Opening and rebuilding Panasonic Toughbook battery packs - Page 1
Forum section: electronics / repair

author: perdrix
author_rank: Frequent Contributor
timestamp: August 22, 2025, 02:10:24 am
content: I have a Panasonic Toughbook CF54 fitted with both battery packs (the main battery pack CF-VZSU0PW and the media bay battery pack CF-VZSU0KW)The battery packs are no longer made, and don't appear to be targetted by the pack rebuilders.Both battery packs will charge and run the notebook, but they won't hold charge for any great period of time, so I'm thinking I need to re-cell them, but:How on earth to you get into them without wrecking the case? I doubt the rebuilders injection mould replacement cases.Once I'm in I may have lots more questions ...

author: Simmed
author_rank: Frequent Contributor
timestamp: August 22, 2025, 04:18:45 am
content: probably need pictures to know moreepecially the seams etc

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 22, 2025, 04:32:19 am
content: problem is that even if you can disassemble it, replacing the cells alone won't make it work.BMS chips detects cell unusual states and blows the fuse. need to reset the BMS chips via SMBus. Not all batteries have this traps, but the ThinkPad X40 does.If you're going to go to that trouble, you might as well use a compatible battery.

author: indeterminate
author_rank: Regular Contributor
timestamp: August 22, 2025, 06:38:32 am
content: https://www.ebay.com.au/itm/116124424774you can still bye them

author: perdrix
author_rank: Frequent Contributor
timestamp: August 24, 2025, 09:57:21 am
content: Here's some pix:

author: perdrix
author_rank: Frequent Contributor
timestamp: August 24, 2025, 10:00:44 am
content: You can still buy them (for now - at a fearsome price), but Panasonic have discontinued them, and no after-market rebuilds have appeared (AFAICT).The BMS chips haven't decided the packs are "toast" yet.David

author: perdrix
author_rank: Frequent Contributor
timestamp: August 24, 2025, 10:03:28 am
content: Quote from: squadchannel on August 22, 2025, 04:32:19 amNone that I can find

author: squadchannel
author_rank: Frequent Contributor
timestamp: August 24, 2025, 10:10:30 am
content: https://picclick.co.uk/?q=CF-VZSU0PWhttps://picclick.co.uk/?q=CF-VZSU0KW"KW" is expensive"PW" from £63.Quote from: perdrix on August 24, 2025, 10:00:44 amThe moment the lithium cell is removed, the brick is complete. BMS chips flagging unusual state bits, and the moment the next lithium cells is attached, the fuse blows.case is usually pried open with a knife.It's okay to try, but considering battery disposal, getting the high quality batteries, cell balancing, and spot welding, panasonic genuine price of £250 is reasonable.

author: asis
author_rank: Frequent Contributor
timestamp: August 24, 2025, 12:03:04 pm
content: Hi,If you decide to repackage your batteries, you will face many difficulties:1. you need to carefully open the battery, keeping in mind the possibility of assembling it back into the same case.2. determine what element base the BMS is assembled on (most likely - on the BQxxx family from Textas Instrument).3. determine the corresponding pins on the connector GND, +VPack, RX, TX, Thermal, and possibly some other.4. having an accurate SMBus layout with a homemade cable you can read the current parameters of the battery, the number of charge cycles, the date of manufacture and other parameters.BUTYou will need SW Battery Management Studio (bqStudio TI) which has support for ChipSet, which you will find, a proprietary interface adapter EV2400/EV2300 or similar, a lot of time and effort to study the accompanying documentation.Search and purchase of battery cells with the same parameters and chemistry.And if you get to the stage of reading the current battery parameters, then you can continue this venture.But I assure you that further there will be even more difficulties associated with the possible blocking of the BMS controller and the impossibility of selecting passwords.Do you need this?

author: asis
author_rank: Frequent Contributor
timestamp: August 24, 2025, 01:02:58 pm
content: .....and moreEven if you find the right battery, you need to understand that at the production stage, most or all products have a production date.This fact predetermines the final assembly and charging of the battery and subsequently the internal BMS is powered autonomously from the battery itself, in any case discharging it.With long-term storage in warehouses (i.e. when packing or delaying the sale of the battery as part of the product), the battery itself can completely run out of discharge, which will lead to the closing of the switching MOSFET's and the impossibility of resuming the charge even when connected to a charger.This scandalous circumstance is unlikely to help you make a claim for the purchased product.As practice has shown, to wake up the Battery pack, you have to open the case, thereby violating the presentation.With practical use of the BMS, you just need to remember that batteries require proper operation, i.e. periodic charging.

author: u666sa
author_rank: Frequent Contributor
timestamp: August 24, 2025, 01:49:33 pm
content: It's welded together using ultra sound. You'd have to unpry it carefully. Replacing cells alone won't help you. You need to program the damn thing.

author: Simmed
author_rank: Frequent Contributor
timestamp: August 26, 2025, 07:56:56 am
content: hmmm so its likethere is a need to supply power to trick the packwhile the pack is being disassembled ?i suppose it is possible to scour the seal lines with something sharp and eventually "remove" the plastic weld seams?there are a number of battery opening vids on YTQuote from: squadchannel on August 24, 2025, 10:10:30 am

author: perdrix
author_rank: Frequent Contributor
timestamp: August 26, 2025, 09:14:45 am
content: Hmmm... "Right to repair" seems not to apply here.Ho-humDavid