4-way battery switches

JV II

Active Member
Nov 17, 2007
2,655
RI
Boat Info
Flybridge
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Volvo V-Drive
Are the new Sea Ray battery switches the Alternator Field Disconnect variety (AFD)? The owner's manual doesn't warn me from switching between 1-Both-2 while the engine is running. This link says it is okay and that all battery switches in the last 30 years are AFD.
http://www.boatus.com/news/askchuck_1107.htm
If I start the engine in the "both" position with a charged cranking battery and a discharged house deep cycle, will the charge energy be mostly directed to the house battery? Will the cranking battery discharge into the house battery as it attempts to even out with it?
 
If I start the engine in the "both" position with a charged cranking battery and a discharged house deep cycle, will the charge energy be mostly directed to the house battery? Will the cranking battery discharge into the house battery as it attempts to even out with it?

I don't know of any battery switches with alternator protection other that a specific Hella. Switching between 1-all-2 shouldn't be a problem. The diodes fry when you go to off.
Using the all when you have a flat battery is a bad idea. Start on the fullest battery then switch to all. This will keep the batteries from equalizing and not allowing you to start at all.
 
With a little more research, I've found the answers. With the switches on "Both," the discharged house battery will have more internal resistance and therefore receive more charge. Batteries wired in parallel will be self-regulating on the charge. Something to do with Ohms Law. The more discharged battery will receive the most charge energy.

With the engines running, the house and cranking battery connected via the battery switch on "Both," 60A going into the two from the alternator, the cranking battery would not contribute any electrons to the house battery. If the engine were off, the cranking battery would discharge into the house battery and the two would even out, netting a weaker cranking battery and a stronger house battery. The two combined could potentially not turn over the engine.

So, it would be safest to put the switch on "both" turn over the engine and leave it there underway. That would eliminate the risk of frying the alternator diodes. It wouldn't be unsafe, to start the engine in "1," switch to "Both" or "2" under way. While stopped, I'd have to remember to switch it "Off" or to "2" to use the house battery and preserve the cranking battery for starting.

The risk of switching underway is turning the knob the wrong way and going to "Off." It seems like good insurance to get a Zap-Stop for $30 from West Marine to protect the alternator in the event that "someone" inadvertently switches the battery switch to "Off" while the engines are running. That would save at least $200 worth of alternator replacement, and maybe even from becomming stranded with a dead battery. Is anyone using the Zap-Stop?
 
Julia, the switches are clearly marked, visualize the switch when making changes.
You are better to start on your most full battery THEN switch to all for charging. The risk of not being able to start is greater than the risk of an accident with the battery switch.
 
I thought for a second, what if someone else besides me takes the boat out, then I realized that there is a better chance of gas prices dropping below $1 a gallon. Then I thought, what if I had a glass of wine and flipped it the wrong way. Then I realized that I wouldn't likely be boating impaired. Then I thought, what if my 3 y/o distracts me while flipping the switch. There is a slim change of that happening. Then I thought, what if I had the Coppertone models, Sweedish Bikini Team, or Hooters Girls are out for a ride and I got distracted...

I need to change my signature so everyone realizes the boat is the Julia Valentine.
 
Mike;

Can you confirm what EXACTLY your battery arrangement is?

Do you have

(a) DEDICATED cranking batteries (one for each engine) with a seperate house battery? Or

(b) is your "house battery" and "Starboard cranking battery" electrically one (i.e. a pair of batteries rigged in parrallel).

If you have (b), I suspect you want both batteries to be the same. If you want more juice, then I would rig three identical batteries in parrallel.

If you have (a), can you explain what the "1", "2" "Both" switch really does? My boat is rigged like (b) . . . and I see little point in the "1", "2", "both" switch.
 
The boat comes stock with 2 cranking batteries and one house battery. They are all 12V. The house is a deep cycle 12V. The starboard cranking battery and house are on the 4-way switch, the port cranking battery is on its own switch.

I'm changing the configuration a little. The only thing I'm doing is swapping out the house 12V for 2 golf cart 6V in series (house bank). With the switch on "Both," the 12V starboard cranking battery will connect in parallel with the house bank. They will be electrically one in that switch position.

I just think I'll need a little extra reserve than the single stock 12V deep cycle house battery. With two 6V golf cart batteries in series on the house, I can switch to "2," while on the hook, preserving the cranking battery (1), and run the lights, radio, TV, fridge all night with no worries about starting the boat the next morning. I definitely don't want to touch the cranking batteries for anything other than cranking the engines. If you repeatedly cycle a cranking battery it will fail before the first season is over.

This configuration will minimize any battery issues for years to come. BTW, I have no genset, so I will rely heavily on the house battery bank. I have a 400W inverter for the TV/DVD. I guess I should have stated that.
 
OK. . . that's clear now. The four position switch is linked to the starboard battery bank. . and that bank has two batteries (until you modify it)

I can't picture at this moment what the battery switch for the port battery looks like; but I do think you want to duplicate that for your starboard cranking battery. That would keep things REALLY simple, and then you don't have to worry about throwing battery switches every time you start the engines.

I have heard the advice to put all the batteries to "off" when away from the boat (I have seen the dealer's techs do that as well); but honestly I don't ever do it. Also, when the boat is at home, the shore power cable is hooked up at all times.

BTW: To what batteries are the bilge pumps and stereo memory hooked to? It is my understanding that these circuits are alive even if all the batteries switches are in the "off" position. You probably want to understand where the juice for those items comes from.
 
If you go to the Searay website you can download the owners manual and the schematics are in there (the 2007 is not up yet but 2006 is)

According to the schematics your starboard battery only starts the starboard motor and the generator. The only other connection seems to be the charger which bypasses the switch. It has a simple on/off battery switch.

There are two port batteries one connected to each 1 and 2, of the 1-both-2-off battery switch. The switch chooses which battery to use to start the port engine and that same battery runs all the house circuits. If you choose "1" then that battery is working and battery "2" is not really being used and vice versa. If you choose both, then they are tied together in parallel. You cannot have one port battery used for starting and the other used for house. Well you could if you manually switched after you started the engine or whenever the port motor was stopped. This is marginally better system than my boat, which has the two port batteries tied in parallel and a simple on-off switch.

Bilge pumps and other "always on" stuff bypass the switch and connect directly to port battery number one. Both port batteries also bypass the switch to the charger.
 
I knew someone would verify that on the diagram. I said the starboard cranking battery and house were on the 4-way, when it is the port as you found.

The Starboard battery is isolated and on the other battery switch that has two positions, on and off. Thanks. As you see from my picture the boat hasn't even hit the water. I'm going to spend the winter studying the manuals like a dissertation, crawling around in it in the showroom, harasing the service manager about all the little things I find needing fixing, stocking up on fender socks, rod holders, and visiting this site.

I've learned so much from reading here. I'm definitely going to sponsor this site.
 
Yeah. . .easy to make mistakes with this stuff. I have a '97. In general, I find the manuals have about 40% of the necessary information to do anything.

If this were my boat, I would either (a) isolate the cranking battery and house battery completely, and put them behind seperate switiches or (b) ensure both batteries were identical. If you don't do this, then you do as you suggest -> and be careful to constantly move the battery switches between starting, running, and anchoring.

Having non identical batteries wired in parrallel sounds like a pain in the butt to me. My batteries are identical. I never move the battery switches. Granted: I don't anchor much -> but I will leave the fridge and a few lights on for several hours without shore power connected with nary a nervous thought.
 
Why not use a battery combiner? It will allow an alternator to charge 2-3 banks of batteries and keep the batteries separate for use.

Xantrex, Charles, etc.
 
The port/starboard stuff isn't important, you would have figured that out as soon as you got on the boat. My point was that you don't have an automatically have a port starting battery and a house battery. You have to manually switch them.

Let's say you beef up the number 2 port battery and use it as your house bank. You will have to remember to switch to "1" for starting. "2" for hanging on the hook and "both" while running, to have the alternator charge both your starting battery and your house bank. You may want to look at a combiner or isolator to automate some of this for you. There are subtle advantages to each so you may want to do some research. Your boat's port side is wired exactly like a single engine boat with two batteries, so there is plenty of information on how combiners and isolators work in that arrangement.

BTW there are no AFD or Zap Stops shown on the schematics, so don't switch either switch to "off" while running.
 
Given this set-up, here is what I would do:

The following is predicated on there being an emergency start switch that will allow you to momentarily combine batteries for engine starting.
Always keep the starboard, 2 position switch in the on position. Always keep the Port switch to both. Get in the habit of starting your starboard engine first. There should always be a good charge on the starboard battery since all it does is start the starboard engine. Start your port engine only after the starboard is running. If there is not enough juice left in the port bank to start the engine, you can always use the combining switch to start it.

As fare as replacing batteries, I would live with the current setup for the first season. See how it goes. You may find that it works fine as designed. Later, if you decide you need more reserve on the house side, you would be best to replace both port batteries at the same time.
 
I don't know about combiners or how they are wired, but it sounds like a good idea. That's my next research project.
 

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