Understanding Cell Arrangement in Laptop Battery Rebuilding

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The discussion focuses on rebuilding a laptop battery using six 3.7V 1800 mAh Li-Ion cells. Participants clarify the voltage outputs, noting that the battery's total voltage should be around 11.1V, not 14.8V, which suggests a misunderstanding of the cell arrangement. It is explained that VM and VH are likely used for balancing the cells, with specific voltage readings expected between cells in series. The importance of monitoring individual cell voltages to prevent undercharging or overcharging is emphasized. Understanding the arrangement and voltage readings is crucial for successful battery rebuilding.
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So I am in the process of rebuilding my laptop battery for higher capacity cells. I would appreciate it if someone can help me understand the arrangement of the cells. From my research, each cell is 3.7V 1800 mAH Li-Ion cells. There are 6 of them in the battery pack. In this arrangement:


Untitled.png


I will guess and say that the VP is receiving 7.4v and VG is the ground. But why is VH and VM receiving both positive and ground of 14.8v? And what do they stand for?
 
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cadaver said:
So I am in the process of rebuilding my laptop battery for higher capacity cells. I would appreciate it if someone can help me understand the arrangement of the cells. From my research, each cell is 3.7V 1800 mAH Li-Ion cells. There are 6 of them in the battery pack. In this arrangement:


View attachment 36565

I will guess and say that the VP is receiving 7.4v and VG is the ground. But why is VH and VM receiving both positive and ground of 14.8v? And what do they stand for?

I think you should redraw the circuit on paper so its easier to understand, you should see what's going on better.
 
It is exactly how I drew it on the image above. From what I see in the battery case, there are wires going from the battery terminals to VH, VM, VP, VG which are solder points on the circuit board. I'm just trying to figure out how can one input receive both + and - ?
 
pardon me for posting to an old thread, but i came across this in a search...

i'm a little confused by your diagram. i don't understand how it would be putting out 14.8v. if your battery is putting out 14.8v i would think you have 4 cells, or pairs wired in parallel then, wired in series (4 * 3.7 = 14.8) do you mean 11.1v?

VM & VH would be used for balancing afaik. if it's an 11.1v battery, VM would be between the first and second cell(s) in series, and would read 3.7v. VH would be between the second and third, and would read 7.4v. then measuring the VP (B+) you would see 11.1v.

those numbers would be appox. if an individual cell is below 2.8-3.0v it's possibly undercharged. above 4.2-4.3v it's possibly overcharged. so you may be getting a slightly different voltage reading.
 
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