Battery Question

[avp]

I read through a few threads about battery charging, discharging, maintenance, etc. Lots of info about Li Ion batteries. I have an NP1 system with 13.2v 50Wh NIMH batteries. Two of my four batteries are fairly new (less than a year) but don't seem to be as robust as they should be. I run them in a JVC GY-DV500u with no accessories.

Does anyone have experience with this type of battery and what amount of runtime should I expect to get with this cam?

Thanks ...Jeffro