Macintosh PowerBook 145/160/170 battery replacement

[Rajel]

Ah, didn't look like you'd used support material in the other print, so I didn't enable them.
Also I typically hate Makerbot's supports. Those look different though, maybe they've improved them.

I literally design stuff around using as little support as possible, due to how much I despise MB's support generation in the past.

 

[Westinghouse]

For the lithium variant, is it possible to get a version without the AA compartments to maximize the amount of usable space for flat lithium cells?

Are you looking for the exact-same model, but without the dividers, or are you looking for one with a larger interior tray space? 

 

[Rajel]

Maybe I'm missing something with the lid, but there's a gap from the ribs on the underside of the lid where it hits the lip in the pack.
Gonna shave the ribs off at the edges so it'll sit flush.

 

[Rajel]

Are you looking for the exact-same model, but without the dividers, or are you looking for one with a larger interior tray space? 

Just without the dividers would be enough, I think.

What are you using for modeling, if I might ask?

Edit: I really don't mean to seem like I'm nit-picking. These are really great and I'm SUPER appreciative of your work!

 

[Westinghouse]

Don't sweat it; I haven't run any of the "refined" version that I uploaded, since my prototype is 'good enough for now' for me. Thanks for being a guinea pig -- the feedback is greatly appreciated.

It sounds like the ribs on the lid run a little too long. I'll revise that and upload a revised STL here. You might need to shave off a bit of the ribs once the cells are in, too, though I think I got that right. If not, let me know!

In the prototype, I now have some minor bow in the tray from the load of the cells + contacts, but it still works well. I'm hoping the secured lid will manage this and mitigate bow.

Do I see a little bit of sag on the lowest levels of the finger pulls in your photo? If so, I'm impressed that they turned out that well without supports -- but they might need trimming to accommodate the sliding cover, if you're using one.

The model was made in AutoCAD. There are better suited programs for this kind of work, but it works for me.

 

[Westinghouse]

Here's an STL of the tray with no dividers.

PB140 Tray_EMPTY.zip

 

[Rajel]

Sweet, I'll give these a run tomorrow!
Yeah, I'm actually pretty impressed with how well the bridging works on the makerbot. I do run a little cooler than average to minimize the sag.
I did a test fit with the cover and didn't see any issues... the rails on the cover don't really latch onto them so it didn't really affect anything.

I've started learning Fusion 360, seems nice but there's stuff I'm still trying to figure out. I'm relatively decent with Sketchup, but that program has some really weird geometry quirks.

 

[zuctronic]

Alright, I got the PrintrBot Jr in my office working... nobody's used it in over a year! It's printing off the tray right now, but it's not fast and I've got a 7hr time estimate so probably won't get to see it until tomorrow.

I'll let you know how it goes!

 

[Westinghouse]

Alright, I got the PrintrBot Jr in my office working... nobody's used it in over a year! It's printing off the tray right now, but it's not fast and I've got a 7hr time estimate so probably won't get to see it until tomorrow.

I'll let you know how it goes!

I hope you saw the updated model here, which picks up the lid rib issue that Rajel identified.

If not, it's probably not worth stopping your print over, there's just some trimming needed.

 

[zuctronic]

I hope you saw the updated model here, which picks up the lid rib issue that Rajel identified.

If not, it's probably not worth stopping your print over, there's just some trimming needed.

Ah, I think I went running with the old file - no problem. I'll probably be needing more of these so there's opportunity for more testing!

 

[Rajel]

Yeah, just shave off a few mm of the rib there at the end and it should be alright.
Haven't been able to find the metal strips like that locally so I haven't put mine together yet, probably going to have to order them.

 

[zuctronic]

They sell the metal strips at Blick's art supply, otherwise there are suppliers on eBay.

 

[Westinghouse]

Hobby / model shops might have the strips as well.

I used .016 x 1/4" strips for the terminals that connect to the powerbook internals, and .016 x 1/2" for the contacts between the cells.

 

[zuctronic]

Hobby / model shops might have the strips as well.

I used .016 x 1/4" strips for the terminals that connect to the powerbook internals, and .016 x 1/2" for the contacts between the cells.

I could see them in the background of one of your photos, I got the exact same strips (they're made in Chicago, too!)

I've just assembled it and test fit everything, looks good. I'll need to solder in the klixon and should be good to go! Thanks so much for the .stl, this will help me get a few old PB back to pushing electrons.

 

[Rajel]

Just got mine built, works great!
i'm concerned about charging while in the device, anyone have a good solution for charging NiMH cells? Otherwise I'll drop a diode in the pack and just remove the batteries and charge them individually.

 

[techknight]

Careful with using a diode, they are anywhere between .5 to .7v drop. It doesnt sound like much, but it will cause the machine to shut off much earlier complaining of a dead battery than it normally would. 

You may need a low voltage drop diode, like a shottky, and use them in parallel to get the drop even lower. 

 

[Rajel]

Excellent advice, thanks! A little bit of a drop wouldn't be *too* bad since it's .6v over the OEM rating already, I'll definitely watch out for that though.

 

[Westinghouse]

I haven't had any issues charging my battery in the PowerBook; is been through about 10 cycles by now I'd guess.

I still feel the need to not leave the PB unattended when charging, though.

Curious to hear your experience with use available out of a full charge.

 

[Rajel]

For now I'm just popping the AAs out and using a dedicated charger. Can't wait to see what battery life I get with a set of Eneloop Pros and SCSI2SD instead of spinning rust.

 

[Rajel]

Brought the 160 out to the office today, still running off the SCSI drive. Several colleagues got a kick out of seeing the thing power up, and then a double kick when I pulled out the battery pack. Had to pass that around as much as the laptop itself!