I somehow broke my Sony MDR-RF925R
I can use the NiMH 2.4v 550mAh battery pack in the headphones and charge them vs the charger stand. I can use 1.5v Alkaline & 1.5v or 3.7v Lithium. The left side gets hot when using the single 3.7v or double 7.4v Lithium batteries but still works. When I go to stick two 1.2v NiMH 1000mAh in it is when it will not charge them but the NiMH 2.4v 550mAh battery pack only. I tried other brand 1000mAh NiMH batteries but they don't want to charge as well. So as you can see I somehow broke my Sony MDR-RF925R headphones. I want NiMH batteries with a higher mAh so the headphones will run longer on a single charge. What it came with dies on me after 14 1/2 to 15 hours each time I am using them.