PowerBook 1xx Series Battery Case

[GiGaBiTe]

Kai Robinson on Discord suggested I post this here.

I reverse engineered the battery pack used in the PowerBook 1xx series (minus the 100, which uses a different SLA battery pack) and designed a new case that can be printed. It is not 100% identical to the original pack, I removed the guides for the door because it was causing issues on my crappy 3D printer, and changed a few things internally to better work printing on FDM printers.

The design is up on Thingiverse if you want to download it from there: https://www.thingiverse.com/thing:5231825

I initially was considering building a few of these for sale to recoup some costs, but after building one, I came to the conclusion it wasn't worth the time. A single soldered battery pack took about 5 hours to construct. I'm sure a spot welded version would go much faster, but I don't have a spot welder.

One big gotcha with this battery is that it can short out when installed in the laptop due to a stupid design issue with the battery bay using an all metal shield. You should install a strip of electrical tape at the back of the battery bay over the metal shield, as well as on the side closest to the keyboard without covering the battery contacts in the laptop to avoid shorting the contacts on the battery out.

10 x NiMH batteries in series/parallel has a lot of oomph behind them, enough to spot weld the contacts on the battery to the metal shield, so a thermal cutout fuse is absolutely required if you don't want an accidental meltdown. The original Apple pack had two Klixon 75C rated thermal cutouts, but these are no longer available. I was able to substitute some axial single shot thermal cutouts from Ebay, they seem to work well enough in testing with a hot air station.

 

[jcs]

I'm interested in building one of these, thanks for making the case design available. Is it better to buy the cells with tabs on them?

Exell 1.2V 4/5A 2100mAh NiMH Rechargeable Battery with Tabs

Exell 1.2V 4/5A 2100mAh NiMH Rechargeable Battery with Tabs Exell 4/5A 2100mAh Batteries are excellent for building custom battery packs. If you are a novice or an old pro, these batteries will keep you powered up. These batteries can be re

www.batteriesinaflash.com

 

[GiGaBiTe]

No, because the tabs are not orientated properly. While all of the tabs in the center of the battery pack are all in the same direction, they're 90 degrees rotated on the outside of the pack, as well as needing space to install the thermal cutouts.

If you want to go the solder method, just solder directly to the battery terminals. All you need is a bit of fine grit metal sand paper to scuff the ends up and solder will stick fine with a bit of flux.

 

[Eric's Edge]

Your timing is perfect. I have a 180c battery pack I was going to refurbish like I did my 520c battery packs. I haven't cut it open yet and planned to reuse the original shell. Can you provide a link to the fuses you used?

 

[GiGaBiTe]

I used these:

6 Pieces TF 75C 167F Thermal Fuse cutoff ry mini micro metal 15A 250V A30 | eBay

Color may vary.

www.ebay.com

In order to get them to sit between the cells, I had to do some creative folding with the leads using needle pliers. I also had to hammer the ends of the leads flat to make a better connection to the battery terminal. The leads are pretty soft, so gentle taps will get them flat, no need to go hulk smash on them that may damage the internal fuse mechanism.

 

[Eric's Edge]

I think it’s worth a try. I had to cut out support ribs on the 520c enclosure to get the replacement cells to fit. Fun times.

 

[Eric's Edge]

I'm interested in building one of these, thanks for making the case design available. Is it better to buy the cells with tabs on them?

Exell 1.2V 4/5A 2100mAh NiMH Rechargeable Battery with Tabs

Exell 1.2V 4/5A 2100mAh NiMH Rechargeable Battery with Tabs Exell 4/5A 2100mAh Batteries are excellent for building custom battery packs. If you are a novice or an old pro, these batteries will keep you powered up. These batteries can be re

www.batteriesinaflash.com

I used these for the 520c build. Only had to cut one lead and flip the cells around to make it work.

Tenergy 9.6V Flat NiMH Battery Packs for RC Car, High Capacity 8-Cell 2000mAh Rechargeable Battery Pack, Replacement Hobby Battery Pack with Standard Tamiya Connectors https://www.amazon.com/dp/B001BA292A/ref=cm_sw_r_cp_api_i_ES0AFS2KZDNN94G3F0Y9?_encoding=UTF8&psc=1

 

[Eric's Edge]

I used these for the 520c build. Only had to cut one lead and flip the cells around to make it work.

Tenergy 9.6V Flat NiMH Battery Packs for RC Car, High Capacity 8-Cell 2000mAh Rechargeable Battery Pack, Replacement Hobby Battery Pack with Standard Tamiya Connectors https://www.amazon.com/dp/B001BA292A/ref=cm_sw_r_cp_api_i_ES0AFS2KZDNN94G3F0Y9?_encoding=UTF8&psc=1

This of course isn’t enough cells. There are other packs with seven cells and two packs are about $2/cell.

 

[GiGaBiTe]

I used these:

10x 1.2V 4/5A Rechargeable Flat Top Batteries For Shavers, Custom, Radios 26190091802 | eBay

Find many great new & used options and get the best deals for 10x 1.2V 4/5A Rechargeable Flat Top Batteries For Shavers, Custom, Radios at the best online prices at eBay! Free shipping for many products!

www.ebay.com

You get all 10 batteries for $17.95, or about $1.80 a cell.

As these are 4/5A, you'll have a lot of extra room in the pack to route wires compared to full A cells. These still give you a greater pack capacity than the original NiCD batteries, which from sources I can find state was originally a 3600 mAh pack. These will give you 4200 mAh, and if you can find 2700 mAh full A cells, you'd get a 5200 mAh pack. It's complete overkill for the earlier B&W PowerBooks, but the later color models would probably benefit from the higher capacity.

When the 4200 mAh pack I built was completely full, I left it to discharge for 4-5 hours and the battery meter didn't even budge. It probably helped that I had a SCSI2SD rather than a spinning disk.

 

[pfuentes69]

Hello,
As I'm a lazy person, I was planning to put this inside the case:

This is AA-size batteries, but I don't really need the laptop to run much time on battery, it's just for the fun.

Is this a bad idea?

EDIT: I plan to add the thermal fuses too.

 

[GiGaBiTe]

Those won't work without significant modification. The battery case is designed to have batteries split into 2+3 pairs with a gap between them for the thermal fuse. The heat shrink will prevent them from being installed into the case at all without snapping those out.

The thermal fuse also has to be in-circuit between those 2+3 pairs for them to be able to detect an overheating condition. You can't mount them on the top or bottom because of space constraints, and mounting them on the side will reduce their effectiveness.

Additionally, if those are AA cells, they're too small diameter wise and will rattle around in the battery case unless you secure them with glue or double sided tape.

 

[pfuentes69]

Those won't work without significant modification. The battery case is designed to have batteries split into 2+3 pairs with a gap between them for the thermal fuse. The heat shrink will prevent them from being installed into the case at all without snapping those out.

The thermal fuse also has to be in-circuit between those 2+3 pairs for them to be able to detect an overheating condition. You can't mount them on the top or bottom because of space constraints, and mounting them on the side will reduce their effectiveness.

Additionally, if those are AA cells, they're too small diameter wise and will rattle around in the battery case unless you secure them with glue or double sided tape.

Ok. I get that, thanks.
But, besides the “mechanical” aspects, it should work,, right? (electrically speaking, I mean)

 

[GiGaBiTe]

If you wired the two packs in parallel, yes.

The first prototype of this battery used one of those packs just wired directly to the terminals on the battery case and it worked.

 

[pfuentes69]

If you wired the two packs in parallel, yes.

The first prototype of this battery used one of those packs just wired directly to the terminals on the battery case and it worked.

That’s my plan… how long could stand the battery? Was the battery level indicator working?

 

[GiGaBiTe]

The battery level indicator works, but it's wildly inaccurate since it just measures the voltage and doesn't do any fancy load calculations. NiMH batteries have a characteristic where they'll hold their voltage almost constant until the very end of their charge and suddenly fall off a cliff. This makes it hard to know the state of the battery. It also means that when the battery pack gets low on charge, you won't have much warning before it is completely discharged, the meter will drop quickly before the laptop shuts off.

Adding to that, it also depends on which laptop you're using the pack in, and whether it has a mechanical hard drive or a SCSI2SD. The earlier B&W PowerBooks with a SCSI2SD get ridiculously long battery life. Like I was saying earlier, the PB 145B I had with a SCSI2SD was on for about 5 hours and the battery meter didn't even budge.

One thing to note about the SCSI2SD is that you MUST disable disk spindown in the PowerBook control panel because the SCSI2SD does NOT like having power suddenly cut to it. if the laptop keeps cutting power to it, it will cause the microcontroller to go into a corrupt state and stop working, resulting in massive data corruption.

Another thing to note is to make sure you use good batteries that don't have fake ratings. There are tons of garbage cells out there with fake capacity ratings, some are more obvious than others. Like you'll never get a 4000-9800 mAh 4/5A or even A cell in any chemistry. But there are also plenty of shady sellers taking trash capacity cells of like 150-450 mAh and remarking them to higher capacities. The same goes for premade battery packs.

 

[jcs]

My cells came and I printed a case, so let's hope this comes together smoothly...

 

[Kai Robinson]

My cells came and I printed a case, so let's hope this comes together smoothly...

Thats a really really nice print you have there!

 

[GiGaBiTe]

My cells came and I printed a case, so let's hope this comes together smoothly...

Probably too late, but I'd not recommend using those cells. You'll get a total pack capacity of 2400 mAh, which is 33% less than even the original Apple battery pack of 3600 mAh.

 

[jcs]

Doh! Not sure how I transposed 2100 mAh to 1200mAh in my searching for cells...

 

[GiGaBiTe]

It's not hard to do when all of the usual marketplaces juxtapose your search terms to try and get more results, even though they're wrong/irrelevant.

I was bombarded with pages of those crappy yellow NiCD 1200 mAh batteries when I was searching for 2100 mAh cells. After awhile the numbers all look the same since you go cross eyed sifting through the huge pile of results. I almost made the same mistake myself, but caught it when I went to my checkout cart.