[dave333]

Seems like there would be a market for a universal adapter that accepts all the different batteries and plugs into all the tools - or at least several of the major brands. Kind of like an octopus cable but with some additional straps to let you bundle the whole thing with whatever tool compactly. Probably the adapters would infringe on everyone's patents or copyright or whatever or someone would have done it.

[StueyGuyd]

The challenge with adapters is that different batteries communicate different things to a tool, such as internal temperature, in different ways.

You cannot just connect + to + and - to -.

What could work is a battery with a new standardized interface, and modular adapters that can match different brands' tool interfaces.

Over the years, maybe some brands might develop tools that mate directly to the universal battery.

But now there are 18V/20V Max, 24V Max, 36V/40V Max, and 54V/60V Max cordless systems. There's no practical solution for this.