Battery/Switch/Engine Setup

[0Gravity]

Yea my theory above did NOT pan out. ....I still can't figure out how I'm supposed to work this. ...lol

[HavaMax]

For what it's worth.....I am close with an owner of a 1997 3200 scr.....he purchased brand new and ordered the boat to his liking....even Maxum at the time of delivery could not explain how to have the 2 perko switches set. I have ran my boat with the switches set to both for over 5 years now. I manage my usage when away from dock power. I just don't see the benefit of me spending close to 20 hours tracing, rewireing, and setting this up correctly. I wish it was wired correct, but hopefully on the next boat it will be "turnkey".......

[RandR]

I did pull my switch panel to take a look. I found that the co2 detectors bilge pumps and vacuflush head are wired directly to the hot side of the port battery so they always are drawing power no matter what the switch position is. The house loads and engines are connected to the starboard battery by the switch, but the stereo is connected directly to the starboard battery. I assume this is so that the stereo will not loose its memory of preset stations if the battey is turned off. So in theory if both batteres are switched to 1 each will start a separate engine and the likely hood of both running dead is minimal as the port loads should be minimal when at anchor

[RandR]

Clarification- each engine is connected the respective battery separately. I know it sounded like both batteries were connected to the starboard battery in my previous post

[Kevlar7r]

After tearing down and tracing my wiring, I found the same set up. I keep my switches on 1. This has worked out, as I ran my port/house battery down, was able to start mt starboard, switch batteries to both, start my port, and switch back to 1 on both switches.

[rip131313]

Now that I have some time I have confirmed that the following is my setup. When I say Bow and Stern I am referring to the physical position of the 2 batteries since they sit fore and aft on my port side.

[0Gravity]

Whatever is on that picture is microscopic and unreadable.

[capn_billl]

I've owned several boats, and every one was wired a different way than I like it.

I prefer a dedicated house battery, that way if my kids, (or wife) leave a light on, I don't come back to a completely dead boat.

I also don't like deep cycling my starter batteries as it shortens life, (even on marine dual purpose batteries).

Optimum is to buy an isolator to charge the house battery off of both alternators, and an isolated charger with 2 * 5 amp, and 1 * 20 amp circuit.

A crossover/parallel switch for the two starting batteries, (each connected directly to an engine starter, and alternator), and a master cutoff for the house.

I would rather need to use a flashlight, and still be able to start both engines, than have lights & radio, but dead engines.


I also don't like not being able to start an engine because of a bad, (switch, isolator, diode, battery, wire, alternator, etc...).

If you parallel the alternators with a diode pack, and one fails, you aren't going to know it, until they BOTH fail.

With dedicated batteries for each engine, you know immediately which one isn't charging, and can still start it on the crossover.

[bobconnors]

I have a 1998 2400 scr. 2 batteries and a 4 position switch. Anybody have a diagram or explaination on which is which ? Or do I go exploring this weekend ?

[mmwjr]

The switch has 4 positions

Off, both batteries disconnected
Bat 1, battery one powering the boat
Bat 2, battery two powering the boat
Both, both powering the boat. This should only be used if both a to low to start the boat.

[bobconnors]

So Mike, does the charger (on dock power) only charge the battery that the switch says is on? Or will it charge both batteries regardless of swich position ? I dont want to rewire it but will if stock makes no sense. Thanks, man

[mmwjr]

The stock charger was a dual bank and was directly wire to each battery so the switch can be off and the charger will charge them when on shore power and the charger is switched on in the cabin electrical panel.

[bobconnors]

Good info brother. One last question if you dont mind. The fridge,If the breaker on the panel is on, while on dock power will run or 120 volts. If I unplug, it switches to 12 volts automatically it seems. Im thinking one of my batteries is for starting and one for the boat. Or if my switch is on both it will draw from both right ?

[mmwjr]

Yes the frig is dual volt and runs on shore power when plugged in. In 12 V mode it runs on whatever battery is selected on the switch. I alternate between the two batteries every other outing so they both stay charged. Only running on one saves the other in case you run a battery down if you sit on the hook to long.

[shrew]

Originally Posted by bobconnors

Good info brother. One last question if you dont mind. The fridge,If the breaker on the panel is on, while on dock power will run or 120 volts. If I unplug, it switches to 12 volts automatically it seems. Im thinking one of my batteries is for starting and one for the boat. Or if my switch is on both it will draw from both right ?

Yes, only start and run on one battery, and only sit on the other battery. A battery charger will directly charge each battery it is connected too regardlass of the position of the battery isolation switch. The switch will dictate which battery is getting charged while running.

Yes, the fridge is dual voltage and automatic. If the fridge is on and the fridge shore power breaker is off, then the fridge is pulling from whichever battery is selected on the battery switch.

You DO NOT want to sit on BOTH at any time, except if both batteries are dying and you need everything you can get to start the engine. If you never sit on the starting battery, this should not be an issue.

I've lost my house power and treated it like a power outage, rather than switch the house to the starting battery for convenience.