jbl low battery indicator message question

[clerky96]

Have had jbl for 2 weeks and using the alkaline batteries that came with it. Yesterday the low battery indicator message came up on the screen and the battery still showed 1/4 charge. My question is to those who use alkaline batteries; do you change the batteries immediately when you get that low battery indicator message, or wait a while longer? If the battery runs completely out will I have problems with the jbl coming back on? I noticed that TheBard had problems (he was using rechargeables) but when his jbl wouldn't come on with fresh rechargeables he put in regular alkaline batteries and his jbl turned back on. It seems like I am wasting 1/4 of the battery if I change them at the point the message appears.

[TheBard]

clerky96 -

AsI remember (with the first set of alkalines), I changed batteries after the low battery warning appeared, and the screen blanked. I don't remember the battery charge indicator status. The JBL booted up appropriately after inserting freshly-recharged rechargeables. (The problems I described in the other thread were with the rechargeables)

I am continuing my tests, using fully charged Duracell 2650 mah rechargeables (plenty of current, but still only 1.2 volt). I have also purchased a brick of 1.5 volt alkalines, just in case.

Hopefully other users will have additional observations and anecdotal evidence of battery usage & performance.

(Too bad the JBL does not have a "run-time clock", so we could determine how many hours the JBL will work per change or charge)

[jrl007]

Originally Posted by TheBard

clerky96 -

AsI remember (with the first set of alkalines), I changed batteries after the low battery warning appeared, and the screen blanked. I don't remember the battery charge indicator status. The JBL booted up appropriately after inserting freshly-recharged rechargeables. (The problems I described in the other thread were with the rechargeables)

I am continuing my tests, using fully charged Duracell 2650 mah rechargeables (plenty of current, but still only 1.2 volt). I have also purchased a brick of 1.5 volt alkalines, just in case.

Hopefully other users will have additional observations and anecdotal evidence of battery usage & performance.

(Too bad the JBL does not have a "run-time clock", so we could determine how many hours the JBL will work per change or charge)

I'm keeping an eye on mine as well. Just got it, using the original batteries that came with it. I'm dying to get a set (8) of rechargeables, but I think for now, I'll stick with the regular alkalines until someone reports sucess with rechargeables.

[DJHARKAVY]

Originally Posted by jrl007

I'm keeping an eye on mine as well. Just got it, using the original batteries that came with it. I'm dying to get a set (8) of rechargeables, but I think for now, I'll stick with the regular alkalines until someone reports sucess with rechargeables.

Been using rechargeables since the original batteries died.

No problems so far, except that the shutdown came almost immediately after the warning.

When the batteries get down below half on the screen indicator, I change them at first opportunity.

[cmbs]

Originally Posted by jrl007

I'm keeping an eye on mine as well. Just got it, using the original batteries that came with it. I'm dying to get a set (8) of rechargeables, but I think for now, I'll stick with the regular alkalines until someone reports sucess with rechargeables.

I'm doing fine with rechargeables. It dies when the battery indicator is still on 50% and if I let it get to the point it shuts itself off, I seem to have problems. So I will just change them as soon as the indicator reaches 50%. I've done it several times without problems.

It goes for 3-4 days with lots of hours reading each day, like 4 hours or more, before reaching the half-way mark (and subsequently dying). As I recall, that's about the same length of time the original batteries lasted.

[kirbinster]

I tried rechargeables (Sanyo Enelopes) that work great in my Nikon SB-600 strobe, but almost a total waste on the JBL. My wife only got like a day or two before they were reported as being low.

[CyberSmoke53]

I use alkaline batteries, since it seems the JBL doesn't really have good calibration for rechargeables. So far I get the low battery message after the battery indicator has been showing 1/4 left. I ignored it once and continued reading and after a few minutes the unit shut off by itself and I had issues reopening the book I was reading at the time of autoshut down.

After battery replacement I turned the unit on and navigated to my book - happened to be a DRM pdb that I had been reading with a larger 24 font size than the default 18. The file hung up on reload with a 149/24 pages indication and unit froze and wouldn't advance - I had to reset to get out of the loop. To get the book back readable I had to do a reset to defaults and rekey in my decrypt codes and setup again, but I got my file back readable.

Since then when the low battery message comes on, I carefully backout of the book, turn the unit off, and go ahead and change my batteries. So far I have restarted again with no problems. After the time of the incident above I had been reading my DRM Pdb books with the default font size ... no more issues and crashes.

[Seabound]

Thanks guys and gals. This thread seems to answer my question about the JBL battery indicator and low battery warning.

[Ken Maltby]

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