Battery's

[MLA]

Originally Posted by rydog

Would adding a third battery be too taxing on the stock alternator? Also if the 1 battery would last for a couple hours that would be fine because then I run the boat a little to charge. Would 1 battery solely used for audio last that long with my set up, estimated of course.

More battery Ah, in the form of either a larger battery or multiple batteries, will be additional load on the alternator, I wouldnt worry about it taxing the alternator. Alternators make for poor battery chargers, so they can struggle to recharge even a single dead battery. So the more battery Ah's you have and the deeper you run that battery bank down, will make you more dependent on some sort of shore charging.

Adding a 2nd house battery would basically double the play time. At the same time, it would meet your current play time goals while only running the bank down half of what it was with only a single battery. This is better for the batteries.

As long as the primary cranking is isolated from the house battery, no need to run engine while anchored, unless the house bank runs down to a point that the system starts to shut down. If you do this on a regular basis, then is time to consider more batteries so you dont need to run the engine (think CO fumes) and the system keeps going without interruption.

[rydog]

Okay that makes sense. Now I would run the system until it dies and still have my starting battery but when I run the audio battery my boat eventually alarms out (because of the lowering voltage?) so I have to turn the boat on and charge. So I can't run my battery dead because the alarm will go off and I have to charge.

[Thrall]

Originally Posted by payne04

Do not sit and play at all... I have to 2 battery's and they are in switch it has 2 0r 1 or all... Not real sure how to set the battery's up like you guys are talking..(house and cranking battery)

With your setup and the fact that you don't spend the day in party cove, any decent pair of combo deep cycle/start batteries will work just fine.
If your setup works fine then I wouldn't worry about it and I'd leave the Perko switch pulling/ charging both batteries.
To run one dedicated for house one for start, isolate those loads to each battery directly preferably with some distribution blocks. At this point, the + to the starter will charge only the battery it's hooked to. Then link the 2 batteries with an ACR auto charging relay and the alt will charge both with the engine running but isolate them once the voltage supply drops below charging volts, 14+V.
This setup has worked well for me and its totally hands off. No switching required.
I installed a shore power charger as well though just to keep the batteries fully charged and maintained but it worked fine without it the first year.

[bsloop]

Originally Posted by rydog

Okay that makes sense. Now I would run the system until it dies and still have my starting battery but when I run the audio battery my boat eventually alarms out (because of the lowering voltage?) so I have to turn the boat on and charge. So I can't run my battery dead because the alarm will go off and I have to charge.

Yes, you need to add a second battery or more.
As MLA writes, deeply discharging a battery significantly reduces battery life so having more batteries that are depleted less will be cheaper in the long run. (assuming you properly maintain the batteries with a full charge from shore power at the end of the day)

If you are idling the boat just to play the stereo, this IS hard on the alternator since the alt is only putting out maybe half its rated amperage. Low output on top of a heavy draw from a depleted battery AND stereo draw is a recipe for alternator replacement.
Fuel cost idling a boat just to run the stereo will quickly mount to more than additional batteries.
Finally the safety factors of carbon monoxide poisoning or some drunk stumbling onto the throttle or jumping into the drivers seat should be considered.
(I have seen ALL of the above happen in the Cove)

[rydog]

What's the most common shore charging set up people use on here?

[supreme112279]

http://www.mrctechnologyinc.com/Page...argerList.aspx

I don't know about common but this it what I use. 12 volt 10 amp version

[waterlogged882]

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[supreme112279]

I like that genius charger better. It's waterproof for starters!

[waterlogged882]

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[rydog]

Thanks for the info. Does this make sense: Since I have 2 batteries, 1 for audio and 1 for starting, I will get a single bank shore charger and use that after every trip to charge the audio battery. The starting battery should remain pretty much fully charged if I use it to only start the boat and charge it anytime the boat is running using the alternator.

Also any suggestions on a good single battery that could power my 3 amp set up for a good portion of the day, assuming I will be shore charging it every night.