The battery went dead in my Tiny Tach. They don't have a replaceable battery(we'll see about that) so I followed Pops guidance in this post: Inexpensive engine monitor? Pop's said, "My Tiny Tach internal battery lasted 5 years. I dug in the potting on the left rear and found the little 3V round battery, removed battery and solder wires to the terminals. Epoxied back smooth. Bought a battery holder for 2 penlight dry cell batteries and wired up for 3 volts. Note-- Changed batteries every year but would take another set of 3V batteries with alligator clips to the battery holder terminals while changing batteries so to not lose the hours listed. Loose 3 Volts to the Tiny Tach and you lost the hours displayed. Still working since 2007."
So I dug into the left end of the back side and revealed the battery. I pried the contact off the top:
Then I lifted the edge of the battery up and pried the contact off the bottom of the battery. The battery is a CR-2325.
I am going to put a CR 2032 in the hole and screw a piece of plexiglass over the back to hold the new battery in and hold the contacts against the battery. The Cr 2032 is smaller diameter than the CR 2325 so it drops right in. It will be much better than new!
So I dug into the left end of the back side and revealed the battery. I pried the contact off the top:
Then I lifted the edge of the battery up and pried the contact off the bottom of the battery. The battery is a CR-2325.
I am going to put a CR 2032 in the hole and screw a piece of plexiglass over the back to hold the new battery in and hold the contacts against the battery. The Cr 2032 is smaller diameter than the CR 2325 so it drops right in. It will be much better than new!