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lululock OP t1_je0wt7o wrote

Reply to comment by Spritzer2000 in Microsoft Surface Pro 4 battery pinout by lululock

The tablet is already disassembled, thanks. I already dealt with similar devices to not break stuff while attempting a repair. I've just never dealt with such a bloated battery.

The idea was to fix that inherent design flaw the Surface Pro 4 has : A massive part of its heatsink is covering the battery and transfers heat to it, damaging it the more the Surface is used.

If I replace the battery, it will do it again in a few years if not sooner due to lower quality cells.

Buying good quality 18650 and making 3D printed parts to fit them outside the casing will cost less than a replacement part from Ifixit...

I not only want to fix it, but I want it to last longer.

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Spritzer2000 t1_je0zb2o wrote

Ah excuse me I misunderstood the original intent. I can't pretend I understand your reasoning, as it sounds like a very non portable solution for a device that was sold on the basis of portability.

I would probably recommend buying the replacement battery and attempting to remove BMS from that rather than mess about with the spicy pillow

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lululock OP t1_je1010x wrote

You're right... I guess I'll salvage the BMS from another dead battery which hasn't expanded yet. I'll ask a few repair places around. Maybe they could even strip out a BMS for me.

But then comes the part where I'll solder new cells to it. Do you think it will get the extra capacity of 18650 cells ?

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Spritzer2000 t1_je151mq wrote

If it's done properly, I don't see why not. The only thing that might get in the way will be if there's an individual bms system in each cell that handshakes with the "central" system. I haven't actually cut into batteries in a while, generally only replace them

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lululock OP t1_je163p2 wrote

I've found a picture of a BMS someone took appart.

The left one is from a Chinese copy but the right one is the original LG one. Looks like both cells would connect to it. Comments say that the original BMS has a temperature sensor and charging control and that's why some Chinese copies won't get recognized by the Surface.

I think I'm getting somewhere with my idea.

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