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 . 

[Chasm]

The thing to mention at this point is that mixing lithium and water is a really bad idea. No problems while the containment is intact, but if not you have a problem.


When it comes to hacking lithium batteries together this video says it all:

[Kiriakos-GR]

When it comes to hacking lithium batteries together this video says it all:

Nop  it does not , lets stick to the subject ....
( He did an silly use of batteries , and he did not build an adjustable output , so to act as an welder,
and so its a massive Fail and waste of parts  )  

[Lance]

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 . 

That's why I want to keep it in a plastic bag. Unless the container itself leaks no water should get to the cell, and it will still sink heat from the soldering.

[Kiriakos-GR]

The true solution about the CGR 18650A , are to be replaced by the industry ,
with something more safer , like an enlarged Sanyo NiMh ,
the new ones that they hold their charge for long time.  

EDIT  

Lance , because of my experiences from my own adventure ( wasted hours about getting info and parts & labor),
I have to discourage you up to the point to let it go , its best of getting even an Chinese medium quality battery,
than wasting human energy about rebuilding this pack.    
Mostly because the rebuild , it has less than 5% success rate.

[Chasm]

Nop  it does not , lets stick to the subject ....
( He did an silly use of batteries , and he did not build an adjustable output , so to act as an welder,
and so its a massive Fail and waste of parts  )  

The use in the end of the video is stupid, it is actually the battery for a electric bicycle.

[Kiriakos-GR]

The use in the end of the video is stupid, it is actually the battery for a electric bicycle.

I should had guess it because of the 36V output,
but I was negatively charged ,
because of the poor video , and the fact that he does not inform, about what he is doing.  

[Hypernova]

Personally instead of trying to make a new battery pack I would build a portable version of the power brick. In that case you just need to satisfy the voltage and current ratings and you can make the pack as big as you are willing to carry. Get it big enough and you can even take it on camping trips. Not being limited by the case of a particular model also means that you may be able to use the pack for other things.

[GeoffS]

Personally instead of trying to make a new battery pack I would build a portable version of the power brick. In that case you just need to satisfy the voltage and current ratings and you can make the pack as big as you are willing to carry. Get it big enough and you can even take it on camping trips. Not being limited by the case of a particular model also means that you may be able to use the pack for other things.

This sounds like an excellent idea. I'm about to take a trip where I'll need my laptop but will not be near mains power to recharge it.
An external, luggable power source would do the job. Size and weight (within reason) would not be an issue.

[Lance]

I guess that works. Depending on how heavy they are. I would still need to put them together though, which brings us back around to the whole soldering issue.

[Hypernova]

I guess that works. Depending on how heavy they are. I would still need to put them together though, which brings us back around to the whole soldering issue.

If you are worried that much with soldering you might as well get premade packs with all the protection circuits, or use a car battery + DC-DC's.

[Mechatrommer]

I guess that works. Depending on how heavy they are. I would still need to put them together though, which brings us back around to the whole soldering issue.

get a replacement battery. EOS.

[Kiriakos-GR]

The all idea behind the laptop battery , are to work :
1) as mobile source
2) backup power if mains stop for any reason.

And so every laptop must have one working battery in it.

About extending the operation time, with out mains .
You can use freely any electrical source that can offer 18V ( or what ever are the specs of your laptop) ,
connected to the external power jack.

The most paranoid about the " external power jack " are that its very hard to find an male jack at the market.
And if you do , they cost as 5$ or more .
The inner pin size VS the external diameter usually , its far away of regular plugs that cost 0.30$   

[Lance]

Or, I could use the cord that goes from the transformer to the laptop, a male version of that would be easier. To come across.

[sonicj]

external is a whole different ballgame. you have a lot of viable options. whats the voltage & current outputs of the ac/dc converter? what type of connector to the laptop? do you own any battery chargers?
-sj

[Hypernova]

The most paranoid about the " external power jack " are that its very hard to find an male jack at the market.
And if you do , they cost as 5$ or more .
The inner pin size VS the external diameter usually , its far away of regular plugs that cost 0.30$   

That's easy, cut off the existing one the brick (by the time you do this its probably out of warranty anyway) and add common jacks, now you can choose if you want to use the original jack for the brick or your new pack.

[sonicj]

The most paranoid about the " external power jack " are that its very hard to find an male jack at the market.
And if you do , they cost as 5$ or more .
The inner pin size VS the external diameter usually , its far away of regular plugs that cost 0.30$  

That's easy, cut off the existing one the brick (by the time you do this its probably out of warranty anyway) and add common jacks, now you can choose if you want to use the original jack for the brick or your new pack.

agreed! i use anderson power poles for all sorts of dc devices. they are non-gender specific, polarized, high current, you can color code for different voltages, self-cleaning, good for 10,000 matings, solder or crimp, lockable or can be left as a breakaway for the inevitable child/dog vs power cord... anywho, an excellent connector for this sort of application
-sj

[Lance]

external is a whole different ballgame. you have a lot of viable options. whats the voltage & current outputs of the ac/dc converter? what type of connector to the laptop? do you own any battery chargers?
-sj

I have a couple, but I don't have any that I can take apart. The output is: 19VDC and 4.74A.

That's easy, cut off the existing one the brick (by the time you do this its probably out of warranty anyway) and add common jacks, now you can choose if you want to use the original jack for the brick or your new pack.

I would have to modify the brick, the cord goes directly from the laptop the the brick. I could just put my own jack in there, not too complicated.

I'll take a look at those connectors, they look useful. What happens after 10000 matings?

[Kiriakos-GR]

What happens after 10000 matings?

 

Interesting question ... 

I do own anderson power poles the SB50 , I had build an extension battery pack for my APC UPS.

About the 10000 matings, its the warrantied limit for 100% good contact.
Logically after that limit , you had to inspect the connectors more regularly.   
 

[sonicj]

I'll take a look at those connectors, they look useful. What happens after 10000 matings?

i would suspect that 10,000 matings would exceed the useful lifespan of most consumer electronics, but if not, you simply clip off the connect and crimp on a new one.

check out what i found in my box-o-wall-warts...
its a compaq 12V to 18V boost converter for a laptop. the pics should give you a good idea of the usefulness of the APPs.

*yea, yea... i know, i know... direct driving the converter from a solar panel is a bit of a stretch/bad idea but you get the picture 

[Kiriakos-GR]

you simply clip off the connect and crimp on a new one.

No no no no no no no , its not that simple !!  

You have to buy another connector = pay the price premium for it , and replace the old.

And something more , I bet that  "anderson" also haves and an special crimping tool,
also wild priced , as the connectors does.

If I was not forced due the UPS to use those "anderson" ( The UPS had the plug on it ) ,
for common things I would use the three pin metallic connectors for microphones ( Canon type ).

Internationally known as XLR   http://en.wikipedia.org/wiki/XLR_connector

[Lance]

Actually XLR would work. The pins are wide enough to handle the current.

[Kiriakos-GR]

Yes practically the XLR  can handle 10A continuously even 15A max.

But if the size of the XLR ( length male + female ), become an issue , then we move at the 3-6A solution,
I do not know the part number ( commonly called as CB-VHF 4 poles power connector )

It has the half length from the XLR ,  3.4cm per connector , 7cm for male + female .
  

[Lance]

That seems like a much better alternative. How about the cells? What are some good places to go for those? Also I haven't been able to find that connector, can you provide a link?

[Polossatik]

IF you're talking about connectors... I like EC3 ones

[alm]

I'm not a big fan of using standard connectors like XLR for non-standard applications like power. What if someone plugged it into their amplifier/mixer, or plugged their microphone into your power supply? But at least low voltage DC is unlikely to kill/seriously injure people.

[Kiriakos-GR]

That seems like a much better alternative. How about the cells? What are some good places to go for those? Also I haven't been able to find that connector, can you provide a link?

Do you have any physical store with parts in your area ?
If yes , just the picture it will help.

Its commonly used on CB (vehicles) or VHF ( boats ) radios.

Or alternatively use ebay search.  

[Lance]

I'm not a big fan of using standard connectors like XLR for non-standard applications like power. What if someone plugged it into their amplifier/mixer, or plugged their microphone into your power supply? But at least low voltage DC is unlikely to kill/seriously injure people.

I'm going to be the only one using it. If I ever did make one for another person I'd pick a more dummy friendly one.

That seems like a much better alternative. How about the cells? What are some good places to go for those? Also I haven't been able to find that connector, can you provide a link?

Do you have any physical store with parts in your area ?
If yes , just the picture it will help.

Its commonly used on CB (vehicles) or VHF ( boats ) radios.

Or alternatively use ebay search.   

Sounds like a plan. There is a store or two around here, when school's out I'll have more time to look around.

Are there any brands of batteries that are particularly good compared to others?

[Kiriakos-GR]

Are there any brands of batteries that are particularly good compared to others?

I have no idea of what batteries you are planing to use.
There is plenty of options , but its one it will drive in to a specific sized battery pack,
plus the weight it will come in the equation too.

Generally I favor Sanyo - Sony - Panasonic .   

[Lance]

Well I guess I'd be going for some lithium ion cells. I guess I should be asking what characteristics should I be looking for in a battery.

[Kiriakos-GR]

I do not suggest any use of lithium ion cells , they need special circuitry about charging that you do not have one.

But hey I got confused again ... are you thinking to rebuild the original pack ? ( My suggestion to it its a big NO )
Or to make an alternative battery pack completely external ?   ( Yes with common batteries like NiMH  AA but you will need many of them,
and the 2700mA version does not come cheap.)

About making the battery pack , you are alone on this , as concept.
Its best before you go for shopping , to make an schematic of what you have in mind and post it here ,
so to get an advice . 

[Hypernova]

My classmate for his final years proj was making a 3ch Li-Ion power supply and charging system for a robot (which I was building) using some TI management chip.

v1: didn't do anything
v2: blew the chip which takes a week to source from farnell
v3: changed mosfet which blew
v4: Works when he enabled each channel by themselves. 

And then when he tried to use all 3 at once they all blew up and he's out of spare chips at this point. 

Oh and this was before the day of the exhibition.

[Lance]

I do not suggest any use of lithium ion cells , they need special circuitry about charging that you do not have one.

But hey I got confused again ... are you thinking to rebuild the original pack ? ( My suggestion to it its a big NO )
Or to make an alternative battery pack completely external ?   ( Yes with common batteries like NiMH  AA but you will need many of them,
and the 2700mA version does not come cheap.)

About making the battery pack , you are alone on this , as concept.
Its best before you go for shopping , to make an schematic of what you have in mind and post it here ,
so to get an advice . 

I was looking at both actually. I know I need special control circuitry for lithium cells, but I'm sure I can come up with that.

[Hypernova]

I do not suggest any use of lithium ion cells , they need special circuitry about charging that you do not have one.

But hey I got confused again ... are you thinking to rebuild the original pack ? ( My suggestion to it its a big NO )
Or to make an alternative battery pack completely external ?   ( Yes with common batteries like NiMH  AA but you will need many of them,
and the 2700mA version does not come cheap.)

About making the battery pack , you are alone on this , as concept.
Its best before you go for shopping , to make an schematic of what you have in mind and post it here ,
so to get an advice . 

I was looking at both actually. I know I need special control circuitry for lithium cells, but I'm sure I can come up with that.

Any half decent battery charger chip will have example circuits spelled out for you.

[Lance]

Sounds good. I'll shop around when I have some more time.

[Lance]

For charger chips, are there any brands that are generally considered better?

[Sionyn]

interesting read

http://www.laptops-battery.co.uk/blog/how-to-replace-battery-cells-inside-laptop-battery/

[Lance]

Yeah, I'll need to wait till the summer before messing around with this. School is keeping me quite occupied at the moment.

[Kiriakos-GR]

interesting read

http://www.laptops-battery.co.uk/blog/how-to-replace-battery-cells-inside-laptop-battery/

 

This is why .... I was suggesting to avoid rebuilding such packs.... there is no simplicity about doing it . 

[Lance]

interesting read

http://www.laptops-battery.co.uk/blog/how-to-replace-battery-cells-inside-laptop-battery/

 

This is why .... I was suggesting to avoid rebuilding such packs.... there is no simplicity about doing it . 

Isn't the challenge the whole point? Or part of it at least?

[Kiriakos-GR]

Isn't the challenge the whole point? Or part of it at least?

Nop , there is no challenge if you try to do something like that,
with out having knowledge - special parts - and tools.

This thread had come to 5 pages , its not wise to speak over and over about already known things.