help, Rebuilding a better battery for no-name netbook.

is it ok to use Li-ion over Li-poly? (it's li-poly right?)

does anyone in the states want to help with this?

I wrote an instructables a while back about replacing the lithium ion/poly cells in laptop batteries. http://www.instructables.com/id/Increase-the-capacity-runtime-of-your-laptop-bat/ I increased the capacity, but it's a useful instructable for replacing the cells in general.

From the picture you took, your battery pack uses Li-poly. You don't want to mix Li-poly with Li-ion because the voltage levels for when the controller stops charging is different (more explained in the instructable)

Nice instructable! I wanted to do this after seeing your guide.

But I dont feel condident enough to do this myself since this is the only battery I have.

Does anyone in the states want to help me out by sending my battery to you?

Thanks

If the batter case says, 3800mah, do i need to 3800mah cells or two cells that add up to 3800mah?

Hellow rayjai, You need two 3800mah cells. From the pic you provided to me the cells appear to be wired in series. Which would make since because I dont think that a netbook could even run on 3.7v. Basically what you have is a 7.4v 3800mah 2s (two cell) lipo and a controller to make sure that the battereis are at a safe level. Lipo batteries are very sensitive to over draning and under/over charging as well. If you can find maybe 4000-4200mah cells you would increase your time you can use it by a nice ammount.

that's going to suck, all the 4000mah batteries I see are too wide to fit into the battery case. but the 500-ish mah ones fit very well, but that's too low. any ideas how I can get this to work? thanks

hey, do you guys think I can hook up two 2000mah batteries in parallel and use it as a 4000mah cell? so I'll have 2x(2x2000mah) cells?

also, what's the difference between these 2 batteries? why is the lower mAh one more expensive? which one would work better for me?

I might just make a battery without the plastic case and wrap it in thick tape.

http://www.batteryspace.com/Polymer-Li-Ion-Cell-3.7V-3650-mAh----UN-spproved.aspx

http://www.batteryspace.com/highpowerpolymerli-ioncell37v3000mah4545125-10c111wh30adrainrate-ullisted.aspx

Thanks

Can anyone help me out?

Hooking up cells in parallel is safe. The cutoff voltage for the two parallel cells is a little higher than the cutoff voltage for one cell,  so your cells shouldn't burn out.

In the ideal case, all cells should be individually connected to the smart circuit (so they may charge individually), however, your laptop draws <1C current so the chances of the cells becoming unsynchronized after you've matched their voltages is minimal (that is, if you dump charge on a pair of parallel cells, it should even out if the charge rate and the discharge rate is slow enough)

As for why the lower capacity cell is more expensive, its because that cell is a high power cell. It's capable of outputting >2C current. In this case, its a 30A drain rate. Typically, 1C means xA where x = the capacity of the cell. So for instance, a 3000mAh cell can discharge at 3000mA or 3A.

You don't need a high power cell because if your laptop has a 4000mAh capacity, and it lasts say 4 hours, then it's draining 1A per hour, so if your cell is >= 1000mAh, it is capable of outputting 1A per hour.

Thanks for your reply.

Do you recommend me getting 2 3650mah cells or 2 4000(2x2000)mah cells?

also, do you think this battery has a flash rom on it? is it safe for me to desolder the cells first? I'm afraid i will desolder the cells as I try to solder the new ones on.