OQO 01/01+ Battery cells

[Guest]

[chadbh74]

Since suppliers have started dwindling even more for the OQO 01/01+ batteries, I have been researching what it would take to rebuild these packs ourselves (if we were technically inclined to do so.)  I did get a couple double capacity units from the last supply dump by Expansys.  Unfortunatley one of the units only seemed to have half capacity.  When fully charged, all lights would light and Windows would report %100 charge.  however, the unit died almost immediately when the power dropped near %50.  After recharging again to %100, I used the BIOS battery display and it only reported %50, seemingly conflicting with the LED status and the Windows ACPI report.  I performed the documented battery reset procedure with no change. I suspected bad cells or a bad connection somewhere, so I figured it might be a good time to take a crack and check out the cells for myself.

I found a web page where someone had dismantled the battery and took pictures, but unfortunately, no information was provided on how to dismantle the battery or what type of cells they were.  So here is what I found..  The metal (aluminum?) inner cover can be very gently pried to free it from the rest of the shell.  This cover is the one with the information printed on it.  I used the thin but strong edge of a hobby razor.  Make sure you are gentle and push in straight down, not slanted, or could potentially damage the cells inside.  The cover has small metal tabs locking it into the shell that can be gently pried up, working your way around the shell.  Once the cover has been loosened, gently remove it from the rest of the pack.  The PCB and cells will remain in the main casing.  Only the cover and a small black plastic liner (including the 2 pegs) will come off.

There is some slight adhesive underneath the batteries but I took a small flat tip screwdriver and gently pried the cell pack up from out of the shell.  The PCB board remains attached to the cells by a ribbon conductor, no wires go to the cells.  The package is well taped but it is easy to determine visually how everything goes together.  The cell pack is made up of a pair of LP355585 cells (double stacked to 4 in the double capacity units)  Each cell (or stack in the double capacity) has its on +/- path on the ribbon conductor back to the PCB board and have tabs point soldered.  One stacks solder points on the tabs seemed partially connected so I fluxed it and applied just a very little bit of solder.

Reassembling the casing was reverse process and extremely easy.  Placing the aluminum cover back over the shell simply involved aligning it in the shell and gently seating the edges down into it until the tabs locked back into place.  Because of the design, no gluing or screws are required.  You couldn't tell the case had ever been open!

Later on I will order some of the LP355585 cells and rebuild a OQO battery or 2.  The cells are cheap (approximately $11 each) and readily available on the internet.

If anyone would like more information or photos let me know and I'll help where I can.  I welcome any thoughts and suggestions on this!  It seems OQO 01 users still have hope for keeping their batteries going in the future after all.

[Picasso]

how will you get the old cells off the controller? Cells are sonic welded to control board. I'm not sure you will have any contact patch after pulling the cells.

Thanks much for exploring this. 


I'd love to hear what happens after a recell and reset of the batt. Not sure how the controller will respond to this.

[chadbh74]

Well, the cells have metal tabs that are not directly soldered to the PCB, but to the other end of the conductive ribbon.  The ribbon is fragile, true.  That's why I used a low heat soldering iron with the surfaces fluxed and very little solder.

As for cell replacements, I will try to keep the tabs intact to the ribbon and snip them to remove the cells.  Then all I have to do is solder-bridge the new cells' tabs to the parts of the tabs that remain.

As a contingency, should the ribbon become damaged, the solder points on the PCB are not that small and it should be very easy to replace the ribbon with very high gauge (small size) wiring to the cells on the new tabs.  The pathway provided by the ribbon from the PCB to the cell tabs is very clear and distinct.. two sets of +/- paths, one to each cell in normal battery case, or one to each double-stack in the double capacity unit.

[labrat]

Later on I will order some of the LP355585 cells and rebuild a OQO battery or 2.  The cells are cheap (approximately $11 each) and readily available on the internet.

Can you please point me to where these are available?
My search only gives me some references to some sites with Eastern European writing of some kind, and also only 1600 mAh capacity cells.
I also had problem with one cell getting disconnected within the battery, have not completely dismantled the packet yet, it came back when I started to open the metal-shield!

[chadbh74]

Later on I will order some of the LP355585 cells and rebuild a OQO battery or 2.  The cells are cheap (approximately $11 each) and readily available on the internet.

Can you please point me to where these are available?
My search only gives me some references to some sites with Eastern European writing of some kind, and also only 1600 mAh capacity cells.
I also had problem with one cell getting disconnected within the battery, have not completely dismantled the packet yet, it came back when I started to open the metal-shield!

Here is one place to obtain these cells.  http://www.batteryspace.com/index.asp?PageAction=VIEWPROD&ProdID=2157
Note that the cells are rated only 1500 mAh.  The highest I've yet seen is 1550 mAh.  Either OQO got some special LP355585 cells or they just overrated the specs on their batteries.  It would take 2000 mAh per cell to achieve the advertised 4000 mAh (standard) and 8000 mAh (Double Capacity) numbers.

What did you mean by "It came back when I started to open the metal shield"?  Sounds like maybe a bad connection like in my case.  I repaired my connections on the double-capacity battery, performed a complete discharge then recharge to ensure proper cell load/charge balance and voila!  I got over 5 hours run time off the battery today before hunting my charger.

[labrat]

I had the same problem as you with my extended capacity battery, only 2 of the 4 LED's would light up after charging finished.
But I took off the metal shield, was fiddling with the battery and pushed the knob on the back of my battery, and all 4 LED's lit up suddenly!
I put the shield back, and have used the battery, running it down and recharging it, a couple of times since that.
I guess there is a poor connection to one of the cells, but I am using it now, and will take some time later if neccessary to open again, to do the solder joints over.

[chadbh74]

Well with mine, all 4 LED's were lit at full charge, and Windows reported %100 charge.  However, BIOS only reported about %50 and when the battery was being used, it all of a sudden dropped to nothing when it got down to about %50 in Windows (2 LED's lit).

While I've only recently become acquainted with the OQO's, I've seen much talk about these "Fuel gauge" and other charge related issues.  Apparently, it might be a problem of the technology, and not entirely the OQO company's fault.

Here is a information page on Lithium batteries in general.  It talks about how to prolong their life.  Note especially what it talks about the "fuel gauge" units in the 4th paragraph... http://batteryuniversity.com/parttwo-34.htm

[labrat]

Good info in that link.
I have been toying with Lithium-Ione cells in other applications; portable miniature amplifiers and digital music players, as well as in flash-lights.
These cells can be dangerous, and should not be fully depleted!
If overcharged, or depleted too much, they can blow up,"vent with flames", as been reported in computers and in flashlights.
The get chemically unstable.
They also age, starting from the day of production!
I have read 20 % reduced in capacity every year, stored in room temperature, so no use in buying for storage!
Lithiums, non-rechargeable cells, can be stored for up to 10 years from date of production.

[chadbh74]

When I did the "recommended" depletion procedure for my OQO battery, there was still enough charge after the unit shut down to show a single flashing led, so it wasn't totally dead.  I have experienced in the past times where I had NiMH or Li-On cells that were TOTALLY discharged and in some cases, the polarity actually reverses when this happens!  As a result, the cells were totally useless and wouldn't take on a charge anymore.

[chadbh74]

IT WORKS!!!

I disconnected the cells from the ribbon on my standard battery pack and soldered in new cells and got the blinking LED's, well just one.  Apparently, the gauge electronics WILL work with new cells but resets to "zero" charge status when re-connected to power, regardless of the actual state of charge of the cells.  All I had to do is perform the battery re-calibration routine and voila!  Charges to %100 and lasts almost 3 hours     Costs? Approximatley $23 for the cells

[chadbh74]

I have placed the conductive ribbon in one of my OQO 01+ double capacity packs.  Though I had repaired this ribbon before with delicate soldering, I found that if the unit is jarred (as happened when it was dropped while in a case that protected the OQO) the connections were jarred loose and the LED gauge "reset" to only one light, though it was almost at full charge.
This is apparently what happens when the gauge circuit looses power as it would when changing out the cells to new ones.  The "Reset" procedure for the cells as below should be followed.  I replaced the conductive ribbon with 4 pieces of fine wire, it was very easy.

I will post photos and further information showing what I did soon.

[chadbh74]

Ok, I got the information together.  I couldn't seem to put the HTML coding here, so I will just give a link to the web page.  Hope this helps anyone who's interested in rebuilding these to save a lot of money.

Approximately $50 bucks for cells to rebuild a double capacity pack versus $300 for new one from OQO or third party?   Umm..for me the the choice is obvious.

http://excalibur1.net/OQO01BatteryRebuild.htm