On Board Battery Chargers

[Jeff T]

I am thinking about adding a charging system to my boat for A: have good power for amps and B: life of the batteries. I have some questions.

First a little background:
-I have the EDIB system and a fairly large stereo that is playing almost constantly.
-I keep the boat on a lift in a covered slip. The slip does have power available.
-The marina isn't but a minute or two from where we ride/anchor. Other than the occasional 10 minute pass, I don't run the boat very long, especially at higher rpms.
-On occasion, an amp will kick off at higher volume. With help from the stereo forum, I think it is because my deep cycle battery gets too low (need to tweak speaker wiring slightly too). The only charge I get is short runs to and from the marina and short passes w/ a boarder. So, after hours of anchoring, I feel like I'm taking 1 step forward and 2 steps back w/ regard to the batt charge.
-I'm looking at the Xantrex and Promariner

Questions:
1-I know that Tige is explicit about disconnecting all wiring before hooking up a charger. I have done the searching for previous posts about on board chargers. This hasn't really been addressed and/or answered? Is it safe to even have these? The last thing I want to do is create electrical problems. With warning posted everywhere...I would have to think that Tige would void any warranty.
2-What is the difference between a regular on board charger and a "smart charger"? Are both the xantrex and promariner considered smart chargers?
3-What is involved in the installation of either unit? I'm not electrically savvy, so easier the better for me.
4-Is it safe to have power from the marina to the charger for up to 2 weeks? The slip, although covered, does create a humid environment.
5-Will the 20+ chargers from Xantrex or Promariner top off a battery overnight? I'm usually out all day both Saturday and Sunday...so I'm sure by the Sunday evening glass runs my batteries have taken a beating.

I would love to get everyone's thoughts on this subject. There are several individual posts scattered throughout the various battery threads, but nothing dedicated to this subject. TIA for any advice.

[Coach]

I have the Xantrex 20 True Charge on my boat. It is what the stereo shop recommended and they used on their own personal boats. It is a smart charger that can do up to 3 banks. It will figure out what bank is the lowest and start giving it the bulk charge then go to the next lowest bank until both are at about 85%. From there it is slow charge to full and then it will cycle on every 20 hours to check to top off the batteries if in storage. My storage unit does not allow for me to keep the boat plugged in so I have to charge the night I get to the river until the next morning to get the charge up. With you having shore power you are in a great situation. You will be able to plug in and leave. The charger is smart an like explained above and will keep your batteries at an optimal level until you use the boat again. I would say it is a must for your boat.

As dumb as this sounds I have to connect 2 extention cords and run them to our awing on the beach wrap it around the metal poles then take the cord to my tower wrap it around and plug it in at night. The cord is never in the water but hanging over it and the plugs are always over beach so they can't contact the water. It is easier than pulling the boat out and plugging in each night. Looks a bit sketchy but works great and I get a full charge on the batteries each night.

[dogbert]

If you get a marine charger, then it will be waterproof, so no issue with humidity. The chargers you mention are designed to plug in and forget. They'll automatically adjust from charging if your battery is low to maintaining it if it is charged.

[Jeff T]

Coach, you don't unhook anything from your battery terminals before you plug in the charger? If you can't tell...I'm still a bit uneasy about all the warnings.

[Coach]

With an on board charger you it hooks up directly to your battery system. No need to unhook anything. I don't have any warning on my boat about it. my charger plug is in the rear left transom center cooler. I just open it up and plug in my extension cord and walk away.

[R&T Babich]

I've used various chargers on our cars and boats for many years and have never had a problem leaving all the accesories connected - radios, LCD monitors, CRT monitors, DVD players, etc. I just added a second battery to our boat and have been charging with 3 different units for the last few months. I just connect them to the center post of the battery isolator where the alternator hooks up. I'll be adding an on-board unit this winter when I figure out a good place to plug in the cord. Just make sure the charger is an "automatic" unit. It will charge at it's rated capacity until the battery is fully charged then switch to a "trickle" or "maintaining" mode automatically.

[FIC]

The reason that tige or marine power would be concerned about a charger is if the charger should ever spike it will damage the computors, you really are not supposed to jump a dead battery for this same reason. As to your stereo amps cutting out , we have been rewiring are speakers in series on the tower speakers only which makes them 8ohms instead of 4ohms , we put a little more gain and you can crank a lot more volume and havent had the amps cut out cause they arent getting as hot.

[Domsz06]

I just put a xantrex 40 on the boat and it's SWEET!! I listen to the music and bump it and it just charges and keeps everything charged. it's nice, plug it and forget it! Granted I tend to unplug it during the day, but I'm not even using the system that much, so a day or two charging a week, should keep the batts full.

[R&T Babich]

FIC - Good point, I hadn't thought about a voltage spike getting to the ECM module. If the alternator voltage regulator dumps the system voltage could go to 16 or 17 volts. I've been concerned about the ECM on our 2000 Mercruiser because it has been discontinued and I haven't seen a replacement anywhere on the internet. If it ever crapped out I guess the boat is dead until I can find a used one somewhere. The ECM is mounted on the engine and I'm adding a small blower fan for added cooling. I'll look into a voltage limiter next.