If you tinker, you find yourself needing to make firm but reversible connections. The standard solution is based on a male-female connectors system, and the only tool you need to make such connection is a set of crimping pliers.
These connector systems are based on the principle of a mechanical connection: the bare wire is literally crushed between small overlapping pieces of metal. The friction between the bare-wire and overlapping metal creates a sound electrical connection as well. Creating a proper “crimp” allows the connection to be made and unmade hundreds of times without failure. Moreover, once you become good at crimping, it will take literally 15 seconds to make a connection—in comparison, a solder gun requires 1 minute just to warm up.
There are a variety of crimp standards, but for POWER connections, I find the JST-style connectors are the best because they are keyed so that the connectors cannot be accidentally joined in the wrong way. To make such connections, I must admit that I love the following set of PA-09 crimping pliers, shown here, from a Japanese company that names itself Engineer, Inc.
I own another set of crimpers, the SN-28B, shown here. Although these were slightly cheaper, and even though they tout the ability to perform both crimps at the same time, I prefer the ergonomics of the PA-09. Moreover, because they are designed to perform two crimps at once, the spacing between the first and second crimp forms is too big to handle the JST-style connectors.
The PA-09 can also crimp the very popular .1″ header pins that are used on Arduino boards, etc. Again, the pliers require two crimps. You can see a full list of the types of connectors that the PA-09 can handle. In the US, I purchased mine from the previously reviewed Sparkfun.
In summary: the tool has perfect ergonomics, the material on the grip and the steap is high quality and a pleasure to use, and because it was designed to do one crimp at a time, it is extremely flexible and precise.
Here is a JST-style female pin that the PA-09 can be used to crimp. Notice there are two crimps that must occur. The lower, longer flaps of metal are crimped around the insulation of the wiring to hold the wire; the upper, smaller flaps are crimped around the bare, stripped wire. I find the 1.4mm setting in the PA-09 pliers are perfect for both flaps.