Audiokarma.org
Audiokarma Featured Sponsor

Go Back   AudioKarma.org Home Audio Stereo Discussion Forums > DIY


We appreciate your help

in keeping this site going.
Reply
 
Thread Tools Display Modes
  #1  
Old 01-12-2009, 06:09 AM
SaSi's Avatar
SaSi SaSi is offline
Rediscovering analog
 
Join Date: Dec 2007
Location: Athens, Greece
Posts: 3,788
Reviving a dead Li-Ion battery

I was given a perfectly working aiwa Minidisk portable player (AM-F70). But the battery was dead. The multimeter read 0.00V after 2 hours of charging.

I seems there is absolutely no source for the obscure battery in this deck, so I tried a trick that I never had the opportunity to test:

Took a 12V power supply and touched the poles of the dead battery with that to trickle charge it. The actual Li-ion battery for the aiwa is rated at 3.6v.

After the first 10-20 second revival charge, the meter read 0.5v or something. After a few more cycles, it read 2.5v.

At that point i mounted the battery back to the player for a proper charging with the unit's charger.

After about an hour or more it stopped charging and I tried the unit off the battery. It works. It played a complete MD of 74min and still was 3/3 charge. The specs for the unit are for 10 hours continuous play, and this is something I will test today, as soon as I find a MD with decent music in it.
Reply With Quote
  #2  
Old 01-12-2009, 07:28 AM
ozmoid's Avatar
ozmoid ozmoid is offline
AK Member
 
Join Date: Jul 2005
Posts: 13,431
Li-ion batteries have a finite life of around three years. The power loss to aging has a very slow taper at first that drops dramatically at the end of the battery's life. I'd keep looking for a replacement. YMMV.
__________________
Nothing outside you can ever give you what you're looking for. I'm gone fishing... see you at the pond.
Reply With Quote
  #3  
Old 01-12-2009, 08:23 AM
SaSi's Avatar
SaSi SaSi is offline
Rediscovering analog
 
Join Date: Dec 2007
Location: Athens, Greece
Posts: 3,788
Well, without any insult intended, I really hope you are wrong (lol). That battery is certainly much older than 3 years. I think this player was bought in 2000 or 2001 - my friend bought that briefly before the Euro was introduced.

I guess there's no way this battery can be sourced anymore. The only other solution would be using an external pack with 3xAA batteries, not something really suitable for this nice pocket player.

I guess I will enjoy whatever life there's left in this battery.
Reply With Quote
  #4  
Old 01-12-2009, 08:39 AM
Ed in Tx's Avatar
Ed in Tx Ed in Tx is offline
AK Member
 
Join Date: Nov 2008
Location: DFW
Posts: 4,763
What you did you the Li-Ion battery sounds similar to what I have done to "fix" internally shorted NiCad batteries.. give the shorted cell a good "zap" with much higher voltage for a brief instant. This can temporarily open the conductive dendrite crystals that form internally in a NiCad that make it read 0 Volts even after a brief charge time (and near 0 Ohms with an Ohm meter too). I've saved several battery packs my zapping cells to open up internal shorts, usually just a temoporary measure though the problems usually come back since this happens mostly on aged batteries. Did not know you could do that with Li-Ion.
Reply With Quote
  #5  
Old 01-12-2009, 08:44 AM
similost's Avatar
similost similost is offline
Rockin and Rollin....
 
Join Date: May 2006
Location: West By God Virginnie
Posts: 36,471
I'd be very careful doing something like this. While yes, it can work to save a battery, or at least get a little longer life out of it, you can also run the risk of explosion.

If a person were to heat a battery up too much, because of a bad short inside or similar, they migh find new meaning to the Big Bang theory... Not really any difference than over charging a capicator and blowing it up.. a battery is basically the same thing...
__________________
Barziwaves Baby!!! It's where it's at.
Reply With Quote
Audiokarma
  #6  
Old 01-12-2009, 09:00 AM
Ed in Tx's Avatar
Ed in Tx Ed in Tx is offline
AK Member
 
Join Date: Nov 2008
Location: DFW
Posts: 4,763
Yep I agree with the hazard. While I have opened up shorted NiCads I've done it with very brief connects, no time for anything to heat up and expand. About 1 second at a time, then check to see if the short's gone, if it is, then put the battery on a regular charger and let it charge normally. Li-Ions though are a different thing altogether. Some Li-Ions have internal charge monitoring circuitry built into the battery pack.
Reply With Quote
  #7  
Old 01-12-2009, 09:23 AM
ozmoid's Avatar
ozmoid ozmoid is offline
AK Member
 
Join Date: Jul 2005
Posts: 13,431
http://www.batteryuniversity.com/parttwo-34.htm

It is a combination of discharge cycles and time. Again, YMMV.
__________________
Nothing outside you can ever give you what you're looking for. I'm gone fishing... see you at the pond.
Reply With Quote
  #8  
Old 01-12-2009, 11:49 AM
mhardy6647's Avatar
mhardy6647 mhardy6647 is offline
AK Member
 
Join Date: Sep 2002
Location: New England
Posts: 43,503
I thought that lithium-ion batteries were (relatively) immune from memory effects and allowed much higher numbers of charge/drain cycles than 'the competition'...(?)
__________________
Preamps need drive, not gain. - G. Kaufman
Reply With Quote
  #9  
Old 01-12-2009, 05:18 PM
SaSi's Avatar
SaSi SaSi is offline
Rediscovering analog
 
Join Date: Dec 2007
Location: Athens, Greece
Posts: 3,788
Well, I started the test early in the evening as soon as returned home. I had left the MD player plugged in so it should be fully charged.

I started playback of a disk in repeat mode with the volume set to 5/20 and DSL (bass boost) set to 3/3. This is pretty loud with the earplug headphones I have.

I started at 19:15 local time (GMT+2) and it is now 1:15 local time. It's been 6 hours and it still plays happily. The battery indicator is at 1/3 for sometime now - I missed the transition. I assume that a 6 hour flat operation is harder for the battery than interrupted use of 30 min ~ 1 hour - is that correct?

Anyway, the battery may still be alive and kicking, but I really need to turn in, so the test will stop now and continue tomorrow evening.

@Osmoid: Thanks a lot for the link. It was very enlightning.
@Mhardy: Li-ion batteries don't suffer from memory effect. What they don't like is a total drain, almost the same as lead-zinc batteries.
Reply With Quote
  #10  
Old 01-12-2009, 05:50 PM
Cantabury Guy's Avatar
Cantabury Guy Cantabury Guy is offline
AK Member
 
Join Date: Sep 2006
Posts: 1,231
Quote:
Originally Posted by SaSi View Post
Well, without any insult intended, I really hope you are wrong (lol). That battery is certainly much older than 3 years. I think this player was bought in 2000 or 2001 - my friend bought that briefly before the Euro was introduced.

I guess there's no way this battery can be sourced anymore. The only other solution would be using an external pack with 3xAA batteries, not something really suitable for this nice pocket player.

I guess I will enjoy whatever life there's left in this battery.
Would the battery in question be one of those BP 2X?
Reply With Quote
Audiokarma
  #11  
Old 01-12-2009, 06:05 PM
DENNYDOG's Avatar
DENNYDOG DENNYDOG is offline
AK Member
 
Join Date: Feb 2007
Location: South Central,MN
Posts: 7,023
You could probably find a single 3.6v lithium ion battery that you could modify to fit. I believe that 3.6v is the standard for a single cell Li-Ion.
Reply With Quote
  #12  
Old 01-12-2009, 06:24 PM
Strawman's Avatar
Strawman Strawman is offline
Moderator
 
Join Date: Apr 2005
Location: Fraser, Mi.
Posts: 8,959
that's what I wou;d be thinking Denny, battery life cycles are going to be a wonderful future for the next generation. Just pay attention to the MaH rating SASI.
__________________
If all 40,000+ of us gave $3 a year, we could completely cover the server hosting and bandwidth bill for AK.
Reply With Quote
  #13  
Old 01-12-2009, 06:27 PM
SaSi's Avatar
SaSi SaSi is offline
Rediscovering analog
 
Join Date: Dec 2007
Location: Athens, Greece
Posts: 3,788
Modifying readily available cells might be what I will be forced to do in the future (perhaps near). Problem is the battery for the unit (LIB-902) is a long (3") and thin rectangular shaped brick. Threre certainly isn't much space for 3xAAA cells. It might be feasible to use 3x3.6V cells wired in parallel.

The LIB902 battery gives a 700mAh rating
Reply With Quote
  #14  
Old 01-12-2009, 06:46 PM
KingBubba's Avatar
KingBubba KingBubba is offline
"Too Much Stuff"
 
Join Date: Mar 2006
Location: Brooksville, Fl.
Posts: 6,047
Some battery places will do rebuilds by replacing the cells inside the cases.
__________________
Sansui G6000,7070
Pioneer SX1250,SX1280
Kenwood KR-8010
Onkyo TX8500II
Pioneer CTF950,Akai GX-S80
DCM TF-600,TF-400 CX-17+ KL Quartets
Reply With Quote
  #15  
Old 01-12-2009, 07:45 PM
cbrworm cbrworm is offline
AK Member
 
Join Date: Oct 2007
Posts: 569
I do a lot of work with Lithium ion battery packs. We have had more than a few of them burst into flames during charging. It is not something you want to witness inside a building or vehicle. This is usually due to corrosion or some other imperfection inside the roll.

In the real world they have a useable life of about 1 to 2 years regardless of number of cycles. They will self discharge to a point that they need to be jump started, but usually that is due to the monitoring circuitry that is typically in the pack not having enough energy to run and thus not allowing any charge current into the cells. In our battery packs we actually have current and voltage limiting devices as well as real time individual cell temperature and voltage monitoring to prevent charging outside of acceptable parameters. The circuitry also has the ability to completely and permanently disconnect the cells from one another in a catastrophic event to keep damage to a minimum. This is all backup to the circuitry which is in the charger that also monitors every piece of data through the SMBUS.

Normally to jump start a battery we will supply it with it's operating voltage, or slightly higher at a medium current rate (depending on it's capacity) and carefully monitor the batteries temperature. Usually they only need 10-20 seconds to get enough of a charge to allow the devices built in charging circuitry take over and work.

What you are describing is pretty dangerous. I would not recommend jumping it again unless you are outside and wearing glasses.
__________________

DD:SX-1250,GX-270D-SS,Sony TC-K850ES,Onkyo DX-C206,Numark TT,GFA-555ii,HTPC,DEQ2496,RSIIIa

HT:Onkyo TX-SR805,ZA SR71,DIYMA12,HTPC

OOS:SX-1010, SX-1050, GX-270D-SS(#2), GX-280D-SS, GX-255,Technics SL-1800, Nak CD-6,INF QLS5,RS4001, Beta20, Seas LOKI
Reply With Quote
Audiokarma
Reply


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 09:28 PM.



Friends of Audiokarma
We appreciate your help in keeping this site going.
Pro DJ Headphones - click here
Amps and Sound
Wargos Electronics
Organ Donor Parts
Sonneteer
Parts Connexion
Sound Stage Direct
Atlantic Systems
AudioClassics
Take Five Audio
AV Solutions
Audio Salon
Tone Arm Audio
Audience AV
Musical Paradise
Simply Speakers
Classic Sound Repair
BD Enterprise
McIntosh Cabinets
Howard Products
Cabledyne
FM DX Antenna
BOI Audio Works
Siliconray
Amplifiedparts
Vinyl Magic Record Cleaner
RSL Speakers
Grant Fidelity
Urban Antigue Radio
Yesterday's Audio
Many Moons Audio
DeWick Repairs
The Tube Store
Vintage Electronics Repair
Audio Doctor
Politicalchat.org
MCM Electronics
Antique Radio Classifieds
Herbies Audio Lab
Videokarma.org
   
Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
ęCopyright 2002-2014 AudioKarma.org, All rights reserved.