Rockbox.org home
release
dev builds
extras
themes manual
wiki
device status forums
mailing lists
IRC bugs
patches
dev guide



Rockbox mail archive

Subject: Re: Trickle Charging
From: Uwe Freese (mail_at_uwe-freese.de)
Date: 2002-12-10


Hello Björn,

Björn Stenberg wrote on Monday, December 9, 2002, 10:05:40 PM:

BS> Being the project Charger Guru, are you planning on adding some type
BS> of trickle charging to the code?

I hadn't planned it yet, but I can do it if you like.

BS> There is currently a problem with charging the Archos overnight. If
BS> the batteries get full at 4am, the unit will stay turned on and
BS> consume batteries for a number of hours until I wake up and unplug
BS> it. Thie is especially a problem if the Deep Discharge option is
BS> enabled.

BS> Would it be feasible to add a small trickle charge that offsets this
BS> so that the batteries remain full in the morning?

Before starting to write code, I have some questions about the design.

My first thought was:
- charger on if voltage < a
- charger off if voltage > b (with b a little bit smaller than the max
  voltage of the last complete charge cycle)

But this has a disadvantage: The batteries are not equally full the
whole time. It depends on when you plug off the charger if your
batteries are completely full or not.

So now I think of this:

Charging on means charging with ~300 mA, charger off means decharging
~100mA.

So start charging at intervals 15 sec (charge) - 45 sec (decharge) (or is
this what you call trickle charge?).
Check the voltage every minute and adjust the values. E.g. if the
voltage is too low, charge 16 s and decharge 44 s.

I think this should work very well and keep the batteries full.

However, the feature should be configurable (on/off), because this is
not good when using the player all the time plugged in.
Another possibility is to only enable it when deep discharge is off. Or
maybe:

- start trickle charge after a complete charge cycle if deep discharge
  is off
- stop trickle charge after 12h, because charging over a long time is
  not good for the batteries

So please comment these ideas. I'll then implement and test it. I think
it will be finished at the weekend.
  
Bye, Uwe.



Page was last modified "Jan 10 2012" The Rockbox Crew
aaa