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
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