A battery pack is a type of resource that you can get in Stardew Valley. While battery packs aren’t necessarily rare, their requirement before you can farm it is pretty inconsistent at best. Battery packs have many uses, particularly with high-tier tools and items.
A battery pack isn’t a rare material, but it can be pretty rare early on. It’s recommended that you use them wisely and you don’t discard them even if you have nothing to use them for.
A single battery pack costs around 1500-2500g from the Travelling Cart. It’s not really recommended to sell them as you can only get so much profit with them for a measly 500g.
One of the best uses of a battery pack in Stardew Valley is for Iridium Sprinkler, Crystalarium, Slime Egg-Press, Lampposts, Jukebox, and Farm Computer.
Completely unrelated, but if you’re trying to find Lewis’ shorts, check out this guide.
Battery Pack in The Tunnel
The Tunnel is a quite hidden area in Stardew Valley that’s only accessible through the lower elevation section of the Backwoods.
There’s a hidden panel in the middle of two lit areas in the tunnel. If you use a battery pack, you’ll be able to get Secret Note #22. This note opens up the questline for Mr. Qi, and eventually the access to the Casino.
Best Way to Farm It
There’s no other way to farm the battery packs other than building tons of lightning rods. Even though you don’t really need all the lightning rods, you’ll be able to get as many battery packs even in just a single storm.