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Poor stand-by battery life?
02-20-2014, 11:18 PM
Post: #1
Poor stand-by battery life?
Has anyone else experienced poor stand-by (ie: off) battery life with their Prime's? I am finding my unit will not switch on only one day after a full charge, and I have tried this a good 7 or 8 times now using a variety of charging methods- PC, original charger, (good quality) after-market chargers etc. Oddly, the unit indicates that it is already half full after only several minutes being plugged in.

Incidentally, this only started occurring after the latest firmware update, but I suspect that is only coincidental- I think I may have a dud battery :/
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02-20-2014, 11:34 PM
Post: #2
RE: Poor stand-by battery life?
How many charge cycles did you had before this issue?
It looks like the battery is dead already, not a good sign for a new calculator.

I got mine just one week ago, new in the box. It didn't power up at all, so the battery was discharged.
I just gave it a full charge of 6 hours using the supplied charger, then connected it to the PC applied the latest f/w revision (Nov-25).
So far, after a week it still shows 100%, considering that I have used it just 1 hour per day at most, and a couple of times it was connected to the PC via USB, so it was consuming power from the PC.

Jose Mesquita
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02-20-2014, 11:49 PM
Post: #3
RE: Poor stand-by battery life?
Did you maybe leave it in the plot view? When my prime shows a plot it does not switch of by itself.

I am pretty impressed by the battery life. I have my prime since end of october 2013 and I am pretty sure I only charged it 3 times since then. On average I'd say I use it for 5-20 minutes every day (sometimes its more, but then there are days were I don't use it at all).
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02-21-2014, 03:28 AM
Post: #4
RE: Poor stand-by battery life?
(02-20-2014 11:49 PM)Stefan Wrote:  I am pretty impressed by the battery life. I have my prime since end of october 2013 and I am pretty sure I only charged it 3 times since then. On average I'd say I use it for 5-20 minutes every day (sometimes its more, but then there are days were I don't use it at all).
I have to agree with this also (and same time purchased too). Same usage and I go long between changes. Perhaps there was a bad batch of batteries at the factory?

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02-21-2014, 03:58 AM
Post: #5
RE: Poor stand-by battery life?
Nope, there is some bug in the calculator. Happened to me too. Sometimes it just dies (like if some app left a loop wasting the battery)

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02-21-2014, 04:48 AM
Post: #6
RE: Poor stand-by battery life?
I don't have this problem, but after 2-3 weeks with little use, my battery is around 75% charge. My TI-Nspire CX is almost completely discharged after 1 week of non-use.

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02-21-2014, 05:11 AM (This post was last modified: 02-21-2014 05:15 AM by eried.)
Post: #7
RE: Poor stand-by battery life?
Well, I just experienced it once in about 5 months, I am very sure is something about some *special* sequence that left a thread running or makes the standby state buggy.

In my tests I wasn't able to replicate the issue, so I think it will be extremely useful for the HP guys if someone finds how to trigger this thing.

(02-21-2014 04:48 AM)Kevin Ouellet Wrote:  I don't have this problem, but after 2-3 weeks with little use, my battery is around 75% charge. My TI-Nspire CX is almost completely discharged after 1 week of non-use.

Well... TI is certainly weaker in every aspect against HP so no big news there Tongue even with their fancy hibernation system that makes you lose time without saving any energy. Or the very slow first boot checking if someone 'evil' edited in a maliciously way the firmware

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02-21-2014, 06:50 AM
Post: #8
RE: Poor stand-by battery life?
(02-20-2014 11:34 PM)jebem Wrote:  How many charge cycles did you had before this issue?
It looks like the battery is dead already, not a good sign for a new calculator.

3 or 4 charge cycles max, all of them before the firmware upgrade. The battery life when both switched on and on standby was outstanding before this issue popped up.
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02-21-2014, 06:52 AM
Post: #9
RE: Poor stand-by battery life?
(02-21-2014 06:50 AM)Oseaco Wrote:  The battery life when both switched on and on standby was outstanding before this issue popped up.

To be exact, your battery in standby will last for about 1141 hours (47,5 days).

http://www.hpmuseum.org/forum/thread-65.html

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02-21-2014, 06:53 AM
Post: #10
RE: Poor stand-by battery life?
(02-21-2014 03:58 AM)eried Wrote:  Nope, there is some bug in the calculator. Happened to me too. Sometimes it just dies (like if some app left a loop wasting the battery)

This is what I suspected for a while too. I am going to try to replicate the problem and try to figure out whether it's a dud battery or a firmware bug. This morning it was left in CAS view, and this evening it still shows a full charge. I will try it plot mode next and see what happens.
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02-21-2014, 06:57 AM
Post: #11
RE: Poor stand-by battery life?
(02-21-2014 06:52 AM)eried Wrote:  
(02-21-2014 06:50 AM)Oseaco Wrote:  The battery life when both switched on and on standby was outstanding before this issue popped up.

To be exact, your battery in standby will last for about 1141 hours (47,5 days).

http://www.hpmuseum.org/forum/thread-65.html

Yes I saw that post, and I got the same mileage before the problem- 3/4 charge left after being left in standby for about 2 weeks. Nothing like that now!
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02-21-2014, 06:59 AM
Post: #12
RE: Poor stand-by battery life?
(02-21-2014 06:53 AM)Oseaco Wrote:  
(02-21-2014 03:58 AM)eried Wrote:  Nope, there is some bug in the calculator. Happened to me too. Sometimes it just dies (like if some app left a loop wasting the battery)

This is what I suspected for a while too. I am going to try to replicate the problem and try to figure out whether it's a dud battery or a firmware bug. This morning it was left in CAS view, and this evening it still shows a full charge. I will try it plot mode next and see what happens.

I tried measuring the waste directly in the USB port without able to find how to replicate the issue, and it always drops to nearly 0 on power off, with small spikes every couple secs. So it might be not something simple, but a combination of things.

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02-21-2014, 09:45 AM
Post: #13
RE: Poor stand-by battery life?
I would not exclude any possibilities, before actually eliminate possible causes. I see 3 possibles causes:

1. Faulty battery: these devices can fail anytime, not because the chemical process fails, but due to faulty electronics inside that disable the charge/discharge normal cycles;
As Oseaco mentioned in his initial post:
"Oddly, the unit indicates that it is already half full after only several minutes being plugged in."
This is typical of a dead battery in my book. But it can be caused by something more elaborate and complex, yes. Usually the simpler explanation tends to be the true one, but not in every case.

So, test it: remove the battery (just need a small philips type screwdriver to remove the two screws) and use an Samsung or equivalent mobile phone to charge the battery and see how it goes;
Or replace the battery with another one. You can easily find these batteries in the market, they are standard.

2. Faulty battery energy management system: Yes, this can be cause by a buggy s/w routine interacting with the Samsung processor hardware.
Test it: see point 1 above.
Try to bypass it: Do full hardware Reset. And use HP support.

3. As Eried mentioned, a s/w bug can trigger a high CPU utilization, depleting the battery at a high rate.
Test it: see point 1 above.
Try to bypass it: Do full hardware Reset. And use HP support.

Please post the results here, so we can all know what to do when it happens to us Smile

Jose Mesquita
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02-28-2014, 11:22 PM
Post: #14
RE: Poor stand-by battery life?
Murphy strikes!

Well now the bugger has decided to work properly. It has been over a week and it is still showing a full charge after switching it on 1 to 2 and then several days apart. The problem was so bad it was at the point where it was justifiable to send it in for a warranty claim. Now I cannot replicate the problem.

Thanks for all of the suggestions. If it plays up again, the first thing I will do is get another battery and see what happens. I'm not sure the USB port will be of much help with tracking down this particular problem- I think connecting an milliamp meter or Oscilloscope in line with the battery will better show standby activity here.
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