I use HF battery tenders on anything that will be sitting a period of time.
About 6 bucks on sale each and have not had any issues yet.
Once the battery is 5 or so years old, it's time for a new one.
https://www.harborfreight.com/automatic-battery-float-charger-69955.html

Don


1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!