I like to wire my sabers in such a way that they can be taken apart and fixed. I try to avoid using glue as much as possible, and most or all of my wires have connectors, if I have room for it. As with wires, connectors take up more space than it would first seem, and finding good small connectors is somewhere between hard and impossible, but here is a summary of what I have found so far.
Left-to-right: JST, Deans, picoblade, brickstuff
This are fairly large, but if you buy a pre-wired battery, this is what you get. The datasheet says they are rated for 3A if I remember correctly, but I’ve tested mine up to 20A. (At that point they get fairly warm though.) These connectors are polarized, so it’s not possible to hook connect them backwards. (Unless you wired it wrong.) These connectors are crimped, not soldered, and the shroud keeps all the electrical part insulated so there is no need for shrink tube or anything like that. I often incorporate slots for these connectors in my chassis designs:
These connectors claim to handle 20A, which they do, but there is no headroom. Basically they handle the same amount of current as JST connectors in actual measurements. Unlike JST connectors, these are meant for soldering, and you need to shrink tube the connections. They are slightly smaller than JST connectors, but that advantage goes away when you add the shrink tube. Personally I prefer JST over Deans connectors.
These connectors are often called “micro-jst” connectors. But that’s wrong, because they are not made by JST. Last I checked, JST doesn’t even have any
connectors with 1.25mm pitch. These connectors are rated for 1A, but can probably handle a bit more. They also come in mult-pin configurations. I like using two-pin connectors for speakers, and 3-pin connectors for accent neopixels and buttons. (One for each button, and one for GND.) While it’s possible to crimp these yourself, it’s fiddly and the tools are pricy, so it’s actually easier to just buy them pre-crimped. There are also kits that come pre-crimped, but the metal bits at the end haven’t been inserted into the housing yet, which is really cool if you want a connector with more than three pins.
These are hand-made 2- and 4-pin connectors. They are probably the smallest option I’m aware of, but I haven’t used them for anything myself. They are not polarized, and I’m not sure how much current they can carry. Also, the connection is not locking, so it’s possible that they could disconnect. That said, if you want small, this might be the right choice.