Lenovo laptop refuses to recognize DIY battery pack.

Thread Starter

Berninia

Joined Nov 21, 2015
19
Hi, I have built a simple DIY 3s2p battery pack from 2170 cells with balancing and overcharge/discharge protection. I want to connect this pack directly to the battery connector of the Lenovo T540 Thinkpad, replacing the Lenovo issued battery pack which is kaput. This connector has 7 terminals, but only three have contacts, Vcc, Gnd, and unknown.

There seems to be some handshaking going on the 'unknown' contact. The laptop does not recognize my DIY battery pack.

I would appreciate any help as to how to accomplish this.

I would not want to connect to the power input terminals, because that would mean my pack has to become a 5s2p -- too large and too heavy.

I can't replace the cells on the kaput Lenovo pack, as it has already self-immolated, and are 18650s.

Cheers

Brom
 

LVrooman

Joined Nov 29, 2019
1
Hi, I have built a simple DIY 3s2p battery pack from 2170 cells with balancing and overcharge/discharge protection. I want to connect this pack directly to the battery connector of the Lenovo T540 Thinkpad, replacing the Lenovo issued battery pack which is kaput. This connector has 7 terminals, but only three have contacts, Vcc, Gnd, and unknown.

There seems to be some handshaking going on the 'unknown' contact. The laptop does not recognize my DIY battery pack.

I would appreciate any help as to how to accomplish this.

I would not want to connect to the power input terminals, because that would mean my pack has to become a 5s2p -- too large and too heavy.

I can't replace the cells on the kaput Lenovo pack, as it has already self-immolated, and are 18650s.

Cheers

Brom
Hi Brom,

You might check out this article;
https://hackaday.com/2020/09/02/building-an-open-source-thinkpad-battery/
 
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