Map battery level to %

[Josar]

It will get easier with the Member of Group Trigger

Features for Rules that work with Groups

Introduction This post provides an overview of two features that have been added to openHAB recently to make it easier to write rules that work with groups of items. These features only apply to rules defined in .rules files (also know as DSL Rules), and not any other types of rules/scripts such as those for the Experimental Rule Engine or JSR223 Scripting. The following sections will provide examples of the usage of each feature. These examples will be based on the items shown here. Group All…

But as @job said when changing transforming the value in the rule don’t set it to the same Item.
This will probably lead to conflicts, but in your case this could be an exception.

1. The Item is only one way. Get info from node.
2. The rule is set to received command
3. The Item state is change by postUpdate which does not trigger the rule again.
4. The incomming and transformed value is a number

As there is no other interaction with this Item, this could work out without issues.