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Generator Switch

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pugwash

Contributing Member
"I know there are other forums

"I know there are other forums to ask this question, but I've come to trust the expertise in all boat matters on this one.
I have a generator (Onan 6.3kw)to install in my Silverton 34 Express (94).
All the rough wiring is already installed by the manufacturer, ie 50amp and control wiring and it's all in good condition as is the rest of the boat.
I have to install a switch to control shore power/gen power, but I don't seem to be able to find one that will switch 2 channels from the shore power (A/C + General power) and single channel gen power. It's all 115V and 12V.
I've seen them switched with sliding covers on breakers and a hard rotary switch, but I'm limited for room on my control panel.
Has anyone or any company used relays to switch the power? I can figure out the wiring diagram and install it myself, the problem is finding relays and switches that are heavy duty, double pole double throw 12v coil all in a marine package.
Any suggestions will be greatly appreciated."
 
"Have missed it several times

"Have missed it several times but in discussing things with some other club members, the deals have been FANTASTIC!

I have an older rotary switch that I had on the ONAN genny but having replaced it with the AC panel lockout, I still don't know it it would work for you as my old AC power was 30A."
 
"When do these "Yard Sales

"When do these "Yard Sales" take place and where.

Rick, thanks for the link, they look very high-end, as I assume are the prices.

I was thinking of installing 3 50-amp solid state relays, 1 for Genny and 1 for each of the two shore powers. Has anyone tried it and able to amaze me with their wisdom.

Al, does the switch you have control 2 sets of lines?"
 
"No reason you can't use r

"No reason you can't use relays, as long as they are properly protected (wiring safety). I'd suggest making a circuit drawing and making sure what you are planning is realizable. If ok there, then make sure you haven't missed something (last SSR I messed with needed a "healthy" heatsink for longevity). If you are good there, plan the physical layout and have at it.

If you do go with SSR's, make sure you have a set of 'spares' around, especially if you cruise....that custom stuff always breaks while away from the spare set you left in the truck."
 
"The SSR route is because I ha

"The SSR route is because I have lots of space behind the breaker panel, but very little on the panel itself. I do have room for a few small switches on the front (Start, stop and select). Lots of room behind means that I have space for a very large heat sink and keep it all nice, neat and safe.

My experience with SSR's is such that I have a lot of respect for them, the ones used in our printers are switching 30 amp hundreds if not thousands of time a day and rarely fail. They are not expensive (about $50) so a spare or 2 is not a problem, plus, they don't spark when energized/de-energized."
 
"Chris,

it controls the rou

"Chris,

it controls the routing of the generator output into the AC panel. I have not looked at in a a year or so and am not too sure of the EXACT set up. Next time I get to the boat, I'll check....I know to replace it a new one is around $350? If that tells you anything...it is a rotary switch"
 
"Chris:

If Al's switch

"Chris:

If Al's switch won't work, the SSR's sound viable. Their reliability can have only increased and it sounds like your experiences justify the claims.

The only added caution is to consider the mounting material for the heat sink and the case mmaterial carefully. As I'm sure you are aware, most power electronics check out early due to two causes - infant mortality and overheating. The last one can be exaggerated in the marine environment due to corrosion. A little planning now can ensure the 'switch' lasts a couple decades."
 
"Your last point is very valid

"Your last point is very valid, the heat sink material is aluminum and I plan on installing it in an open area behind the breaker panel, question is whether to install with a fan underneath or leave it with convection cooling. How does aluminum hold out in a freshwater environment?

The switch route may not be as viable unless I install it behind the panel also. The wiring is very dense behind the panel and of course it bunches up right where the switch would be installed making it rather awkward to say the least. I have a couple of months to work with it, I''ll let you know how it works out.

Now, about this Silverton yard sale...."
 
"Hey Chris,

I do recal the

"Hey Chris,

I do recal the switch has a depth requirement of about 3" It has a face place mount of about 3 x 4" and a rotary knob in the center. On our 34C it was mounted in the wall next to the sliding door. I should be there this weekend IF we do not get any more snow and I can send you a picture of it. Its yours for the postage if you can use it"
 
"Thanks Al, I'll watch for

"Thanks Al, I'll watch for it. We just got snow too. Not as much as UK, but then here in Canada, we don't get much snow!
snow.gif


Check this out:

http://www.thestar.co.uk/headlines/Police-plea-over-snowball-calls.6091331.jp"
 
Chris:

I have limited exper

Chris:

I have limited experience w/ AL in freshwater. It is kinder than the brine but the metal still needs to be protected. I'd research an anodized (hard) coating to protect it and then ensure the thermal grease used has enough viscosity to widthstand any heat load due to operating at full load in the summer.

Good luck.
 
"Chris, Im surprised you don&

"Chris, Im surprised you don't get much snow.... My in-laws live in VT 3-4 miles from the Canada border about 40 minutes south of Montreal. They get so much snow a few years back it measured over 540" during the season, more than Colorado"
 
"Last few years in Toronto sno

"Last few years in Toronto snow has been somewhat sparse. Global warming I guess.
When we got here in 1974, snowfalls were more in line with what you'd expect for Southern Ontario. I'm not sure of the numbers, but this is one of the mildest and least snowy winters on record."
 
"Mark, Are you ready for this

"Mark, Are you ready for this next round? I heard today 12 to 20" for NJ....I am sure you're in that same band of weather.."
 
"Al:

we are supposed to be

"Al:

we are supposed to be on the edge, literally. The local forecast this morning said rain tonite, then snow after midnight but less than 2". The local WX guy on the radio said if the wind shift and it comes a "bit further south", we could see up to 8".

Since this morning was the first time in a while I saw NO ICE on top of the stones, we'll probably get at least 12"....."
 
"I hope you guys realize that

"I hope you guys realize that up here in Toronto, we are getting a bit fed up of all the snow you are sending us. If it weren't for you we would have our normal frigid cold weather and we'd all be happy!!
rain.gif
happy.gif
"
 
"I've been thinking about

"I've been thinking about this a little more and figure the best way to go about it (and the simplest) is to use the Gennie to power the Air conditioning and Battery charger.
The reason is, I installed an inverter into the 15amp outlet circuit last year and that is good for boiling kettle etc. The only thing I won't have is hot water heater, but that is not a major deal, if I need a shower, I can take a dip.
This way I only need a single line switch, probably what Al has, so Al, if you can measure the depth behind the switch, I can check the clearance when the boat comes from under wrap, which, by the amount of snow you just sent us (10"), will probably be July."
 
Chris:

You won't run an

Chris:

You won't run an A/C unit on the inverter for long.....unless you have a battery bank about 2X what EJ's is (and he has the biggest bank I've ever seen on a boat).
 
"The A/C will be run through t

"The A/C will be run through the selector switch from the Genny, as will the battery charger, this will keep the house and engine batteries charged up. The inverter will only power the 15 amp outlets so I can boil the kettle. Gotta have a cup of tea in the afternoon."
 
"I second that. In fact, when

"I second that. In fact, when the electrical engineer who re-designed my ac/dc systems with the inverter, we specifically reouted the AC unit and hot water heater away from the inverter 110 outputs. My bank of 3 group 31 gel batteries for house use only gets about 20 hours of use IF we ration it properly. When the loads go up the available use really goes down. If I am not mistaken you cannot use the generator to run the inverter to charge the batteries ...or something like that

I was going to head to the boat today..but the snow yesterday easily stopped that.. I'll measure that switch as soon as I get there"
 
"The inverter isn't used t

"The inverter isn't used to charge the batteries, it has a seperate charger, so I can't see it being a problem.
Incidentally, a problem occured when I first installed the inverter, the electric blanket controller burned out. The manufacturer replaced the blanket and controller, but I won't try it again, the blanket was fine right up to running it from the inverter. It is a solid state controller (the blanket), so you might want to watch that if you use one."
 
"Chris, If all of this is for

"Chris, If all of this is for a cup of tea then buy yourself a 12V teapot and save a lot of money and effort."
 
"Tried it, it takes 1/2 hour t

"Tried it, it takes 1/2 hour to boil. When an englishman NEEDS a cup of tea, he can't be sitting around waiting half an hour!"
 
"Coming in late on this one, b

"Coming in late on this one, but it got my curiosity.
First, is this a snow thread, or a thread about a rotary switch?
happy.gif


Chris..... I have a couple of questions if not too late and if you don't mind responding:

Is your S/P divided? IOW's, two 30 amp sources of S/P!

And is your main panel also divided as to accommodate the two S/P sources?

Is your concern that you wish for your generator to power ALL A/C (I.E., both sides)?

If so, then you do have an issue regarding the split panel.... Yes/No?

It would seem to me that your simplest solution is that you pick and chose which side of the A/C panel you wish to power with the generator and keep it simple.
You could then use a standard three position rotary switch..... I.E., Gen/Off/Shore-Power and ask the rotary switch to power ONLY that side that you deem necessary!

However, from the size of your generator, powering ALL A/C would appear to be doable with some complex connecting..... hence the relays!
Is it worth it?


What about changing your panel to accept a single 50 amp S/P source and no longer having it divided?

Forgive me if I have misunderstood what you are attempting to accomplish!
If so, we'll go back to snow balls!

."
 
"Ah yes, the snowball tangent,

"Ah yes, the snowball tangent, that's what happens when old farts get talking, they digress! (Sorry guys, hope I didn't offend any one)
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The shore power is split, 2 x 30 amp inputs. That is all that is available at the marina.
1 side goes to the A/C, the other line does everything else, hence the complication.

Actually it's not overly complex, a circuit diagram would explain all, but I don't know how to add graphics to this forum.

I was trying to do this on the cheap. God knows boating is expensive enoughand with the economy the way it is...well....ya know. Also the amount of space immediately behind the panel is limited, but behind the wiring, well, I could probably climb in, if I could limber up a bit.
A double pole double throw 30 amp switch designed for marine use I thought was be quite pricey but I just got the West Marine catalogue today and it's only $100. The relays are about $50 each. So I may just go back to the drawing board. I thought it was going to be lot more.
I've been going back and forth on this, but now if Al's switch is just a single throw, then I was replanning on simply using the genny to power the A/C and add the charger circuit to it.
The 15Amp circuit for kettle, TV etc would be powered from the inverter.

Are you following me? I hope that clarified the situation, basically it is what you suggested.

The snow came into it because Al couldn't get to his boat to check the switch.

I still haven't got an answer on the Silverton yard sale though, so if anyone knows....."
 
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