is it safe to plug my onboard battery charger in and leave in pluged in? i am told it's ok to do that but kinda leaves me uneasy. Do you guys do this?

how long are you talking about some leave it over night some leave it  for a month  both will say theres no damage done both will say it causes damage  id say it would be fine for a week or so

I have a charger with an auto setting, it slowly charges the battery and shuts off when it is done. But like cajun said how long are you going to keep it plugged in?

I have a mk 220 on my boat that i keep plugged in all season long except for when it is on the water and have had no problems.Minn kota chargers will go into maintenance mode after they are done bulk charging to maintain a constant charge in your battery.I like to leave mine pluuged in all the time so it is always ready to go.

I have a new MK 230 on my boat, and I plug it in when I come back from fishing and the night before I go out. I don't leave it plugged in all the time.

Plug it in and leave it until you get ready to go again, even it that's next year. That's what it's designed for and doing that is only going to help the batteries, not hurt them. Just be sure the keep the water level maintained with distiled water.

I have the MK-330.  There are no issues leaving it plugged in 24/7.  This is stated directly in the manual.  They will go into a maintenance mode when the batteries reach full charge.