[Fredster]

I use the tenders on my cart, cars, and cycle batteries, when they sit unused for months.
I have found that my batteries all have a much longer service life, since I’ve used tenders while in storage!
Here is some information I found on-line
Is a battery tender necessary?
  Answer   A battery tender is not nesessary if a battery is used regularly - as in at least once week - where the battery tender becomes necessary is in recreation vehicles where the battery sits long period of time, making them vulnerable the voltage stored slowly draining away - requiring charging to keep the battery from going dead, and to prevent sulfation of the lead plates in the battery due just sitting, or partially/completely drained of power...   Prime candidates are any vehicle stored for winter/summer - and others that are not used regularly, such as RV's, jet ski's, 4-wheelers, boats, antique cars/trucks, etc...