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  1. #41  
    A very informative thread; thank you all.

    Now I know what to do with the Centro that my daughter just borked. It'll become a spare battery charger. Maybe I'll re-engineer the case to make it more visually appealing on my desk.
  2. #42  
    just did a few tests... First test I used a meter called a huntrun tracker 1000 on the pre input contacts. The huntrun sends 5vac through the circuit or component you are checking using 2 leads red(+) & black(-) and displays a signal on the display according to how the voltage is run. You get different signals from different components. Across the outside leads I got a capaciter which is normal and will be polorized which means voltage can only flow one way through it but you can blow this cap if you put to much voltage across it in the wrong way also caps are used as a filter blocking ac voltage. Across the right & middle contacts I got a signal for a diode or transistor also a component that will only allow voltage to flow in one way. The second test I performed was trying to power up the pre without the battery using a power supply and found out which I had assumed that it won't power on without a sense voltage to the middle pin instead on the screen there is a giant battery with a question mark in it lol nice one palm. So with all that said I don't think that if you reversed the polarity on the input would actually kill the device esp since the middle contact requires a sense voltage that won't be activated unless you insert the battery the correct way because the fets have to switch to apply that sense voltage and they won't switch without the correct polarity.
  3. #43  
    If the batteries really are different and Palm didn't want us to use Centro batteries, they shouldn't have let them fit perfectly.

    But thank you all for the incredible scientific data!
  4. Me2
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    #44  
    Quote Originally Posted by zechzz View Post
    a little background on me I'm an electronic technician for a company with contract to pretty much all the telephone equipment providers in the usa with that said I don't work on cell phones there isn't really any money in repair for those. But am familiar with power.
    Really? I'm glad I'm not your employer or customer then.

    Quote Originally Posted by zechzz View Post
    mostly likely with it only being 4vdc it wouldn't harm anything if it were ac it might be more likely but just as if u plug in your batteries for your remote in the incorrect order there are no negative effects from such a small voltage level.
    Makes you wonder what sort of training they give "technicians" [1] these days, as you clearly don't understand even basic electrical principles or Ohm's law if you think 4V cannot cause any harm, or that the only reason it's safe it because it's DC. "Familiar with power" indeed. Talk about a little knowledge being dangerous!

    1) The only reason your remote doesn't expire when you insert the battery in the wrong way round is because they incorporate reverse polarity protection diodes to protect against misuse.

    2) Anybody who claims to be an electronic technician, no matter how junior, would know that low voltage does not mean low power. Lithium cells can pass a very high current due to their low internal resistance (part of the reason why they are so efficient) and the effects of that can be catastrophic. Ever wonder why cellphone and laptop batteries are regularly in the press for setting on fire and exploding?

    Here's an old electrician's adage - "It's the volts that jolts, but the mills that kills." Geddit?

    [1] should that be "card swapper"?
  5. #45  
    actually i have a Verizon Pre...
    When i first got it the battery after even minimal use was completely gone by 8-10 at night maybe sooner if i used it more..

    I actually ended up getting a new Pre because mine was acting up but had to keep my same Pre battery and it just died just as quick so i didnt know what the life was supposed to be honestly never looked i jsut figured that it would die insanely fast and faulted the battery...

    Before i got my new pre i was looking into all the patches and homebrew and stuff...then i learned how to do most of it and to be honest i have no idea what homebrew/patches i used without looking but i know all of a sudden my battery even with more use than i normally would use it the battery is still at 35-50% instead of 10-dead it last a few hours longer and does way better when its not in use and on stand-by or whatever..
  6. #46  
    @ me2 perhaps you should read the rest of my posts if you think I know nothing esp since I posted about the diodes and fets also the cap that prevents reverse polarity and again it's impossible to have current if the circuit isn't being complete
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    #47  
    Quote Originally Posted by Bob-C View Post
    "Yeah, it works, but something is eventually going to give in a big way. " My wife and I have been using Centro batteries for over a year and nothing has gave, let alone in a big way.
    I agree, somebody needs to step back and say all this testing is interesting but in real life it amounts to a crock - the centro batteries work and painlessly.
    I also have 4 batteries, 3 are $5 new OEM Centros I got off of Ebay, I can neither tell a difference in run time between my OEM Pre battery, nor have I had a single problem or issue of any kind. This is after a year and countless cycles on all of them, being charged in the phone and also in a cheap standalone wall charger I got from china/HK off of Ebay for like $5.

    I bit too much drama being made over something that is moot. The Centro batteries work fine without any danger.
  8. #48  
    fyi. I don't know anything about electricity. But, i believe that there is a difference is in the battery case. But that may not be true of the original Pre battery. When the Pre came out last year, some had a problem with the phone powering off when the slider snapped shut. The fix was to wedge paper or tape to force a tighter fit. Same was true with aftermarket batteries. Palm changed the design of the battery case slightly (and so did Seidio) to make a tighter fit.

    all of my Pre and Seidio batteries were purchase in feb, so they are a very tight fit. Also, I have a verizon Pre plus. The minor battery update was already shipping long before the verizon launch.

    all that to say: there are minor size differences between my Pre battery and my stack of centro batteries. The little tabs are slightly bigger on the pre battery. .

    with the cheap external chargers. the pre battery doesn't fit in the old one, but the centro battery fits in the new one. the tabs on the pre battery are slightly larger.

    so, if you plan to use centro batteries, wedge them with a little paper or something to make them tight and avoid having it shut off when the slider shuts.

    the electrical differences discussed above may well be accurate, but I don't understand the topic to know what they are saying. We just got 'lektristy in these parts recently...

    but there are physical differences you should be aware of...
    Last edited by Workerb33; 07/02/2010 at 08:16 PM.
  9. #49  
    one more thing... Any batteries you buy off ebay may be 'new' as in not used. But they wererobably manufactured 3 or 4 years ago. I would assume they would have lost some capacity sitting all that time with no charge. That was true for camera batteries I bought recently.
  10. #50  
    since I am using my centros battery I put my pre battery in my centro & gave it to my dad when his razr broke a few months ago poor guy can hardly work the thing lol anyway I did wedge some paper in my pre to try and fix the slider problem & it didnt .
  11. #51  
    Quote Originally Posted by zechzz View Post
    since I am using my centros battery I put my pre battery in my centro & gave it to my dad when his razr broke a few months ago poor guy can hardly work the thing lol anyway I did wedge some paper in my pre to try and fix the slider problem & it didnt .
    THen wedge more paper, or use two sided tape, etc.
  12. #52  
    Quote Originally Posted by zechzz View Post
    most likely the mah wouldn't matter bc there would be no current draw if reversed because there has to be a input protection of some kind the most basic being a diode which will only let the current flow one way therefore it wouldn't be completing the circuit and nothing happens. If I get bored enoug at work today I may try it out I have a small vdc power supply in which I can adjust the amps aswell. Sprint will replace it all I have to say is it stopped working this is my second pre bc my first blew the speaker a month ago.
    It has a power filter Prob a capacitor a diode or 2 and a small mosfet regulator same kind used on new computer boards and what not this one is of course a lot smaller mosfet's can not handle revers of polarity The MAH does matter the reverse of polarity simply would damage the mosfet beyond use. I have seen this happen before some people have managed get the battery in back-words and reported smoke from inside the Pre the reason the tabs are on the batter to prevent it from being in upside down but if you press hard enough it will go in (don't ask me why people would want to do this but they managed it) I am not trying to disrespect you or anything your know your stuff but in the case your wrong.

    The Capacitor Is used as a filter and also as a bridge for the data bus If that capacitor is damaged or destroyed in any way the phone would no longer work. That Capacitor is also used to trigger the mosfet regulator chip inside the phone with out that trigger it would dump the entire load in to the mosfet and fry it.
  13. #53  
    Quote Originally Posted by nyquistJack View Post
    If I remember correctly Palm's early comments on the batteries was about this exact thing. They said there were safety features on the Pre battery that weren't on the Centro battery. They claimed it could wear out your device faster. I am not going to pretend to understand how these numbers reflect that, but that is what they said and this does prove there is some minor difference in the batteries. But since its been a year and I don't think anyone can link an issue to a Centro battery, I would imagine its a ok.
    The pre battery has no added safety feature Did you read my other posts i extensively tested both the Pre and Centro battery's even took one of each apart they are identical in every way right down to the firmware on the battery controller. Both have the same chip numbers and there is not difference in the boards the chip is on.

    I have emailed foxcon Makers of the battery's and phone for that matter And they are emailing me a schematic of the battery controllers of each battery once i receive the mail i will post it on here so you call can see they are the same... Hope that does not tick off palm...
  14. #54  
    doesn't make sense how the voltage got past the diodes and cap sense that is what they are there for I wonder if they had been previously damaged I even put 5.3 vac across mine today and it protected it just fine. Also I thought that the device and battery had sense voltages that had to be activated inorder to allow voltage in. Even the cap should blow before the mosfet in most cases. I know that I have seen people put caps in backwards cuasing it to smoke and make a lot of noise.
  15. #55  
    Quote Originally Posted by zechzz View Post
    doesn't make sense how the voltage got past the diodes and cap sense that is what they are there for I wonder if they had been previously damaged I even put 5.3 vac across mine today and it protected it just fine. Also I thought that the device and battery had sense voltages that had to be activated inorder to allow voltage in. Even the cap should blow before the mosfet in most cases. I know that I have seen people put caps in backwards cuasing it to smoke and make a lot of noise.
    First off the Battery is DC not AC so that's not a proper test. 2nd once that cap is damaged it will no longer have the proper trigger for the mosfet thus ruining the phone to were it will not work...

    I use to work for US Power Management we made all kinds of power management devices i worked in the mobile electronics department so I know what i am talking about i am not saying you don't know anything about electronics but this phone IS NOT made to be able to with stand reverse polarity... if it was the cap. would not in line like it is. it would be isolated behind the protection and you would not be able to scan for it.
    Last edited by gitit20; 07/02/2010 at 10:16 PM.
  16. #56  
    ha I know the battery is vdc I'm just saying that the protection was able to block ac from hurting it as well. Thanks for all the info on the chip it was interesting.
  17. #57  
    What I think would be interesting to see is how many people overclock yet refuse to use a centro battery.
  18. #58  
    Quote Originally Posted by vasekvi View Post
    What I think would be interesting to see is how many people overclock yet refuse to use a centro battery.
    That would be rather interesting...
  19. #59  
    For the record:

    Using a 1350 mAh Centro battery in my Pre+, Govna set to Screenstate (500/800) and Uberkernal, and all is good here!

    "The more I learn, the more I realize just how little I really do know!" -Albert Einstein

  20. #60  
    Quote Originally Posted by LCGuy View Post
    For the record:

    Using a 1350 mAh Centro battery in my Pre+, Govna set to Screenstate (500/800) and Uberkernal, and all is good here!

    Hey i started a pole here VOTE AWAY...

    http://forums.precentral.net/palm-pr...ro-battey.html
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