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jmvotto
10-01-2012, 09:16 PM
If I have a dual battery switch plus the dual bank on board charger, do I really need and acr unit.

Boat sits on the lift with electrical access right there at the house.

Never had a problem this year, but liked the vsr in the old boat but I did not have the on board charger.

I assume when I run the boat with switch on 2 while under way, the alternator will top both batteres off.

Any thoughts..

lewisb13
10-01-2012, 10:03 PM
I'm with you on this one. I'm about to sell my blue sea system. When you have a shore charger you don't really need this. Not to mention its more shit that can break and it adds complexity to your setup.

EarmarkMarine
10-02-2012, 11:59 AM
There are two real benefits to an ACR/VSR.
One, is pure convenience because it is automatic.
Two, is that it can keep your alternator from being suddenly introduced into an inordinate load of combined boat operations, a large audio system draw plus a large and depleted battery bank.
Nothing that you can't manage with a manual dual battery switch if you are so inclined.
The behaviors of an ACR/VSR can also vary and are circumstantial. And ACR/VSR can also increase your dependency on AC shore charging.

David
Earmark Marine

MLA
10-02-2012, 12:05 PM
I would not approach this as a "I have one, I dont need the other" as they perform entirely different functions at entirely different points of the boat outing. An ACR does nothing for you when off the water and back at the dock and a shore charger does nothing for your house bank while on the water.

As Ive mentioned on a few other forums and maybe here, alternators make for a poor battery charger, therefore, the need for shore charging grows as the stereo loads and battery bank grows. With a larger, high-draw system relying on the alternator to recharge the depleted house bank will leave you with undercharged batteries with a short life. So, a shore charger can be a benefit on almost any boat with dual batteries and some house loads, and a must on those with a sizable stereo and house bank.

A simple description of an ACR is that its just an automatic battery switch. It takes away some of the manual work involved in isolating your house loads from the main starting battery and combining your house bank to the alternator once the engine is running.

Does every boat need an ACR...no. Does every boat need shore charging....no. Does every boat need both...again, no. But take the whole stereo, battery bank and intended use into account and decide if either is needed based on their own merits, rather then a one or the other.

EarmarkMarine
10-02-2012, 12:20 PM
^^^Very good post Mike.
There is such a wide discrepancy from system to system and usage habits to usage habits. When it comes to charging systems and all the considerations that must be included, one size and one prescription can't possibly fit all systems/boaters.

David
Earmark Marine

jmvotto
10-02-2012, 01:02 PM
Thanks for the info David and Mike.

my decion is clear as mud.....LOL

EarmarkMarine
10-02-2012, 01:30 PM
Joe,
The decision is one of pure convenience with zero down side when/if you have a moderate to large audio system. Now, if you have a multi-killa-watt system, low efficiency, with 500 amp/hours of battery reserves and you play the system at rest for extended periods then there is much more you need to analyze. At this point, I wouldn't look past the convenience aspect.

David
Earmark Marine

jmvotto
10-02-2012, 01:44 PM
Joe,
The decision is one of pure convenience with zero down side when/if you have a moderate to large audio system. Now, if you have a multi-killa-watt system, low efficiency, with 500 amp/hours of battery reserves and you play the system at rest for extended periods then there is much more you need to analyze. At this point, I wouldn't look past the convenience aspect.


David
Earmark Marine
three amps and two batteries consiidered a mutli killa watt system???

EarmarkMarine
10-02-2012, 07:14 PM
Joe,
I look at the total draw of the audio system, boat operations and the depleted battery and compare that to the alternator output. If the alternator output is adequate in comparison then the ACR/VSR will close normally as it should so that the stereo battery gets a charge when underway. If the draw is too great and the ACR/VSR oftentimes will not close then this translates to deeper battery discharges and shorter battery lifespan. In that case it gets more complicated. I don't think you are approaching that threshold of concern from your rough system description.

David

sandm
10-02-2012, 08:28 PM
I kind of figure that the last thing in the world you want to be left with on the water is a dead battery after several hours in the cove. current boat has a acr/vsr and am adding a 3rd battery to the stereo bank and a promariner charger. even though I'm running class H amps, figure better safe than sorry and will be nice to know you're hitting the water each time at peak charge..