Is that the BP-180 with four AA cells staggered? If so
it is the same pack used in the BC235 and BC245. Check
Uniden's website. There are 3rd-party vendors including
improved capacity NiMH packs out there, I just can't
point to one. If you're a bit daring, you can make your
own, but it's a bit tricky and not for the faint of heart.
Dave