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30 AMP to 15 AMP safe?

Old 02-22-2013, 10:06 PM
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Default 30 AMP to 15 AMP safe?

I have a Promariner Quad Charger that has 4 banks hooked up in my 2400 Century WA. It's run great over the last 2 years hooked up to a heavy duty straight plug extension chord at my last home, but now I have it in a rented slip that has a standard 30 AMP plug. I looked around the dock and noticed a few of these 30-15 connectors.



The Promariner is supposed to be rated for 30 amps, but comes with a 15 amp plug, so it seems like is should be fine.

Any safety or electrolysis issues here?
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Old 02-22-2013, 10:13 PM
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In short - 15 amp running on 12 volt is not the same power as 15 amp running on 110 volt.

Your charger is 30 amps - 12 volt = 360 watt
Your shore power cable is 15 amp - 110 volt = 1650 watt

So you have plenty of safety margin.

But please remember to use proper installation when using shore power so your boat is galvanic isolated. That will ensure you won't cause other boats to corrode or other boat will corrode your metal fittings under water.
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Old 02-22-2013, 10:23 PM
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I want to do this right, as I don't want to corrode my boat, or worse, do the same to my neighbors. When you say "proper installation," my charger was put in by Century in the plant in Florida. I'm thinking they did it right, but what do I need to do to make sure the shore power plug to boat hook up is right?

Thanks!

Originally Posted by kaz911 View Post
In short - 15 amp running on 12 volt is not the same power as 15 amp running on 110 volt.

Your charger is 30 amps - 12 volt = 360 watt
Your shore power cable is 15 amp - 110 volt = 1650 watt

So you have plenty of safety margin.

But please remember to use proper installation when using shore power so your boat is galvanic isolated. That will ensure you won't cause other boats to corrode or other boat will corrode your metal fittings under water.
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Old 02-23-2013, 06:08 AM
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You're cool with the pictured plug adapter. Nothing more to worry about on the other issues if your boat was in the water before.
BTW, if it is going to be a permanent hook up, consider taping the connection between the two cords real well or otherwise protecting it from the weather.
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Old 02-23-2013, 07:10 AM
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Originally Posted by A.Vern View Post
I have a Promariner Quad Charger that has 4 banks hooked up in my 2400 Century WA. It's run great over the last 2 years hooked up to a heavy duty straight plug extension chord at my last home, but now I have it in a rented slip that has a standard 30 AMP plug. I looked around the dock and noticed a few of these 30-15 connectors.



The Promariner is supposed to be rated for 30 amps, but comes with a 15 amp plug, so it seems like is should be fine.
You're comparing apples to oranges there.

As Kaz pointed out, your charger's "30 Amp" rating is in the context of its OUTPUT, which is of course DC at (nominally) 12 volts. The 15-Amp socket on that adapter cable is in the context of the dockside power, which is AC at (nominally) 120 volts. The two have NOTHING to do with each other.

You battery charger actually draws FAR less than 15 amps from the AC line; probably significantly less than 5 Amps (tho' ProMariner apparently does not actually specify this -- shame on them!).


Any safety or electrolysis issues here?
Safety, per se, near-certainly no -- as long as you exercise due care in how you plug everything in, keep the connections protected from water (including rainwater), etc.

By "electrolysis", I'm assuming you really mean "galvanic corrosion". This is a much trickier issue; and it depends in large part on how your boat (and that charger in particular) is currently configured. Refer to http://www.boatus.com/seaworthy/galvanic/default.asp, https://law.resource.org/pub/us/cfr/....E-01.1973.pdf, http://www.devill.net/Infos/Electric...al-systems.pdf, and http://www.cruisersforum.com/forums/...ical-1471.html for the gory details.

If you have a permanently installed AC distribution system on that boat, things get (at least potentially) a little easier; just install a good isolation transformer / galvanic isolator on the AC input (i.e., just downstream of the dockside power inlet), if you don't already have one, and this covers a multitude of issues -- including the very real possibility that your slip-neighbor's boat is NOT properly configured and is therefore causing your underwater metals to dissolve like sugar candy.

But I'm guessing that you do NOT currently have a permanently installed AC distribution system; and that makes things trickier. If that's the case, it basically all comes down to that charger, and whether or not there are any internal interconnections between the AC ground and either the AC Neutral or the DC Ground. You'll probably need to contact ProMariner to determine this.


Originally Posted by A.Vern View Post
I want to do this right, as I don't want to corrode my boat, or worse, do the same to my neighbors. When you say "proper installation," my charger was put in by Century in the plant in Florida. I'm thinking they did it right,
That isn't as certain as you might think. Boatbuilders -- particularly volume-production boatbuilders -- are notorious for NOT getting their electrical systems right.


but what do I need to do to make sure the shore power plug to boat hook up is right?
The FIRST thing you need to do is make sure that the dockside power outlet you plan to plug into is right. These too are "wrong" far more often than they ought to be. Get yourself a plug-in polarity and ground-fault tester, such as http://www.homedepot.com/p/t/2028678...ctId=202867890



and use it religiously BEFORE you plug into any dockside power outlet. This one simple precaution will let you side-step the single most common cause of severe galvanic corrosion problems in marinas.



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Old 02-23-2013, 07:58 AM
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^^^^^^^^ Lots of good info.
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Old 02-23-2013, 10:01 AM
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Originally Posted by JoseG View Post
^^^^^^^^ Lots of good info.
Agree. Thanks for all of the info.

To be more specific, here's how my Century is setup.

When I had the boat in my backyard (canal home), I had it in the water with 2 extension chords running to it. These were fed over a rod holder and were kept clear of the water.

The first chord ran to the Promariner and hooks up on the transom. The promariner chargers 4 banks (starboard, port/house, port/house/starboard, and the inverter banks).

The 4th inverter bank runs a 1500 Watt inverter that has an AC unit and a standard household GFCI plug plugged into it. While at shore, the inverter is off and there is no pull on the 4th bank.

The second extension chord from the house hooks to a sealed plug that houses a short extension chord. While at shore, I would unplug the GFCI outlet from the AC inverter and plug it into the extension chord. This gives me AC inside the cabin without having to run the inverter, and is basically just an extension chord routed through a GFCI.

I only use this outlet while at shore to run a West Marine dehumidifier that uses less power than a light bulb. picture here:



I had no issues with this setup for 2 years in the water, and my zincs still look in great shape.

What I'm hoping to do is use the adapter to run the promariner, and a second adapter to run AC into the GFCI so I can run the AC powered WM dehumidifier.

I'll pick up one of those GFCI testers and make sure all is good.

Thanks again all!
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