They do a *lot* of business.

I've had both
VOltman and PrimeCell rebuild NiCd tool batteries. PrimeCell was
significantly cheaper last time I looked. Both did good work. $35 is
about right. The last one I had rebuilt was for a tool that the
cordless versions are no longer sold and batteries are unobtanium.

I took one of my useless cordless drills, removed
the batteries and put in a plug cord with spring clamps.
I connect it to a live 12vdc battery. Not as handy as the
original, but OK around the shop.

What a kludge. Just spend the $35 or buy a corded drill.

In any case, NiCads are especially prone to the thing where
conductive crystal "fingers" creep across the plates and
short out the cell. Yes, they're better than they used to be,
but "better" doesn't always add-up to "good". Frankly I've
just come to hate NiCads.

They have their place. The "primary" tools are all LiIon, now but the
NiCds have their place and I still use the other-than-drill
components.

Pb-A are clearly not suited for portable power tools, but to
power an environmental datalogger forr five years at a
stretch isn't anything to be sneezed at. An 18v solar panel,
a UPS battery, a charging-management chip and gettting
that five years becomes attainable.

Hey ... I distinctly remember Walter Cronkite promising
us atomic batterues for *everything* when he served as
the voice for Union Carbides "The 21st Century". I want
my damned atomic batteries ! The flying car would be
cool as well

No Surprise. Water Crankcase was about as dumb as they come. *WAY*
overrated, even for his time.

He also promised us "home computers" that'd only be
the size of a writing desk .............

Some years later, I came across an IBM computer in
a science museum which actually was just the size of
a desk (not counting the external memory - a few K of
magnetic-core RAM inside a meter-square box. Looked
neat-o and I wanted one.

Probably had 1/10th the computing power of your iPhone.

Since I wouldn't have an iPhone... ;-)

 

On Sat, 11 Jan 2014 22:01:06 -0500, Mr. B1ack <nowhere@nada.net>
wrote:

On Sat, 11 Jan 2014 12:30:53 -0500, krw@attt.bizz wrote:

On Sat, 11 Jan 2014 02:37:04 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...

Oh, good grief. They're new cells. They do a *lot* of business.


And there's a higher profit margin if you use old cells
that were found in the back of a Chinese warehouse

Oh, good grief.

> All I'm saying is "buyer beware".

All I'm saying is that you're a dumbshit.

I've had both
VOltman and PrimeCell rebuild NiCd tool batteries. PrimeCell was
significantly cheaper last time I looked. Both did good work. $35 is
about right. The last one I had rebuilt was for a tool that the
cordless versions are no longer sold and batteries are unobtanium.

I took one of my useless cordless drills, removed
the batteries and put in a plug cord with spring clamps.
I connect it to a live 12vdc battery. Not as handy as the
original, but OK around the shop.

What a kludge. Just spend the $35 or buy a corded drill.


The adaptor cord cost me about three bucks.

I can't help it if you're a loser.

In any case, NiCads are especially prone to the thing where
conductive crystal "fingers" creep across the plates and
short out the cell. Yes, they're better than they used to be,
but "better" doesn't always add-up to "good". Frankly I've
just come to hate NiCads.

They have their place. The "primary" tools are all LiIon, now but the
NiCds have their place and I still use the other-than-drill
components.


They MAY have their place ... the low internal resistance
lets you get a lot of amps out of them. However power
is "I" x "E" so you can put a few more Lithiums in series
and make up for the loss of amperage.

In some circumstances. Tell Boeing how great LiIons are. There's a
place for both.

Pb-A are clearly not suited for portable power tools, but to
power an environmental datalogger forr five years at a
stretch isn't anything to be sneezed at. An 18v solar panel,
a UPS battery, a charging-management chip and gettting
that five years becomes attainable.

Hey ... I distinctly remember Walter Cronkite promising
us atomic batterues for *everything* when he served as
the voice for Union Carbides "The 21st Century". I want
my damned atomic batteries ! The flying car would be
cool as well

No Surprise. Water Crankcase was about as dumb as
they come. *WAY* overrated, even for his time.


Hey, uncle Walter was *god* dontchankow ... he
had "the voice"

He talked a lot and said very little. Well, he lied a lot.

He also promised us "home computers" that'd only be
the size of a writing desk .............

Some years later, I came across an IBM computer in
a science museum which actually was just the size of
a desk (not counting the external memory - a few K of
magnetic-core RAM inside a meter-square box. Looked
neat-o and I wanted one.

Probably had 1/10th the computing power of your iPhone.

Since I wouldn't have an iPhone... ;-)

Wise.

 

[Mr. B1ack]

On 11 Jan 2014 10:26:05 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:

On 2014-01-11, Mr B1ack <nowhere@nada.net> wrote:
On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...


last time I had a pack rebuilt I watched the guy spot-welding the
strip to brand new cells.

Well ... there's a difference between "shiny" and "new".
The things could have been in a box for ten years before
he welded 'em together. Sometimes there's a little code
on the cells indicating the date of manufacture, sometimes
there isn't. Beware.

But, if you got lucky, good for you.

 

[Mr. B1ack]

On Sat, 11 Jan 2014 12:30:53 -0500, krw@attt.bizz wrote:

On Sat, 11 Jan 2014 02:37:04 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 22:55:06 -0500, krw@attt.bizz wrote:

On Fri, 10 Jan 2014 22:07:39 -0500, Mr. B1ack <nowhere@nada.net
wrote:

On Fri, 10 Jan 2014 05:30:08 +0000 (UTC), mroberds@att.net wrote:

Mr. B1ack <nowhere@nada.net> wrote:
On Tue, 7 Jan 2014 21:34:07 +0000 (UTC), mroberds@att.net wrote:

In sci.electronics.design Mr. B1ack <nowhere@nada.net> wrote:
Alternatives are, of course, Ni-Cad (charge memory effect

Much less of a problem in the real world than the vendors of all
other chemistries would have you believe. There will now be 500
follow-up posts arguing this point to death.

Tell that to the three dead expensive cordless drills I have in the
toolshed ... all NiCad powered.

I bought the $100 DeWalt drill-driver kit, and a spare 12 V NiCd for it,
at Home Depot in 2007. In 2007-2008 I used them at work; after that it
was just homeowner-type occasional use. By 2012 both batteries were
pretty tired, but I could still get some work done by juggling them on
the charger. One thing that I think helped is that I kept the charger
and batteries in my kitchen, and approximately whenever I thought about
it (which probably means once every 1 or 2 months), I would top off both
batteries on the charger.

By 2013 the batteries were pretty much gone. In mid-2013 I got both of
them rebuilt with new NiCd cells at Batteries Plus for about $35 each,
out the door. I figure 5 to 6 years of use for $35 is not a bad deal.
Also, they at least say they recycle the batteries in some acceptable
manner.


I don't know where you're getting $35 replacement NiCad
packs. Typical off-the-shelf price is more like $75 ... which
is like half of more the price of the original tool + batteries.

He told you. The had them rebuilt by Batteries Plus.

I wonder how old the cells are that they're using to
do the rebuilds ...

Oh, good grief. They're new cells. They do a *lot* of business.

And there's a higher profit margin if you use old cells
that were found in the back of a Chinese warehouse

All I'm saying is "buyer beware".

I've had both
VOltman and PrimeCell rebuild NiCd tool batteries. PrimeCell was
significantly cheaper last time I looked. Both did good work. $35 is
about right. The last one I had rebuilt was for a tool that the
cordless versions are no longer sold and batteries are unobtanium.

I took one of my useless cordless drills, removed
the batteries and put in a plug cord with spring clamps.
I connect it to a live 12vdc battery. Not as handy as the
original, but OK around the shop.

What a kludge. Just spend the $35 or buy a corded drill.

The adaptor cord cost me about three bucks.

In any case, NiCads are especially prone to the thing where
conductive crystal "fingers" creep across the plates and
short out the cell. Yes, they're better than they used to be,
but "better" doesn't always add-up to "good". Frankly I've
just come to hate NiCads.

They have their place. The "primary" tools are all LiIon, now but the
NiCds have their place and I still use the other-than-drill
components.

They MAY have their place ... the low internal resistance
lets you get a lot of amps out of them. However power
is "I" x "E" so you can put a few more Lithiums in series
and make up for the loss of amperage.

Pb-A are clearly not suited for portable power tools, but to
power an environmental datalogger forr five years at a
stretch isn't anything to be sneezed at. An 18v solar panel,
a UPS battery, a charging-management chip and gettting
that five years becomes attainable.

Hey ... I distinctly remember Walter Cronkite promising
us atomic batterues for *everything* when he served as
the voice for Union Carbides "The 21st Century". I want
my damned atomic batteries ! The flying car would be
cool as well

No Surprise. Water Crankcase was about as dumb as
they come. *WAY* overrated, even for his time.

Hey, uncle Walter was *god* dontchankow ... he
had "the voice"

He also promised us "home computers" that'd only be
the size of a writing desk .............

Some years later, I came across an IBM computer in
a science museum which actually was just the size of
a desk (not counting the external memory - a few K of
magnetic-core RAM inside a meter-square box. Looked
neat-o and I wanted one.

Probably had 1/10th the computing power of your iPhone.

Since I wouldn't have an iPhone... ;-)

Wise.

 

[Greegor]

It's a good thing you didn't ask anybody to explain hysteresis!