battery types & charger option

[elwopo]

Hi,
I'm bringing my boat (96 bayliner 17' capri) out of 2 year storage (sitting) due to bad engine.
The batteries seem beyond help. They take a charge to full then, when left overnight, when I hook the charger up it says they are at 40 -50% charged.

The boat came (used) with two batteries and a switch. Both batteries are cranking type. I'm thinking I should get one cranking and one deep cycle? I use a trolling motor sometimes and the radio is used quite a bit. The space is small and the larger size batteries don't fit well (27 size?)

Should I go with a cranking and deep cycle?
Is 27 size better or can I go to 24?
It is possible to buy too big (amps) of a battery? I would assume the highest is best.
Do the batteries have to come out of the boat after every trip and be put on some kind of "trickle charger"?

If it matters as far as amps...I'm putting on a brand new 115 e-tec.

Thanks for any assistance.
Tony

 

[eastern27]

Re: battery types & charger option

Use 2 batteries, 1 for cranking (marine starting) and 1 for electrical loads (deep cycle) when the engine is off. Use the switch to cycle between the 2. If you can get you hands on a smart charger that has an equalization stage up might get more life out of the old batteries by equalizing the cells. Were the batteries maitained while the boat was laid up? You can't have to many amps. A smart charger is best. They are normally 3 stage chargers 1 or more banks.

 

[Boatist]

Re: battery types & charger option

What kills most batteries is not being charged. All batteries self discharge over time and any time a battery is discharged damage is done. Starting batteries should not be discharged below 80 percent and deep cycles should not be discharged below 50 percent.

So in summer month should charge the batteries once a month weather you use the boat or not. If you use the boat the starting battery should be charged up ok. Your trolling motor or deep cycle can be charged by to motor but on most boats the motor is not run long enough for the battery to fully charge. So get a automatic or smart charger to charge your batteries and make sure they get fully charged after every trip and once a month between trips in summer. In winter can charge every other month as the cold slows down everything including battery self discharge.

I personaly like auto batteries not marine unless your batteries are mounted up in the bow where they get a lot of pounding. Reason is they are cheaper and places like Cosco and Walmart have longer warranties. Cosco for example had 3 years free replacement and 100 month pro rated. Marine batteries will probably be a year.

Bigger batteries will hold more energy but also take longer to charge. On my 1980 boat I have two group 24 batteries one Starting and one deep cycle but I do not have a electric trolling motor. Trolling motors and high amp radios take a lot of current and bigger batterys are better.

Your new motor will likely have a alternator about 30 amps and will charge the starting battery in minutes. Trolling motor deep cycle can take 12 hours to charge. Even with a high amp charger it will supply about 14 volts to charge the batteries but the batteries will charge fast at first but slow as they charge up to zero amps. A group 27 deep cycle discharged will take at least 8 to 10 hours to charge.

I charge both my batteries thru a battery isolator with a 65 amp alternator but neither of my batteries are ever discharged very much. Still when I get home the first thing I do is hook up the battery charger to a plug on the bow of the boat that also use the same battery isolator to charge both batteries.
Then unload the boat and clean the fish. Cover the boat and check the charger output. On my boat it will always be fully charged by this time and charger will be setting at zero amps but with big deep cycles may still need many hours of charging.

For most people good idea to buy a 2 bank on board charger and plug it in when you get home. They will not over charge like a trickle charger will. I like charger with at least 10 amps per bank to get the battery charge up with the least damage done from being discharged.

Advantage to onboard charger or one like mine with a plug on the bow where can charge both batteries with out taking the cover off and climing in the boat is it easy to hook up so you will charge more often.

My boat has not had any battery that did not last at least 6 years.

 

[jtexas]

Re: battery types & charger option

A cranking battery will not last long in a deep cycle application.

Under ordinary conditions, a trickle charger won't overcharge a good battery, at least not overnight - but it can happen. and sometimes they don't get a complete charge.

Better to use a 10- or even 15-amp charger with auto-shut-off.

Best bet is a "smart charger" with "maintain mode".

I get 5 to 6 years from cranking batteries, and a couple from the trolling batteries, 3 if I'm lucky. Trolling motor is hard on batteries.