What is this and why isn't it conducting electricity anymore?

[zuctronic]

I rebuilt this powerbook 1400c battery and it was working beautifully until suddenly it wasn't. I tested everything and narrowed it down to this mysterious component no longer conducting electricity... any ideas what this is, can I find a replacement? Can I just cut this out and patch with wire? What would have caused it to fail after working for a few weeks?

 

[bibilit]

Hi,

looks like a thermal fuse to me:

https://www.google.fr/search?q=thermal+fuse&client=opera&hs=Ukw&tbm=isch&imgil=S1duuxmm_kXDDM%253A%253BVeqyUh7lgj96YM%253Bhttp%25253A%25252F%25252Ffreek-heaters.com%25252Fproducts%25252Faccessories%25252Fcut-outs-and-thermal-fuses%25252F&source=iu&pf=m&fir=S1duuxmm_kXDDM%253A%252CVeqyUh7lgj96YM%252C_&usg=___xzbot67B7ZQwMGQ6_YU2Z-XRG4%3D#imgrc=S1duuxmm_kXDDM:

you can patch it, but i will not advise to do so.

 

[zuctronic]

Thanks, that makes sense. It was definitely getting hot and I kept plugging it in and unplugging it to test things out and see how long it would run on battery... but I wonder if it's some dodgy connection in there. I ordered some new fuses from Newark and I'll re-assemble it with solder instead of conductive tape.

Also realized this is not a 68k PowerBook but not sure how to move the thread. Sorry!

 

[Trash80toHP_Mini]

Definitely needs to be replaced. Interesting re-cell project. Did you document it?

 

[Gorgonops]

That thing shouldn't blow out unless the cells get too hot, so definitely replace it in kind and try to figure out why your new batteries might be getting hot. Just patching around it could lead to a an earth-shattering kaboom. (Or, more likely, a fire.)

 

[Trash80toHP_Mini]

My God that battery pack is a hack of beautyI  Did you intentionally make it in 1400/PGA or is it just coincidental?

BatPack Magic Smoke is likely on the better to be avoided short list of MacHazMats.

 

[Unknown_K]

A bad solderjoint/connecton will heat up when you put some AMPS over it so check your connections.

 

[zuctronic]

My God that battery pack is a hack of beautyI  Did you intentionally make it in 1400/PGA or is it just coincidental?

BatPack Magic Smoke is likely on the better to be avoided short list of MacHazMats.

Ah... lol ... it's coincidental, I guess. The cells came that color and I used the yellow masking tape to tape the cells together and the black electrical tape to replace the black sticky foam that was insulating the end caps before the re-cell.

I was able to pull the case open without damaging it, so when I snap it back together it looks great.

I'll replace the thermal fuse with a new one and make sure there's better contact between the PCB and what I suspect is a thermal sensor inside the BatPack casing.

 

[techknight]

Now, this is NiMH right? 

If so, there should be a small sensing thermistor somewhere which has to be positioned in the cells, or the unit WILL overcharge them and itll get super hot, super fast. 

NiMH and NiCD batteries release overcharge as heat. 

If its a lithium ion battery, STOP now and get the smart PCB re-virginized/re-calibrated or you can blow the whole area to smithereens. Li-Ion batteries do not accept overcharging well at all. 

 

[zuctronic]

Now, this is NiMH right?

If so, there should be a small sensing thermistor somewhere which has to be positioned in the cells, or the unit WILL overcharge them and itll get super hot, super fast.

NiMH and NiCD batteries release overcharge as heat.

If its a lithium ion battery, STOP now and get the smart PCB re-virginized/re-calibrated or you can blow the whole area to smithereens. Li-Ion batteries do not accept overcharging well at all.

Hi TechKnight,

It's NiMH, I looked for cells that are as close to the original spec as possible in this case. I think the thermistor is actually on the backside of that PCB and it makes contact with a flat heat sensor built into the case of the battery that in turn makes contact with all the batteries. I don't know if that contact was being made after the rebuild, now that I've had a closer look - it's just a pressure contact and the original cells had thicker cardboard tubes holding them in pairs whereas I'm using masking tape so the upshot is there's a bit of "play" inside the batpack now. This will be easy to fix.





Additionally, I suspect I was overcharging it because I wasn't really understanding the battery meter in the OS - which should probably not be trusted after a battery pack rebuild! It would jump from 50% to 100% very fast, so I unplugged it and plugged it back in and it would charge for another 20 minutes or so. In retrospect, this was probably ill-advised and I'm glad there is a thermal fuse in there.

 

[rsolberg]

I was about to embark on a similar rebuild of my 1400c's battery pack when I decided to see how long it would actually run. Initially, it went into "reserve battery" mode after about five minutes, then into sleep after another five. I was able to wake it back up and it ran for about fifteen minutes before going into sleep again. This time, it wouldn't wake up until I plugged it in. After it topped up again, I got about ten minutes before the reserve warning, then twenty before it slept.

I recharged for several hours, then installed Battery Amnesia 1.5.2 from Macintosh Garden and ran a discharge cycle. It ran for an hour and twenty eight minutes before shutting down hard. It might be worth running to calibrate your battery with the system's PMU.

 

[techknight]

Thats not a heat sensor bro. That is a GND shield. 

If the battery has a processor or any smarts to it whatsoever, it WILL need recalibrated. 

Usually you disable all the energy save stuff and let it run completely down until its dead. THEN charge it. it will need a few cycles. 

I think there was a utility that did this, battery recondition? 

 

[zuctronic]

Thats not a heat sensor bro. That is a GND shield. 

If the battery has a processor or any smarts to it whatsoever, it WILL need recalibrated. 

Usually you disable all the energy save stuff and let it run completely down until its dead. THEN charge it. it will need a few cycles. 

I think there was a utility that did this, battery recondition? 

Alright so that GND shield is not the issue. There is a blue bulb "thingy" sticking out of the PCB and it was fastened to the cells with what looks like hot glue. I reckon that's the thermistor.

Battery recondition is the one, it's in the Apple Extras folder with 7.6 and later, I think. Once I get the replacement fuse in there I'll run that to discharge it all the way, then charge it back up  all the way.

 

[rsolberg]

Rob Shaw's original post in this thread is good reading if you haven't found it already: https://groups.google.com/forum/m/#!topic/comp.sys.mac.portables/kcT1Uf2j3Ac

These batteries have a thermal fuse, something that sounds like a self-resetting polyfuse, and a thermistor. The thermal fuse breaks the connection if overheated and will have to be replaced if open. The polyfuse is designed to open if too much current passes through it and/or it gets too hot. It will normally "heal" or reset after a period of time, closing the circuit again. The thermistor is wired to two of the battery pack's terminals and by varying resistance, allows the PowerBook to measure battery pack temperature. The pack doesn't have any "smart" circuitry, just an ID chip the computer uses to differentiate different battery packs. The PMU on the 1400 handles all the "smarts" as far as I know. It's what requires the calibration. Do post whether the Apple utility works on your machine. It didn't install into the Extras folder with a full 8.1 install and when I tried running it from CD it told me it wasn't "compatible with this PowerBook."