I got one of those minn kota onboard chargers. Now that my boat is sitting for most of the winter, is it ok to leave the charger plugged in? I know it has a trickle charge to maintain batteries, during in between trips, but is ok for winter storage?

Mine stays on 24/7. I just clean the terminals and check the battery water levels monthly.

Be sure to use distilled water, not tap water when you refill.

Mine stays on 24/7. I just clean the terminals and check the battery water levels monthly.

Be sure to use distilled water, not tap water when you refill.

2X I think most of the onboard chargers can be left on 24/7 but I would check the owners manual to be sure.

That's what it's made for. Just to keep the confusion down from others reading, it would be better not to refer to it as a trickle charge. It goes into a float mode. A trickle charge is a low current, slow charge, but it's still enough voltage to be charging a battery. A trickle charger left on a battery 24/7 will overcharge and fry most any standard size battery used in boats.

A float mode is a maintenance voltage, usually 13.2 - 13.4 VDC. This is not enough to charge a battery, only maintain it's current full charge state and will not harm the battery in any way. Keeping one on a float voltage 24/7 is the recommended way to store batteries.

I would recommend you always check your chargers float voltage the first time you use it, after it has been on for a couple of days to ensure it's no more than 13.4VDC. Not all chargers are exactly the highest quality and I've seen more than one that it's float voltage was too high. To be exact, many companies get very specific and recommend a 13.17VDC float level, US Battery and Trojan are just two. My ProMariner PT 300's give exactly 13.17VDC float. The BatteryMinder maintainer is adjustable, you just have to take the cover off to adjust it, and can be set to any manufactors recommend float voltage.