I had good results with the electric traps. At least 10 kills and no signs of slowing, on the same set of batteries. I've eventually moved to a rodent free zone, so I have had no reasons to continue using it.
what was your trap called?
did you wipe down the trap after each kill? from what i read on amazon, after a kill and it sits there for a bit, the bowels are released and urine/fecal matter are left on the trap, which turns away other rodents.
so after each kill, they recommend wiping it down