PowerBook 5300 Series Battery

[jmacz]

Ok, my turn to try to rebuild the 5300 battery pack for my 5300c. I'm just starting so will provide updates in this thread as I attempt to figure things out and hopefully don't fail. I couldn't find a successful rebuild on the forum but maybe I'm not searching properly? Anyhow..

The 5300c I bought came with what appears to be an aftermarket battery from BTI.



The outside enclosure is identical to the Apple one. I can't tell the capacity -- not sure if by the model number I can infer it's a 1900 or 1950 mah? But it opened pretty easily using the knife method. I just used an x-acto knife and made several passes on the center seam and it came apart pretty quickly. The case is pretty much intact so I should be able to reuse it later.

Inside I found 12 cells from Toshiba. They are NIMH cells, 1.2V each. Total 14.4V = 12 * 1.2.



The label says these are 4/3A size cells.



Along with the batteries, there was what appears to be an inline fuse, a thermal sensor, and a circuit board. The circuit board seems to be powered via 5V which it's drawing from the batteries.



There's a wire coming from the 5th cell from the end so roughly 6V being taken to power the circuit board. And then for the 5 pins on the exterior of the battery housing, it looks like here's what they are for:



Closest to the edge is the positive end of the battery. 2nd is connected to the thermal sensor. 3rd is ground for the circuit board. 4th is Data. 5th is the negative end of the battery.

The batteries were arranged in two rows but staggered to reduce thickness.

Seems straightforward? I didn't test the fuse yet but will check whether it's intact. Hopefully the thermal sensor still works. There was a little bit of crystallization where the 5V/6V wire was attached and in one other spot but I don't see much from a corrosion standpoint. And the circuit board looks very clean.

They still sell 4/3A batteries... but wow, they are expensive. Amazon is showing them for around $8 USD for a single cell (3800mah). There's a cheaper 10 pack for $52 that are pre-tabbed. And they have a long lead time. Will have to shop around.

Will continue this after I find some suitable cells and get them delivered.

 

[jmacz]

Cells look to be a little bit cheaper if you get them direct. Tenergy's website has 3800mah 4/3A cells pre-tabbed for $4.65 USD per cell.

EDIT: actually they are cheaper anywhere outside of Amazon but still roughly $4.50-$5 per cell.

 

[3lectr1cPPC]

Lucky that you had an aftermarket battery. The cells in the original seem to have a tendency to go REALLY leaky.

 

[3lectr1cPPC]

I also just moved the size, 4/3A. Last I remember hearing that the OEM batteries used AA size cells. Maybe this was wrong? It was a long time ago that I saw that, and I can’t remember where. Either that or the aftermarket pack used different ones.

 

[jmacz]

Well, I have a stock one that I acquired that I will also cut up in a few days so I can check if that one also had 4/3A or AA.

 

[jmacz]

I'm working on the PRAM battery as well which hopefully I can try out if I can get the main battery to work.

The stock one is obviously two coin cells stacked so I cut it open and they are Panasonic VL2330 3V Lithium batteries. They are readily available on Amazon pre-tabbed. So I got a pair. They are around $15 for a pair. Here's the stock one:



And with the shrink wrap cut open:



And the replacement pre-tabbed ones from Amazon ready to be used.



Transplanted the wiring onto the new cells and put some heat shrink around it.



Black is ground, red is the two batteries in series, and the white is actually between the two batteries. So 6V on the red, 3V on the white. I will probably remove the shrink wrap and redo it to cover the entire battery and I also need to rewire it so that I can get the combined unit to be thinner.

I also cut open the PRAM battery pack on my PowerBook 540c. It's the same Panasonic coin cells. Just the 500 series is side by side whereas the 5300 series is stacked.

Hopefully I can get the main battery to work so I can use this.

 

[bigmessowires]

They still sell 4/3A batteries... but wow, they are expensive.

You could rebuild the battery pack using standard size AA instead of 4/3A: they're the same length but the diameter is smaller, so you'd end up with extra space in the battery case that you'd need to fill with something. Of course the battery capacity would be less, if you care.

 

[jmacz]

You could rebuild the battery pack using standard size AA instead of 4/3A: they're the same length but the diameter is smaller, so you'd end up with extra space in the battery case that you'd need to fill with something. Of course the battery capacity would be less, if you care.

Yeah, I wanted the capacity. I have a set of 4/3A coming from Tenergy directly.

 

[mdeverhart]

Of course the battery capacity would be less, if you care.

The other thing to watch out for is that different cells have different discharge rates - even if the physically smaller cells had the same nominal voltage and capacity, they might have a lower discharge rate and so the voltage might drop under load.

 

[jmacz]

Ok so I got the set of twelve 4/3A 3800mAH NiMH batteries directly from Tenergy. Unfortunately, don’t have pictures as in the midst of transferring some files around on my main computer, I deleted them on accident

Anyhow, it was really really straightforward. I hot glued together packs of six cells (alternating the direction like the stock ones). This held the batteries in position so I could solder the tabs together. So this resulted in two packs of six. Then soldered the board, the thermal sensor, the fuse, exactly as it was in the original cells. I reused everything but the cells.

After that it was just putting it back together. I taped the case together with kapton tape as it’s thin, resistant to heat, etc. I did not glue as I wanted to ensure it would be easy to take apart if something went wrong and/or I needed to ever get back in there.

Popped the battery into my 5300c and it was immediately detected and works great. This was actually pretty straightforward compared to the mess I’m going through with the battery on my 540c.

 

[3lectr1cPPC]

Good job! Is this the BTI battery?

 

[jmacz]

Good job! Is this the BTI battery?

Yup!

 

[3lectr1cPPC]

Well, I have a stock one that I acquired that I will also cut up in a few days so I can check if that one also had 4/3A or AA.

Have you had a chance to do this yet? No problem if not.

 

[jmacz]

Have you had a chance to do this yet? No problem if not.

Not yet... on my todo list still. Maybe get a chance to crack it open and take a look inside this weekend. The stock battery I have does show signs of corrosion on the outer connector so not sure what I'm going to find inside. But at least in terms of checking out the battery size, should be no problem.

 

[3lectr1cPPC]

The originals all seem to be fried by corrosion. I’ve never honestly seen a battery that’s worse about it, except of course for the Varta clock batteries, and probably also the IBM ThinkPad 701c.