Github Project Link:

Macintosh Portable Battery Adapter

[Image: Macintosh Portable Battery Adapter v1.0 PCB front] [Image: Macintosh Portable Battery Adapter v1.0 PCB back]

Macintosh Portable Battery Adapter

This project was created to allow current rectangular 6v lead-acid batteries with spade terminals to be used as a Macintosh Portable battery in a cost effective manner. This is achieved with a spacer made of plastic or cardboard and PCB for the battery contacts. The lead-acid battery is then connected to the PCB via wires with female spade connectors.


The spacer and PCB is sufficient and the cheapest way to use a 6V lead-acid battery in the portable. This is useful for testing since the battery can be easily swapped.


There's also a cover that can be 3D printed to give the battery a complete case. Padding should be added to keep the battery from moving around inside the case.


The case is a modified version of the Macintosh Battery Enclosure 3D model done by Stephen Arsenault. Thanks!

v1.1 Notes

This version moves the solder pad for the wire to provide clearance between the case and the wire. Slots were added to the PCB for the case cover to slot into. This was done prevent the sides of the case being pushed in easily.

v1.2 Notes

This version adds supercapacitor support to the PCB. This will allow you to run you're Macintosh Portable with no lead-acid battery! The supercapacitors cover the brief power spikes during hard drive spin up and such that the battery normally handles, so the computer won't shut off when running off the adapter. Supercapacitors are not a substitute for a real lead-acid battery. You won't be able to run without the AC adapter connected. Another difference is that it takes a few minutes for the supercapacitors to charge up before you can use the computer. You can still use a lead-acid battery along with the supercapacitors if you want to.

The supercapacitors need to be balanced since they are used in series. I give two options on the PCB. The best option is to use ALD810025 which is a purpose built supercapacitor balancing IC. The ALD810025 will prolong the life of the supercapacitors and has very low to no leakage. The cheaper alternative is to do passive balancing with resistors. Zener diodes can also be used but I haven't done the calculations to know what the appropriate rating should be. If you're interested in the different types of supercapacitor balancing here's a wonderful PDF by Wurth Elecktronik that explains it all.

It's important to have a recapped Macintosh Portable AC adapter or another 7.5v adapter that actually produces 1.5A. If you haven't recapped your Macintosh Portable adapter and try to use super capacitors only then chances are it will output a lot less than 1.5A and the computer will just shut off when just running on supercapacitors.

TODO

I would like to modify the v1.2 case so it will protect and separate the supercapacitors from the lead-acid battery if both are installed.

Upload images of v1.2.

3D Printing Notes

This can be printed without supports. If you're using a FDM printer with a 0.4mm nozzle like I am, then I would recommend printing with at least 3 outer/shell layers to give more strength to the screw holes.

v1.0 and v1.1

v1.2

All the same parts as v1.0 and v1.1 with the addition of the supercapacitor stuff. Use either the IC or the resistors but not both. You can use a supercapacitor with a different capacity, but if you use resistors for balancing, you'll probably need to recalculate the resistance value. Refer to this PDF by Wurth Elecktronik to do the calculation.

Pictures

[Image: Macintosh Portable Battery Adapter v1.0 PCB stack] [Image: Macintosh Portable Battery Adapter v1.0 soldered wires] [Image: Macintosh Portable Battery Adapter v1.0 without a case] [Image: Macintosh Portable Battery Adapter v1.0 case top] [Image: Macintosh Portable Battery Adapter v1.0 case angled]

License

[Image: Creative Commons License]


Macintosh Portable Battery Adapter by Alexandre Marcoux licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.

Attribution

Macintosh Portable Battery Enclosure (M5137) by StephenLulz is licensed under the Creative Commons Attribution 4.0 International License.

Fantastic project!
My problem is that I don't yet have a Macintosh Portable. I've always wanted a backlit one. I just never pulled the plug on a purchase, mainly because of its reliance on that battery which I thought might be trouble to maintain. But this project sounds like a very interesting solution.

>> JDW said:

Fantastic project! My problem is that I don't yet have a Macintosh Portable. I've always wanted a backlit one. I just never pulled the plug on a purchase, mainly because of its reliance on that battery which I thought might be trouble to maintain. But this project sounds like a very interesting solution. Click to expand...

To my direct experience, the main issues with the Portable are the internal HD which invariably fails, and - more serious - the lcd panel that delaminates. The battery has to be maintained in working order for operating the machine, but can be easily rebuilt.

Ok just finished updating the git repo with the info for v1.2 with supercapacitors.

I've tested only with a M5120 with copying between the floppy and mechanical hard drive. If anyone is able to test on a Macintosh Portable with backlight (M5126) let me know. Pretty sure it will be no problem but would like confirmation.

wor...impressive, thanks for sharing

>> alxlab said:

Ok just finished updating the git repo with the info for v1.2 with supercapacitors. I've tested only with a M5120 with copying between the floppy and mechanical hard drive. If anyone is able to test on a Macintosh Portable with backlight (M5126) let me know. Pretty sure it will be no problem but would like confirmation. Click to expand...

I've got a M5120 with the backlight upgrade. I have a 6v battery I've been using (waiting on a reproduction flex cable and BlueSCSI adapter (the machine's cables were cut). I'd love to have the ability to test this. I've not printed my own circuit boards before. Is it feasible for me to purchase my own from PCBWay or similar? Any advice on how to do it. I could do a test run with the super capacitors on the backlight upgraded machine.

Also, my DV input jack is cracked (this machine had a rough life, apparently. Any idea if that is a standard DC005 input? Something like this looks like it could work as a replacement: https://a.co/d/gUT0MyK ?

I just made my own. You don't need anything fancy honestly... this went into my Portable over the weekend for the first time and it works a treat. A sheet of PCB, two holes for the wires, and then I hacked the copper down the middle like a caveman! :)

>> pocketscience said:

I just made my own. You don't need anything fancy honestly... this went into my Portable over the weekend for the first time and it works a treat. A sheet of PCB, two holes for the wires, and then I hacked the copper down the middle like a caveman! View attachment 12670 Click to expand...

I actually figured I should know how to order PCBs from gerber files, so I ordered 10 of each the 1.1 and 1.2 versions of the PCB. I also kind of want to try the supercap version with no battery. I started printing some cases for when they come in. If you want one of my spares, let me know, although your method clearly has more street cred.

>> wottle said:

I actually figured I should know how to order PCBs from gerber files, so I ordered 10 of each the 1.1 and 1.2 versions of the PCB. I also kind of want to try the supercap version with no battery. I started printing some cases for when they come in. If you want one of my spares, let me know, although your method clearly has more street cred. Click to expand...

Just curious but why both v1.1 and v1.2? v1.2 allows you to use a battery like v1.1 with the addition of the super cap stuff.

>> pocketscience said:

I just made my own. You don't need anything fancy honestly... this went into my Portable over the weekend for the first time and it works a treat. A sheet of PCB, two holes for the wires, and then I hacked the copper down the middle like a caveman! Click to expand...

Love it! Very much in the spirit of this project.

Toolmaking knuckle dragger methodology . . . doesn't get better! :D

>> alxlab said:

Just curious but why both v1.1 and v1.2? v1.2 allows you to use a battery like v1.1 with the addition of the super cap stuff. Click to expand...

I didn't realize the 1.2 board could function as a pure battery without the caps and IC installed. I was simply trying to have some options in case I was concerned the super capacitors were not compatible with a M5120 with the backlight upgrade. Good to know that I can simply use the v1.2 board with no components installed and the battery terminals will still be connected properly.

Just an update about the using supercapacitors based on recent tests. It seems like using 6F or 10F supercaps is not sufficient to spin up newer SCSI hard drives with higher current draw.

The original drive `CP-3045` 40MB is alright and another `IBM-H3171-S2` 160MB drive worked alright, but when I tried my `Quantum Fireball 1280S` 1.28GB drive it would not work.

I just bought a bunch of higher capacity supercaps to test. The price increases quite a bit for the 22F and up.



We'll see what works ... or not :)


If you plan to use the orginal hard drive or a BlueSCSI, RaSCSI, SCSI2SD, etc or plan to use a battery this is a non-issue.

There's a replica stl of the original battery pack online. It's very acurate. I think it's a 3d scan. I used it to make my battery. I cut some strips of copper sheet and made some 3d printed fasteners to lock them into place. Worked perfect but I'm not sure how well the copper pads wil hold up over time.

How'd the printing of that case go?

One reason I didn't go with the original Macintosh Portable battery case design for my battery adapter is because it would take a lot of support material or compromise the surface finish of one of the sides to print on an FDM printer.

The main reason though is that I didn't want to require printing the whole case. Only the spacer is really needed with some padding so the battery contacts won't be bent.

>> alxlab said:

How'd the printing of that case go? One reason I didn't go with the original Macintosh Portable battery case design for my battery adapter is because it would take a lot of support material or compromise the surface finish of one of the sides to print on an FDM printer. The main reason though is that I didn't want to require printing the whole case. Only the spacer is really needed with some padding so the battery contacts won't be bent. Click to expand...

It went well. Yeah lots of support material inside but I needed to test my new replacement printer out anyway and I have support pla which is really nice. It falls right off the part.

Update on the supercapacitor tests I did to try to get the Quantum Fireball hard drive to work.

The bottom line is that my Macintosh Portable had problems spinning up that Quantum Fireball drive even with a SLA battery in the end. It would work sometimes and other times it wouldn't (not spin up or partially and then fail).

So the conclusion I've come to is if a hard drive has problems spinning up with a 6F or 10F supercap then I shouldn't be using it in a Macintosh Portable at all. Some drive just draw more power than it can handle.

So 6F+ supercap should be fine for a M5120.