Onboard battery charger recommendation for Freedom 235

[NoVAMike]

Owned my boat for two years now and love it. Dropped in water this Spring but didn't use for seven weeks due to Covid. Battery 1 (of 2) died and I replaced it today. Theory is that bilge pump and radio draw killed it. Want to install an onboard batter charger to avoid this in the future. Does anyone have a recommendation for a charger?

Also, where is the best place to mount it and get a shore plug to it? The door to the battery compartment opens down so leaving it open for a cord will expose it to rain and deck drainage. Do I cut/drill a notch in the door to put the cord through?

Thanks much!

- also... my dealer told me today that he recommended never going to either battery 1 or 2 specifically (leave in on Both). I just read an old Grady post from their website where they recommended starting on Both and then always switching to either 1 or 2 while underway. Anyone know the scoop?

 

[Summertop511]

Personally I start on either battery but never both. I like to know one battery is strong enough to start the engine. Then I leave it on that battery for the rest of the day. Then when coming home I switch and start on other battery. I wouldnt run on both because then if motor stops charging u can get closer to home on the other charged battery. You can buy a battery isolator kit from Yamaha to charge both batteries but have one selected. Look up the kit for your motor.
As far as the battery tender I do not have any experience with them.

 

[dogdoc]

I replaced my factory charger on my 92 Marlin with a Pro Nautic 30amp 3 bank and love it. My boat does spend significant time on the lift so battery maintenance was a must. Easy to set up easy to use and all the features needed to maintain batteries when not in use, but a little pricey. You will also need to add a galvanic isolator if one not on board already. This allows in water charging without galvanic corrosion issues. Mount the charger somewhere that you can easily access and see digital display if the one you get has it. As for ac input. If all you have is a charger you do not need more than 15 or 20 amp plugs/cord. My charger 12v at 30amp max so uses 360 watts power max. Other side of charger at 120v needs only 3amp to produce that power. Bottom line you do not need one of those giant Marinco inputs and cables to hook up. There are many smaller options available. You do need to drill a hole more than likely to provide weather resistant access. On my boat I dc'd the ac input on starboard side and am in the process of removing all ac stuff and eventually add a small inverter for limited ac applications. I put my ac input (all it powers is the charger) just above the raw water wash spigot under the port gunnel. You may be able to use that spot as well

 

[DennisG01]

If you're looking for a true, onboard, full-time "smart" charger, the Pro Mariner ProNautic series is one of the best. This is the type of charger often used on cruiser-style boats so you know it will definitely work for your boat. Including my own use of this brand, these are used in the Sea Ray boats I work with so I have experience with, literally, hundreds of them. Excellent product and will actually extend the life of your batteries the more you use it.

You can mount the unit below decks and install something like this: https://www.marinco.com/en/products/connect/inlets/15-amp somewhere convenient.

The purpose of "both" on a battery switch is in case neither battery has enough juice, on it's own, to start the engine. It's always best to isolate batteries - both during starting and running. A failing battery can draw down a good battery if combined. Even when the engine is running, the battery will charge better when specifically selected.

Couple quick tips:
-- Your engine may already be setup with an aux charge wire so both batteries are always being charged. Check.
-- Switch use... use #1 battery on odd days and #2 battery on even days to even out use.
-- Consider an Automatic Charging Relay. Blue Seas makes excellent products. Go to their website and look into it.