battery pack rebuilt for Netbook Pro

I ordered 18650 2600 mA japanese batteries form batteryspace.com, opened the battery pack and soldered the new batteries in the place of the old ones.

I got the idea from a Russian guy: http://linux-7110.sourceforge.net/howtos/netbook_new/LIbattery/LIbattery.html , that claims a 12 hours duration with a old PSION netbook (not PRO). Incidentally I used exactly the same old battery pack of a NON PRO netbook, that worked many hours when it was new.

The result is not encouraging. I rebuilt two battery packs, that work, but only 20 minutes. After that they are completed discharged.

I have read that the PCB of some battery pack keeps in memory the state of each battery and even if you put in new batteries, the PCB gives them the same current as if they are the old ones. So changing batteries without changing the PCB too does not work. Well, may be, but how is it that the Russian guy was able to get it working?

I considered changing the PCB with one of the PCBs sold by batteryspace.com, but it does not seem trivial because of the form factor of any new PCB, that does not correspond to the custom PCB of the battery pack of the netbook pro.

Anyone tried to change the batteries of a netbook pro? Any better idea?

Do the packs get hot? Did you get 18650's with the built-in PCB (not that I think it'd matter)? I think there is a recalibration of each battery pack. That might require a hard reset and then leaving the unit for a few hours to recharge.

FWIW (too late now), with the MP 2-cell packs I've rebuilt, I keep the tabs on and don't bother with the soldering (unlike your reference) if possible. There's enough tension in the tab to act as a spring and it avoids the issue of overheating the cell.

Edited by hmascience 2009-06-30 7:13 AM

No


No, I bought just the 18650s and used the old PSION PCB


If I go to settings/power there is written "recalibration not done"


I tried to hard reset it putting a pin into the hole, but nothing changed. May be I need to totally reset the NP taking away main batteries and AA security batteries and power supply?


Do you means MP or NP? If you mean NP you were able to rebuild two battery packs of Netbook pro? Did they work?


Overheating and possible explosion is a issue if 18650s do not have tabs, but I bought ones with tabs and soldering everything, was a matter of 5 minutes, with the help of my wife keeping together the pieces. With tabs there is no problem because the tabs are long and the heat takes a long time to move along the tab and reach the battery and also the tab itself dissipates much of the heat. Finally it is much easier and faster to solder a tab, so the trasmitted heat is very little.

Thanks

That is a hard reset. What you did (pin in the hole) was just a soft reset.

Well it is dangerous to instal litium ion batteries without a separate PCB connected with specific wires to each battery to check its state. The PCB monitors the batteries and lowers or cuts the current if any of the batteries gets in risky state. I am unaware that it is possible to incorporate a mini PCB inside each battery and doubt it because of space and of the corrosive chemical environment


Well you helped indeed your hard reset worked! Thanks



Well thanks, a real total hard reset worked. Now the NP is recalibrating the batteries and considering the speed it is discharding them, it should last more than 8 hours

For any other cell pack rebuilders, I bought mine at http://www.batteryjunction.com/18650.html and they claim to have individually protected cells (although presumably the ones sold specifically for battery pack rebuilding do not). I must have gotten ones without PCB protection since those appear to be the only ones with tabs... and it has been a few years, so my memory is slipping.

jt

My Netbook pack only lasts about 2 hours with wi-fi on. It would be nice to be able to rebuild the battery pack without any soldering. How did you do it?

Cheers
SainT