low battery peroformance

i bought my inspiron 1420 (with 6 cell Sanyo battery) last november. Then it gave me a battery life of 2hrs 45min (wifi on, display full brite, music in windows media player, balanced power plan)

yesterday (march 8, 2008) i checked the battery life again in same conditions. the result was 1 hour 55 min !!!!!!!!!!!!. Battery wear is 5% according to everest and 6% according to 'notebook battery info'. why is this happening. i am very frustrated over this. should i call dell and ask for a battery replacement.

Is there any problem with the battery calibration if so. how can i recalibrate battery ??? thanx on advance

 

Hi.

have you tried a full discharge, to calibrate the battery.

run the laptop on battery till you get the battery low warning, the boot into the bios and leave the laptop till till it shuts down automaticaly and then do a full re-charge with the laptop switched off.

regards

John.

PS. my last laptop battery showed 7% when i received it.

 

Cycle (discharge then charge) your battery a few times and you should get most of the battery life back. Unless your battery cells are really dead.

 

Hi.

you only need to do this once every couple of month`s, just to recalibrate the battery runtime circuit in the battery.

You cannot recover lost capacity from lin-ion battery`s once it`s gone it`s gone.

regards

John.

 

Yes im aware that once battery cells are gone, they cannot be recovered. Ive worked with NiMH, NiCD, LiPo/Li-Ion battery chemistrys alot from RC cars and Heli's. The best way to take care of them is to discharge it to a certain voltage and charge it back up, aka cycling.

If his battery is not calibrated right then its not showing the correct % which means he could get restore some of the 2:45min battery life he used to have

 

Hi.

I just tried everest on my laptop and i got a shock

battery wear level 66% and i have only had it a month

Everest gives battery capacity levels in MWH.

so i decided to do some research my battey is 14.8v at 4800mah = 71040mwh

I found a webpage telling me how to calculate a battery`s MWH from the voltage and capacity of the battery it turns out to be 71040mwh and everest is saying my battery is 222000mwh - 15,000 mah battery not the 4.800mah that it is.

I think my battery is giving the wrong maximum capacity.

full capacity for my battery is 71040mwh and i am getting 73770mwh so i have less than 0% wear level

regards

John.



*******************************************************
Field Value
Power Management Properties
Current Power Source AC Line
Battery Status 100 % (High Level)
Full Battery Lifetime Unknown
Remaining Battery Lifetime Unknown

Battery Properties
Device Name BATBL50L8H
Serial Number 0000
Unique ID 0000BATBL50L8H
Battery Type Rechargeable Li-Ion
Designed Capacity 222000 mWh
Fully Charged Capacity 73620 mWh
Current Capacity 73770 mWh (100 %)
Voltage 16767 mV
Wear Level 66 %
Power State AC Line
*******************************************************

 

I read somewhere that everest gives battery wear % calculating it from a 12cell battery or something like that. Just ignore it

 

Hi.

I have tried mobmeter, but it does not appear to work in vista just gives an error.

anyway else to measure battery wear.

regards

John.

 

OP numbers are not out of line with the regular wear of a Li-Ion batt, I assume these numbers were actual time to run down. 20% per year is not out of line. Here is a link that says a Li-Ion fully charged for one year 25C/77F will loose 20% capacity. Keeping in the notebook fully charged will exceed 25C/77F. So throw in cycles which are limited and Batt is normal.

 

so for wht the website said, is better to take out the Li-Ion battery if you are not using it? and store it with a little charge and in a dry place?? correct?

 

Yea if you have the time. I don't. And dry has nothing to do with it keep it cold, that is what matters.

 

Correct, you do want to keep in a cool place if you really want to maximize it. Also this is not taking out at the end of the day this is actually storing and not using. 40% to 50% is recommended, because you can not under run your batt as it has a safety circuit. But if you store with a low charge and the natural chemical reactions happen you could fall below the safe point which would ruin your batt.