Re: [EVDL] [EVADC Listserve] Exploding cell

2014-06-18 Thread Cor van de Water via EV 
Was it compressed?
Plenty others have found that uncompressed cells will not just
bulge but actually destroy themselves when they charge fast enough
to generate a lot of gassing...

Cor van de Water
Chief Scientist
Proxim Wireless Corporation http://www.proxim.com
Email: cwa...@proxim.com Private: http://www.cvandewater.info
Skype: cor_van_de_water Tel: +1 408 383 7626


-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Robert Bruninga
via EV
Sent: Wednesday, June 18, 2014 8:01 AM
To: ev...@yahoogroups.com
Cc: ev@lists.evdl.org
Subject: Re: [EVDL] [EVADC Listserve] Exploding cell

The prius has 28 modules, and each module (about the size of a paper
back
book, only taller) has 6 cells.  Each cell is about a 5 AH cell.  So the
module voltage was about 7.5  volts.



Bob



*From:* ev...@yahoogroups.com [mailto:ev...@yahoogroups.com]
*Sent:* Wednesday, June 18, 2014 9:20 AM
*To:* ev...@yahoogroups.com
*Cc:* ev@lists.evdl.org
*Subject:* Re: [EVADC Listserve] Exploding cell






Were you testing a pack of cells, if so, how many cells total in the
pack
and what is pack voltage? Just curious Bob, I don't know much about
NimH.



On Wed, Jun 18, 2014 at 8:54 AM, Robert Bruninga bruni...@usna.edu
[EVADC] <
ev...@yahoogroups.com> wrote:



Kaboom goes the cell!



Was testing a battery module from my Prius on a battery analyzer.  The
test
plan begins with a several  minute no-load, then a 1C load for up to 1
hour, then a several minute no-load, then a charge at 1C until peak
voltage
is detected.



After 3 minutes, a cell exploded that could be heard all over the
building.



Best I can tell, there was a less than perfect connection to the battery
terminal.  The initial 1C load only lasted 3 seconds (when it determined
that the low-voltage had been reached).  So then, 10 minutes later it
began
a 1C charge (on what was a full battery).  And we all know that charging
a
full NimH battery will explode.



Lesson learned.  1) Hang around and WAIT for  the initial discharge and
WATCH that it is going correctly before leaving the test.

2) Always assume a battery may explode and do testing where it will do
no
damage.



Programmers:  When programming battery analyzers consider a bad
connection
on the DIScharge cycle that might give an erroneous indication of a
discharged battery and fault the test.  Do not then continue to the
charge
cycle.



Bob, WB4APR








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Re: [EVDL] [EVADC Listserve] Exploding cell

2014-06-18 Thread George Tyler via EV 
Was the module you were charging in a pack? i.e. was it compressed mechanically 
by the end plates? There modules will explode if you charge them without 
pressure being applied to the sides. I have also seen modules that are properly 
mounted that have had an internal explosion in a dead cell. The cell it's self 
was totally dry, all the water having been converted into hydrogen and oxygen.
My 4 Priuses are all the NHW10 original Japanese only models with "D" 
cells. I have done a lot of work on these and have never seen a exploded cell, 
all that happens to these is that the cells leak electrolyte if they get to hot.

-Original Message-
From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of Robert Bruninga via EV
Sent: Thursday, 19 June 2014 3:01 a.m.
To: ev...@yahoogroups.com
Cc: ev@lists.evdl.org
Subject: Re: [EVDL] [EVADC Listserve] Exploding cell

The prius has 28 modules, and each module (about the size of a paper back book, 
only taller) has 6 cells.  Each cell is about a 5 AH cell.  So the module 
voltage was about 7.5  volts.



Bob



*From:* ev...@yahoogroups.com [mailto:ev...@yahoogroups.com]
*Sent:* Wednesday, June 18, 2014 9:20 AM
*To:* ev...@yahoogroups.com
*Cc:* ev@lists.evdl.org
*Subject:* Re: [EVADC Listserve] Exploding cell






Were you testing a pack of cells, if so, how many cells total in the pack and 
what is pack voltage? Just curious Bob, I don't know much about NimH.



On Wed, Jun 18, 2014 at 8:54 AM, Robert Bruninga bruni...@usna.edu [EVADC] < 
ev...@yahoogroups.com> wrote:



Kaboom goes the cell!



Was testing a battery module from my Prius on a battery analyzer.  The test 
plan begins with a several  minute no-load, then a 1C load for up to 1 hour, 
then a several minute no-load, then a charge at 1C until peak voltage is 
detected.



After 3 minutes, a cell exploded that could be heard all over the building.



Best I can tell, there was a less than perfect connection to the battery 
terminal.  The initial 1C load only lasted 3 seconds (when it determined that 
the low-voltage had been reached).  So then, 10 minutes later it began a 1C 
charge (on what was a full battery).  And we all know that charging a full NimH 
battery will explode.



Lesson learned.  1) Hang around and WAIT for  the initial discharge and WATCH 
that it is going correctly before leaving the test.

2) Always assume a battery may explode and do testing where it will do no 
damage.



Programmers:  When programming battery analyzers consider a bad connection on 
the DIScharge cycle that might give an erroneous indication of a discharged 
battery and fault the test.  Do not then continue to the charge cycle.



Bob, WB4APR








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Re: [EVDL] [EVADC Listserve] Exploding cell

2014-06-18 Thread Robert Bruninga via EV 
The prius has 28 modules, and each module (about the size of a paper back
book, only taller) has 6 cells.  Each cell is about a 5 AH cell.  So the
module voltage was about 7.5  volts.



Bob



*From:* ev...@yahoogroups.com [mailto:ev...@yahoogroups.com]
*Sent:* Wednesday, June 18, 2014 9:20 AM
*To:* ev...@yahoogroups.com
*Cc:* ev@lists.evdl.org
*Subject:* Re: [EVADC Listserve] Exploding cell






Were you testing a pack of cells, if so, how many cells total in the pack
and what is pack voltage? Just curious Bob, I don't know much about NimH.



On Wed, Jun 18, 2014 at 8:54 AM, Robert Bruninga bruni...@usna.edu [EVADC] <
ev...@yahoogroups.com> wrote:



Kaboom goes the cell!



Was testing a battery module from my Prius on a battery analyzer.  The test
plan begins with a several  minute no-load, then a 1C load for up to 1
hour, then a several minute no-load, then a charge at 1C until peak voltage
is detected.



After 3 minutes, a cell exploded that could be heard all over the building.



Best I can tell, there was a less than perfect connection to the battery
terminal.  The initial 1C load only lasted 3 seconds (when it determined
that the low-voltage had been reached).  So then, 10 minutes later it began
a 1C charge (on what was a full battery).  And we all know that charging a
full NimH battery will explode.



Lesson learned.  1) Hang around and WAIT for  the initial discharge and
WATCH that it is going correctly before leaving the test.

2) Always assume a battery may explode and do testing where it will do no
damage.



Programmers:  When programming battery analyzers consider a bad connection
on the DIScharge cycle that might give an erroneous indication of a
discharged battery and fault the test.  Do not then continue to the charge
cycle.



Bob, WB4APR








__._,_.___
--

Posted by: jo reyes 
--



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*

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