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Laptop battery



 
 
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  #1  
Old November 28th 17, 08:34 PM posted to microsoft.public.windowsxp.general
Andy[_17_]
external usenet poster
 
Posts: 594
Default Laptop battery

I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy
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  #2  
Old November 28th 17, 10:23 PM posted to microsoft.public.windowsxp.general
No_Name
external usenet poster
 
Posts: 177
Default Laptop battery

On Tue, 28 Nov 2017 13:37:58 -0800, mike wrote:

On 11/28/2017 11:34 AM, Andy wrote:
I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy

Test it.
No, you can't tell by asking the seller.

What's the battery life claimed by HP?
Depending on what you're doing, an hour may be good performance.

Problem with a battery for an old computer is that most any brand
name battery you find has been sitting in a container in Arizona
for a decade. It's toast. The vendor probably made any new ones
since two years after introduction.

If you buy it from China on EBAY, it was probably made by cutting up
old batteries that were stored for a decade in China and putting
them into a new-looking battery case. Or maybe used batteries.
Or maybe sub-quality cheapo cells.

You might be able to have the pack refurbished with quality cells,
but you won't like the price.

Low price is a good indicator of a weak battery.
High price is no guarantee that you won't get a weak battery.


I bought a new battery for my Lenovo T43 on ebay. When I got it, it
would not even take a charge. I left it charging for 2 days and still
nothing. I complained to the seller. He sent me another one. That one
worked great. I've been using it for a year now and still works great.
It holds a charge for 2.5 to 3 hours. The old battery that came with the
computer was so weak it woulod only hold a charge for a half hour at
most.

I find the same with cordless tools. When I bought a cordless drill, the
batteries would last several hours for intermittent use, or about 45 min
for continuous use. Three years later, I have to recharge them every
hour and they wont last more than 10 min on continuous use.

Even my car battery is dying. I have to make sure not to leave my lights
on when I leave te car, or it wont start after 15 min. I used to be able
to leave the lights on for hours....

Batteries are all meant to die. That is inevitable. Some last longer
than others though. I guess it depends on how much you pay for them. The
costly ones were made better (usually).

I'm still waiting for someone to make some liquid that you pour in the
battery to bring it back to life. I'll probably wait for this for
eternity.....



  #3  
Old November 28th 17, 10:37 PM posted to microsoft.public.windowsxp.general
mike[_10_]
external usenet poster
 
Posts: 1,073
Default Laptop battery

On 11/28/2017 11:34 AM, Andy wrote:
I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy

Test it.
No, you can't tell by asking the seller.

What's the battery life claimed by HP?
Depending on what you're doing, an hour may be good performance.

Problem with a battery for an old computer is that most any brand
name battery you find has been sitting in a container in Arizona
for a decade. It's toast. The vendor probably made any new ones
since two years after introduction.

If you buy it from China on EBAY, it was probably made by cutting up
old batteries that were stored for a decade in China and putting
them into a new-looking battery case. Or maybe used batteries.
Or maybe sub-quality cheapo cells.

You might be able to have the pack refurbished with quality cells,
but you won't like the price.

Low price is a good indicator of a weak battery.
High price is no guarantee that you won't get a weak battery.


  #4  
Old November 28th 17, 10:54 PM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default Laptop battery

Andy wrote:
I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy


I can give you a basic inventory on what is in
a battery system. I don't know all the details well
enough, to provide the exact right diagnosis.

*******

The battery consists of:

1) Multiple LiCo cells, with welded conductors between
cells. The cells have protection features, like each
cell has an internal fuse, to prevent accidents.
If a battery pack goes "open circuit", a protection
feature may have tripped to prevent a fire. It can never
work after that.

2) The battery has a PCB with a small "fuel gauge" chip
on it. This communicates over a serial bus, to the laptop.
The "fuel gauge" chips, there are many brands, and the
right chip must be in there for the laptop to work with it.
The fuel gauge keeps track of "charge cycle count", as
well as a "capacity loss parameter", so that the laptop
can figure out the reduction in capacity with time, and
be in a better condition to detect when it's time to
hibernate the computer (before the battery drops below
0%). If the battery loses 0.1% of its life on each full
recharge, and the gauge logs 100 charge cycles, then the
battery has lost about 10% of absolute capacity. The fuel
gauge includes a number of registers, with information like
that stored inside. It must be properly programmed at the
factory, to represent the behavior of the cells well.

3) The plastic casing on the battery has eight contacts.
Two for VCC. Two for GND. At least one contact of the
remainder is used for the serial bus. Some packs also
have an ENABLE pin, and that prevents energy from appearing
on VCC and GND, unless the battery pack is seated in the bay.
So if you drop your screwdriver across the power blades while
the pack sits on your desk... it might not catch fire :-)
The ENABLE pin inside the laptop, would ground the pin
and signal the pack is now inside a laptop, so it's safe
for VCC and GND to connect to the actual battery cells.

4) The laptop itself has an autonomous charge management
subsystem. Even if the CPU isn't running, some kind of
chip in there charges the battery, and stops charging
before the battery is overfilled in a dangerous way.
A battery may not be properly charged, due to a failure
in that subsystem, or a failure of the power adapter.

*******

It could be that the charging process is
stopping after the CC phase. That would leave
you with 65% fuel (second graph). Maybe it takes
less time than normal, to fill to 65%. And then
less time than normal, to empty it.

http://batteryuniversity.com/learn/a..._ion_batteries

I can't say much more than that.

A battery bought from HP, probably works correctly.

Batteries should always be bought from "high volume"
sellers. A battery sitting on the shelf in a "mom and pop"
computer store, could already be ruined by aging. You
want "freshly constructed" laptop batteries for
best results. A ten year old battery, may not take
a lot of charge cycles due to age.

I suspect a disagreement between (2) and (4), and the
pack might not be properly designed for G60. The aftermarket
suppliers try their best, when making this stuff. They
probably weren't trying to save money, by cutting corners.

Savvy buyers, use the reviews from previous customers, to
get some idea whether the packs are "good". If the supplier
is a middle-man and not a manufacturer, then there can be
lot-to-lot variation. Like, if the middle-man buys
from Larry one day ("good" pack) and from Moe the next
day ("bad" pack), then even sellers with reviews may
not be enough.

If the batteries were nickel cadmium, like many years ago,
there wouldn't be all these features. Batteries are
this complicated, because of the risk of fire with this
particular battery chemistry.

Paul
  #5  
Old November 28th 17, 11:19 PM posted to microsoft.public.windowsxp.general
Andy[_17_]
external usenet poster
 
Posts: 594
Default Laptop battery

On Tuesday, November 28, 2017 at 3:54:51 PM UTC-6, Paul wrote:
Andy wrote:
I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy


I can give you a basic inventory on what is in
a battery system. I don't know all the details well
enough, to provide the exact right diagnosis.

*******

The battery consists of:

1) Multiple LiCo cells, with welded conductors between
cells. The cells have protection features, like each
cell has an internal fuse, to prevent accidents.
If a battery pack goes "open circuit", a protection
feature may have tripped to prevent a fire. It can never
work after that.

2) The battery has a PCB with a small "fuel gauge" chip
on it. This communicates over a serial bus, to the laptop.
The "fuel gauge" chips, there are many brands, and the
right chip must be in there for the laptop to work with it.
The fuel gauge keeps track of "charge cycle count", as
well as a "capacity loss parameter", so that the laptop
can figure out the reduction in capacity with time, and
be in a better condition to detect when it's time to
hibernate the computer (before the battery drops below
0%). If the battery loses 0.1% of its life on each full
recharge, and the gauge logs 100 charge cycles, then the
battery has lost about 10% of absolute capacity. The fuel
gauge includes a number of registers, with information like
that stored inside. It must be properly programmed at the
factory, to represent the behavior of the cells well.

3) The plastic casing on the battery has eight contacts.
Two for VCC. Two for GND. At least one contact of the
remainder is used for the serial bus. Some packs also
have an ENABLE pin, and that prevents energy from appearing
on VCC and GND, unless the battery pack is seated in the bay.
So if you drop your screwdriver across the power blades while
the pack sits on your desk... it might not catch fire :-)
The ENABLE pin inside the laptop, would ground the pin
and signal the pack is now inside a laptop, so it's safe
for VCC and GND to connect to the actual battery cells.

4) The laptop itself has an autonomous charge management
subsystem. Even if the CPU isn't running, some kind of
chip in there charges the battery, and stops charging
before the battery is overfilled in a dangerous way.
A battery may not be properly charged, due to a failure
in that subsystem, or a failure of the power adapter.

*******

It could be that the charging process is
stopping after the CC phase. That would leave
you with 65% fuel (second graph). Maybe it takes
less time than normal, to fill to 65%. And then
less time than normal, to empty it.

http://batteryuniversity.com/learn/a..._ion_batteries

I can't say much more than that.

A battery bought from HP, probably works correctly.

Batteries should always be bought from "high volume"
sellers. A battery sitting on the shelf in a "mom and pop"
computer store, could already be ruined by aging. You
want "freshly constructed" laptop batteries for
best results. A ten year old battery, may not take
a lot of charge cycles due to age.

I suspect a disagreement between (2) and (4), and the
pack might not be properly designed for G60. The aftermarket
suppliers try their best, when making this stuff. They
probably weren't trying to save money, by cutting corners.

Savvy buyers, use the reviews from previous customers, to
get some idea whether the packs are "good". If the supplier
is a middle-man and not a manufacturer, then there can be
lot-to-lot variation. Like, if the middle-man buys
from Larry one day ("good" pack) and from Moe the next
day ("bad" pack), then even sellers with reviews may
not be enough.

If the batteries were nickel cadmium, like many years ago,
there wouldn't be all these features. Batteries are
this complicated, because of the risk of fire with this
particular battery chemistry.

Paul


Thanks to all for the good info.

I will stick to buying only HP batteries and not use the battery at all if I am using the charger.

Andy
  #6  
Old November 28th 17, 11:34 PM posted to microsoft.public.windowsxp.general
No_Name
external usenet poster
 
Posts: 177
Default Laptop battery

On Tue, 28 Nov 2017 16:54:50 -0500, Paul wrote:

be in a better condition to detect when it's time to
hibernate the computer (before the battery drops below
0%). If the battery loses 0.1% of its life on each full


How can a battery go BELOW 0% ???
That dont seem possible....

  #7  
Old November 29th 17, 12:19 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default Laptop battery

wrote:
On Tue, 28 Nov 2017 13:37:58 -0800, mike wrote:

On 11/28/2017 11:34 AM, Andy wrote:
I bought a battery for my HP G60 laptop.

It must be a poor quality battery cuz it only lasts an hour at most.

If I buy a battery, is there a way I can be sure that it holds a full charge ?

Thanks,
Andy

Test it.
No, you can't tell by asking the seller.

What's the battery life claimed by HP?
Depending on what you're doing, an hour may be good performance.

Problem with a battery for an old computer is that most any brand
name battery you find has been sitting in a container in Arizona
for a decade. It's toast. The vendor probably made any new ones
since two years after introduction.

If you buy it from China on EBAY, it was probably made by cutting up
old batteries that were stored for a decade in China and putting
them into a new-looking battery case. Or maybe used batteries.
Or maybe sub-quality cheapo cells.

You might be able to have the pack refurbished with quality cells,
but you won't like the price.

Low price is a good indicator of a weak battery.
High price is no guarantee that you won't get a weak battery.


I bought a new battery for my Lenovo T43 on ebay. When I got it, it
would not even take a charge. I left it charging for 2 days and still
nothing. I complained to the seller. He sent me another one. That one
worked great. I've been using it for a year now and still works great.
It holds a charge for 2.5 to 3 hours. The old battery that came with the
computer was so weak it woulod only hold a charge for a half hour at
most.

I find the same with cordless tools. When I bought a cordless drill, the
batteries would last several hours for intermittent use, or about 45 min
for continuous use. Three years later, I have to recharge them every
hour and they wont last more than 10 min on continuous use.

Even my car battery is dying. I have to make sure not to leave my lights
on when I leave te car, or it wont start after 15 min. I used to be able
to leave the lights on for hours....

Batteries are all meant to die. That is inevitable. Some last longer
than others though. I guess it depends on how much you pay for them. The
costly ones were made better (usually).

I'm still waiting for someone to make some liquid that you pour in the
battery to bring it back to life. I'll probably wait for this for
eternity.....


There are good battery types out there.

But they're not suitable for end-users.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

Time durability 20-30 years
Cycle durability 100,000 cycles

Not every battery type is doomed. Just the
battery types they sell to consumers. It wouldn't
make sense to sell you a battery that would last,
now would it.

*******

And you know car batteries are a scam, right ?

It is possible to make good car batteries. I had
a Panasonic sealed battery (no-maintenance) last
for seven years. The replacement batteries I
get locally, aren't nearly as good.

**** car batteries now, last for around two years.

Battery construction varies, as to whether a battery
is suited to deep discharge or not. The thing about
car batteries (the ones with a little calcium added
to the plates to "resist vibration"), is they're
ruined after only one or two deep discharges.
You had better have automatic headlights which
switch off on the car, with that battery type.

Paul
  #8  
Old November 29th 17, 02:51 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default Laptop battery

wrote:
On Tue, 28 Nov 2017 16:54:50 -0500, Paul wrote:

be in a better condition to detect when it's time to
hibernate the computer (before the battery drops below
0%). If the battery loses 0.1% of its life on each full


How can a battery go BELOW 0% ???
That dont seem possible....


Yes, it is possible.
Let's draw a picture.

Voltage "Nominal capacity"

4.2 + 100%
| \
| \
| \
Min | ----------- 0% --- laptop hibernates
| \
| \ Battery pack damaged down here.
| \ Capacity not considered usable down here.
| \
0.0 +-------------------- Time

When the battery hits 0%, the laptop is trying to
avoid damaging the battery. The battery still has
a bit more reserved capacity. Let's call it 5%. If
you don't get around to charging the battery when it's
at 0%, there is still that margin. But if you leave
the battery long enough, it will drop below the safe
charging voltage (whisker growth inside battery).

A laptop charger for a multi-cell Li battery, will
not charge the battery once it drops below the safe pack
voltage.

On a digital camera, there is a single Li cell, and
the charger for the digital camera, *will* charge
a completely flat battery (I know, because I verified
my digital camera battery was 0.0V and it recharged no
problem at all). The reason this is possible, is a
single cell battery has no possibility of reverse bias.
No possibility of bad chemistry inside the single cell
by reverse biasing.

In the case of the laptop battery pack, if there is even
a tiny load, and the battery drop too low, one
of the cells can become reverse biased (i.e. charged
the wrong way, by its peers). And that's when the
damage happens to that cell. The same sort of thing
used to happen with nickel cadmium batteries. The
difference is, when it happens to Lithium, there
is a fire hazard and so on. It's a safety issue,
and that's why, if you were to drain a laptop battery
completely flat, the charger won't touch it and it'll
stay at zero volts forever.

VCC -- (+)(-) -- (+)(-) -- (+)(-) -- GND Three cell pack
above min level.

VCC -- (+)(-) -- (-)(+) -- (+)(-) -- GND Three cell pack
too low, middle
cell is being damaged
and plates out.

The min voltage level is worked out by determining
the "knee" voltage where the cell voltage drops
real quick towards zero. The cell is no longer in
control of its own destiny when that happens. So
if one of the cells "stops pumping" the other
cells "drown it" :-) And this is also why there
is an interest in "matching the cells", as a weak
cell causes the whole battery pack to be unusable,
even though the other cells could have been used
for some purpose.

The min voltage is an estimate of how far you
can safely deplete the pack, before the cells
get into a knife fight with each other
("the weak cell loses").

So the 0% capacity point, there is still a significant
amount of voltage across the battery terminals.

Paul
  #9  
Old November 29th 17, 09:47 PM posted to microsoft.public.windowsxp.general
No_Name
external usenet poster
 
Posts: 177
Default Laptop battery

On Tue, 28 Nov 2017 18:19:56 -0500, Paul wrote:


There are good battery types out there.

But they're not suitable for end-users.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

Time durability 20-30 years
Cycle durability 100,000 cycles

Not every battery type is doomed. Just the
battery types they sell to consumers. It wouldn't
make sense to sell you a battery that would last,
now would it.

*******

And you know car batteries are a scam, right ?

It is possible to make good car batteries. I had
a Panasonic sealed battery (no-maintenance) last
for seven years. The replacement batteries I
get locally, aren't nearly as good.

**** car batteries now, last for around two years.

Battery construction varies, as to whether a battery
is suited to deep discharge or not. The thing about
car batteries (the ones with a little calcium added
to the plates to "resist vibration"), is they're
ruined after only one or two deep discharges.
You had better have automatic headlights which
switch off on the car, with that battery type.

Paul


I have an "antique" Allis Chalmers farm tractor from around 1960. When I
bought it, I found that the generator (not alternator) was polarized
backward. The body of the tractor was intended to be POSITIVE GROUND.
However when I connected a battery charger I saw lots of sparks. A
multimeter confirmed the polarity was reversed, meaning that the battery
itself was charged backward. In other words, the post marked (POS+) was
Negative and vice versa. (Yes, this even puzzled several pro mechanics).
It turns out that this can and did happen with the old generators if
they were not polarized everytime the battery is disconnected. (but it
was a rare occurance).

While trying to understand this whole mess, I noted the punch out date
thingie on the battery. That battery was 15 years old, and it still took
a charge. I was stunned..... If they made them half as good as that
now-a-days, I'd be happy. Not only was that battery 15 years oold, but
it had been abused to the limit by reversing it's polarity.

I did replace it though. It was weak, and I was told to NOT try to
reverse the polarity another time, since that could completely ruin the
battery, damage the charging components, or possibly even make the
battery explode. In order to reverse it, it needs to be drained to ZERO
volts and remain that way for many hours. (in other words, leave the
headlights on for several days).

My guess is that this tractor was not being used and the battery was
completely dead. Someone used jumper cables and put the NEG jumper to
the ground. Thus, the battery began charging backwards and remained that
way.

By the way, this was a common 12V battery just like those in cars.

  #10  
Old November 30th 17, 05:55 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default Laptop battery

wrote:
On Tue, 28 Nov 2017 18:19:56 -0500, Paul wrote:

There are good battery types out there.

But they're not suitable for end-users.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

Time durability 20-30 years
Cycle durability 100,000 cycles

Not every battery type is doomed. Just the
battery types they sell to consumers. It wouldn't
make sense to sell you a battery that would last,
now would it.

*******

And you know car batteries are a scam, right ?

It is possible to make good car batteries. I had
a Panasonic sealed battery (no-maintenance) last
for seven years. The replacement batteries I
get locally, aren't nearly as good.

**** car batteries now, last for around two years.

Battery construction varies, as to whether a battery
is suited to deep discharge or not. The thing about
car batteries (the ones with a little calcium added
to the plates to "resist vibration"), is they're
ruined after only one or two deep discharges.
You had better have automatic headlights which
switch off on the car, with that battery type.

Paul


I have an "antique" Allis Chalmers farm tractor from around 1960. When I
bought it, I found that the generator (not alternator) was polarized
backward. The body of the tractor was intended to be POSITIVE GROUND.
However when I connected a battery charger I saw lots of sparks. A
multimeter confirmed the polarity was reversed, meaning that the battery
itself was charged backward. In other words, the post marked (POS+) was
Negative and vice versa. (Yes, this even puzzled several pro mechanics).
It turns out that this can and did happen with the old generators if
they were not polarized everytime the battery is disconnected. (but it
was a rare occurance).

While trying to understand this whole mess, I noted the punch out date
thingie on the battery. That battery was 15 years old, and it still took
a charge. I was stunned..... If they made them half as good as that
now-a-days, I'd be happy. Not only was that battery 15 years oold, but
it had been abused to the limit by reversing it's polarity.

I did replace it though. It was weak, and I was told to NOT try to
reverse the polarity another time, since that could completely ruin the
battery, damage the charging components, or possibly even make the
battery explode. In order to reverse it, it needs to be drained to ZERO
volts and remain that way for many hours. (in other words, leave the
headlights on for several days).

My guess is that this tractor was not being used and the battery was
completely dead. Someone used jumper cables and put the NEG jumper to
the ground. Thus, the battery began charging backwards and remained that
way.

By the way, this was a common 12V battery just like those in cars.


There is a "formation" process for lead acid batteries, but
I don't know whether it's reversible or not, or even what
chemical step it causes.

https://www.google.com/patents/US3929505

I thought the idea was, that the electrodes in a lead acid
battery weren't the same (weren't perfectly symmetric),
so the battery properties won't necessarily be all
that good if it's reversed. Or if there was a way to
reverse it.

As for the tractor, apparently you can get alternator
conversion kits for at least some generator based
tractors.

Generators are horrible devices, in that the output
rises with RPMs. There is no closed loop feedback
system to tame them.

The generator on my bicycle is an example. It produces
6V at 500mA. It's considered to be a "constant current source".
It tries to pump the 500mA, no matter what the voltage.
If you "overload" the bicycle generator, the voltage
drops (maybe it makes 5V at 500mA). On the other hand,
if you leave the bicycle generator open circuit, it *still*
tries to push the 500mA, but the resistance of the air
is too high to allow that. So the generator voltage rises
to a voltage proportional to RPM rate. The faster it
spins, the higher the voltage. Apparently you can get
50 to 100V off the thing in that condition (open circuit).
No, I haven't tested for that :-) But I did take these
properties into account when designing a LED headlight
for it.

The 500mA was selected as a saturation condition during the
design of the generator. You select light-bulbs with
12 ohms of resistance (when glowing), and everything
works perfect. If you use the wrong bulb, the voltage
can shoot up, ruining the bulb. (I lost a very nice
sealed beam headlight that way, while riding down a hill.)

The tractor generator should be similarly untamed. At
low RPMs, it's not going to charge the battery. At
high RPMs, a means is needed to tame the output. And
I cannot imagine what cack-handed solution they would
have used. The automotive industry always finds a
"hunk of iron" way to fix stuff like this, so I really
don't want to know how that works :-) Nothing in electrical
design around engines, is ever pleasant to read about.
It always involves abusing stuff, stuff that wears out.

The "alternator" on the other hand, is a closed loop
feedback system. By adjusting the field winding,
the output can be tamed for the engine RPMs
at the moment. And the voltage regulator is in
control of the field winding. It's still a pretty crude
system, as, for example, the voltage regulator
might not be temperature compensated, and who
knows whether the "charging target voltage" of
the voltage regulator, is correct for the
atmospheric temperature applied to the battery
casing. Battery voltage varies wildly with temp,
and the terminal voltage isn't the same at -20C
versus +20C. And this is why doing a simple-minded
multimeter voltage check on a battery, is
meaningless... unless you used a chart to
correct for temperature. As otherwise, in the
cold, a "full" battery can look "empty", just
based on a multimeter reading.

Paul
  #11  
Old November 30th 17, 07:54 AM posted to microsoft.public.windowsxp.general
mike[_10_]
external usenet poster
 
Posts: 1,073
Default Laptop battery

On 11/29/2017 8:55 PM, Paul wrote:
wrote:
On Tue, 28 Nov 2017 18:19:56 -0500, Paul wrote:

There are good battery types out there.

But they're not suitable for end-users.

https://en.wikipedia.org/wiki/Vanadium_redox_battery

Time durability 20-30 years
Cycle durability 100,000 cycles

Not every battery type is doomed. Just the
battery types they sell to consumers. It wouldn't
make sense to sell you a battery that would last,
now would it.

*******

And you know car batteries are a scam, right ?

It is possible to make good car batteries. I had
a Panasonic sealed battery (no-maintenance) last
for seven years. The replacement batteries I
get locally, aren't nearly as good.

**** car batteries now, last for around two years.

Battery construction varies, as to whether a battery
is suited to deep discharge or not. The thing about
car batteries (the ones with a little calcium added
to the plates to "resist vibration"), is they're
ruined after only one or two deep discharges.
You had better have automatic headlights which
switch off on the car, with that battery type.

Paul


I have an "antique" Allis Chalmers farm tractor from around 1960. When I
bought it, I found that the generator (not alternator) was polarized
backward. The body of the tractor was intended to be POSITIVE GROUND.
However when I connected a battery charger I saw lots of sparks. A
multimeter confirmed the polarity was reversed, meaning that the battery
itself was charged backward. In other words, the post marked (POS+) was
Negative and vice versa. (Yes, this even puzzled several pro mechanics).
It turns out that this can and did happen with the old generators if
they were not polarized everytime the battery is disconnected. (but it
was a rare occurance).
While trying to understand this whole mess, I noted the punch out date
thingie on the battery. That battery was 15 years old, and it still took
a charge. I was stunned..... If they made them half as good as that
now-a-days, I'd be happy. Not only was that battery 15 years oold, but
it had been abused to the limit by reversing it's polarity.
I did replace it though. It was weak, and I was told to NOT try to
reverse the polarity another time, since that could completely ruin the
battery, damage the charging components, or possibly even make the
battery explode. In order to reverse it, it needs to be drained to ZERO
volts and remain that way for many hours. (in other words, leave the
headlights on for several days).

My guess is that this tractor was not being used and the battery was
completely dead. Someone used jumper cables and put the NEG jumper to
the ground. Thus, the battery began charging backwards and remained that
way.

By the way, this was a common 12V battery just like those in cars.


There is a "formation" process for lead acid batteries, but
I don't know whether it's reversible or not, or even what
chemical step it causes.

https://www.google.com/patents/US3929505

I thought the idea was, that the electrodes in a lead acid
battery weren't the same (weren't perfectly symmetric),
so the battery properties won't necessarily be all
that good if it's reversed. Or if there was a way to
reverse it.

As for the tractor, apparently you can get alternator
conversion kits for at least some generator based
tractors.

Generators are horrible devices, in that the output
rises with RPMs. There is no closed loop feedback
system to tame them.

The generator on my bicycle is an example. It produces
6V at 500mA. It's considered to be a "constant current source".
It tries to pump the 500mA, no matter what the voltage.
If you "overload" the bicycle generator, the voltage
drops (maybe it makes 5V at 500mA). On the other hand,
if you leave the bicycle generator open circuit, it *still*
tries to push the 500mA, but the resistance of the air
is too high to allow that. So the generator voltage rises
to a voltage proportional to RPM rate. The faster it
spins, the higher the voltage. Apparently you can get
50 to 100V off the thing in that condition (open circuit).
No, I haven't tested for that :-) But I did take these
properties into account when designing a LED headlight
for it.

The 500mA was selected as a saturation condition during the
design of the generator. You select light-bulbs with
12 ohms of resistance (when glowing), and everything
works perfect. If you use the wrong bulb, the voltage
can shoot up, ruining the bulb. (I lost a very nice
sealed beam headlight that way, while riding down a hill.)

The tractor generator should be similarly untamed. At
low RPMs, it's not going to charge the battery. At
high RPMs, a means is needed to tame the output. And
I cannot imagine what cack-handed solution they would
have used. The automotive industry always finds a
"hunk of iron" way to fix stuff like this, so I really
don't want to know how that works :-) Nothing in electrical
design around engines, is ever pleasant to read about.
It always involves abusing stuff, stuff that wears out.

The "alternator" on the other hand, is a closed loop
feedback system. By adjusting the field winding,
the output can be tamed for the engine RPMs
at the moment. And the voltage regulator is in
control of the field winding. It's still a pretty crude
system, as, for example, the voltage regulator
might not be temperature compensated, and who
knows whether the "charging target voltage" of
the voltage regulator, is correct for the
atmospheric temperature applied to the battery
casing. Battery voltage varies wildly with temp,
and the terminal voltage isn't the same at -20C
versus +20C. And this is why doing a simple-minded
multimeter voltage check on a battery, is
meaningless... unless you used a chart to
correct for temperature. As otherwise, in the
cold, a "full" battery can look "empty", just
based on a multimeter reading.

Paul

Car generators have had regulators for as long as I can
remember. 1955 was the oldest car I've had. Was sloppy.
Just a relay that had a soft spring that gave a couple
of levels of control.
  #12  
Old November 30th 17, 08:33 AM posted to microsoft.public.windowsxp.general
Paul[_32_]
external usenet poster
 
Posts: 11,873
Default Laptop battery

mike wrote:

Car generators have had regulators for as long as I can
remember. 1955 was the oldest car I've had. Was sloppy.
Just a relay that had a soft spring that gave a couple
of levels of control.


So I take it then, it was just designed to
destroy the battery ? :-) That sounds like the
car companies I know and love.

Does it ever stop charging the battery, or does
the '55 battery get ruined ? There are two ways
to ruin a battery - sulfation (too little charging
between uses) and corrosion (too much charging).

https://en.wikipedia.org/wiki/Lead%E..._desulfatio n

I had the exact opposite problem here with my car,
where the alternator and voltage regulator were
hardly pumping any current into the battery. And
I couldn't really tell if the net charging rate
was sufficient to keep the car starting or not.
I kept having to throw the charger on it in the
winter. And the headlights behaved normally, not
like headlights behave on older cars (dim at low
RPM). It was almost like the voltage regulator
wasn't regulating to the correct voltage.

Every time I work on cars and their charging systems,
none of my measurements make any sense :-) The car
battery voltage is never even remotely close to
textbook, and I end up not really knowing what's
going on. I have a hydrometer, and that's the only
sanity check that really works.

https://en.wikipedia.org/wiki/Hydrometer

Battery hydrometer

... Tables are used to correct the reading
to the standard temperature

Paul
  #13  
Old November 30th 17, 09:42 AM posted to microsoft.public.windowsxp.general
No_Name
external usenet poster
 
Posts: 177
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On Thu, 30 Nov 2017 02:33:58 -0500, Paul wrote:

mike wrote:

Car generators have had regulators for as long as I can
remember. 1955 was the oldest car I've had. Was sloppy.
Just a relay that had a soft spring that gave a couple
of levels of control.


So I take it then, it was just designed to
destroy the battery ? :-) That sounds like the
car companies I know and love.

Does it ever stop charging the battery, or does
the '55 battery get ruined ? There are two ways
to ruin a battery - sulfation (too little charging
between uses) and corrosion (too much charging).


That generator obviously did not ruin my tractor battery which lasted 15
years. THe generator has a voltage regulator, There are 4 wires going to
it, there are 3 relays inside and some other parts. I dont know exactly
how it works, but it does work. However those generator voltage regs do
seem to need a lot of care, and/or replacements.

My Allis model is one of the few tractors which are very difficult to
change to an alternator. Changing the wiring is easy, but not mounting
the alternator, which needs to line up with the fan pulley. The engine
mount and bracket are in the way, and they cant be modified, so it's
very hard to mount the alternator, other than cutting away part of the
hood and having it sticking way outside the tractor. Otherwise I'd have
an alternator in there. My old International Farmall tractors, which
I've owned 3 of, are easy to convert. I have also converted a Case
tractor and a few more Farmall's owned by friends.


https://en.wikipedia.org/wiki/Lead%E..._desulfatio n

I had the exact opposite problem here with my car,
where the alternator and voltage regulator were
hardly pumping any current into the battery. And
I couldn't really tell if the net charging rate
was sufficient to keep the car starting or not.
I kept having to throw the charger on it in the
winter. And the headlights behaved normally, not
like headlights behave on older cars (dim at low
RPM). It was almost like the voltage regulator
wasn't regulating to the correct voltage.


Dont matter if it's a generator or an alternator. If the voltage
regulator is not working properly, it wont charge properly.
However, the V.R.s on alternators are simpler, and most are now soild
state. No one has made a solid state V.R. for generators (that I know
of).


Every time I work on cars and their charging systems,
none of my measurements make any sense :-) The car
battery voltage is never even remotely close to
textbook, and I end up not really knowing what's
going on. I have a hydrometer, and that's the only
sanity check that really works.

https://en.wikipedia.org/wiki/Hydrometer

Battery hydrometer


A hydrometer is a good tool, so is a battery tester. But a battery
tester is not just a multimeter, it has a large resistor that loads the
battery. A battery must be under load to test it properly. (even the
small D C AA or AAA batteries need a tester that loads it.


... Tables are used to correct the reading
to the standard temperature

Paul


  #14  
Old November 30th 17, 10:00 AM posted to microsoft.public.windowsxp.general
mike[_10_]
external usenet poster
 
Posts: 1,073
Default Laptop battery

On 11/29/2017 11:33 PM, Paul wrote:
mike wrote:

Car generators have had regulators for as long as I can
remember. 1955 was the oldest car I've had. Was sloppy.
Just a relay that had a soft spring that gave a couple
of levels of control.


So I take it then, it was just designed to
destroy the battery ? :-) That sounds like the
car companies I know and love.

Does it ever stop charging the battery, or does
the '55 battery get ruined ? There are two ways
to ruin a battery - sulfation (too little charging
between uses) and corrosion (too much charging).

Was the best affordable technology available.
Not having an alternative is a strong motivator
to accept what you get.

 




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