Repair or discard? BE550G ...

[divide_by_zero]

While testing a BE550G, I connected a 40-watt string of novelty lights and they have a slight, rapid flicker with no apparent pattern. I put that battery in another 550 and the test lights are stable.

The unit was made in 2012. Is there a known practical fix or given its age should it be thrown away?

[ant_apc]

I'd recycle it if it is that old and not working correctly with another battery.