Building an 18650 battery pack!

I'm searching for suggestions on how to construct a 12V battery using 18650 cells. I've so far built a battery utilising Headway and Sinopoly prismatic cells. But I've stayed away from 18650s because they seem to be so difficult to find for a good price and decent quality. But I still want to make one.

This post is to get advice on the best course of action. I can solder even though I don't have a spot welder, but I'm not sure if it would be a wise idea for these cells. One thing I'm curious about is how many cells a regular 12V battery should have in series. If we were to use three AAA batteries, I was thinking of something around 60Ah.

With LiFePO4 we do 4s batteries but apparently with the lithium 18650s we do 3s?

Any thoughts on methods to hook these together would be appreciated. If it helps, the modem batteries I'm looking at are here

The specs are here

Thanks in advance!
It's generally not recommended to use 18650 cells to build a 12V battery, as they are typically designed for use in 3.7V or 3.6V lithium-ion battery packs. If you want to build a 12V battery, it's generally better to use cells that are specifically designed for that voltage, such as lead-acid cells or sealed lead-acid (SLA) cells. These cells are more readily available and tend to be more cost-effective than 18650 cells.

If you still want to use 18650 cells to build a 12V battery, you can connect them in series to achieve a higher voltage. For example, if you want to build a 12V battery using 3.6V 18650 cells, you would need to connect at least 3 cells in series. However, it's important to note that the capacity of the battery (in Ah) will be determined by the capacity of the individual cells, not the number of cells connected in series. For example, if you use 3.2Ah cells, the capacity of your 12V battery will be 3.2Ah, regardless of the number of cells in the pack.

As for the specific cells you linked to, it looks like they are 3.6V cells with a capacity of 3200mAh (3.2Ah). If you want to build a 12V battery using these cells, you would need to connect at least 3 cells in series, resulting in a pack with a voltage of approximately 10.8V and a capacity of 3.2Ah.

In terms of how to physically connect the cells, you can use soldering or a spot welder. If you don't have a spot welder, you can use a soldering iron to connect the cells, but it's important to be very careful when handling the cells and the soldering process, as lithium-ion cells can be dangerous if damaged or misused. It's also a good idea to use a battery management system (BMS) to protect the cells and ensure safe charging and discharge.