I have a 12v / 4500mAh battery that I’ve been using with my FT-817nd. It is NiMH technology and is lighter than a comparable SLA battery. The problem has been charging, since I only had a SLA charger. Today I picked up a Thunder Power TP610C-ACDC charger from Hobbytown that can charge LiPo, LiFePO4 (and other lithium types), NiMH, NiCad, Lead acid and maybe others. It has some really nice features. I’m planning to also put together a Li-ion pack using surplus camera batteries, so I wanted a versatile charger.