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Rockbox mail archiveSubject: Re: More aggressive Rockbox battery chargingRe: More aggressive Rockbox battery charging
From: Jens Arnold <arnold-j_at_t-online.de>
Date: Mon, 07 Feb 2005 19:17:17 +0100 Hi, >> Matthias is using a 9+v charger which, according to the FAQ, >> gives him about >> 140mA current into the Archos. The problem is, this is only >> slightly more than is necessary just to run the AJR (and less >> than needed when the disk spins up). With a limit of 40% duty >> cycle (24/60), his charger is falling behind. > The Recorder hardware can measure both the cell voltage and > the DC input voltage, and could derive the charging current > from that. Perhaps the duty cycle should be a function of > this? That should definitely be done instead of simply taking out the max. duty cycle safety measure (by allowing almost full time as maximum). The problem is that (1) Voltage is *not* a reliable indicator for NiMH charging state, (2) Voltage measurement may differ between individual units about 1..2%, (3) the trickle algorithm tries to regulate the voltage and (4) doesn't check the input voltage in order to estimate the charging current. So it may happen that the batteries get overcharged, and that should be avoided if possible. Continuous overcharging of NiMHs with >0.05C (that's only 75 mA with stock batteries) *will* damage the cells over time. Regards, Jens _______________________________________________ http://cool.haxx.se/mailman/listinfo/rockbox Received on 2005-02-07 Page template was last modified "Tue Sep 7 00:00:02 2021" The Rockbox Crew -- Privacy Policy |