I have hard-wired, linked smoke detectors and most are not easily accessed by household members who don't do well with step ladders.

Can I run two additional wires to a smoke detector and locate the backup battery in, for instance, a wall box on floor level so anyone can easily replace a battery?

And/or can I run those two wires to all the smokes so they all are linked to the backup battery which could be rechargeable and remain plugged in so that the battery would virtually never fail?

Thanks, Zito