Onboard charging system??

Well....When the engine is running it charges the batteries and should provide plenty of juice to run what you have listed.

When the engine is off the batteries are draining unless you have them hooked up to a charging source. You have two options:

1. Dockside power - Which will hook to your boat and then you need a battery charger onboard that will charge your batteries. Battery chargers are made for this purpose and I believe Guest makes a pretty good one. You will need to retrofit dockside power to your boat (Add it) unless you already have it. Of course, you could always use an extension cord and a regular trickle charger but this really isn't safe unless the boat is out of the water.

- This method will keep your batteries charged when not in use.

2. You need a generator....Connected to a battery charger. Unless your boat already has a generator (Based on the single engine configuration I'm guessing it doesn't)....The generator can be a small portable type and you could then use a regular trickle charger hooked directly to your batteries.

- This method will keep you going while you are anchored/drifting.

However, it is cumbersome and you have a portable gas/diesel generator making a mess of things (And they are noisy).

My advice (FWIW) is install a battery switch (If you don't already have one). Run the boat on both batteries on the way out. Then put the switch on 1 or 2 (Whichever is the "House" battery) and when it gets low put the switch back to "Both" to start the engine. The engine will then recharge the low battery.

FYI...If you are running a livewell pump, stereo, radar, fishfinder, chartplotter and an electric toothbrush (LOL) you WILL drain the battery fairly quickly. You should make sure the "House" battery is the type that supports electronics best....I'm sure someone on here who knows more than me can recommend a good one but a solid deep cycle should work well.

As stated above, your batteries charge while the boat runs, for best charing, use a starting battery, it is all Grady and Yamaha recommend, some guys use dual purpose and get away with it, but your cutting down on that batteries life even though it is better suited for it's task's, a starting battery drains faster but also charges faster and correctly, a dual purpose will drain slower from electronics but drain harder from a start, and will take longer to charge back full, neither is perfect, but being that the starting battery charges the best and was what Yamaha's alternator and charging system are designed for, it is the only type builder's recommend. also, only flooded cell batteries can be used, outboards cannot charge gel or dry cell batteries.

If you are Away from the boat for possibly 2 weeks at a time, having a shore power chord and charger might not be a bad idea, it makes sure your batteries are charged and when full they trickly charge so you never get to the dock and have dead batteries. I would stay away from guest charger's, they are cheap and do not last long, my 265 is a 2002 and has gone through 2 of them in that time, go with a Pro Mariner Sport charger. They are economical and seme to last, seems to be what many guys on here are replacing their stock guest charger's with when they go. For group 24's, a 6amp per battery bank is the correct charge rate, for group 27's, 10amps, you likely have 24's in your boat. If both batteries are wired off one switch you only need 1 lead to charge both batteries, unless you choose to wire them seperately, I wouldn't though.

... only flooded cell batteries can be used, outboards cannot charge gel or dry cell batteries.

But they can charge Absorbed Glass Mat (AGM) batteries just fine. Any portble chrger may also be used when necessary.

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