Different dual battery and stereo approach

[MachSchnell]

I've gone through as many opinions as I can find, but have yet to see my idea described by anyone who wants to maintain starting power after sitting with the stereo on for a while. Many seem to stop at their favorite spot and switch to their accessory battery only (deep cell, small cell or otherwise), then switch back to their starter and accessory to charge both simultaneously. That means switching frequently during a busy day where you might change spots a few times. My Perko is near to the batteries in my engine compartment and requires lifting the engine hatch to make a selection.

With dual starting batteries and a standard Perko 8501 selector, isn't it sensible to just alternate the battery you use on any given day. For example, if the day of the month is odd, run battery #1 - and if the day of the month is even, then run battery #2? Depending on the stereo draw, I suppose it is possible to run down both batteries. I'd switch to "All" on the way home to be certain that they are both getting charged.

This means that the only time I have to change the switch is when I lift the hatch at startup - something we should all do every time anyway.

Does anyone have any opinion about this approach? Thanks for the advice!

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(My specifics: 22' runabout, 350 cu.in. V8 Volvo I/O DuoProp, Sony marine receiver with max output 52w x4 channels off a 10a fuse and 4 6.5" speakers, dual marine starter 500cca batteries. I run on Lake George, NY and generally travel from .5-1.5 hours at a time at around 3000rpm)

 

[seabob4]

Re: Different dual battery and stereo approach

Some people actually do that. Although, I have no problem switching between batts while out on the water. Helps to keep my mental awareness more "in tune"...

 

[DianneB]

Re: Different dual battery and stereo approach

I use an ACR (automatic charge relay) - that ensures the house battery gets charged any time the engine is running. I haven't even bothered with a battery switch but carry a jumper cable in case I ever need to start the boat from the house battery.

 

[seabob4]

Re: Different dual battery and stereo approach

DianneB,
I'm a strong believer in ACRs or VSRs, but they tend to confuse a lot of people...

 

[MachSchnell]

Re: Different dual battery and stereo approach

Will an ACR charge only the diminished battery or will it just charge both simultaneously? I'd like to be sure that an older battery does not drag down a newer one.

 

[Silvertip]

Re: Different dual battery and stereo approach

An ACR does two things. 1) it isolates the two batteries so they cannot discharge each other. 2) It does not charge both "simultaneously". It defaults to the start battery so it gets the full charge initially. When it is topped off the ACR directs the charge to the house battery. I feel ACRs are far less confusing to people than a Perko switch since they don't have to do anything. However it does not solve the failed start battery issue unless there is a "COMBINE" feature. Otherwise, a simple set of jumper cables takes care of that issue. For some reason folks just can't seem to grasp how the switch can be used to their advantage. If they thought about like this they might get a better understanding. When set to OFF, everthing on the boat is OFF since all power is disconnected. The only thing that might be working would be an automatic bilge pump. When set to BAT 1 (typically the starting battery) the system behaves as though the starting battery is the only one on the boat. It powers everything and is the only one being charged. It works the same way when you set the switch to BAT 2. Set it to BOTH and both batteries are powering things and also being charged. This system is so versatile that apparently confuses people -- and there is virtually nothing to break..

 

[seabob4]

Re: Different dual battery and stereo approach

ST,
Isn't 12VDC pretty much based entirely on logic? I mean, compared to 120VAC, it's a piece of cake...or am I missing something?

Don't get me wrong, I'm perfectly comfortable with 120. But the concept with 12V is far easier to grasp for most...

 

[RickJ6956]

Re: Different dual battery and stereo approach

They're exactly the same thing in my book. Except one has ten times the voltage.

There seems to be a lot of confusion about grounding, though, when a vessel has both 12vdc and 120vac systems.

 

[Silvertip]

Re: Different dual battery and stereo approach

I'm not disagreeing with anyone. I'm just stating my observations regarding the many questions about dual battery setups. I agree that an ACR is a neat device and for most people it requires no interaction by the operator. The switch seems to puzzle folks as to when to use what setting when in fact 90% of the time it doesn't matter where you set the thing. If you happen to camp out for hours at a time with a stereo or other high current running, you better know what each position does for you. But then I simply go back to what I said. If BAT 2 is your house battery, set the switch there. If you want BAT 1 to charge -- set it there. BAT 2 -- same thing. Both -- set it there. Each setting is quite simply "the currently selected power source".

As for 12 volt DC vs 120 AC there is a big difference. One can kill you while the other will only burn you. 120 is also a sine wave whereas 12 volts is not. But I think we all agree that both have current passing around a complete circuit generally consisting of a source, a fuse/breaker, a switch a device, and back to ground.

 

[sasto]

Re: Different dual battery and stereo approach

To combine (parallel) the batteries I mounted a solenoid near the batteries, wired 2 battery banks to it. Activated the solenoid with a momentary switch on the dash.