HXT4mm charge marker

I slide these rings onto the battery contacts of lipos with HXT-4mm connectors after charging them. Only charged batteries have charge markers. The rings block the contacts and are removed before the batteries are used so it is impossible to forget to remove the charge markers. This is a simple system for keeping track of which batteries need to be charged after a trip to the field.

I am thinking of printing rings in a different color and use these to mark storage charged batteries. I have no