MobileRead Forums - View Single Post - jbl low battery indicator message question

Ken Maltby · 06-04-2010, 03:09 PM

I think there may be a missunderstanding of what the power display is actually
able to display. It can't really display the actual level of the charge in the battery
pack. It is most likely only providing a display based on the programed response to
the voltage sensed from the battery pack.

You have probably noticed that often when you shutdown your JBL with the power
indicator showing three bars and later start it up again, it will show four bars again,
for a while.

There are enough differences in the discharge characteristics of the various batteries
and how they are effected by the JBL's load and voltage regulation, to make for a large
number of voltage based power level display options. None of them would be at all likely
to actually indicate the level of charge in the battery pack.

After my test runs I use a voltmeter to test the free voltage of each battery in the
battery pack, with normal operation, they all have read at 1v or very close to that.
(While it is likely that the JBL's voltage regulator is able to supply a useful voltage,
from the lower battery pack under load voltage, the nominal 4v point is consistent
with my results so far.)

You may want to take a close look at the way the changes in the JBL's power meter fluctuate in the various test runs, in this thread:

https://www.mobileread.com/forums/showthread.php?t=74936

Jump to page 5, for my latest results.

I ended the test runs as soon as the Low Battery warning appeared and as you can see, for these rechargables it is a simple and problem free process. (Except for the NiZn 1.6v batteries) In the last test runs I'm getting close to 30hours of reading time, which
is plenty of time, I have no problem with the fact that the power level display doesn't
show the one or zero bars before the low battery warning appears.

Luck;
Ken

06-04-2010, 03:09 PM	#9
Ken Maltby Wizard Posts: 4,466 Karma: 6900052 Join Date: Dec 2009 Location: The Heart of Texas Device: Boox Note2, AuraHD, PDA,	I think there may be a missunderstanding of what the power display is actually able to display. It can't really display the actual level of the charge in the battery pack. It is most likely only providing a display based on the programed response to the voltage sensed from the battery pack. You have probably noticed that often when you shutdown your JBL with the power indicator showing three bars and later start it up again, it will show four bars again, for a while. There are enough differences in the discharge characteristics of the various batteries and how they are effected by the JBL's load and voltage regulation, to make for a large number of voltage based power level display options. None of them would be at all likely to actually indicate the level of charge in the battery pack. After my test runs I use a voltmeter to test the free voltage of each battery in the battery pack, with normal operation, they all have read at 1v or very close to that. (While it is likely that the JBL's voltage regulator is able to supply a useful voltage, from the lower battery pack under load voltage, the nominal 4v point is consistent with my results so far.) You may want to take a close look at the way the changes in the JBL's power meter fluctuate in the various test runs, in this thread: https://www.mobileread.com/forums/showthread.php?t=74936 Jump to page 5, for my latest results. I ended the test runs as soon as the Low Battery warning appeared and as you can see, for these rechargables it is a simple and problem free process. (Except for the NiZn 1.6v batteries) In the last test runs I'm getting close to 30hours of reading time, which is plenty of time, I have no problem with the fact that the power level display doesn't show the one or zero bars before the low battery warning appears. Luck; Ken Last edited by Ken Maltby; 06-04-2010 at 03:15 PM.