On Tue, 13 January 2015 Dave McLaughlin <[email protected]> wrote: > I am running Android sunxi-linux 3.4 and on boot up, with battery power > only, I see the following in the debug output. > > [0.148] boot1 version : 2.0.0 > [0.149] script installed early ok > [0.149] pmu type = 3 > [0.253] bat vol = 3894 mv > > > This corresponds pretty much with what I am reading with a multi-meter > across the battery temrinals. Battery is a 6600mA Li-Ion type. > > The issue is that once Android starts, it shows a low battery warning > and a reading of around 13% when the actual reading should be around > 55%. The battery voltage with a meter is still > 3800mV > > > I/PowerUI ( 1826): updating low battery warning: level=13 [-1] > > > If I plug in a charger it stays at the same reading and now shows charging. > > If I power off and then on again, it repeats this reading. If I apply > external power via the charger, it boots up and shows the correct > percentage 55%. > > Monitoring the battery voltage during the startup process sees only a > few mV of drop as the loads switch in. > > It's always a lower percentage and dependent on the starting rate. For > example, a higher 80% on the charger shows are around 30% when powered > up on the battery. > > Looking into /sys/class/power_supply/battery/voltage_min_design the > value is 3400 and in voltage_max_design it is 4200000 > > The MIN value is not the same as I have in the FEX. That is 3300 > > Is this a known issue with a fix? It's causing a major headache with > the system running on battery power as the user thinks the battery > needs recharging when in fact it could run for longer and the OS goes > into shutdown when it gets too low. Plugging in USB and it reboots with > over 50% left.
You should read AXP registers for both cases. At least the code in sunxi-linux 3.4 does store some information about the battery in there. In addition to that, there are the OCV values in fex file that will also influence the reported battery percentage. As such it might be disagreement between 3.4 and android on how to preserve battery status information in AXP registers. Probably using battery so voltage drops enough will also trigger the percentage value to be corrected. Bruno -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
