Has anyone else rebuilt a FNB-4A (12 volt) battery pack with Ni-Mh as an upgrade to the original Ni-Cad cells? I am wondering if there are any issues when using the original Yaesu equipment for charging. The NC-15 has quick and trickle modes. I am guessing that the NC-18B/C probably take 4 hours to charge the 12 volt battery pack? 73 de KI4CYM, Bill