I have had my boat up for a good month, and I just learned this week that I will be down and out for a couple more months. It will now be around April or may before I can fish again. So my question is should I leave my batteries on the on-board charger the whole time or is it best to take it off for that much time? Anyone had to store a boat for 4-5 months and not get to use or start it? Just worried that something may happen. Thanks!!

What kind of charger do you have ? If it's a Dual Pro, the batteries will have to drop in power a good bit before it will even start charge them. That's what Iv learned.

They can't set that long without being recharged. If they are flooded cell then at least monthly you need to charge them. If you leave them plugged in then check the water monthly.

I have a 93 tracker pro17. With two batteries. One for cranking and all the electronic stuff. And one just for the TM. I bought a on board 2 bank charger from a guy who had a brand new ranger boat and wanted to upgrade to a 4 bank changer I think. So this one just says Ranger on top. It has two set of lights that act like a meter. And I was told that it will come on if it sees the battery needs a charge. My worry is to leave it that long parked in my basement plugged in. I can and will check the water level tonight. But should I do anything else? Should I buy anything other then water to put into the battery? Should I unplug it once. Month? Should I have someone take and use it?

True for older DualPros chargers (OEM'ed & relabeled to Ranger boats) that the batteries had to drop (self-discharge) before the charger kicks in reapplying its' float charge back on. The latest Dual Pros though do not wait until the voltage drops as they repeatedly cycle back ON momentarily based on time; not just battery voltage. This will keep a continuous higher % state of charge on the battery never allowing it to drop. The battery still does not overcharge as the charger shuts off if the battery does not need topping off,

So still yes, it is best to leave them on the charger 24/7. They should not require water except to replace evaporation. there are auto watering devices avail, if you are concerned.