Anyone with Pismo Li-Ion Battery Restoring Tips?

[J English Smith]

Took a chance on a new old stock Apple Li-Ion on the 'bay, for $20, as I had bought one a couple of months ago and it came back to life very nicely. This one, not so much. Any advice from anyone re info below?

Battery is recognized; can charge; charge drops from 100% to 0% in a matter of about a minute (can't get through a full boot, for instance). I have cycled charge-discharge about 6 times now after giving long, full overnight charges. The full charge capacity of the battery keeps dropping as shown in the system profiler. It has gone from showing 4500mAh to 2452mAh now. When it charges, it goes slowly from 0% - 5% and then jumps to showing 100% very quickly.

Any benefit in keeping at the charge-discharge method, or is this one toast?

I assume the "freezer overnight" method is only useful for NiMh batteries, not for Li-Ion?

I'm quite honked at the seller, he had two return policies in his listing and I only saw one of them. I've been mostly fortunate with eBay, but this was a case of a dirty seller. Battery probably had high heat exposure at some point and so it's n/g.

 

[techknight]

Well, As far as rebuilding a "smart" li-ion battery, I havent found a good way to do this.

The problem is not re-celling it, the problem is the microcontroller writes the cells condition and capacity in the eeprom of the controller. So without a way to reset all that, the battery will still think its dead/shot even with brand new cells.

it all depends on the individual controller circuity, some of them have re-learning capability, but if the battery thinks its dead and the cells are fully charged, it can explode thinking the battery is dead. I had this problem with the old thinkpad batts. New cells, the control IC registered the battery as defective so the orange light never stopped blinking. Once i got it to somewhat work right, the batts exploded because it thought they were dead. lol.

 

[J English Smith]

Thanks. Yes, seems this is not going to work. I've cycled it many times, and tried a freeze-thaw to see if I could get anything different with those darned electrons. The charge capacity has continued to drop every time I cycle it, so the processor is tracking the lack of charge life. It went from 4500 mAh when I first tried to charge it to about 950 mAh after two days of attempts. I am trying one more freeze-thaw just to be anal, but if that doesn't produce a different result, I will just have to toss this one. I was hopeful because another NOS Apple battery I bought charged and held like a champ. I imagine heat in storage damaged this one...oh well. The number of new batteries I am seeing for Pismo online are dropping and their price is rising... Lowest price I've seen for a new Chinese-produced one is about $50 shipped.

 

[techknight]

The cells are junk. They have been sitting too long. Batteries have a capacity loss of so much per year, per temperature scale, and is also dependent on level of cell charge. Knock on wood, the 3400 battery I have still holds a decent charge, and is original to the machine. not NOS.

Would have been more productive to get a NOS battery, and swap the cells while the controller was still fresh and had a virgin EEPROM. But, Eh...

 

[James1095]

Anyone know if it works to simply erase the eeprom, or does it have to be loaded with specific information? If erasing it works, that's pretty easy, something like a Bus Pirate, or even just a microcontroller can easily talk to a serial EEPROM, they're quite standardized parts. If you don't want to bother with that, you can buy new blank parts for ~50 cents and simply replace it.

I wouldn't recommend even trying to restore any type of lithium battery that has been deeply discharged. They are notoriously fickle and easily damaged by discharging too far as well as overcharging. Having seen the results of several lithium batteries that caught fire, I would err on the side of caution and throw out the dead cells.

 

[techknight]

Depends on the controller of the battery.

Older smart batteries the eeprom was external. I tried the erasing thing, Some batteries it worked, but the IBM batteries it would cause an orange flashing light and battery failure to be recognized. the serial number, model, and the battery's odometer is in the eeprom. Also some batteries firmware checksum the eeprom, so if you modify it anyway you have to know the algo otherwise it again is rejected. So many varieties. I eventually gave up the whole smart battery thing. I guess if you had a battery that the firwmare was available for it, and in plain text, your life just got loads easier as you can just simply reflash the micro.

Newer batteries, the micro has everything integrated and in which case your screwed as most of those have thier security bits set.

if we are to rebuild smart batteries, we need tools to do so. Such as reverse engineering of the data protocol, firmwares, etc.. Because what would be nice is if an "open controller" was created, that supported a multitude of different battery/ACPI protocols. Then we can just replace the cells, put an open source controller in it, and done.

Its also possible that some batteries have a function built in that you can call, and it revirginizes the eeprom/odometer and resets it back to "refurbished" or new state. I cant verify that though. Again depends on the firmware/controller.

 

[J English Smith]

I am in the process of checking all my remaining batteries for maximum charge. Not too bad. The worst is about 2900mAh, the best so far my NuPower #1 that had 5950mAh. If I keep using them in rotation, I hope to keep them running for several more years. Looks like fewer new batteries are being made than a year ago... Eventually will be like my 1400s, just usable when plugged...Pismos are great, I want to keep using for as long as I can. Thanks for the great info, folks. I won't try rebuilding a li-ion battery, that sounds too complicated for the likes of me.

 

[J English Smith]

Interesting, finished going through my batteries, quite a bit of variation there but decent life in most of them. All are Apple originals other than the 2 NuPower ones.

capacity mAh: 1863, 1934, 3893, 2924, 3425, 3685, 5950 (NuPower 1), 4032, 3051 (NuPower 2). One left to test at my Pismo that I keep in my other office.

I was bummed when NuPower discontinued their Pismo batteries last year. Was always planning to get a fresh one of those.

I was surprised by the difference between my two NuPower ones, didn't realize that the one was so much better than the other. I will guard that one carefully...

Next, I'm going to clock real-use runtime on the 1863 battery and see where that one sits.

I guess I can always get one of the remaining $50 Chinese 6000 mAh ones and see how that does. Is anyone using these, do they hold up?