I just spent some time reading an online manual for the potential new boat and was particularly interested in familarizing myself with systems that I haven't had experience with before. Namely, the electrical system - shorepower, genny, DC etc and was not surprisingly quite confused by the interplay and complexity of the systems.

Anybody feel like giving me some pointers on the basic knowledge base so when I go back to read the manual more I'll "get it"?

Bear in mind, the basics won't be "below" me. Thanks. I pretty much know what DC is, what AC is. I don't know how the breakers are utilized, how you set it up for shorepower versus DC versus Genny and the steps you go through to use each.

Cincy,

Basically there are two side-by-side electrical systems on that boat. One is a 12vdc system, the other a 110vac system.

Some of the applicances are made to run on both and will switch automatically betwwen the two systems. Take the refer, for example. When the boat is on shore power (or the genset running)the refer will automatically select the 110vac. When you are not on shore power (and no genset) the refer defaults to 12vdc. The water heater works the same way.

The stove and microwave only run on 110vac.

There are also dual lighting systems though they don't automatically switch. You'll find some 12vdc lights and other 110vac lights in the cabin and cockpit.

Now here's where it gets fun. When you are plugged into shore power, there is a dual switch system on the 110vac power panel. It is used to select between shore power and genset power, and you have to turn one off before you can turn the other on. There's a slide switch that moves back and forth from one of those two switches to the other that prevents having both of them turned on at the same time. It's much simpler than you would think.

When you unplug from the shore power and hit the water you are without 110vac. At that point the boat is running the water heater and refer on 12vdc.

If you want to run the microwave or stove (or make coffee, etc.), you start the genset. Once it is running, you flip the "Shore Power" switch off, slide the slider thingy to the shore power switch side. That can only be done when the shore power switch is turned off. Once that slider is over the shore power switch you can turn on the genset switch and that puts the genset 110vac power into the system.

When you are done making coffee, you shut off the genset and turn that switch off. Now the boat only has 12vdc power. Before you get back to the dock you flip the slider thingy over to cover the genset switch then turn on the shower power switch.

It's really pretty simple. Trust me.

Come on GFC..add in the 3rd complexity...an inverter.

Was just gonna say...

Doesn't have to be all that complex. This is the power switch on our houseboat, it's a no-brainer, just put it where you need it...





The only other power panel in the whole boat:




There ARE other switches here and there, the flybridge has running light and spotlight switches, etc, but there's no huge, nuclear power-plant type switch panels anywhere...

On many boats, as GFC indicated, some items are AC, some are DC, and some are both.

For instance, the fridge is typically dual powered, however, the fridge is usually capable of more cooling BTU on AC rather than on DC. For this reason it is sometimes recommended to initially cool the fridge running on AC, but then only run on DC (when you are away from shorepower) to maintain the cold temperature.

I also found that on my boat, to run on DC, it has the same sized compressor as my last boat, but the fridge is about double the size. Consequently, the fridge doesn't cool down as fast, even on AC.

On our old boat, we used to leave the fridge off until we needed it on the weekend, as it cooled down pretty quickly, but on this boat, I need to leave it running all week to maintain cool. Some of these idiosyncrasies are gonna be different between boats for sure.

On the DC side, on my last two boats, all of the lighting is DC powered only, along with the fresh water pump, shower sump, CO detectors, ventilation fans, and head, regardless of whether the boat is on shorepower or not. For this reason there is always a load on the batteries, and it is essential to keep the battery charger running while on shorepower as it assumes the duty of a DC power supply.

Also for fridges, many of them auto switch, so that as soon as you remove AC, they switch to DC. This can cause your batteries to drain pretty quickly if you don't remember to turn off the fridge DC supply if the boat is left off shorepower or the engine is not running.

On the last boat, the AC breaker for the fridge AC was connected to the battery charger, if I recall. Never knew why this was so, other than maybe they were breaker-stingy, or what the reason was.

It almost seems counter-intuitive as if you flipped off the battery charger breaker, the AC side of the fridge would be off, forcing the fridge to go on DC (unless it was turned off at the fridge itself). This almost guaranteed draining the batteries.

There are a lot of different configurations here, so you have to be sure how your boat works.

On the AC side, there is always a danger of connecting to a shorepower connector that is reverse wired, i.e. hot and neutral are reversed. For this reason, there is usually a "Normal" and "Reversed" light on the AC panel to tell you this.

Also, the main 30Amp breakers on the boat normally interrupt both hot and neutral, not just hot like a home, as this also protects against reverse wiring.

Finally, the ground wire is never connected to neutral on the boat. Again, this is dissimilar to house wiring. The reason for this is again the chance of the shorepower pedestal being wired incorrectly.

However, the netural and ground wires are normally wired together at the pedestal, so as soon as you connect to the pedestal, the netural and ground wiring is connected together in the boat via the pedestal connection, which then is like house wiring.

When you go a genset or inverter, hot and neutral are typically disconnected from the shorepower pedestal, but the ground normally stays connected. Some boats also have a transformer to help isolate the genset, but again, depends on the boat.

One other interesting item is the hot water heater. Due to its huge current demand, it is never connected to DC (at least I have never seen one that way), but to give you hot water away from the dock, the typical marine hot water has a line that connects to the engine cooling system so that the engine itself will heat the water through the hot water tank.

Air Conditioning systems are normally always AC powered, but some small systems might have the capability to run off an inverter. So unless you have an inverter or genset, you won't have AC while underway.

AC should not be required while underway anyway (unless you have a cruise ship like FR).

So most of the wiring is pretty straightforward, but there are some little idiosyncrasies like the ability to discharge your batteries via the DC powered fridge that you have to be mindful of.



Sorry this is not the best photo of my electrical panel, and I'll try to find a better one. But the top half of the panel is AC power, and the bottom half is DC. The two systems are isolated from one another on the backside.

Also under the step is the Battery 1-both-2 switch, and about 10 additional breakers for the bilge pumps, head pump, windlass, voltmeters at the helm, and other goodies.

the other thing to be careful of is keeping the starting battery charged because these comfort devices and mean trouble if you've been on the hook for several hours and try to startup the engines. in many cases, there are separate starting batteries (one for each engine) and then a set of "house" batteries that are used to run everything else when away from shore power. if you've got an inverter, it changes the dc in your house batteries to ac for stuff that can't run off ac. if you've also got a genny, it is run to charge the house bank of batteries, but the usual cautions about carbon monoxide need to be considered. i don;t have a genny on my boat. instead i have four 6volt golf cart batteries (trojan t150's), wired together to give me plenty of amp hours when away from shore power.

Thanks for the crash course guys. I too was wondering as our next boat down the line will have all this fun switches to play with.

So Cincy, what boat are you looking at now. Last I posted my ideas you had the same taste as me so I'm curious.

Yes! Thanks for the crash course. This is "sticky" material. I'm sure I'll have many questions as things move along. Buying privately I can't expect the prior owner to spend an entire day with me doing an orientation. But I'm sure he'll give me what I need to know to get going.

I'm zeroed in on the 2007 Sea Ray Sundancer 290's.

Likes:

Perfect cockpit lay out for us as we tend to have lots of people mingling on board. So, its open with lots of floor space. No, "shimmying" past people".

Ample seating with the number of people we will likely cruise with.

LOVE the styling.

Plenty of room for 2 to overnight on.

Really feel that its solid and well built.

Having twins

But still a manageable tow option at 9250 dry with a friends F350 when we secure a trailer.

Windlass since we anchor every time out. Sometimes multiple times

Genset - what's not to like

The '07's have some nice improvements over the '06's. No change to '08. Can't believe the discontinued the model in favor of the 280.

Dislikes?

None really. Headroom in aft cabin is a little shallow for a 31 foot boat but that's why the lines don't make it look like a tadpole.

Only 5.0's as max power. Would like have seen some 6.2's.

Decided to skip the sport cuddy and pocket cruiser altogether but don't want the expense or the size of a 310 or bigger. No other boat in this size blows my hair back like this one.

You may be surprised how well twin 5.0 perform especially mated to Bravo 3 drives. Each of those MPI's produces 260 hp. Plenty of juice in my opinion.

My slip neighbor has a Maxum 2900 that is powered by twin 4.3L B2. Similar in weight and beam. Has no problem pushing the boat on plane and cruising very comfortableat 25-30.

Done.

A friend's Monterey of similar size/weight has twin Volvo 5.0s and does fine. Cruises at 30 easily and tops out near 50. The local Marine Max outlets here usually equip 280s with twin 4.3s and alpha drives. Wouldn't be my choice in powertrain, but they must be "ok" at least.

Cincy, if you have access to an F350 with a diesel, don't let the 9250 dry weight limit you. Mine comes in at about 17,500 on the trailer and the Powerstroke F350 tows it just fine. I've made 4 long distance (over 200 miles & up to 300 miles each way) tows with that truck. I set the cruise at 60 and it just keeps on truckin'.

Just remember when the Powerstoke can't pull it out of Norris, The Duramax will:)

You lucky man.

http://www.searay.com/2007_sea_ray_sport_cruisers_290_sundancer.asp

Semper Fi 75

I can only add, that too much advice, can be complex.