Thinkpads Forum

Hi, I was just wondering if anyone has taken a part a T60 battery. What made me curious was seeing a walk through for disassembling another laptop battery to replace the cells. Sometimes, but not always, manufacturers use AA Li-on cells and arrange them together inside the compartment.

This could work in theory with nimH AA cells that are 1.2volts in a 9 cell configuration, since the T60 uses 10.8volts in the 9cell battery. The benefit of this would be a very high drain capacity, for example 9x2.6ah(2600mah)= 23.4ah's.

The drawbacks could include:
*added weight(nimh mass density is very high)
*recharge method in question(I wouldn't want to recharge
compartment in the laptop until I knew it was safe)
***faster self-discharge from nature of nimh cells.

***the last issue I mention could be a non-issue for many, because if you used your laptop battery on a weekly basis you wouldn't have to worry about this, and especially if you used it on a daily basis.

Anyways, I just thought this would be interesting and if anyone had at least taken a part the battery compartment to confirm if it used AA cells. If I do get the T60, I just may purchase a cheap battery on ebay to play with this, we'll see. Right now I'm just playing with the idea. The gains would be amazing!

I thought that most laptop battery packs use the 18650 battery type (i.e., bigger than AA; 18mm diameter 65mm length). Looking at an R61 battery pack, I think this is what is inside.

Li-Ion cells are also 3.6v (nominally). They are arranged 3 cells in-line to get the 10.8v and combined with other 3-cell packs in parallel to get the extra current. So a 6-cell pack has two 3-cell stacks and a 9-cell has three.

I also believe that the technique used for charging a Li-Ion battery is quite different than for a NiMh. Something to do with how much current you are trying to push into the battery over a period of time. If the charger is not specifically designed to accept both (i.e., a "universal" charger), then you may encounter problems.

Ok, yeah I see what you mean now.

However, I have seen some aftermarket nimH replacements around,
but for other notebooks(not completely sure what kind of cells were used), I'll find a link. But if what you stated is correct then I suppose this mod is out of question, =[

rkawakami wrote:Li-Ion cells are also 3.6v (nominally). They are arranged 3 cells in-line to get the 10.8v and combined with other 3-cell packs in parallel to get the extra current. So a 6-cell pack has two 3-cell stacks and a 9-cell has three.

T6x battery packs come in 4, 6 and 7 cell varieties, so clearly some other arrangement of Li-Ion cells occurs in them.

BTW, for 18650 batteries, the 18 part of the number is the diameter in millimetres and while 650 is the length in millimetres.

Cheers,

Bill B.

bill bolton wrote:T6x battery packs come in 4, 6 and 7 cell varieties, so clearly some other arrangement of Li-Ion cells occurs in them.

Yes, and that confuses me...

bill bolton wrote:BTW, for 18650 batteries, the 18 part of the number is the diameter in millimetres and while 650 is the length in millimetres.

ACK! You're right. I made a typo up there.... and it's spelled "millimeters"

You're going back about 10 years in battery technology. If you could even find a 18650 NiMH cell it wouldn't have as much power as a Li-ion. If you could use a li-po cell it would be better.

An 18650 sized NiMH doesn't exist the closest would be a Sub-C and you would get about 4.3Wh out of 2 Sub-Cs. While you'd get 7.9Wh out of the latest li-ions. Li-ions are way lighter as well.

There's a good reason why manufacturers use li-ions.