rebuilding laptop (iBook G4) battery

I have an iBook with low battery capacity, about 60% of what it used to be, but 450+ cycles. Not too bad.

Still, I could buy a new battery for $100+ (129 from Apple, maybe 10-15 cheaper online or on eBay). But I am also considering if it is worth taking the battery apart and replacing the weak cell. Any ideas if this kind of project is feasible, or it's more PITA and I should just get the new battery?

Remember, all of the cells have 450 cycles on them. You would have to replace them as a matched set. You can figure the cost of the cells.

Next, computer batteries are not designed to be opened. You will have to cut it open (very carefully). Then unsolder the old cells and install the new cells. After that, figure out some way to reclose the package.

It can be done. You decide if it's worth the time and risk.

Not in my G4. I would buy an OEM battery either from Apple or eBay.

Mark

viorel00 said:

I have an iBook with low battery capacity, about 60% of what it used to be, but 450+ cycles. Not too bad.

Still, I could buy a new battery for $100+ (129 from Apple, maybe 10-15 cheaper online or on eBay). But I am also considering if it is worth taking the battery apart and replacing the weak cell. Any ideas if this kind of project is feasible, or it's more PITA and I should just get the new battery?

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Many times the laptop battery can be disassembled and the individual cells replaced. I would recommend replacing them all as a set, not just one.
It really depends on whether the plastic case has been sonically welded together. You should be able to find an online guide that will help you learn how to change the cells in the battery.
The most common cell in a laptop battery is an 18650 I believe. You should be able to change them all for much less than the price of a new complete battery.

any good place to buy 18650? dealextreme or kaidomain?

Also, do I need protected or unprotected cells?

I did the math on a Powerbook battery last year. They have groups of 2 parallel cells in series up to the required voltage. And a lot of smart charging circuitry in them. When I added up the number of cells I would need I was going to save around $25 over buying a new one, and the amount of work involved was going to be HUGE. they are very compact, there is no room in there for fiddling around. They are not meant to be taken apart, you will end up with a battery held in by tape and glue.

Save yourself the trouble and get a real one, it's not worth it!

Check this link out - nice video showing how to replace a laptop battery pack.

http://shizzville.com/laptop-battery-hack

Should give you some idea on how go about replacing the battery pack.

Thanks everyone, I've been thinking of doing this myself.

mulki said:

Check this link out - nice video showing how to replace a laptop battery pack.

http://shizzville.com/laptop-battery-hack

Should give you some idea on how go about replacing the battery pack.

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Great video, but the "when doing any soddering" line had me worried.

viorel00 said:

any good place to buy 18650? dealextreme or kaidomain?

Also, do I need protected or unprotected cells?

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to know for sure you need to measure the original batteries. Protected cells are longer than unprotected. Also is there room for slightly longer batteries in the case?
The originals are probably unprotected, but I recommend buying protected.

I wrote a reply to this, and somehow got it entered in the wrong thread, haven't been quite feeling myself lately In case anybody didn't happen to read it in the SAMS club HID thread I'll put it back here...

yea... heh, but that video shows that the battery case just pops open and that there are only 6 batteries in there. There were 12 (I think) batteries crammed into about the same space in the powerbook battery that I took apart (and it costs the same as the gateway with half the insides.. hmm... shame apple is so overpriced...) and absolutely no space to work, no tolerance for sloppy soldering or even folding over a wire that you trimmed too long or anything. And Im pretty sure that the newest batteries are using lithium polymer batts, which you can probably also get replacements for, but are going to be even more expensive so the savings will be even less.

So you save $20 or even $30 bucks, but the dis and re-assembly of a more modern pack is going to be a LOT more trouble than what he showed in that video.

The battery is toast, go ahead and rip it apart just to see if you think you can do it Post pictures of what you find. But I'm still betting that it's not worth the $20 or $30 saved.

As far as protected vs unprotected cells. There will be absolutely no wiggle room in that battery case (probably). so you will almost certainly have to get exactly the same battery as is in there. They are in a series parallel arrangement, so cell matching becomes an issue. Soldering those little tabs on the ends of the batteries is possible, but it takes some practice and patience and guts...

Decided that rather than working here I'd dig up the pictures I took of my old Powerbook battery You have to peel off the label to see inside:



and then you see that they actually had to provide beveled slots in the case material itself to fit in the cells into the size of battery they wanted:



and there is no way to open it, so I cut around those thin plastic pieces:



so only 8 cells, but no easy way to get at them to remove them, much less replace them. When I did the math on proper replacement cells at the time (this was a couple of years ago) my savings after purchasing them even from a cheapo place on ebay was only going to be a little more than $20 so I opted for just ordering a new pack. I'm sure the prices have come down a lot, but tear into the thing before you order them as I doubt that there is more room inside a newer pack than there was in this one.

Don't bother doing this unless you know exactly what is inside the case. I thought it would be pretty easy to carefully open a sealed case and solder up a few batteries together. Wrong. My HP pack was pretty complicated with a whole series of connections both at the front and back of the pack. After a great deal of time and experimenting I hooked it all together but I just couldn't quite replicate the very tight fit of the original and consequently could not fit the case back together cleanly. In the end it all proved academic as it didn't work-I must have fried the circuit board at some stage.
I, too, saw some of the web tutorials that made it look a cinch to do the job. I think that most of these were based on early models where it was quite straightforward to unscrew the case and drop in a few new cells. Mine was nothing like as easy.
I've now got 6 high capacity li-ion cells that cost me £40. I thought that I might be able to utilise them in a drill battery pack or perhaps make a pack for bike lights. However, looking around here, charging them seems to be a big problem so I guess that they are a write off for now. Altogether I wish that I'd just ignored my parsimonious instincts and just bought a new battery. Grrrr.

Don't waste your time and money.

All modern laptop battery packs have build in microcontroller and charging cycle counters.

When the factory set number of charging cycles is reached, the controller will not allow any more charging.

Sound advice. Take heed!
Incidentally, I've now discovered that there are plenty of high capacity non-generic (Chinese) copies of most complete laptop batteries for about the same money as it costs just to buy the individual batteries. Much easier and just as cheap to give them a go.

When the factory set number of charging cycles is reached, the controller will not allow any more charging

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So the battery just shuts off and tells you that its time for a new one? Wow, that would suck. The Apple ones dont do that, they will keep trying to charge but just run shorter and shorter until they are useless.

They do keep track of a lot of information in that charging chip in there. Disconnecting it from power though does reset all that data. There was a bug in some firmware somewhere a couple of years ago where the data got confused and the batteries would not take a full charge. There was actually nothing wrong with the batteries themselves but the computer would switch to maintenance charging them too early and they never reached 100%.

The user hack fix that we did to reset the count after the firmware update fixed the computer issue was to actually SHORT OUT the battery pack! That caused the hard short protection to actually disconnect the battery for a moment which reset all the data in the charging controller chip inside the battery. This was not something for the feint of heart to perform, as if you happened to have a defective protection circuit or just a lazy one the potential was there to do you some harm. I certainly wouldn't recommend doing that...

But there is a lot of stuff in there. There is actually a PIC of some kind that keeps track of current in and out and charge cycles and watches the temperature and it communicates to the MacBook via a serial line on one of those multiple ports on the battery connector.

rhuck60 said:

The originals are probably unprotected, but I recommend buying protected.

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The originals already have protection circuitry built in the pack.
Said protection circuitry could freak out if it had to handle the additional protection in the cells themselves, so unprotected cells are the way to go for laptop pack replacement.

Also: eBay knockoff battery prices are, in my experience, MUCH lower than those for the original packs.