A better alternator delete

[mpg_numbers_guy]

Originally Posted by Xist

I think it is funny you are attempting to murder your alternator and MetroMPG is trying to bring his back from the dead.

Exactly! Why resurrect it when you could just delete it!

[Daox]

Haha, yes it is a bit ironic.

[MetroMPG]

But I want the satisfaction of choosing to kill it myself! A natural death is no fun.

[Piotrsko]

Explosives decompression of the assembled parts could help kill it.

[Daox]

I got the batteries today. The box was a lot lighter than I had expected.

Opening it up was this:





And inside the pink bags were these. Their part number is SMPC 9 or SMPC9. Rated at 11.1V, 2.55Ah and 28.305Wh.





They were a lot smaller than I expected... Seems to be a theme I guess.

I'll have to look more into the BMS and connector stuff. I think I will probably end up breaking them up to make what I want, but its worth looking into.

[Daox]

And a quick google search even finds us some interesting laptop connector info.

From: https://batteryuniversity.com/learn/...laptop_battery



The picture is a little deceiving. When I look at the actual connector, there are no electrical connections in the top and bottom big grooves. It must just be for alignment. The very thin grooves are the only ones with metal showing. There are 5 slots.

I am not sure if this works the same for these modem batteries, or if the pins do something else. I'll have to look more into the BMS info. However, it does seem pretty easy to just buy a male connector and get easy access to a 3S1P setup.

[Daox]

The other night I tore the first battery pack apart. The disassembly process was a little easier than I expected. The case came apart relatively easily with a small straight blade screw driver.









Inside each case is three 18650 cells in series, and a small circuit board with the BMS on it.









I found out the BMS is a S8254A chip. It has a bunch of functionality that I am still reading up on. However, the transistors I do not think will be able to handle the amperage that this pack will see. So I think I am going to ditch them and build my own pack.

So, I continued disassembling the pack into individual cells. This also went pretty easily. The only possible issue is the welds peel up and sometimes leave some residue on the connection. I would like to find a way to clean this up better.

[Daox]

Here is an image of that welding residue I was talking about. Most guys say they just hammer this down. I'm not sure what I'll do with it yet.

[teoman]

The transistors should be ok if the pack is how I imagine it to be.

I.e. they are only used to discharge individual cells to keep pack balanced.

[Daox]

I started disassembling the packs the other day. I took apart 14 of them to get the 40 cells I wanted to use for this project. It took a while haha. Here they are laid out in roughly the pattern they will be assembled, 5S8P.





Here is the current thought on how they'll be assembled. I'll mainly consist of a large top and bottom plate that is bolted together. The plates will be 3d printed. Getting the cells to all align properly will be the biggest issue I think.