battery protection components

L

legg

Guest
In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening and
demonstrably firmware-corrupting manner.

No access to scope firmware....

RL
 
In article <jdlrua9rhnlnvgolvqpqfppdku2d5qe918@4ax.com>,
legg <legg@nospam.magma.ca> wrote:

In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening and
demonstrably firmware-corrupting manner.

No access to scope firmware....

RL
Click to expand...

Usually the protection cuts discharging below 2.4V and charging above
4.3 volts, with some temperature compensation. A PTC fuse limits
current. There's nothing else to it - it's strictly for momentary fault
protection.

An old battery may have a high impedance that's triggering firmware
bugs. Fancy chargers have a lockout timer for restarting a charge cycle
to prevent constant top-offs of a failed battery that no longer appears
to be charged.

--
I will not see posts from astraweb, theremailer, dizum, or google
because they host Usenet flooders.
 
On Sat, 12 Sep 2015 22:16:03 -0700, Kevin McMurtrie
<mcmurtrie@pixelmemory.us> wrote:

In article <jdlrua9rhnlnvgolvqpqfppdku2d5qe918@4ax.com>,
legg <legg@nospam.magma.ca> wrote:

In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening and
demonstrably firmware-corrupting manner.

No access to scope firmware....

RL

Usually the protection cuts discharging below 2.4V and charging above
4.3 volts, with some temperature compensation. A PTC fuse limits
current. There's nothing else to it - it's strictly for momentary fault
protection.

An old battery may have a high impedance that's triggering firmware
bugs. Fancy chargers have a lockout timer for restarting a charge cycle
to prevent constant top-offs of a failed battery that no longer appears
to be charged.
Click to expand...

I expect these to be fairly simple devices, but need more accurate
info on what thresholds are expected, and method used to introduce
hysterisis etc.

This is a brand-dedicated series/parallel pack that expects ~constant
voltage charge limit ~ another issue of this end-use. Thermal fuse is
present (no ptc).

Even new packs have the same issue at end of discharge in these
scopes, though with less bizarre symptoms. Aim is to prevent firmware
from tripping over itself, even if it means external rework in
hardware.

Batteries become 'aged' fairly rapidly under the circumstances, with
capacity halved in the first year, but they don't require a remote
depot servicing at inconvenient times, as a result.

RL
 
Once upon a time on usenet Kevin McMurtrie wrote:
In article <jdlrua9rhnlnvgolvqpqfppdku2d5qe918@4ax.com>,
legg <legg@nospam.magma.ca> wrote:

In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening
and demonstrably firmware-corrupting manner.

No access to scope firmware....

RL

Usually the protection cuts discharging below 2.4V and charging above
4.3 volts, with some temperature compensation.
Click to expand...

4.2v is a better cutoff voltage for lithium cells, most are specced for
4.2v. Charging to 4.3 will halve the life of the cells and only slightly
increase capacity. (4.1v will increase cell life by about 20% but reduce
stored energy by about 15%.)
--
Shaun.

"Humans will have advanced a long, long way when religious belief has a cozy
little classification in the DSM*."
David Melville (in r.a.s.f1)
(*Diagnostic and Statistical Manual of Mental Disorders)

A PTC fuse limits
current. There's nothing else to it - it's strictly for momentary
fault protection.

An old battery may have a high impedance that's triggering firmware
bugs. Fancy chargers have a lockout timer for restarting a charge
cycle to prevent constant top-offs of a failed battery that no longer
appears to be charged.
Click to expand...
 
In article <mt7vvm$ocv$1@dont-email.me>,
"~misfit~" <shaun.at.pukekohe@gmail.com> wrote:

Once upon a time on usenet Kevin McMurtrie wrote:
In article <jdlrua9rhnlnvgolvqpqfppdku2d5qe918@4ax.com>,
legg <legg@nospam.magma.ca> wrote:

In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening
and demonstrably firmware-corrupting manner.

No access to scope firmware....

RL

Usually the protection cuts discharging below 2.4V and charging above
4.3 volts, with some temperature compensation.

4.2v is a better cutoff voltage for lithium cells, most are specced for
4.2v. Charging to 4.3 will halve the life of the cells and only slightly
increase capacity. (4.1v will increase cell life by about 20% but reduce
stored energy by about 15%.)
Click to expand...

The protection circuit is only for momentary faults, like a short to 0V
or a high unregulated voltage. I've never seen one that provides
continuous protection.

From what I've read, 4.1 volts (temperature compensated) is the only
safe trickle voltage and it never produces a full charge. I'm using a
pair of LTC4070 for a pair of solar charged LiPo cells. So far, no
explosion.

--
I will not see posts from astraweb, theremailer, dizum, or google
because they host Usenet flooders.
 
On Mon, 14 Sep 2015 22:30:32 -0700, Kevin McMurtrie
<mcmurtrie@pixelmemory.us> wrote:

In article <mt7vvm$ocv$1@dont-email.me>,
"~misfit~" <shaun.at.pukekohe@gmail.com> wrote:

Once upon a time on usenet Kevin McMurtrie wrote:
In article <jdlrua9rhnlnvgolvqpqfppdku2d5qe918@4ax.com>,
legg <legg@nospam.magma.ca> wrote:

In a non-smart Lithium battery used in an oscilloscope.

BV3P1N SOP8 body - some kind of fet used back-back in series.

CGH1 SOT23 6pin possibly an undervoltage controller.

Any accurate info out there? At present the scope firmware interacts
with the battery at end of charge in a potentially life-shortening
and demonstrably firmware-corrupting manner.

No access to scope firmware....

RL

Usually the protection cuts discharging below 2.4V and charging above
4.3 volts, with some temperature compensation.

4.2v is a better cutoff voltage for lithium cells, most are specced for
4.2v. Charging to 4.3 will halve the life of the cells and only slightly
increase capacity. (4.1v will increase cell life by about 20% but reduce
stored energy by about 15%.)

The protection circuit is only for momentary faults, like a short to 0V
or a high unregulated voltage. I've never seen one that provides
continuous protection.

From what I've read, 4.1 volts (temperature compensated) is the only
safe trickle voltage and it never produces a full charge. I'm using a
pair of LTC4070 for a pair of solar charged LiPo cells. So far, no
explosion.
Click to expand...

The charging isn't the immediate issue, its interaction with the
hardware at end of charge I'm looking at, hence need for info on
internal UVLO circuit (assumed) components.

CGH1 SOT23 6pin

This is a series/parallel pack with trickle voltage speced at 8V4.
If charging is aging the cells prematurely, it would only mean that
EOC conditions were reached more often.

Distinct odor of outgassing from these devices, when plugged in, so
the charging circuit will need some looking into.

RL
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top