MacBook battery (Rom) cycle reset

Discussion in 'MacBook' started by advance, Mar 9, 2011.

  1. advance macrumors newbie

    Mar 9, 2011
    Hi, guys i have done some DIY job here, my macbook battery started to display REPLACE NOW , so i purchased new one from ebay which is not best fit, so to sort this problem out i decided to change the outer casing, when i disassemble both battery casings i saw that there are 6 batteries(cells) inside, So i decided to swap the batteries Cell. which i have done nicely but now I am stuck as when i put my original battery in with new cells it still says that Replace now as battery Rom has still the same cycle count. Question IS there any way of resetting Battery Rom?
  2. GGJstudios macrumors Westmere


    May 16, 2008
    What you're doing is a VERY bad idea. There is no way I would risk my Mac to what you're doing. Just buy an Apple battery. What you're doing may save you a few dollars on the price of your battery, but cost you your whole MacBook.

    This should answer most, if not all, of your battery questions:
  3. iLog.Genius macrumors 601


    Feb 24, 2009
    Toronto, Ontario
    Isn't there a system/controller in the battery that stores this information? Although you've swapped out the cells (don't know why you would even try...) that system/controller is still there which has the information that's telling your Mac to replace the battery even if it is a "new" battery.
  4. advance thread starter macrumors newbie

    Mar 9, 2011
    Yea there is a rom which keeps all the information regards battery inside battery, i can access it. Normally any rom if you require to reset you need to short two-three connections in order to format rom memory(for example computer mother board to reset bios etc). I just dnt know which wire to short. as its a critical point if i short wrong wires it can burn Rom chip.

    Any Genius ?
  5. advance thread starter macrumors newbie

    Mar 9, 2011
    Thanks for your reply, I am not trying to get away for saving few quids, its not about money its about getting right knowledge. job which i have done so far it may not be recommended by Apple but Dont worry i know what i am doing, Trouble is i am not sure which points to short on chip in order to wipe memory.
  6. dave.mckiernan, May 10, 2011
    Last edited: May 10, 2011

    dave.mckiernan macrumors newbie

    May 10, 2011
    MacBook Batteries

    I work as an electronics & IT engineer and I have five MacBook batteries, which all have good cells inside them. Unfortunately the on-board micro has shut down the DC controller ICs, effectively rendering all five batteries useless.

    I know the cells are all good because I have manually charged them and the power-check button illuminates all of the green power meter LEDs.

    I am appalled that the batteries seem to have been designed in such a way that if the minimum charge level is lost they are no longer functional and will therefore end up in a landfill.

    If anyone has successfully reset the on-board microcontroller then please tell the world, because there must be millions of good cells, and ultimately whole £80 batteries, being wasted by this seemingly consumerist design.

  7. advance thread starter macrumors newbie

    Mar 9, 2011
    So far nothing from my side. I haven't been able to find any solution. but I am dam sure that there should be some way of resetting a chip.
  8. blackburn macrumors 6502a


    Feb 16, 2010
    Where Judas lost it's boots.
    If the battery works you can try and start using it, maybe the reported capacity will go up.

    Nowadays those chips are nasty, if they lose power they will refuse to work again.

    Anyway there was/is a be2works forum, and there was a way to reprogram the eeprom. The forum still exists, maybe you can try and check it out.
  9. discounteggroll macrumors 6502


    Aug 6, 2006
    Greenwich, CT
    no bueno.

    I got dibs on what's left of your macbook should something 'asplode
  10. hotshotharry macrumors 6502

    Sep 6, 2007
    So just recently i left my macbook for a couple days in sleep mode and when i got back to it i guess it had discharged too far and the replace battery now icon was on ... the first led flashes rapidly for about 5 seconds. This is a permenant failure flag and the battery will no longer work in your computer. After a bunch of fiddling and manually charging cells etc trying to get the cel voltage parameters in range i had the battery in pieces now lol anyways there is a charge controller chip in the battery that handles all the battery power management. The chip number is bq20z80 and uses and smbbus interface (I2C) for communication, it looks like the management chip can be reset by sending the appropriate commands. According to the data sheet there is a master reset pin, although i cant seem to find what it all resets. Anyways since its summer now thats as far as I will be taking this ... perhaps in the winter I will tackle it again if i havent hacked the battery packs apart for something else! lol

    let me know if you take this any farther, it seems to me though its prolly much faster to just get another pack for 40 bucks off ebay ... :) ! LOL and i dont say that with the same ignorance most do! :)
  11. Nick Gillard macrumors newbie

    Sep 17, 2013
    I also believe there must be a solution to the MacBook deep-sleep battery problem. It's not about saving money, it's about reviving these batteries so they can be used rather than disposed of and replaced. We have dozens of these and have invested a lot of effort to date to find a way of kick-starting them back into life. Here is what I have tried and discovered to date and I hope someone can contribute to the thought process to find a way forward.
    My understanding is that when Lithium Polymer (LiPo) cells are connected in series as they are in MacBook batteries (3 pairs of cells in series), they must all be evenly charged. The battery management circuitry will trigger an alert and close down charging for a number of conditions including the cells being significantly different charge or the charge level being too low. In faulty batteries I have tested, the charge level across the middle cell pair is very low and below the operating voltage of the control circuits.
    The attached photo shows the two Texas Instrument battery management chips on the control boards from within an A1185 battery, and I have also attached the spec documents for both of these.
    I purchased a LiPo balance charger and made up a lead with croc clips to recharge the cells safely. See attached pic.
    The TI bq20z80 controller chip has a hardware reset pin and I traced this and the +ve rail it needs to be pulled high to, to a pair of solder pads. See attached pic of battery controller board. Shorting these pins resets the bq20z80 controller and the first battery charge light illuminates to signal this.
    Having fully charged the cells evenly and reset the bq20z80, the battery lights indicate the charge correctly when the button on the battery is pressed, the battery is recognised by the host MacBook and it reports it's cycle counts. However, it reports a full charge capacity and current charge of 0, and it will not accept charge from the MacBook. If the magsafe charger is removed from the MacBook it immediately powers down so even though the battery cells are charged, it is not providing power to the MacBook.
    This is where I am currently stuck. There does not seem to be a hardware reset on the secondary bq29312 chip, only a reset through a command but I thought the bq20z80 would send a reset command to the bq29312 when it was reset. Maybe not! I feel I am tantalisingly close.
    I will post back if I discover anything more and hope someone is able to add some fresh insight.

    Attached Files:

  12. gergleup macrumors newbie

    Feb 27, 2014

    Hi Nick,

    I am at the same place as you. I have manually recharged the batteries, and have 5 lights showing when I press the button, but still the battery will not power the computer. So I was wondering whether you have made any further progress. Surely there must be a way to solve this problem?
  13. gergleup, Mar 2, 2014
    Last edited: Mar 9, 2014

    gergleup macrumors newbie

    Feb 27, 2014
    It can be done! But it ain't easy. The bq20z80 has set a "Permanent failure flag" which needs to be cleared. To do this you need to communicate with the microprocessor using some software and an interface board, all of which is available from Texas Instruments.

    You also need to switch the microprocessor from "Sealed" to "Unsealed" mode before you can clear the flag. To do this you need the Mac unseal password which is (0x04143672).

    There is an excellent pdf called "Battery Firmware Hacking" which will help you with all this.
  14. brettinlj macrumors member

    Jun 13, 2008
    Are the replacement batteries from the Apple Store actually "new" anymore. In other words, is the manufacture date late enough that they are really full capacity? I have a late 2008 "Aluminum" Macbook and my battery is still above 80% but have been thinking about buying one while they are still for sale. My concern is that these were manufactured some time ago and have been sitting around in a warehouse and are not going to last.
  15. Richdmoore macrumors 68000


    Jul 24, 2007
    Troutdale, OR
    I can look at my wife's plastic macbook battery that I purchased a few months ago, but I am not sure how to tell the manufacturer date.... Is it in the system prefs, or printed on the battery? Can it be decoded from a serial number?
  16. gergleup macrumors newbie

    Feb 27, 2014
    When the MacBook battery goes flat due to the computer being left sleeping for an extended period, the microcontroller deliberately blows a chemical or thermal fuse, and sets a Permanent Failure flag. The reason the microcontroller takes such drastic action is because it is dangerous to try to recharge flat LiPo cells. So proceed at your own risk!

    To reactivate the battery you have to replace the fuse. It is circled in green in the pic. It is a NEC/SCHOTT SEFUSE type 6X, rated at 12 A. I am currently trying to buy some, but they are not a commonly available component. An alternative is the Uchihashi EC-200 thermal fuse, also not commonly available.

    You also have to reset the Permanent Failure flag, as described in my earlier post

  17. ReneR macrumors 6502

    Jun 18, 2008
    Berlin, Germany
    Did you had any change settings these batteries?
    --- Post Merged, May 19, 2016 ---
    Any update? ;-)

Share This Page

16 March 9, 2011