90W enough to charge a T61p with ultrabay battery?

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arlab · #1 Post by **arlab** » Sun Mar 30, 2008 11:42 am

I'm thinking of buying an Ultrabay battery. Anyone knows if the normal 90W charger can charge both the 9 cell battery and the Advanced Ultrabay battery?

Also, anyone knows if the ThinkVantage Power Manager can also set thresholds (like setting the battery to start charging when below 65% and to stop charging at 85%) for the second battery (the one that will be in the second threshold)?

lithium726 · #2 Post by **lithium726** » Sun Mar 30, 2008 1:09 pm

If it's anything like the old T series, it will charge the main battery and then go on to the secondary battery, but it doesn't do both at the same time. I think you'll be fine.

arlab · #3 Post by **arlab** » Sun Mar 30, 2008 2:08 pm

OK. I thought it would charge both at the same time. What about the thresholds? Is it possible to set them to the Advanced Ultrabay Battery?

Zender · #4 Post by **Zender** » Sun Mar 30, 2008 5:51 pm

Yes, you can set thresholds for batteries separately - there was a bugfix for PowerManager not a long time ago concerning this.

Though personally I'm not sure I can recommend anyone buying Ultrabay battery, because ThinkPad's discharging power management is pretty dumb when it comes to using two batteries. It will completely discharge the Ultrabay battery and then switch to the main battery.
Today's Li-On and Li-Pol batteries are sensitive to being fully charged and full discharged, they lose capacity quickly (especially in the latter case) - it would be more wise to get the Ultrabay battery to 5-15% level, then use the main battery and in the end use the Ultrabay battery again, or perhaps kill the Ultrabay battery first, but only after main is at the 5-15% level too.

If it's an option for you, try larger main battery. If not and you can live with what I've said, then go for the Ultrabay one.

#5 Post by **Harryc** » Sun Mar 30, 2008 6:04 pm

If the machine completely discharges the ultrabay battery, what's the purpose of thresholds? The question was "What about the thresholds? Is it possible to set them to the Advanced Ultrabay Battery?" Your answer was yes....

Zender · #6 Post by **Zender** » Sun Mar 30, 2008 6:07 pm

Sorry, I might have not made it clear. You can set two thresholds - when to start charging the battery and when to stop. I have set these to 75% and 92%, so now I have 78% and it does nothing, because it's not below the "start" threshold. When it goes below 75%, it will charge it to 92%.
But I can't set, for an Ultrabay battery, to which level to discharge it. And it will kill it completely before switching to main. And that's much worse than charging it always 100%...
And because the secondary battery is always used first, it will wear out quickly.

#7 Post by **Harryc** » Sun Mar 30, 2008 6:08 pm

So, the answer should have been no, not possible for the extended battery.

Zender · #8 Post by **Zender** » Sun Mar 30, 2008 6:10 pm

Not really. You can't set discharge threshold for the main battery either and it makes no sense for it. Yes, you can set when to hibernate/sleep the laptop, but that does not help, as the secondary battery is first killed completely, when the system's total battery time left is more than 50%...

aaa · #9 Post by **aaa** » Sun Mar 30, 2008 6:13 pm

I thought there was an option somewhere to force a certain battery to go first...

SHoTTa35 · #10 Post by **SHoTTa35** » Sun Mar 30, 2008 6:17 pm

nope, no such luck. I've always wanted that option or like the Dells where it uses them both at the sametime. My Dell Latitude C610 seemed to do that.

aaa · #11 Post by **aaa** » Sun Mar 30, 2008 6:25 pm

There seems to be a force_discharge option on Linux here... I'm not on a machine that supports thresholds at all right now so I can't try it out.

#12 Post by **gator** » Sun Mar 30, 2008 6:53 pm

On no thinkpad till date can you "select" or choose between the battery to discharge (this is in windows, have not tested in linux). It has always been ultrabay battery first (fully, which I agree will wear it out fast) and then to main. This has been the case from the T2x series, why even the 600X. I have personally noticed this feature in each of the thinkpads in my signature.

I guess the idea behind it is that ultrabay batteries are considered as disposable, too bad they are so expensive.

#13 Post by **bill bolton** » Sun Mar 30, 2008 7:43 pm

gator wrote:I guess the idea behind it is that ultrabay batteries are considered as disposable

The idea appears to be to free up the Ultrabay for other devices once you have discharged the battery, by using that battery capacity first..... which does matter for some users.

Cheers,

Bill B.

Tony Chan · #14 Post by **Tony Chan** » Sun Mar 30, 2008 7:50 pm

Getting back to questions arlab asked initially :

arlab wrote:.. Anyone knows if the normal 90W charger can charge both the 9 cell battery and the Advanced Ultrabay battery?...

Yes, both 65W and 90W works just fine. I use both chargers to charge the 2 batteries with my T60. One **might** need more time to fully charge the batteries but I didn't bother to time it.

arlab wrote:...Also, anyone knows if the ThinkVantage Power Manager can also set thresholds...

Again, yes. You actally HAVE to setup the threshold separately for the 2 batteries.

I can also confirm that it will finish charging the main battery ( to the threshold % ) before start charging the ultrabay battery.

Hope this helps

Zender · #15 Post by **Zender** » Sun Mar 30, 2008 7:51 pm

bill bolton: There's still the "Bay->10%, Main->10%, Kill Bay, Kill Main" approach, which would allow both usage of external devices and reasonable lifespan of the battery.

Linux tp_smapi module is repored to support switching battery using software means. Seems I'll have something new to play with once I'm finished with BIOS

[implement some simple tool to allow setting thresholds for switching batteries when discharging]

90W enough to charge a T61p with ultrabay battery?

90W enough to charge a T61p with ultrabay battery?

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