Hacking A Laptop Battery

[Lance]

The battery on my HP laptop recently kicked the bucket. I'm looking to see if I can get a replacement, but I would rather make my own, reason being that this machine takes a fair bit of power to run, and even when I first got it I could only push the battery to 2 hours at most. Add to that the bad placement of air intakes, and things got silly. I would like to build my own little set of batteries that both elevate the back end of the machine, and provide power for longer periods of time. The thing is that there are multiple pins on the battery (6 if I recall correctly), and I'm guessing that they aren't all for power. Some must be for data from a controller of some sort that's in the pack.

I'm also wondering what I'll find if I go poking around in there. I know most battery packs on laptops are just off the shelf cells that get shoved into a housing, but I'm wondering if this battery pack has some other cells that could be dangerous if I crack the pack open.

[joelby]

Most laptop battery packs contain a circuit that monitors individual cell voltages and temperatures, identifies the battery's model and total number of charge cycles, and so on.

You could replace the cells if you can find a comparable replacement, but engineering an entirely new battery pack with a different capacity may be more difficult.

[Mechatrommer]

revive the built in circuit, replace the cells with any compatible. if you are me, i'll take it apart before its totally dead, "characterized" the cells (voltage), have a rough look at the circuit and find out if "hack possible" and find the compatible cells/battery and start modding. and if you have extra buck, buy a spare battery, in case your mod dont work out well. my 2cnts opinion.

[kaptain_zero]

Lithium Ion packs in laptops are part of an engineered system. If you can find the exact same cells used in the pack, it is possible to safely rebuild it. Attempting to modify the pack, different cells, different capacities etc. will all cause problems with the on board charging system that was designed for a specific capacity/brand/type of cell. Most likely you'll have 18650 cells inside, but depending on who made them and when, the actual charging specifics can vary... higher or lower peak voltage and discharge limits. It's not something to fool with, failure of one or more cells can be accompanied with the always delightful "Vent with Flame" event.

If the laptop is of use to you, then spring for a factory replacement pack and relax. If you must tinker, I'd would build an external pack with cables to the laptop and devise a separate charging system.... The so called hobby chargers come to mind, as then you can set the charge rate and such to suit the pack you built. Not a very convenient way of doing things, but if you must, you must. Me.... I'd just buy a replacement from the manufacturer..... that "Vent with Flame" event, while highly entertaining at a distance, really sucks when it occurs in your lap.

That's my $0.02 worth....

Regards

Christian

[GeoffS]

I've just been through this exercise with my IBM laptop (R50p about 2004 vintage)
It's not bad specs for and old machine and the only problem was that the battery was not holding charge for long.

The IBM/Lenovo batteries were about $230 each so I went for a Chinese 'equivalent', actually a couple of them from different sources.
So far, no problems. The Laptop recognises the battery capacity and reported charge/recharge times seem reasonable. No overheating that I can detect.
I did consider rebuilding an existing battery but getting the pack apart, sourcing cells with (hopefully) the same specifications, was all too hard.

Should my laptop burst into flames, I'll be sure to report it here. 

[Lance]

Would there really be a large issue in increasing the capacity? More batteries in parallel would give a higher current and voltage, I guess I could study the battery and build a regulator that would keep the current and voltage within the limits.

[joelby]

If the charge circuit monitors the voltage of and controls the flow of charge current to individual cells (which is a good idea with lithium batteries), then you won't be able to add extra parallel cells without compromising performance and lifetime.

[Kiriakos-GR]

There is in-battery "charge controllers" , that if they detect an single Cell with very low voltage  or disconnection (for adding an new cell),
they lock down , and they do not start an charging sequence, ever again !!

Currently there is no easy way , so to reset those " in-battery controllers" .

My experience comes from an battery from an ACER , that I still own.
I ended up, getting an Chinese battery , that has poor performance ,
the scam that they do , are that they buy very aged Cells  "made in Japan ".
And when you get the pack , it is all ready with half life or less in it.

The cells on the original ACER battery was the Panasonic lithium Ion CGR 18650A . 
The lithium Ion gets " chemically active"  by the first second from the manufacturing, and they die even with out any of use , in 3-4r years time. 



 

[Jimmy]

Maybe it is a good excuse for new laptop

[Kiriakos-GR]

I was not aware that the price of an single lithium Ion 18650A Cell , are about 9$ ( fresh and shiny ).
And imagine that an medium laptop pack will have eight in it , and the smaller ones just four.

Those battery packs comes close to an manufacturing cost of 100$ its.

Still there is brands of laptops , that they overcharging their retail price by allot.

Example: Toshiba VS Acer ,  the first one will ask 200$+ the second about 130$

Maybe it is a good excuse for new laptop

Ebay are full of Toshiba laptops ,  yes they sell them due the high cost, of the new original battery.
But why in earth ? they did not asked to get informed about it , before even buy it !!  

[PeterG]

I have been down this path before with an old IBM laptop.
It turns out most Lithium Ion battery packs have a counter that will prevent the battery from charging once the counter reaches 1000 recharges. Therefore changing the cells wont restore the battery to a working state.
The same goes for the new lithium Ion power tools. reading the paperwork shows the battery can be re charged 1000 times. Not Approx 1000 times but a flat 1000.

Regards

[saturation]

I considered rebuilding the pack, until I found, like Kiriakos, the replacement cells cost more than buying a 3rd party battery pack.

http://www.batteryspace.com/lifepo418650cell32v1500mah45arate432whullistedunapproved.aspx

Even if you bought a full pack from some unknown China maker, the same unknown freshness goes for the cells,  $6 @ with delivery,  unless you get it from an authorizes distributor to guarantee the distribution chain and will costs 1.5-2x more, just for parts, $9-15 @.

I just bought a no-name Chinese Acer 6 cell replacement 5200mAH pack for $26 delivered, and it rocks; the eBay seller has sold over 100 of them, with no complaints about safety or charge capacity.  Still testing and am very skeptical about its charging safety, so I keep an eye on it with my lab.  But it gives over 4hrs of battery life prelim testing, I estimate it will run ~  5 hours once fully conditioned.

But if you look above, building it by cell wll cost $36 parts only with cheap no-name Chinese Li, not including my time and labor.  With the name brand that's ~$90 in parts alone.








!

[saturation]

I use my Acer mostly for reading and web stuff.  For the most part a netbook does the same, and I have a $200 Acer netbook that does the same with up to 15 hour battery life.  With heavy use, 8 hours.  

Its not good enough for 720p video streamed, but OK if downloaded.

I agree with you, if your laptop need is very defined, a netbook is a potential path for whole day working on battery alone in lieu of a new battery for an old power hungry laptop.  It also weight much less than 1/2 a laptop.

If it weren't for the cheap Chinese Li replacements, I'd probably make my laptop a permanent lab computer to run USB test devices.

Maybe it is a good excuse for new laptop

[Lance]

The same goes for the new lithium Ion power tools. reading the paperwork shows the battery can be re charged 1000 times. Not Approx 1000 times but a flat 1000.

Are you kidding me!? Ugh, this is gonna get messy. That would explain why it reads as "fully charged" at around 64%. Either that or ubuntu is reading stuff funny. Well then, I guess the roundabout method of getting in through the side power port seems like the only way to go.

Although this does make me wanna hack it apart even more. I would need to find a way of spoofing the identification and such to make it work...I wonder what communication protocol the battery uses to communicate with the machine.

[Neilm]

Lithium Ion packs are required to have not only charging but protection circuits as well. These monitor the cell voltages, temperatures and current drawn from them. They are set up to prevent short circuit and overcharge conditions. In order for a manufacturer to ship the pack they will have to be qualified to a UN requirement.

If making your own, remember that if a cell gets too warm it might catch fire.

Yours

Neil

[Lance]

Fire would be bad. Hence why it would be best to stick new cells in the same housing, but if there is a counter that limits recharges, I won't have much of a choice.

[Kiriakos-GR]

Direct soldering over Lithium Ion , is forbiten.

You need to buy batteries with tags at list.

[Mechatrommer]

Direct soldering over Lithium Ion , is forbiten.

who said?

if you afraid of fire, you can do this hack.

[GeoffS]

Direct soldering over Lithium Ion , is forbiten.

You need to buy batteries with tags at list.

A good excuse to make one of these so you can spot weld your own tabs! 

[Lance]

Direct soldering over Lithium Ion , is forbiten.

who said?

if you afraid of fire, you can do this hack.

It's like magic!

Direct soldering over Lithium Ion , is forbiten.

You need to buy batteries with tags at list.

A good excuse to make one of these so you can spot weld your own tabs! 

Forbidden...but if I'm fast enough I bet I could solder the tabs on without blowing them up. It seems safer than using a spot welder. Dang, now I want to build that too...

[Mechatrommer]

It's like magic!

Direct soldering over Lithium Ion , is forbiten.

http://linux-7110.sourceforge.net/howtos/netbook_new/LIbattery/LIbattery.html
there alot more, google "Lithium Ion solder"

[sonicj]

for stick packs like that, i would tin both ends with a big solder gun then use a hammerhead bit to assemble.

rarely is it worth the effort to re-cell a laptop... most i've opened resulted in destroying the case to get at the cells. keep a bucket of sand next to your bench if you try this inside. ABC extinguisher won't put out a lithium fire. i think its class d for lithium.
-sj

[Kiriakos-GR]

Forbidden...but if I'm fast enough I bet I could solder the tabs on without blowing them up.

No one are fast enough .... so to not heat the battery .
By heating the battery "gets internally damaged " and looses an portion of the internal capacity.

About blowing , its not that easy to happen, but it does happens , and the fire looks unstoppable, until the battery to burn out all the way .

[Lance]

for stick packs like that, i would tin both ends with a big solder gun then use a hammerhead bit to assemble.

rarely is it worth the effort to re-cell a laptop... most i've opened resulted in destroying the case to get at the cells. keep a bucket of sand next to your bench if you try this inside. ABC extinguisher won't put out a lithium fire. i think its class d for lithium.
-sj

Yes, it's class d for metal fires.

Forbidden...but if I'm fast enough I bet I could solder the tabs on without blowing them up.

No one are fast enough .... so to not heat the battery .
By heating the battery "gets internally damaged " and looses an portion of the internal capacity.

About blowing , its not that easy to happen, but it does happens , and the fire looks unstoppable, until the battery to burn out all the way .

I wonder if there's a way to prevent that. I wonder...if you put the cell in a plastic bag, and then placed the bag in ice water, would the water sink the heat from the head of the battery before it reached the rest of the battery? Possibly have some other metal strips just sitting on there to help. Of course the cell could ignite if the plastic leaks.

[Kiriakos-GR]

I did direct soldering by having  the half battery body sunken in to water .

Even If I did wipe the battery with a cloth , few days after, there was signs of rust.

Even today, I could not tell , if the rust caused by the water , or  , if the heat damaged the shield that protects the battery from leaking .