Shore power inlet for battery charger

Quickstep192

Anarchist
680
118
Chesapeake
I'm planning to add a battery charger (Sterling Pro Charge Ultra) and trying to decide whether to install a "real" shore power inlet, or just use one of the three prong inlets from Marinco or NoCo. 

I don't intend to use this for anything other than the charger. I have no dreams of a microwave, air conditioner or refrigerator or anything like that. I'm normally a "do it right or don't do it" kind of guy, so I was planning on using the SmartPlug system, but it kind of seems like overkill in this application.

I know it's hard to pry an opinion out of you guys, but what do you think? 

 
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longy

Overlord of Anarchy
6,282
888
San Diego
Unless you plan to breaker & wire for 30m amps, do not use a 30 amp socket!! Using a three prong (15 amp) socket will let you build the rest of the system to that spec without danger of overloading

 

Bump-n-Grind

Get off my lawn.
14,114
2,892
Chesapeake Bay/Vail
I never installed any sort of inlet or built in 120v system for the charger. Just ran a drop cord to the boat.

couldn't justify the weight of all that crap built into the boat. I know it aint a lot but lots of little shit adds up.

 
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George Dewey

Super Anarchist
2,071
118
Charleston, SC
I never installed any sort of inlet or built in 120v system for the charger. Just ran a drop cord to the boat.

couldn't justify the weight of all that crap built into the boat. I know it aint a lot but lots of little shit adds up.
This is how I run my charger. However, if I were to add shore power (and I'm considering it) I would go with a smart plug and a galvanic isolator. There are rules about how far from the inlet a breaker has to be, and many boats have two breakers: A main breaker close to the power inlet and then a breaker on the panel. 

 

Ultraman

Anarchist
818
48
Vancouver
Just use one of these: https://www.marinco.com/en/p/199128/Pigtail-Adapter-30A-125V-Male-To-3-Way

They work great if only running a charger and heater.

199128_MAIN.jpg


 
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SimonGH

Member
365
74
Westbrook CT
I think it would be helpful to have more context.

For my 40' boat with everything that comes with it, the answer is far different than a 25' racer.

What's the mission?

A shore connection needs a breaker within 5 ft (if i recall the ABYC specs correctly), and if you're then connecting to a ground system on the boat then a galvanic isolator is also something you want.  So to Bump's point, it starts to add up quickly - socket, wire, breaker and housing, galvanic isolator, etc.  At least $200 of stuff too.

If you're just trying to charge the battery, why are you even bothering with a built in charger?  Why not just get a good quality portable charger, or even leave it dockside and just route the low voltage (12v?) output to your boat?

 

toddster

Super Anarchist
4,144
943
The Gorge
Also depends on where the boat is.  Most marinas insist on real weatherproof marine shore power cords and inlets, appropriately sized for the pedestal.  And will preemptively remove non-conforming stuff from their docks!

 

Rain Man

Super Anarchist
7,015
1,938
Wet coast.
If your 12V system is grounded to the engine, and the engine has a saildrive leg or a prop shaft, consider getting a galvanic isolator as well to put in the ground wire.  We found that our zincs were getting about 3-4 months with the shore power cable connected to the shore power connection on the boat vs. 9-10 months with the shore power directly run inside the boat to run just the heater and dehumidifier.

We just installed our isolator this fall and have started connecting the supply cable to the shore power outlet and running our charger along with the heater and dehumidifier.  We have yet to check the zincs.  Hope the isolator fixes the problem.

 

slug zitski

Super Anarchist
5,076
808
worldwide
I'm planning to add a battery charger (Sterling Pro Charge Ultra) and trying to decide whether to install a "real" shore power inlet, or just use one of the three prong inlets from Marinco or NoCo. 

I don't intend to use this for anything other than the charger. I have no dreams of a microwave, air conditioner or refrigerator or anything like that. I'm normally a "do it right or don't do it" kind of guy, so I was planning on using the SmartPlug system, but it kind of seems like overkill in this application.

I know it's hard to pry an opinion out of you guys, but what do you think? 
Google 

IEC 60309 pin plugs 

order male and female  3 pin , 16a

the American style plugs are overpriced and prone to failure 

https://www.ebay.com/itm/401849776782

C06BED90-4D73-4C58-9795-6E934C45389C.jpeg

 
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slug zitski

Super Anarchist
5,076
808
worldwide
I'm sure the marina will have no issue with him re-wiring their dock pedestal with a European 220V connector
The shoreside  end of plugs varies from country to country and marins to marina to marina  … choose the correct one 

The boat end is permanent … use three pin socket plugs 

 

Will1073

Anarchist
690
105
I have a little notch cut in the top corner of my drop boards for halyard tails and an extension cord to drop into the boat for this reason. 
 

I think it really depends on what your yacht club/marina is comfortable with, but there is technically nothing wrong with either the extension cord into the boat, or the Marinco inlet — and letting the GFCI on the post protect the cord. 

 

George Dewey

Super Anarchist
2,071
118
Charleston, SC
Hey, not trying to hijack, and this question is relevant to the OP's question anyhow... I run an extension cord in and use a power strip to power a fan, a dehumidifier and a battery charger. My diver reports that my zinc (I have a saildrive boat) are consumed more quickly than my slip neighbors and more than he would expect. Any reason for that?

 

weightless

Super Anarchist
5,607
581
I run an extension cord in and use a power strip to power a fan, a dehumidifier and a battery charger.
I suspect it's the battery charger. It's possible to DIY an off the shelf full bridge rectifier or diodes into a galvanic isloator. It was done that way for years but eventually ABYC came out with a standard that can not be met with that kind of setup. I think that put an end to the inexpensive commercially available devices.

 

George Dewey

Super Anarchist
2,071
118
Charleston, SC
I suspect it's the battery charger. It's possible to DIY an off the shelf full bridge rectifier or diodes into a galvanic isloator. It was done that way for years but eventually ABYC came out with a standard that can not be met with that kind of setup. I think that put an end to the inexpensive commercially available devices.
Hm, I just went looking for an isolator I could plug between the power strip and extension cord, so far no luck. I guess I can make my own or else just install proper shore power. I would unplug the battery charger but it's primary job it to keep the fridge going. 

 

Zonker

Super Anarchist
9,126
5,041
Canada
Isolation transformers are the gold standard.

A small one suitable for just a fridge / battery charger might be 500 W or less. (I figure a 30A DC battery charger might draw < 4A x 120V = 480 W. Read your charger nameplate to be sure)

 

weightless

Super Anarchist
5,607
581
Hm, I just went looking for an isolator I could plug between the power strip and extension cord, so far no luck. I guess I can make my own or else just install proper shore power. I would unplug the battery charger but it's primary job it to keep the fridge going. 
I wonder if it'd be wise, safe or useful to add a couple of diodes between the batt and charger neg? On the idea that low voltage between the battery charger rectifier and the battery would be blocked.

[Edit] -- ...The battery charger might not properly read the battery voltage... That could be less than ideal...

 
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