Laptop battery rebuild, any suggestions?

[johnny13oi]

Hey guys, I am planning on buying a used laptop that is about 3 or 4 years old and knowing that it is so old the batteries of these systems must be shot. I plan on rebuilding the battery as that would be much much cheaper than buying a new one. Are there any suggestions as to what precautions should be taken or any other ideas? Thanks. The laptop would be only worth about $250 so I am really trying to go really cheap here.

EDIT
I actually just won a bid for a Toshiba Portege 2000. Is there any way to rebuild the battery and if not does anyone know where to get one for really cheap?

 

[viorel00]

I read some instructions about rebuilding some PowerBook batteries and I think it is a very risky business and I would not take the risk. You have to make sure the cells are fully discharged before you open the battery, and the cells you put in are also discharged. You have to make sure you use the same chemistry, same capacity, same size, etc. And then you risk that something goes wrong and you laptop catches on fire.

Remember, there was a massive recall of laptop batteries last year, DELL and APPLE amongst other manufacturers, all because of some bad SONY cells.

SO be careful. I know I would not risk my life/house with these things.

 

[johnny13oi]

well .. ive been looking really hard and the battery appears to be a li-ion polymer battery. battery alone costs like 60 dollars. the battery voltage was 10.8V which comes out to be 3.6V a cell 10.8 seems weird compared to the normal 11.1V batteries have. Anyone with more help? Wouldn't cheap generic batteries pose the same risk?

 

[chris_m]

If it's LiIon, then your best bet would be to get a complete replacement from Ebay. That's based on the fact I get my LiIon cells from Dell laptop batteries I buy on Ebay, since that's cheaper than buying the cells on their own!

 

[johnny13oi]

It's Li-ion polymer though, so I don't think they're regular cylindrical cells. The batteries appear to be about $60 online and was wondering if there was a way to rebuild it for cheaper.

 

[VidPro]

you can aquire huge li-poly type cells for laptop power.
as long as you just removed the cell itself (out of the pack) and replaced it on the same protection curcuit the pack uses, and insure that the temp probe and all that is the same way it was , its entirely possible.
the key to a replacement like this is to:
change ALL the cells,
have all the exact same capacity and age/batch of cells for the series
have all the cells at the exact same charge level before assembly
put the cells back connected the exact same way they were connected to the packs protection.
dont overheat the tabs going into the cells
determine the orientation of any thermal probe, and insure that it is in the same place.

a Cheap China replacement would be about the same price as the cells and your time, but if you have the skill and take all the care and precaution, and get correct sized cells and do everything right, i bet it will work better for longer than a cheap e-bay overrated replacement.

 

[johnny13oi]

Hey thanks, could you possibly point me in the direction on to where to get the cells that are most likely used in this battery pack. From the specs of the battery pack ... The individual cells must be pretty thin and I tried searching for the cells but couldn't find any that fit the description. And are all Li-ion polymer cells the same in regards to voltage as the battery pack states 10.8V and that would make each cell 3.6V but typically Li-ion are 3.7V a cell and was wondering if this makes a difference or is the toshiba battery pack just charging each cell to 3.6v?

 

[VidPro]

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=871
there are 4 8 and 10amp ones here, but space is critical you might have to go with the custom ordered
http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=872

note i am not recomending any particular seller, its just the one i have linked that has the full "catalog" puts up good pics and has most specs listed.

the 3.6 3.7v thing means little, its the "nominal" voltage, its more important to know the total specs, the max and min voltages, discharge rate, capacity, and all that other good stuff.
your 10.8V type pack is probably a 3cell li-ion bagged type pack, it can go as high as 12+volts.
It is likly that the toshiba charges to ABOUT 4.1-4.2v per cell when in series.

Disclaimer: sombody purposfully fired up one of them 8-10amp li-polys and it has a LOT of ability to start a house fire if dealt with improperly. it has a load of juice in it.

 

[rivethead147]

the time, effort, potential hazards, and money spent on it, mind as well get the li-ion polymer replacement. incase you haven't looked into it, li-ion polymer is the "safe" alternative to li-ion, there is a polymer layer that is used in place of the organic solvent in battery chemistry and build, so in case for some reason the normal li-ion organic barrier corrodes or the battery pack is punctured with enough pressure, it won't spotaneously combust and worse case if it's a small punture can explode.

li-ion polymer batteries will also have an increase in battery capacity as well as lighter in desing since there will be no metal caseing as in the normal li-ion structure.