T30 Battery questions ...

[FreddyH60]

When fully charged, the battery in my T30 shows a remaining time of 1:38 (batterry icon in tasktray), which I judge to be pretty decent for this type of battery.
I also installed the BatMax software from Lenovo, which provides this information :
- Battery Health : RED
- Chemistry : Li-Ion
- Full Charge capacity : 26.06 Wh
- Design capacity : 47.52 Wh
- Cycle count : 10
- First used date : 2003-10
In the BatMax 'Battery Tips' it is advised to recondition the battery by performing a "deep cycle", i.e. completely run down the battery, beyond the shut-down limits.

My questions :
Anyone have some experience with this deep cycling ?
Does this actually improve battery performance ?
Given the rather decent state of my battery, should I do the deep cycle from now on or wait until further battery degradation occurs ?

Thanks in advance,

Freddy

[Harryc]

My experience with deep discharging on older batteries such as the one in your machine is that it degrades performance. I have seen more than one member here who swears by never discharging lower than 10%.

[vanaya]

That is bad for battery with only a cycle count of 10!! I have done this to a few T2x series batteries and it does help. I wouldn't expect to go from a red to yellow, but you will increase the wh by a few .2 - .8wh. for each deep cycle. On an R30 battery that had 30 cycles it did improve by 3.2 wh. with a deep cycle, YMMV!

[FreddyH60]

This weekend, I decided to do a deep cycle on my battery.

First I wrote a battery drainer program (for those who are interested, I'm willing to share the source and/or executable) which just loops (can be stopped) and writes timestamps & loop count to a file.

With a fully charged battery and the energy management scheme set to 'Disable Shut-off Timers', just running the drainer program, it took an amazing 2 hours 27 minutes 47 seconds (and 80563 loops) before the battery was totally empty.

After reloading the battery to full charge :
- Battery Health is back to YELLOW !!!
- full charge capacity is now 30.81 Wh (4.75 Wh increase!!!)
- cycle count 12

After this, I'm convinced I have a very decent battery in my T30.
Unless advised differently, I'm thinking of doing this deep cycle stuff every 2 weeks.
What's your opinion on this ?

[madkat]

interesting
as i have one of may batteries in the same condition as yours - i'm tempted to try your method
if you're ok with it i'll give you my email in order to send me the exe file

[FreddyH60]

Madkat, no problem I'll send you a PM.

[jronald]

OK
I hooked up a 40mm Fan and a 12 volt light bulb to the leads
It is no to the point of running then shutting off, then running again
Why?

Ron

[madkat]

@Freddy - thankyou - recieved the file - tonight i'll do the testing

the mobmeter said about my battery:
designed capacity 47520mWh
Fully Charged 19640mWh
12501mV
wear 58%
i'll post the figures after the deep discharge/recharge

[FreddyH60]

@jronald : provided you have the hardware laying around, your method to drain a battery seems as good as mine.
The minor advantages that I see for my method are that draining occurs under 'regular' working conditions (but I'm not the specialist who can say whether this makes a difference to the battery) and that there's a chrono integrated in the program, so duration of the draining is logged and comparisons can be made (FWIW).

[FreddyH60]

@madcat :

Designed capacity is identical (47520mWh = 47.52 Wh)
Looking forward to see your results.

[madkat]

yeah, it works!
after 33721 cycles during 1 hour 2' 46" - the battery was fully discharged (normal working time with the battery was around 50 minutes
results: (according to the same mobmeter)
designed (same) 47250mWh
Fully charged 23320mWh - compared to 19640mWh before - 3680mWh increase!!!!
Wear (!) - 50% - 8% decrease!

now i'll let it charge - and i'll do this thing again in a week or so
thanks again Freddy!

btw - the medium consumption of the laptop during the discharge was 21.45Wh (with peaks from my opening some windows occasionally) - power scheme - all shuttoff timers off, max processor speed and brghtness max

[vanaya]

Glad to hear that the deep cycle helped. I have done an average of 3 deep cycles before increase flattens out. I think, I have read you should deep cycle continuously.

[jronald]

OOppsie
Looks like I killed one of them
The other appears to be charging, Ill leave it alone over night and check it

Ron