-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Somebody in the thread at some point said: | Am Di 24. Juni 2008 schrieb Yorick Moko: |> It is known that the way you charge a battery influences the lifetime. |> Have there been any tests as to which is the "best" way to charge the |> freerunner? | | Nope, didn't find the time to do the expected >500 charge/discharge cycles ;-) | Honestly, this is nothing FR or OM specific. Considerations valid for all | LiIon batteries apply here as well. | AFAIK, it's much more important not to push the last electron into the battery | that might fit in here, than to charge with lower current. Some notebooks | allegedly have a "treat battery nice" option, that stops charging at | ~75%..90%. You could do this by adjusting the Vbat-max setting of PMU. Til | now, nobody cared about it yet.
Actually with the charging LED patches in I have been able to see when we charge for a while now, it seems it does an OK job with current settings of recognizing a full or nearly full battery and not needlessly charging it. It does continue to charge the battery past the point that the coulomb counter in the battery reports 100% capacity reached, but it does it in constant voltage mode where the current it pushes in varies according to the effort needed to keep the voltage up. In the final phase of the charging this decreases second by second to under 100mA and then cuts off as full. I had a read through this which seems to be written by an experienced Li-ion person: http://www.batteryuniversity.com/parttwo-34.htm First he shows a graph about charging voltage: ours is set to 4.2V right now so we fit the best lifetime curve he shows there. Second he shows a graph about rate of charge and discharge, I don't really know how to map that on to our performance, except that I never saw a battery heating under charge to more than 30 degrees C and that on a hot day, and I don't think our discharge rate of ~200mA typ when not transmitting will be "excessive". Well, dealing with high currents during transmit it what a mobile phone battery is for. But he doesn't seem to mention charge level except to say that for storage, you don't want a 100% charged battery but 40% charge level. So AFIK what we do now does not make any special trouble for battery life. - -Andy -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org iEYEARECAAYFAkhhU8sACgkQOjLpvpq7dMp8NwCffPs2qd/ekBEfMsJ/UQ3+/izE 3SwAnjEuGIxtDyXBUFbUj1Dc514bPLEp =O5gA -----END PGP SIGNATURE----- _______________________________________________ Openmoko community mailing list [email protected] http://lists.openmoko.org/mailman/listinfo/community
