"Ed" wrote in message
...
Unless you maintain them, they will both be dead when you want to use
them. Use a battery switch... start and run on one battery (to charge it)
Then when you stop to play with your toys, switch to the other battery.
When you are ready to go home, try and start on the battery you used....
if it works.. great... it will charge on the way home... if not, switch to
the other and start the engine to get home and then don't forget to charge
both when you get home.

another option... I have 2 batts on my 17' tender and I use a perm mounted
2 battery charger so they are both always fresh. They will last longer
and within 2 years, they will have pd for the charger due to fewer battery
replacements.

I plan on a dual switch so I can run 1 for the engine/starting and 2 for
house.