Sennheiser BA 151 Rechargeable Battery for IR and RF Wireless Headsets (Electronics)

I love my Sennheiser wireless headphones -- except for the battery. This battery rarely lasts more than 2 hours. That's why I have a charging unit that charges two batteries. Also to keep in mind -- these batteries wear out fast. There's only so often you can recharge these things before they die completely. If I'd known how many of these $20 batteries I'd be going though, I would probably have picked a different brand of wireless headset.

   Battery works very well. I fall asleep with my wireless headphones every night, so they basically run out of charge every night. These batteries seem to last me about 1.5 years of this 'abuse'!Not much more to say than that. :-)

Yeah, this proprietary case is ridiculously expensive. If you are a little bit handy, you can take the case apart using an exacto blade. Pry along the edges, it is plastic welded, but comes apart pretty easy. There are two V80H batteries inside made by Varta. These are 1.2V Ni-MH cells for a total voltage of 2.4V. You can buy the batteries inside the case here on amazon for [...] (1.2 Volts .08 Ahmps.), or from batteryspecialists.com for [...] when you buy 6. You will have to desolder the tabs from the old batteries and solder the new ones in there. Have fun.