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Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Thu Jun 04, 2015 12:07 am
by -Tech-Noir-
I bought a T420 Model# 4178-C9U from Craigslist last night. This is my first ThinkPad and did not think to try and remove the battery before I bought it.
I have tried pushing the battery in towards the machine and moving the latch, but the latch will not budge.
Can you all take a look at the
picture of the battery I took and give me some advice on how to remove it? I would really appreciate it.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Thu Jun 04, 2015 2:10 am
by BillMorrow
try the battery IN so as to take any possible pressure off the latch and then push the latch toward the open padlock image..
i don't have a T420 but looking at a T400 battery i see no reason other than a broken latch or pressure preventing the latch from fully moving to the unlatch position..
the latch mechanism is in the battery and should have three latching surfaces.. one on the left, middle and right, any of which could be binding and preventing the entire latch from unlatching..
welcome to the forum..

Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Thu Jun 04, 2015 2:03 pm
by bit_twiddler
the latch mechanism is in the battery and should have three latching surfaces.. one on the left, middle and right, any of which could be binding and preventing the entire latch from unlatching..
The T420 is the same.
I would avoid trying to slide the latches with a credit card or a spudger - there are some plastic locating pins which protrude from the body of the laptop into the battery, as well as some electrical pins which you might damage by so doing.
One option would be to take the entire bottom cover off, although I have no idea how practical this is. It might be the safest way to proceed.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Thu Jun 04, 2015 2:47 pm
by theterminator93
I've seen that a few times on both T410s and T420s. In each case, the battery wasn't put in straight when it was installed so it's jammed in the bay. As Bill said, the solution is to first try and fully seat the battery by identifying where it's contacting the bay where it would prevent it from sliding all the way in. Usually they go in a bit crooked such that the "lip" at the bottom (as shown in the photo) jams up against/under the corresponding "notch" in the bay. Rocking the battery slightly to "lift" this area usually clears the jam, allowing it to seat fully so it can be removed.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Thu Jun 04, 2015 3:20 pm
by rkawakami
When looking at the OP's picture last night, it seemed to me that the battery isn't fully mated to the laptop. There's a noticeable gap between the edge of the battery and the laptop's battery bay, as well as misaligned "humps" of the battery pack and bottom of the laptop.
If pushing/rocking the battery doesn't allow usage of the release slider, I can measure one of my own batteries and indicate where you might be able to Dremel (verb) some notches in the battery's case so you can manually free the three hooks that are holding the battery to the laptop. One way that the release slider can get jammed is if there's something in the way of one or more of those hooks.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 12:17 am
by precip9
It does appear that it is not completely inserted. I've seen sloppy moldings with 3rd party batteries, but nothing like this with a factory battery.
Push one end in, and exert maximum pressure on the latch. Push on the other end, and exert maximum pressure on the latch. As stated, a plastic tool is useful. If I recall correctly, even if the the latch knob breaks off, the latch bar is accessible through the resulting hole. A tool can be inserted through the hole to exert additional pressure on the latch bar.
When you get it out, throw it out.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 5:37 am
by Temetka
If he gets it out, and it's broken but holds a good charge, I would vote to keep it, but properly insert it. He can always use a small flat head screwdriver to operate the latch mechanism.
But as to what others have said, I would push both corners in completely - even if they look like the are in. Then I would push in the middle area. Then try the latch. I've never had a battery get completely stuck. Some are difficult to remove if inserted improperly, but not impossible.
Take your time and be patient. It will come out.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 6:02 am
by RealBlackStuff
Those batteries have 3 hooks, that are all attached to each other via the one slider, as shown here:
http://www.ebay.com/itm/161129258829
However, the middle hook can break off from the slider, but still remain in its slot.
Turn the laptop bottom up, battery away from you, then press the laptop against your belly/chest and pull both ends of the battery towards you.
Try to wiggle it a few times. Try the slider again and see if it loosens a bit.
Rather than Dremel it or take it apart, get a sharp (Xacto) knife and cut a small strip from the battery, no more than 2mm wide on the 3 places where the hooks are, between battery and laptop.
Seen from the left, the middle of the hooks are at 16, 83 and 190 mm (9/16, 3 1/4 and 7 1/2 inch).
The hooks are about 8mm (1/4 inch) wide.
Once you have those cuts, use a knife to free the hooks.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 7:11 pm
by -Tech-Noir-
So many replies! Let me try them out. I have pushed on the battery and had friends pushing the latch but no go. It doesn't budge. It is pretty crazy.
Power Manager says the battery is in good condition. I have 87% remaining right now and have 3:28 hours left. It has a cycle count of 103 and FRU part number 42T4911.
The real reason I want to remove the battery is to be able to install more ram and add an SSD hard drive. Would I be able to make those modifications if I just let the battery drain to zero? Or must the battery be removed to add ram or replace the hard drive with an SSD?
Thanks for all your replies! What a helpful and friendly forum.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 7:55 pm
by bit_twiddler
Best to play it safe and get the battery out.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Fri Jun 05, 2015 8:47 pm
by Hans Gruber
Have you thought about taking a rubber mallet to the battery? You need to push it in a bit more.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Sat Jun 06, 2015 5:48 pm
by Temetka
Hans Gruber wrote:Have you thought about taking a rubber mallet to the battery? You need to push it in a bit more.
I'll be honest, at first I was shocked after reading your comment. Mallet a Thinkpad?!? Nevar!!!
But then I thought about it some more. A few gentle taps might just do the trick.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Sun Jun 07, 2015 2:40 pm
by precip9
The possibility that one of the 18650 lithium cells might take a dent scares me. Explosion, fire, all that good stuff.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Sun Jun 07, 2015 3:07 pm
by hhhd1
-Tech-Noir- wrote:
The real reason I want to remove the battery is to be able to install more ram and add an SSD hard drive. Would I be able to make those modifications if I just let the battery drain to zero? Or must the battery be removed to add ram or replace the hard drive with an SSD?
Replacing the HDD/SSD/Optical-drive should be fairly safe with the battery connected.
The RAM however may be a different story.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Sun Jun 07, 2015 5:51 pm
by -Tech-Noir-
I got it out! Here are the steps I took.
- First, I tapped the battery with a rubber mallet. I tapped on the left, middle, and right. I stopped because I thought I could break the screen or something else.
- Second, I put the laptop on my desk and against my chest and pushed in on the left, middle, and right sides of the battery. I tried to lift the battery and wriggle it in general all while pushing on the latch with just my hand.
- Finally, I pushed the right side of the battery in as hard as I could while at the same time pushing against the latch towards the unlock with a AAA battery for leverage. The latch finally gave way and the battery was freed.
At first I was scared to put the battery back in because the bottom of the laptop on the side where the Windows COA sticker is on does not look like it is flush with the battery compartment. The gap is noticeable at the battery connector. You can see it in my new set of
pics here.
Luckily my concerns were for naught. I was able to seat the battery perfectly. The battery is now flush with the laptop and there are no gaps. The previous owner must not have known how to properly install the battery and somehow jammed it in.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Mon Jun 08, 2015 1:03 am
by Norway Pad
Good job! I got a little curious to see how this ended.
-Tech-Noir- wrote:First, I tapped the battery with a rubber mallet. I tapped on the left, middle, and right. I stopped because I thought I could break the screen or something else.
IMHO, I think leaving it at that was a good choice.

A rubber mallet is rarely a part of an IT toolkit.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Mon Jun 08, 2015 4:41 am
by Temetka
Glad you got it sorted.
So you can easily remove and replace the battery at will?
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Mon Jun 08, 2015 7:55 am
by Hans Gruber
There were 3 different techniques I was going to suggest with the rubber mallet since it was my idea. The first was a wedge tapped by the rubber mallet followed by the rubber mallet tapping the battery around the stuck area. The 3rd method was to use a hammer on top of the rubber mallet. The vibration is what I was thinking would release the stuck parts.
Nice to hear you got your battery out.
Re: Battery pack latch stuck in locked position on T420. I can't remove the battery. Help!
Posted: Tue Jun 23, 2015 6:42 pm
by -Tech-Noir-
Temetka wrote:Glad you got it sorted.
So you can easily remove and replace the battery at will?
Yep!