I was able to fix this for my blinds by replacing line 104 and 105 of the blind driver to (make sure to back up your driver by making a copy of it before making changes):
if (debugOutput) log.debug "attr: ${descMap?.attrInt}, value: ${descMap?.value}, descValue: ${(Integer.parseInt(descMap.value, 16)/2)}"
sendEvent(name: "battery", value: (Integer.parseInt(descMap.value, 16)/2))