Acer Aspire 5745 booting/running on power adapter with no, or bad, battery pack

stepher
stepher Member Posts: 17 New User
edited March 2023 in 2017 Archives

I approached this question a while ago and thought I'd circle back around from a slightly different angle.

 

I understand most laptops will boot/run with only the AC adapter plugged in (battery pack removed). Will an Aspire 5745 operate this way? Also, what happens when the battery pack starts to die (mine shows 100% recharge but doesn't last very long)? Will the laptop still boot/run on an AC adapter if the battery pack is at the end of life?

 

Thanks in advance.....cheers....

Best Answer

  • stepher
    stepher Member Posts: 17 New User
    Answer ✓

    Sorry so long to get back to this......

     

    Been thru 2 replacement M/Bs and this is the best of what I understand to date - Installed and ran the 1st replacement M/B and it seemed to do just fine...until I plugged in the battery pack. Then it showed same problems as the original. Unplugged the batttery pack, but the problem never went away (erratic boot ups), just like the original M/B.

     

    Got a 2nd replacement board, installed and booted. Worked fine. However, I never reconnected the battery pack and just continued to test with AC/DC adapter only. No problems. Consistent boot ups, good performance (for an older machine Smiley Happy

     

    My best guess it that the battery pack was the problem , however, not in the way I would have expected. Seems either something in communications (over the serial bus) between the battery pack and the M/B caused the M/B to become "glitchy" at start up (that resetting the BIOS to default wouldn't fix) or there's a h/w problem on the battery pack control/management board that caused a h/w problem on the M/B to screw up the boot up process permanently (so money spent on the M/B was prob'ly not a waste...yayyy!).

     

    I still ahve to fix the battery pack problem (maybe I'll see if I can figure how to create/use some kind of external battery pack like an AC/DC Adapter), but it looks like I've got my laptop back and functioning.

     

    Thanks for the help and input....Cheers.....

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Answers

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    The laptop may or may not operate (properly or at all) with only the charger and no battery.  But it's not a real good idea to try to do so. The battery has a imbedded controller chip that, among other things, can affect how charger output voltage is regulated.

     

    As for the battery itself, this same embedded chip will sometimes but not always issue a warning on the battery monitor that it should be replaced. If the only symptoms are that a 100% charged battery lasts maybe a half hour or so before the system automatically shuts itself down after pulling the plug, I'd guess the laptop should still boot and run OK in this way.

     

    Jack E/NJ     

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    Appreciate your input.

     

    As I mentioned in my original post (see link above) this problem started a few years ago. If I boot battery only, the laptop boots everytime without any problems at all. Once up and running, if I plug in the AC adapter, occasionally it will continue to run, mostly it freezes. After it's been running for a while (or rebooted a few times) it will run great (and reboot) on the adapter alone (but not if it sits off overnight). I tried different adapters, even went to a 19V linear supply in case of noise...same problem.

     

    After doing some limited circuit debug and analysis (have schematics but with different graphics), I couldn't locate any obvious problem area, so I assumed it was most likely something in/on the motherboard that I couldn't fix (temp sensitive trace or ic). So I ordered up another m/b (pulled from working system but different BIOS). Thought that would solve the problem, but same exact symptoms. On the wild odds and off-chance I got 2 boards with the same exact problem (chip/mfg issue) I've RMA'd for 1 more m/b.

     

    If this 2nd replacement m/b shows the same, I have no idea what it might be. Have new hdd, upgraded CPU, have done limited testing on memory, etc.

     

    This is why I asked the question about the impact a failing battery pack has on the circuit. The only other things it could possibly be is some issue with the LCD display and the associated logic (not on the m/b) or something related to the plastic case (I have seen some conversations regarding possible static issues Smiley Sad

     

    I guess if this 3rd m/b shows the same symptoms, I'm going to assume you are onto something wrt to the logic in the battery pack and focus my debugging there (maybe that's where I should have started and saved myself the cost of a m/b Smiley Sad

     

    I guess I'd like to think a well-designed laptop would be able to run on its AC adapter alone, with or without battery pack. Maybe this specific laptop was designed to be a consumable and for obsolescence. Ughhhh  Smiley Sad

     

    Thx again and cheers.....Cheers....

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    >>>I guess if this 3rd m/b shows the same symptoms, I'm going to assume you are onto something wrt to the logic in the battery pack and focus my debugging there (maybe that's where I should have started and saved myself the cost of a m/b >>> I'd like to think a well-designed laptop would be able to run on its AC adapter alone, with or without battery pack. >>>

     

    Heh-heh. You can find out for ~$20 with free shipping on a new battery. Maybe even blow ~$10 more on a new charger just for good measure.  If the symptoms disappear with either or both, you'll still have 3 good mainboards at least. 8^) Jack E/NJ       

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

     Not so sure about the battery pack for $20/free shipping....you usually get what you pay for  Smiley Sad Having said that, tho, I'll take on the possibility of a battery pack issue as soon as I receive the "new" m/b (should be in next week).

     

    Wish I had the xtra m/bs. The original m/b had some minor issues that were more of an annoyance than a problem, so replacing the m/b isn't a total loss. And the 1st replacement board I bought had to be returned to get the "replacement" replacement board. So I really only have 1-1/2 m/bs.

     

    I'm fairly certain the adapter/charger isn't a source of the problem (as I mentioned having subbed out the adapter w/a 19V linear supply). The chip/logic in the battery has certainly been in my head for quite some time. I'll have to do some more research and see if there is a way I can mitigate that from being an issue.

     

    Thanks again and cheers.....

  • stepher
    stepher Member Posts: 17 New User
    Answer ✓

    Sorry so long to get back to this......

     

    Been thru 2 replacement M/Bs and this is the best of what I understand to date - Installed and ran the 1st replacement M/B and it seemed to do just fine...until I plugged in the battery pack. Then it showed same problems as the original. Unplugged the batttery pack, but the problem never went away (erratic boot ups), just like the original M/B.

     

    Got a 2nd replacement board, installed and booted. Worked fine. However, I never reconnected the battery pack and just continued to test with AC/DC adapter only. No problems. Consistent boot ups, good performance (for an older machine Smiley Happy

     

    My best guess it that the battery pack was the problem , however, not in the way I would have expected. Seems either something in communications (over the serial bus) between the battery pack and the M/B caused the M/B to become "glitchy" at start up (that resetting the BIOS to default wouldn't fix) or there's a h/w problem on the battery pack control/management board that caused a h/w problem on the M/B to screw up the boot up process permanently (so money spent on the M/B was prob'ly not a waste...yayyy!).

     

    I still ahve to fix the battery pack problem (maybe I'll see if I can figure how to create/use some kind of external battery pack like an AC/DC Adapter), but it looks like I've got my laptop back and functioning.

     

    Thanks for the help and input....Cheers.....

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    A WHILE AGO>>>If I boot battery only, the laptop boots everytime without any problems at all. Once up and running, if I plug in the AC adapter, occasionally it will continue to run, mostly it freezes. After it's been running for a while (or rebooted a few times) it will run great (and reboot) on the adapter alone>>>

     

    TODAY>>>Been thru 2 replacement M/Bs>>> 1st replacement M/B and it seemed to do just fine...until I plugged in the battery pack. Then it showed same problems as the original.>>>Got a 2nd replacement board>>Worked fine. However, I never reconnected the battery pack and just continued to test with AC/DC adapter only. No problems.>>>My best guess it that the battery pack was the problem>>>

     

    So, are you gonna buy a new battery pack or try to make one first? Jack E/NJ

     

     

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    Battery Pack - Make vs. buy...haven't gotten that far, yet. Have to do more thinking/research. What I've come to so far is....

     

    * A brand new pack (from Acer) is about $85...not sure I want to spend that much.

     

    * Might try your suggestion of a pack off eBay for $20.....battery quality and true compatibility is questionable...but may be able to replace the batteries if I have to (assuming the pack logic is good)

     

    * DIY pack (that charges from something other than the laptop) - I have to design/build a step up/boost converter (easy part) that takes the battery pack output (figure 10VDC or 12VDC....12V could make it "car compatible") to the 19V adapter voltage level (switching circuits in the laptop require this). It also means the battery pack will have to provide more current than the adapter (Power In = Power out kind-of-thing).

     

    Not enuf info yet on available DIY battery pack options. If it gets too expensive, might end up better to get a new Acer pack, or maybe never again worry about being portable at all.

     

    Cheers....

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    >>>Might try your suggestion of a pack off eBay for $20>>>

     

    But then what are you gonna do if it works? 8^) Jack E/NJ  

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    1st, I'd be surprised (mainly by how long it did, or didn't, last). My bigger concern is that if the electronics in the battery pack that came w/laptop (from Acer) screwed up my m/b (and while that is yet unconfirmed...could still be a battery-specific issue), what's to say another mfg'r had done any better (and might mean another m/b replacement). Tempting, but very hesistant. If I could find some info on the communications that goes on between the battery pack and m/b, I might be able to work with/around it.

     

    At least with a DIY pack that came in thru the AC/DC adapter plug the battery circuit is rendered mute (by design).

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    >>>At least with a DIY pack>>>battery circuit is rendered mute (by design).>>>

     

    And therein may lie an unforeseen electrochemical issue. 8^0  Jack E/NJ

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    >>>>And therein may lie an unforeseen electrochemical issue<<<<

     

    Sorry, not sure what you mean. What I meant was that the laptop would always see power coming from through AC/DC adapter power plug (battery pack would go thru here as well). It would never try to charge any batteries nor would it ever try to run from battery since there would be no battery inserted into the battery socket of the laptop.

     

    For charging the DIY battery pack, that would be either internally managed (if I bought a more universal battery pack), or I would use separate batteries (18650?) that could be removed and charged separately when needed. I suppose I could also use NiMH, tho the power density mgiht not be as good as LiIon.

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    >>>separate batteries (18650?) that could be removed and charged separately when needed. I suppose I could also use NiMH, tho the power density mgiht not be as good as LiIon.>>>

     

    18650's might be OK with proper charger. Home Depot also has decent amp-hr Li rechargeables with charger for standby and emergency stuff if you wanna try to adapt that. Prices seem reasonable.  But if you value power density more than energy density, good ole sealed lead-acid gel cells are hard to beat, no fancy chargers needed and self-discharge is low. Jack E/NJ

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    A proper charger I have, so that's a non-issue.

     

    wrt sealed lead acid....yeah, I can get a nice car battery for ~$80 from Costco, but I'd like to be a little more portable than that Smiley Wink 

     

    Some of the battery-based backup chargers (10/15/20? amps) for cell phones, etc. look interesting, as well. Problem is they typically only output 5V @ 1-2A,so I'd have to modify for my purposes...maybe string together a couple of them in series.

     

    Like I said, just starting to look at options. Appreciate the HD suggestion.

     

    Cheers....Steph

     

    18650's might be OK with proper charger. Home Depot also has decent amp-hr Li rechargeables with charger for standby and emergency stuff if you wanna try to adapt that. Prices seem reasonable.  But if you value power density more than energy density, good ole sealed lead-acid gel cells are hard to beat, no fancy chargers needed and self-discharge is low. Jack E/NJ


     

  • stepher
    stepher Member Posts: 17 New User

    Had to circle back around on this with new info.....

    I've installed 3 "refurbished" motherboards and all showed the same problems with freezing on bootup. The last 1 I never installed the battery pack (ran only from AC Power Adapter) so that seems to eliminate the battery pack as a source of the problem (unless the battery pack circuitry is the problem and Acer had some kind of design flaw or mfg issue in a number of their battery packs for this laptop  Smiley Sad

    I've tried using only 1 of my memory modules (2GB each) at a time and that didn't change things. Could it be both my modules are bad? Unlikely, but I suppose a possibility.

    Thinking the LCD display control circuitry/interface could be an issue. No way to test except to replace it.

    The 1 constant here, tho, is that the laptop still boots and runs fine off the battery pack alone. Whcih tells me everything is working fine....on battery power.

    So, I guess I'm back to thinking it's' something to do with the AC Power Supply adapter itself, or some issue/design flaw/component temp or voltage sensitivity in the AC Power Supply control or sensing circuit on the m/b. Already checked the power adapter, but maybe I need a different approach.

    In short, I'm back to where I was at the beginning....no idea where this problem is sourced from Smiley Sad

    Sigh......

    stepher wrote:

    A proper charger I have, so that's a non-issue.

     

    wrt sealed lead acid....yeah, I can get a nice car battery for ~$80 from Costco, but I'd like to be a little more portable than that Smiley Wink 

     

    Some of the battery-based backup chargers (10/15/20? amps) for cell phones, etc. look interesting, as well. Problem is they typically only output 5V @ 1-2A,so I'd have to modify for my purposes...maybe string together a couple of them in series.

     

    Like I said, just starting to look at options. Appreciate the HD suggestion.

     

    Cheers....Steph

     

    18650's might be OK with proper charger. Home Depot also has decent amp-hr Li rechargeables with charger for standby and emergency stuff if you wanna try to adapt that. Prices seem reasonable.  But if you value power density more than energy density, good ole sealed lead-acid gel cells are hard to beat, no fancy chargers needed and self-discharge is low. Jack E/NJ


     


     

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    A WEEK AGO>>>Got a 2nd replacement board, installed and booted. Worked fine. However, I never reconnected the battery pack and just continued to test with AC/DC adapter only. No problems. Consistent boot ups, good performance (for an older machine >>>My best guess it that the battery pack was the problem>>>

     

    TODAY>>>I've installed 3 "refurbished" motherboards and all showed the same problems with freezing on bootup. The last 1 I never installed the battery pack (ran only from AC Power Adapter) so that seems to eliminate the battery pack as a source of the problem (unless the battery pack circuitry is the problem>>>

     

    Last week the 3rd board seemed OK without the pack. This week, not OK. What changed? Jack E/NJ  

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    A day (or 2) after I wrote that the 2nd board was working it, too, started showing the same problems. So, I RMA'd for a 3rd (my current) board.

    Like I said, either the board has an inherent design/mfg flaw (maybe why so many are available now as "refurbs") or there's something else I'm not seeing (yet).

    Turns out this 3rd board, while not completely devoid of the issue, "seems* to be booting up more consistently after I did a BIOS reset/default on it.

    I may not have found the problem, but it seems I'm eliminating suspects (tho, not always a sure thing, as I've come to learn).

    Back to more research/testing/head scratching



    JackE wrote:

    A WEEK AGO>>>Got a 2nd replacement board, installed and booted. Worked fine. However, I never reconnected the battery pack and just continued to test with AC/DC adapter only. No problems. Consistent boot ups, good performance (for an older machine >>>My best guess it that the battery pack was the problem>>>

     

    TODAY>>>I've installed 3 "refurbished" motherboards and all showed the same problems with freezing on bootup. The last 1 I never installed the battery pack (ran only from AC Power Adapter) so that seems to eliminate the battery pack as a source of the problem (unless the battery pack circuitry is the problem>>>

     

    Last week the 3rd board seemed OK without the pack. This week, not OK. What changed? Jack E/NJ  


  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    Carry on! 8^) Jack E/NJ

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    Been here a couple of times before (Acer Aspire 5745 booting running on power adapter.....) unable to sort things out. Thought I had it solved last time, but realized I do have it this time (YaaaYYYY!!  Smiley Happy

     

    Turns out there must have been a particular production version (including mine Smiley Sad with time-delay issues. I went thru 3 motherboards (ordered off eBay) and all seemed to exhibit the same (not just similar) problem - may or may not (most of the time) boot (fortunately, all the sellers were honest and provided refunds). Originally thought it might be a heat issue in reverse (mostly booted OK after the unit warmed up) because most of the problems seemed to occur when it was cool/cold, even on autumn mornings (which aren't very cold here in Nor. Calif.). Then I started thinking it might be related to the battery pack having seen better days...but that got tossed when the same problem happened with the battery pack out..which led me to my (previous) 2nd posting here.

     

    I finally took a chance and ordered one last reclaimed/"refurbished" board from China and it's been running just fine for ~week, so far. The boards all have the same PCB (printed circuit board) rev code, but could never figure out how to tell if there were any circuit/part (non-PCB) changes. The 1 thing I did notice was that on all the units that failed the CMOS backup battery had a date stamp of either Oct or Nov. of 2010 (year I bought the laptop). The 1 that finally worked (from China) has a date code of March 2011, nearly 6 months later. Based on my unscientific results, I'm guessing something may have been changed somewhere in the design in that 6 mo. period.

     

    Anyway, got my laptop back and working fine so far. In the process I upgraded the CPU thinking it might be the problem (wanted better performance anyway) and the HDD (went to 1GB and 7200 RPM). Now the laptop is fairly perky Smiley Happy Next step is to replace the battery pack (figure out how to carefully replace the 18650 batts used in the pack) and I'm really good to go.

     

    So, just circling back around to provide my final results.

     

    Moral of the story? Never give up!!  Smiley Wink

     

    Cheers....

  • JackE
    JackE ACE Posts: 44,908 Trailblazer

    >>>Next step is to replace the battery pack>>>

    Yay!

     

    >>>(figure out how to carefully replace the 18650 batts used in the pack)>>>

    Boo!

     

    So does this mean that, with the new reclaimed/refurbished mainboard, the machine runs on the charger alone without the old battery pack installed? 8^)

     

    Jack E/NJ

     

     

    Jack E/NJ

  • stepher
    stepher Member Posts: 17 New User

    That's exactly what it means. I installed the m/b and booted the sys 1st w/out the batt pack and it came up fine. Then I put the batt pack in and rebooted...ran perfectly. My best guess is a new version of 1 of the chips on the m/b must have installed in that 6 mo. window and that seemed to fix the problem. And if it was a pin-for-pin replacement, the m/b pcb would not have to be rev'ed, only the BOM/parts list and schematic, neither of which I could get access to  Smiley Sad

     

    Understand the "Yay!" on the batt pack. Why the "Boo!" on replacing the batts? New batt pack for this laptop is pretty spendy. ALmost 1/2 price if I can just replace the batts (and I might be able to go with bigger current ratings Smiley Happy

     


    JackE wrote:

    >>>Next step is to replace the battery pack>>>

    Yay!

     

    >>>(figure out how to carefully replace the 18650 batts used in the pack)>>>

    Boo!

     

    So does this mean that, with the new reclaimed/refurbished mainboard, the machine runs on the charger alone without the old battery pack installed? 8^)

     

    Jack E/NJ