3S (3 cells @ 11.1v) and 1A. The Duo power supply seems to limit charge current to around 600ma, but that's fine.
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Duo 2300c - Battery rebuilds?
- Thread starter LaPorta
- Start date
3S (3 cells @ 11.1v) and 1A. The Duo power supply seems to limit charge current to around 600ma, but that's fine.
Sounds good, thanks
Yep, that's the baseline diagram, much clearer, but I thought you'd get more out of the one I posted with the standard Type III overlay. :/ The PIC Board replaces the two wire EEPROM for sure. But though I don't think that board is super intelligent, it does fool the Duo's Power Manager into fully charging higher capacity cells. That's what's kept me curious as to the way it does that for all this time?
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Power Manager IC
The Power Manager IC is a 68HC05 microprocessor that operates with its own RAM and
ROM. The Power Manager IC performs the following functions:
- controlling sleep, shutdown, and on/off modes
- controlling power to the other ICs
- controlling clock signals to the other ICs
- supporting the ADB
- scanning the keyboard
- controlling display brightness
- monitoring battery charge level
- controlling battery charging
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WAGs would be that BTI may have managed to: break into the power manager's ROM to source battery IDs reserved for incremental future development, figured out how to patch the Power Manager ROM for such or to jigger settings on the fly for pulse charging to higher than provided capacity? Dunno at all really and haven't much of a clue.
However we do know from the two wire EEPROM implementation that I2C runs though it! So I'm wondering just what that PIC chiplet might be doing over that nifty little communications setup? Why EEPROM? Was serial EEPROM the only readily available (overkill) component suitable to the identification task at hand or could the Power Manager be keeping notes on accumulating charge cycles of each individual battery pack?
Should I drop the NiMH aspects here for the two of you to continue along the lines of Li-ion development/howto?
I take the path of least resistance here, so whoever comes up with an easy-to-follow diagram that allows full charging of cells we can put in there wins 
.
On a related note: has anyone gotten apart the battery and not killed the sliding front plate that locks it in and completes the front of the Duo>
.On a related note: has anyone gotten apart the battery and not killed the sliding front plate that locks it in and completes the front of the Duo>
I have managed to do it but it is very difficult, there doesn’t seem to be much of a science to it, just cut it apart slowly and carefully.
I have two batteries right now but the sliding bit on one of them was crumbling when I received it, I wonder if I can find one on Ebay.
It just slides along the front of the battery and snaps In place, just make sure that the casing fits tightly together
I take the path of least resistance here, so whoever comes up with an easy-to-follow diagram that allows full charging of cells we can put in there wins
Let the games begin! Original plan was to set up one BTI High Capacity circuit and a standard Apple Type III circuit for testing high capacity AA or AAA in holders on an A-B switch just to see what happens before sending the PIC board to sameone for reverse engineering. @bigmessowires didn't have time to take that on back then, maybe now or someone else might be willing to take up that task if I can get longer run time out of NiMH cells in the test setup.
It won't match the fabulous Li-ion pack @sutekh came up with, but with the BTI PIC setup maybe you can get a better charge on those cells?
View attachment 36714
This is the pic I took of the BTI
@futurebiscuit are you still around to share more details on your successful build?
View attachment 26367
Here's where I got for comparison, more detail in the thread of the finished mechanicals including my Gummi Bear latch hack. Doing a printed case as Sutech did would make this setup clean as a whistle!
View attachment 20524
Project Case with Minimalist Power Duo and lots of room in the lid for battery holders etc.
View attachment 39858
Not at all. The Li-Ion dialog was itself a bit of a hijack I merely posted upon request.
Very interesting certainly. Would love to scope it and do a little bit banging. If it can manipulate the power manager's behavior, that could open all sorts of possibilities, including possibly overriding the 11v cutoff that necessitates an internal boost converter in my Li-Ion packs.
You don't perhaps happen to have any info on what differentiates the 3 types of batteries do you? I haven't been able to find much of anything in the various Duo-related Developer's Notes or Service Source docs, but the way they distributed info throughout those publications is infuriatingly inconsistent. You really have to consume all of them to get a complete picture. There's nuggets of info sprinkled throughout the "Duo System" and platform specific 270c and 280c dev notes, but I haven't found much of anything about the batteries themselves, other than that using type-IIIs on older OSs requires a system extension for them to charge properly. Hmm...
I frankly wonder if, instead of some sort of I2C wizardry and power manager manipulation, BTI went exactly the opposite direction. What if these hypothetical charging algorithms, likely introduced to combat memory effects and with the unintended consequence of thwarting attempts to use higher mAh cells, were only introduced in type II or type III? BTI may just be using earlier type S/Ns that only perform voltage-referenced charging? As for the overkill PIC, who knows? Maybe that's the best way they could figure to reverse engineer and re-create the Apple-proprietary ID chip?
What I do know for certain, is that my 3500mAh Li-Ion pack based on a cannibalized type-II pack charges all the way up to full capacity using an M7783 charger just fine. It also still doesn't make sense to me that the power manager could somehow keep track of the pack's overall capacity, and only impart that much energy. What if I swapped the pack into a different Duo and discharged it halfway? It's gotta be voltage referenced.
I wonder if the cell chemistries differ? What if a type-III used an at-the-time new, higher capacity, but slightly lower voltage cell or something? Using modern, conventional NiMH, cells (higher capacity or otherwise) would then result in them being under-charged? There's also the possibility that folks are buying falsely advertised cells and not getting the fictional output they expect. I'd estimate that half the cells I've ever purchased on eBay, AliExpress, etc., were mis-labelled with some hilariously overrated.
Anyway, here's a bit of interesting but still agonizingly unspecific info from various dev notes:
Duo System:
- The charging current is programmable, with an external voltage supplied by the Power Manager, which also controls the charging functions, by monitoring battery voltage and battery temperature.
270c:
- The latest release of the Power Manager code, which resides in the PowerBook Duo 270c ROM, allows you to modify the system time without impacting the battery-charging algorithm. Firmware features added for the PowerBook Duo 270c computer also support a sleep LED, version dependent code, 4/5A Panasonic battery support, and battery conditioning.
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That can fairly easily be arranged. Best to bang the snot out of it before I pummel it and the PIC to death with fumble fingered bodgery. I've another battery conditioning toy you might find interesting for your Li-Ion experimentation as well as NiMH. Send me an address in PM if you'd like a C.A.R.E. Package? :grin:
Dunno offhand what differentiates the pack types, but I'd think that would be found in DevNotes for models in each generation? Never read the 270c DevNote, is the tidbit above from there?
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