Battery "Bank" ????

[jzmolik]

im thinking about adding underwater leds, led strips, tower lights, and maybe a few more interior leds in my 95 SKI NAUTIQUE.... question is:

Is 3 deep cycle marine batteries in addition to the "starter" battery plenty of power for the lights and stereo?
Would mounting them in the enclosed bow a good idea?

[Laketexoma]

LEDs take very little power. Your sound system will be the main power hog. What all are you going to run? Do you do a lot of parking and jammin the tunes or are you mainly running when the stereo is on?

[EarmarkMarine]

jz,
The hotter halogen tower lamps can draw 5 amps each but you wouldn't use these without the boat running.
Some of the larger underwater LED lights can draw several amps each.
Those are the big draws.
The other LED lights such as rings, strips, courtesy and step lights are very low current draw. In this category you could have tons of lights with no more than 5 amps of total draw. A single large battery could run this type of lighting all night.
A fairly large audio system can exhaust a large battery in two hours. The particular system and efficiency can make a big difference so you can't go purely by the power specs. There are calculators to determine this but the best way is to measure the depletion. For battery longevity, you do not want to run your deep cycle batteries below 50 percent, which is 12.0 volts.
Then you have the issue of restoration. An alternator cannot run the boat operations, large audio system and recharge three depleted batteries simultaniously. Too much load can be unhealthy for your alternator. More amp/hour reserves than can be restored can be a liability rather than an asset. So with three stereo batteries you will need to use a large AC shore SMART battery charger.

David

[perry386]

jz,
The hotter halogen tower lamps can draw 5 amps each but you wouldn't use these without the boat running.
Some of the larger underwater LED lights can draw several amps each.
Those are the big draws.
The other LED lights such as rings, strips, courtesy and step lights are very low current draw. In this category you could have tons of lights with no more than 5 amps of total draw. A single large battery could run this type of lighting all night.
A fairly large audio system can exhaust a large battery in two hours. The particular system and efficiency can make a big difference so you can't go purely by the power specs. There are calculators to determine this but the best way is to measure the depletion. For battery longevity, you do not want to run your deep cycle batteries below 50 percent, which is 12.0 volts.
Then you have the issue of restoration. An alternator cannot run the boat operations, large audio system and recharge three depleted batteries simultaniously. Too much load can be unhealthy for your alternator. More amp/hour reserves than can be restored can be a liability rather than an asset. So with three stereo batteries you will need to use a large AC shore SMART battery charger.

David

i don't know it was bad for your alternator to run a high-draw stereo while your boat was on...my boat has two batteries that are constantly running my stereo and the boat at the same time...we never turn the boat off once we get out usually....is there any way to change it to not hurt my alternator without having to re-route my stereo system?

[EarmarkMarine]

Just for an example....let's say you have two very large capacity batteries that are seriously depleted after a long stay at rest and initially could pull 20 amps each until they get a charge. Then you have 20 amps of boat operations. Then you are still running a large stereo at full tilt when underway which could be drawing 50 amps. 110 amps of draw exceeds the 90 amp alternator rating which is at high rpms for limited duty. That is straining the alternator (hot) and pulling down the starting battery which is in parallel with the switch in the 'Both' position. The solution is simple. Give something a rest until you burn enough gas for long enough to restore a charge. Ten fully charged batteries are not a load. But discharged batteries are a liability. Btw, NEVER run your boat at idle while at rest to restore a charge. The mixture of exhaust and beverage is particualrly lethal.

David

[jbach]

Btw, NEVER run your boat at idle while at rest to restore a charge. The mixture of exhaust and beverage is particualrly lethal.

David

please explain. what does exhaust have to do with "beverage"?

[EarmarkMarine]

Carbon monoxide is toxic. And, it is odorless. Mixed with alcohol it takes less carbon monoxide to be dangerous. While the boat is idling for a long period and people are sitting on the transom on a still day, people have passed out and drowned without anyone realizing that they disappeared. So I discourage this practice.

[Chexi]

And you aren't charging all that much at idle anyway. Sound advice from David as always.

If you can separate your audio batteries from your starting battery with something like an isolator/combiner system, that would probably be ideal. The blue seas system I use will automatically combine the audio bank with the starting bank when charging conditions are within an acceptable range. But if my audio bank is too depleted, the relay will open and not allow the audio bank to either (a) suck the charge off the starting battery or (b) burn up my alternator. I've never actually had that condition, since I don't park in a cove and run the stereo for hours, but it is good to know I have that protection if I ever do.

[Missing]

This is the setup I have in my closed bow 2001. might give you some more ideas. (2) group 27's hooked together for the stereo. They sit in the battery tray pictured. Built a platform to mount it all to in the bow.

Just plug in the onboard battery charger when in the garage and keep's them topped off. I have yet to be able to drain them, even on a 4 day trip blasting the stereo. Keeps it really simple and no worries about alternator or not being able to start engine.

I use group 24 battery for starting only.