Login or register (free and only takes a few minutes) to participate in this question.
You will also have access to many other tools and opportunities designed for those who have language-related jobs (or are passionate about them). Participation is free and the site has a strict confidentiality policy.
Explanation: A 'charging back' certainly does exist; it may be a dual-purpose unit that can either be used stand-alone to charge a battery, or to power the equipment direct from the mains when available.
Without more details, I think this is the most likely possibility.
I speak from 20 years personal experience in the electronics and video industry.
Tony M France Local time: 17:02 Native speaker of: English PRO pts in pair: 14202