Panasonic CF-28 Toughbook Battery Info

Panasonic put the antennas pretty mcuh where you have it. I'm not sure what type they used though. I bought a CF-28 where someone had used a crappy Broadcom card and used the dual "paddle" type antennas andhad them stretched out to the side. It picked up a signal but not even as good as my Dell Inspiron or Sony Vaio. Close... But not as good.

Are you replacing the cells in your battery yourself or paying a service to do it? I've thought about it but I've never cracked a lithium ion battery before. I've rebuilt nimh batteries before. I just redid my 14V Dewaly battery with SubC batteries off ebay.

 

There was a thread on the Yahoo group about the batteries. Someone replaced the cells with aftermarket high capacity ones, but did not realize any improvement over the stock battery life. They came to the conclusion that there is a programmed circuit inside the battery that "knows" the capacity of the original cells and won't allow any greater capacity.

 

Hmmm... The circuit is usually in the form of a diode that keeps the battery from draining if you accidentally unplug the power supply and leave the other end plugged into the laptop. I've never seen or heard of a circuit to limit the mAh of a battery cell. But I guess stranger things have happened... It would be worth it to open one up just to see. I'll have to fins a dead on in my pile of them and see... I've only git a few of the 6.3mAh batts. Most are 5.4mAh... It would be nice to come up with a 7 or 8 size...

 

Here's a quote from the thread on Yahoo:

More to add to this again. If anyone was thinking of changing the cells in a
cf-28 pack, my advice would be not to bother. Same goes for getting the pack
rebuild by a company.
The 'smart' charge controller is a little to smart for its own good, it will
only allow the battery calibration to go one way. Down. If you have a battery
that is still charging to some degree then rebuilding should work ok but the
red light will come on early. I had a pack that ran for 4 hours but the light
came on after 7 min.
If the pack wont charge at all (nothing but a flashing red light) then forget
about trying to re-pack it. There is an internal fuse which will blow if the
cells are to far gone and (as far as I can see) the internal 'brain' cuts in
part of the circuit to make sure this fuse stays blown even if you replace
it.
If the pack attempts to charge (steady yellow light) but gives up after
around 30 secs (flashing red light) then more than likely this internal fuse
is the problem. It is a small 3 pole surface mount unit around 7mm x 4mm
mounted beside the external charger plug and visible on the outside face of
the controller without removing it from the cells.
7A SF 30 and the manufacturers mark in a small box, SC . link to datasheet:
http://www.newlist.ru/battery/images2/Fuse.pdf
Test amps with a multimeter (cells connected) before replacing, guess how I
found out about the part of the circuit that keeps the fuse blown and ensures
the pack is scrap. Its connected through a tiny 6 pin chip below the external
charger plug, I would give the reference but it got 'removed' when the magic
smoke got out...
So, if the eeprom can be re-programed then it will be possible to rebuild the
packs, if not then a new pack is the way to go. The CF-27 packs work very
well though, I'm still getting 5 hours from the 2 I have here after
rebuilding and the charge indicator is 100%.

 

I'll do it myself, my battery holds charge about 10 minutes I've ordered some 18650 cells from China, not shipped yet(9 pcs, i've paid about 45$ for them). I'll try replacing them as soon as possible ;] If You need photos of the battery give me PM.

If it won't work i'm going to sell this cells and give the battery to service (it costs about 100-120$ here (Poland)).


I did it on my CF-27 and it works fine, holds a charge for about 4 hours.

 

Let us know if it works. If you take pics of the guts of the battery it would be appreciated. I found a place that rebuilds the CF-28 batteries for pretty cheap (I think it was around $80 from what I recall). I'll have to find where I bookmarked their page

 

It's not the right topic for this info but i've changed the cells in cf-28 battery. No effect The battery holds charge as before, about 10 minutes. I've tried "refreshing" the battery (BIOS).

 

see the quote that i posted above. apparently the logic in the battery only allows for deterioration.. not renewal!

 

Some batteries charge at full capacity after changing cells (CF27, some older laptops). I hope that CF28 battery should also be rebuildable.

 

I just bought 9 2200mAh Li-Ion cells on ebay. I was going to pony up the money for the 2600 series but I figured I'd start with the 2200 first. I have 5 dead batteries I need to revive. I thought about shipping them to a battery rebuilder but figured I could save the money doing it myself.

As far as the "fuse" that was brought up... After doing research... There is no fuse that blows if the batteries are drained completely. There is only a fusible link that is blown if the battery overheats. It is to stop the battery from catching on fire. If this fuse blows... You cannot repair it. (Supposedly) Other than that... They are open game to swap.

 

Post pic's I am also interested as I'm not to bad with a soldering iron.

 

You are doing it with CF28 battery? Do You have any idea how to reset the battery chip? How are You going to connect batterys together (there is no space for soldering wires inside plastic case)?

 

I'll post pics if I can get it working.

Yes... A CF-28 battery. What chip are you talking about... There are many in there? I bought batteries with tabs and plan to use the same thing that put them together when new... I'll reuse the thin, flat connector cable.

I've rebuilt all sorts of batteries and never had a problem. I've never rebuilt the CF-28 battery however...

 

everything i know about the 28 batteries has been gleaned from the yahoo toughbook group, but it is the consensus over there that you can't take a dead or near-dead battery and restore it to long life with replacement cells alone

 

What may be happening is a relationship between proprietary battery sensors and proprietary
mainboard technology.

We may have to disable the internal charge controller in the CF-28 battery and mainboard (probably by
clipping a lead or two) and use an external one. If that causes the BIOS to get weird then we may need
to "lie" to the mainboard with a small watch battery that tells it all is well - or whatever signal condition
they used to monitor the battery.

That way we may rebuild to any capacity we want and recharge safely.

We will need to figure out an alternative means to monitor battery condition - perhaps using a
resistor or diode or zener and the test strip from the side of an alkaline battery?

WDYT? doc

 

If it comes to this... I'd just go ahead and get mine rebuilt or pay for new ones. While I might think of doing this to my personal one if I had to... I resell my laptops and couldn't/wouldn't resell something like this.

I'd like to see someone do it though.

 

i think the yahoo guys are the farthest along with this.

 

I just joined there. It looks like I have some reading to do...

 

Wow, I've been quoted ! Wow. Must say, it's a nice feeling
The fuse is both a current fuse and a thermal fuse.
The communication protocol is smbus (subset of i2c) for the battery to laptop and spi for the battery monitor internal communications. (both standard).
The problem is with the internal brain and memory that does things like preventing the battery exploding and telling the laptop whats left and how long it will last.
Li-ion cells are high strung things that tend to explode if they don't get their way (some say they should be banned altogether..), plugging them in to a wall wart through a resistor is a quick way to a big bang.
Trouble is beside doing usefull stuff the user, the controller also does usefull stuff for the manufacturer by saying 'buy a new one cheapskate' and blowing its internal fuse.
Post to long already, cut the crap...
The internal memory is what needs to be altered, it should be possible over the external i2c (smbus) line. There are tools for windows (boo, up the penguin ) that may be able to alter this. Give them a try ('smart battery manager' if my memory is working today), if they work and you can write to the memory then you have everything you need, just keep power to the controller when you de-solder it.
If not then the internal communications to the memory need to be tapped to read from a good pack and write to an old. This should be easy enough as the internal com is either 12c (different line to the external) or another standard protocol.
My guess is the windows tool will work ok as its more or less the same controller (different shape, wont fit) as a lot of IBM packs.
I'm in the middle of learning microcontroller and communications related stuff so will probably have another poke at the thing some time soon, I'll post on the yahoo group if I get anywhere. If anyone tries the software can they post back with what they find ?
cheers

ps, the guy who re-built the pack and had the laptop shutdown after the same time. That's software shutdown, turn it of and you should get around 4 hours, 3 hours and 50 min with the red light flashing but still 4 hours

 

Couldn't find the damn 'subscribe to this thread' to get emails so may as well add the bit that helps starve the lawyers...
Do not tamper with li-ion batteries or related charging circuits as they can explode. Do not, for instance, plug them into 12v quick chargers to test this. When not doing this be sure to stand at least 3 meters away and keep your beer covered as the chemicals are very hazardous.
Cheers

 

Hmmmm... Makes me wonder if I should keep my rebuilt battery plugged in down in the shop!

I just rebuilt one... (2200mAh Batts) It took me 2 hours of careful soldering and bending the tabs to mimic what Panasonic had done. I reused all of their sticky spacers and insulators. The batteries were already covered with a plastic wrap so I didn't have to worry about that. I have an external charger. I plugged it in there and it started with the red blinky light. CRAP! I thought, "Oh well... Put it together and try again" (I tested it out of the case) I put it all back together and got the orange light on the charger! I put it in one of my laptops just to see where the charge rate was... It was at 12%. So I took it out and hooked it up to the external charger. I was waiting for it to explode or catch fire! (You never know!) It didn't so I just put it out in the middle of my concrete shop floor just in case it decided to pop. It's still going strong after an hour of charging.

I'll let it go while I work on my other CF-28s (Stripping a few more and repaint, then logos for a customer.) I'll keep an eye on it every 10-15 minutes. It's not warm so I guess that is a good thing!

EDIT - Oh... And 4 out of 5 of the batteries were completely dead. The other 4 were reading 2.8V. It looks like those are still okay. I'll test them in another project.

I'll post later after it has charged... I'll time how long it takes to discharge.

 

Sounds good When you had the flashing red, was it yellow then flashing red or just flashing red straight away? So far any I've tried that flashed red immediately was scrap.
They are a pain in the neck to solder, I put a few pics in the files on the yahoo site of a cf-27 pack using a cut up beer can to go between the poles. That worked ok, next time I'll have a look for a few high capcity capacitors (that was a pain to type) and built a tab welder. There are a few howto's on the net for them and they are very simple.
cheers

 

Well... It started out green... Then later when I checked on it... It was blinking orange (Not red). Per the manual... Blinking orange means that it is outside the temperature limits and when it returns to normal temps it will start charging. Hmmm... The battery was 71 degrees.

Soooooo... I guess I'm back at square one. The good news is that the $50 in batteries will most likely be able to be used in some other project... Like an external battery pack for something else!

 

In my CF28 batetry it didn't help at all. The charging took about 5 hours, but after 10 minutes it turned off.... I've tried charging and discharging it in BIOS (to disable software) and still get 10 min of battery life.

 

Hi All
This site looked like a good How To on battery rebuilding. With great Photos

http://www.electronics-lab.com/articles/Li_Ion_reconstruct/index_3.html.

I have seen other How To's and they indicated that the battery needs be discharged and recharged a few times in order to rebuild the batteries memeory.

 

Hey Randy... Welcome to the forum!

The problem that we have is the circuit board inside the battery pack. It tells the batteries NOT to charge... Unfortunately.

Again.... welcome to the show and we look forward to your participation!

Have a great weekend!

 

Something else that may work. The controller is more or less the same in a lot of thinkpads. If the bios battery refresh utility in them is able to reset the memory both up as well as down then it may work for the toughbook packs, just need a few jumper cables to connect them. If the 'language' for the thinkpad is different it simply wont be able to write so it wont do any damage to either the panasonic pack or the thinkpad.
The smartbattery utility for windows would be the best thing to try but its expensive for something that may or may not work.
Mr toughbook (who sounds familiar from the yahoo group ), if the pack was charging and it was putting out power in the laptop then everything should be ok. 71 degrees is fine for most cells, 80 is generally the limit (check datasheet) but the controller is definately not dead. Trouble is the controller has a charge graph plotted into it and this is different between makes/models of cells, a glance over a few datasheets for different cells will explain it better, this needs to be re-programmed or it may have a serious effect on the packs lifespan.
Again a commercial application to re-program the pack would be the way to go. Getting the info from a good pack is easy enough, check i2cdetect and i2cdump on linux but keep away from address 0x50 as that is the RAM controller and will make a serious mess if changed (ie. brick). Writing it back is a different thing, monitoring the line when using the bios refresh utility would find the write code sequence.... eventually and somewhere amidst thousands of other instructions but its not going to give the data needed to change the charge graph.
All in all a lot of work to save maybe 20 euro over getting a new pack every couple of years. An open source utility would be usefull though, I say open source as it would not come to a dead end as developers loose motivation. There will always be dead packs to rebuild and this here forum would be a great place to share the data needed.
When I get the time I will try hooking up a cf-27 pack to the 28. The older controller is a great thing that sets its memory based on the previous run time/amps and has a potentiometer for a basic adjustment of the charge graph (more of a charge curve but it works ok). They should talk to each other ok but the ACPI wont know what to do (power management) as they use the older APM power management. A bit of tricky wiring and they should go into the cf-28 case though.
cheers

 

Tell me what you think about this.. This is the second CF27 battery I've seen with this problem. It seems to charge normally.. amber light for a long time.. then it goes to flashing red. However, it is NOT a bad battery! Both of the ones that did this kept the computer going for 1 hour+. The power meter in windows xp seems to show a normal discharge cycle.. it starts at 100 and gradually decreases, but as some point it suddenly drops to 4% and the light goes solid red. The battery is still good at that point though! This particular 27 I'm typing on right now has this problem.. It has been at 4% for the last 15 minutes but is still keeping the system running. At some point it'll just suddenly go dead, but I may have another 15 minutes or more of run time before that happens. strange huh?

 

Not sure but it sound a bit like a few cells are stone dead and the controller cant get a fix on the rate as the volts/amps are out of its range. Running something that needs heavy hard drive access when its red will probably cause it to shut down after just a couple of minuits as the amps wont be there to keep the needed voltages inside the laptop. Drop the backlight and avoid moving/saving files and the remaining good cells will have enough to keep going for a while.
The cf-27 packs are well worth re-building. The two I did here will get well over 5 hours with the backlight dropped one step under its brightest and after the first 3 or 4 charges the battery monitor was dead accurate. The packs are a real pig to get open though
cheers

 

I figured I would breathe some life back into this thread. I have rebuilt a few of the CF-28 batteries... But the problem that I always run into is that even with careful soldering... It (the solder) creates too much space between the batteries and the cells won't easily fit back into the case. Soooooo....


I just built a spot welder to weld battery tabs. It works like a charm and I am anxious to get started. I've already welded one but for some reason the battery went from a glowing orange and quickly discharging to flashing red... The kiss of death. I think I may try charging the batteries BEFORE I put them back in the case. As soon as I finish working on this stupid Dell for a neighbor I will jump back in and weld some batteries. I'll keep everyone posted!

 

My battery pack is still working perfectly after the experiment I did with it....

Where can I get the cells?? I have an IBM stinkpad with a bad battery...[/I]

N_R

 

Nissan... Refresh my memory please.... Was your batery flashing red or did it just have poor reserve time?

I bought my 18650 2200 mAh cells and also some 2600 mAh cells from ebay. The 2200s were around $45USD the 2600s were around $56USD IIRC.

You should open the battery up first to see what yours takes... Not all are the same.

Just my too scents

 

When I plugged it in, it would show amber for about 15 seconds or so, then go to flashing red. There was 0 capacity. Unplugging the power cord resulted in immediate power off. I did have the battery apart. Desoldered the control module to charge the cells...

N_R

 

So you took the battery apart, desoldered the leads to the pc board and then what voltage did you charge it with?? 15V comes to mind for some reason.... How long did you let it cook?

 

I used one of my 16 volt IBM power supplies and hooked it up to the batteries through a 20 Ohm, 9 watt wirewound ballast type resistor. Let it charge for about 4 hours, give or take. The resistor got quite warm, the batteries stayed cool. At the end of the charge, the batteries were holding 11.3 volts. I then put it all back together, taped the case so it would stay together (LOL! It's STILL just taped ) and put it back into the computer. When I powered up, the charge light remained and the next morning, it was green with over 4 hours capacity showing, since proven correct.

N_R

 

So you took a dead, flashing red battery and fried the little ions inside into new life and you are STILL getting a 4 hour useage?

Don't mean to be dense... Just want the facts....

 

Yessir, exactly. I must say that I do not know WHY the battery was in the dead state that it was. I do not know whether it was a NOS battery that sat for way too long, or even a used one that had been run down and then let sit, again for too long. I won't pretend to know what it was that went right here. It was an off the cuff thing I did during a 'fix it or fsck it' procedure in which I was going to rip out the old dead cells and put just three goods ones I have into the case so the computer wouldn't just instantly die if the power cord came out of the socket or something like that. I got the computer to be the heart of a nav system for my boat. Hmmmm... Now I like it well enough to take it everywhere! Oh, and I wish I had the gps unit you use for your mobiles. The guy who I bought this toughbook from on ebay was very misleading about this computer. Well, I won't hijack this thread any further about that crappy deal...

N_R

 

How many Amps are you using when you charge them?

 

HOLY COW!!!!! I had several of the Energy+ batteries that were just blinking red... Some had dates on them that were only a year or so ago... Presumably the date of purchase... I unsoldered the controller... Hit them with 15V for about 10 minutes... Just long enough to get them up to 10V-11V and voilà! Presto-Chango... I have a 4+ hour battery!

Nissan... You're a genius my friend! Rep+ to you for that find.

One thing... the Panasonic batteries don't respond the same way. I guess they have more programming in them.

I guess the Energy+ batteries were just sitting around for too long. I was reading about 1.2V on them... The computer saw them as dead... Now they have new life... And Everest 2006 sees them as having only used 3% - 7% of their life. So... I have a bunch of NEW batteries!

 

Makes me really sad I sold off nearly all my dead batteries

 

I didn't measure the amperage. I did a 'seat of the pants' match-up with the resistor and monitored the temperature rise of the resistor by hand until I was satisfied I wasn't going to burn anything up; I know, I'm lazy!

I am ever so pleased that this has worked for you with your batteries. My battery has panasonic cells in it... How many batteries did you end up with being good??

N_R

 

Well... You'll cry (or laugh... or shout.. or...) when I tell you how I did it! LOL

Me... Being the impatient soul that I am hooked the batteries up to a 15V - 12 Amp battery charger for about 1 minute... Just enough to get the voltage to read around 10V.... Then the laptop will see it's not dead and will then charge it from there! So far... The two I have measured with Everest show an average of 5% life used with 95% life left!!! And the 2 fully charged batteries that I have played around with are showing that it will give right around 4 hours life!

When I first hook them up they are showing about 5% - 10% charged. It is taking around 2-3 hours to charge them. Of course I won't know how all of this will play out until I do further testing... But the results so far look VERY promising!

 

I feel your pain brother!

What did you get for how many?

 

Heh.. I probably had 6-8 of them and was getting $5-10 each. I didn't figure they were going to be worth ANYTHING to me!

 

Sooooooo.... How did the battery 'hack' work out?? Do they all work now??

N_R

 

TB,

Did you open the batteries to hit them with the battery charger, or just apply the voltage to the pins on the outside of the battery (i.e. throught the logic board inside the battery)? Just want to figure out if I have to split the case of the batteries...

Thanks,

Robert

 

you need to actually open the battery case...

 

Rick,
I'm sure I am not the only one who's waiting to learn more about the battery hack. Any chance of a picture-by-number guide for those who are less electronics-inclined? That is, if the new job isn't taking up all of your play time.
Regards,
Ron in SG

 

That's the problem with Lithium-Ion batteries.. if you let them sit too long and it doesn't even have enough juice to power the protection circuitry, you're SOL.

Most high-end chargers (I have an Anton Bauer charger for my video camera batteries) have algorithms to slowly charge up a totally dead battery to revive them. And analyzers will have even more algorithms to charge/discharge batteries to exercise them.

And the horrors of overcharging: http://video.google.com/videoplay?docid=3690260570423705609

 

WOW!! At first I was like, what's the big deal? It was just a little 'pop'. But then, WOW, that was amazing!!