Need Some Battery Education

Getting close to launching my new to me pontoon (60HP merc 4 stroke) for the first time, and I'm finding all sorts of things to be paranoid about.
The battery...After signing on the dotted line the boat sat for 30 days waiting for service. When the dealer went to start it, the battery was dead. He charged it and said it should be fine. It is three years old so I'm thinking about replacing it anyway. This led me to the following questions:
There are marine chargers and car chargers. Is there any difference? My car charger is a 12vt 2/10 amp. Will it work?
What would be a good way to provide a starter battery backup? I thought about just carrying a spare battery to use if the other turns up dead.
I have also looked at some jump starters that I could carry.
I'm trying to keep this as simple as possible so as not to involve any two battery system or any rewiring.

Re: Need Some Battery Education

Marine chargers are usually chargers that are designed to be mounted in potentially wet environments. Your car charger is fine...use the lowest setting for a better charge.

I carry a second battery just in case. I would trust my second battery before I would count on any of the run-of-the-mill jump boxes. I could transfer the leads in short order, but also have a short set of jumper cables that would be easier.

Happy boating!

Re: Need Some Battery Education

Thanks RR, I hadn't thought about the wet/dry issue. The marina I may lease at prohibits non-marine chargers so I may be ponying up the cash for a new charger.

Re: Need Some Battery Education

No on the lowest setting. That is a maintenance or "trickle" charge rate. Batteries should be charged at the end of the day and not just before you decide to go but first things first.

1) For starting backup a second battery (fully charged of course) or a quality jump start unit (fully charged of course) will be the simplest and least expensive option.

2) Your car charger is fine. Batteries can be charged at a rate of 20% of their AHr rating. 100 AHr battery = charge rate of 20 amps. So why not buy what is called an "on board" charger which simply means it is a charger designed to mount permanently on the boat. When you are at the dock or at home, plug it into AC power and forget it. They are automatic and will provide whatever charge the battery needs. In fact mine was plugged in last November when the water in the lakes here in Minnesota went solid. A 5 or 6 amp charger is very sufficient for just a starting battery.

3) Unless your boat has an unusually high number of accessories you will not have starting issues. Just keep the engine tuned, and use a fuel system stabilizer like Sea Foam or Stabil in the fuel. If you add high current draw items like a killer stereo system you are into a totally different power issue.

Re: Need Some Battery Education

I use both, but i fish for a week straight with no access to ac power. I personally like the portable jumper box. because you can use it in the winter when not useing your boat. also if you don't carry a back up power supply,box or battery you better know if you can pull start your engine if battery goes dead.I would try while still at dock.

Re: Need Some Battery Education

I have two batteries in my boat and would not leave the dock without a jump box. You just never know. And if I don't need it there is usually someone at the lake that can use the help. I think the jump box is the easiest. With a second battery you have to make sure it is secured and always upright. The jump box can just be thrown in a storage compartment and forgot about until needed.