Confirming plan for replacing shot battery charger (Longish post re: electronics)

[Monheganlover]

I have my 2002 Catalina 310 on the hard and, when plugging my original equipment C-Charger Model 12205E into the GFCI protected 110 AC outlet at my marina yesterday, using my 30 Amp to 110 adapter, then turning on the charger, the GFCI kept popping. I reset it with the charger turned off on the AC panel and the GFCI was fine, but, as soon as I turned it on, the GFCI popped again. To test it, I tried another GFCI outlet and the same thing happened. However, when I plugged into a non-GFCI protected outlet, the charger turned on fine.

I researched it online and learned two things. 1. This is, apparently, not uncommon when others with this old model charger plug into GFCI outlets...something to do with the GFCI outlets not liking the rush of current draw (this C-Charger is rated at 12V and 20 amps and has no switch for different battery types) and; 2. More marinas are going to be moving to GFCI/ ELCI protected shorepower systems as a safety precaution.

So, after researching further on the "MarineHowTo" channel (I made a cash donation to the gentleman who created that great resource) I have decided to follow the below path and wanted to gut-check it with knowledgeable people on this board. Here are the steps I am taking.

First, my current setup: I have two Discover EV4DA 4D Dry Cell AGM traction batteries rated at 235 amp hours each (c20 rate) -- wired in parallel -- for my house bank and a NorthStar AGM 27 starting battery. I have a Blue Seas ACR connected to charge both banks as needed. The current C-Charger is connected to the house bank. I also have solar installed wired to a Victron solar charge controller. I also have a "smart" bluetooth Victron battery monitor that monitors both banks. During the season I run exclusively on the solar and rarely hook up to shore-power. My starting battery is wired to its own "engine" switch so I can shut it down in an emergency.

For my new charger install this is what I am planning:

• Per MarineHowTo's review and recommendation, I ordered the Victron Energy Blue Smart IP65 12-Volt 15 amp 120VAC battery charger with an AC power cord. This is a one bank 15 amp smart charger .
• Based on further research I also ordered an outdoor GFCI outlet that I plan to have a qualified tech mount my lazarette to plug the charger into. I intend to have him wire the GFCI outlet into the existing battery charger circuit on my electrical panel. I have ordered an outdoor battery box and cover for the outlet. I will run the charger's power cord through the bulkhead where the current charger is mounted into the lazarette and plug it into the GFCI outlet.
• I will wire the charger to the house bank as my current charger is.

Here are my questions in case any one has any input:

1. Is this a sound setup? Am I being overcautious in installing a dedicated GFCI outlet to plug the charger into? I suppose I could just install a non GFCI protected outdoor outlet but my understanding is the ABYC standards would require it to be GFCI since it is mounted in an outdoor area inside lazarette which, conceivably, is a wet environment.
2. Am I correct that since I am using a one bank charger wired to the house bank and because both banks are the same chemistry (AGM), linked by the ACR, that there should be no issue with the "smart charger" charging both banks if I set the charger to AGM mode? I am comfortable with not having all the smart features as I have a good Victron battery monitor to keep an eye on things.

Thanks in advance for input!

 

[Davidasailor26]

Overall I think your wiring plan is an ok way of tying in the plug-in style charger. I would be concerned about the size of your battery bank relative to that charger. Between your 2x4D house bank and your engine battery you’ve got over 500 AH of battery capacity. The general rule of thumb, which is even more important to follow with AGM’s, is to get a charger that’s at least 10% of your bank capacity plus your typical house loads. That puts you at nearly 60 amps of charger capacity. If you run your 4D bank down to 50% it’ll take that charger at least 16 hours to recharge it, which isn’t great for the long term health of the AGM’s.

 

[Project_Mayhem]

@Maine Sail is the gentleman behind MarineHowTo. As you already know, he is extremely knowledgeable

 

[Benny17441]

I fail to understand why you would want to install a plug in charger when you already have the set up to hard wire a new charger. Hard wiring provides a better and safer connection. If you insist on having a GFCI breaker it does not need to be an electrical receptacle, there are sealed units which can be hardwired which just provides the breaker and reset functions. These have been used for years in Jacuzzis. The ideal battery system requires a balance between the size of the batteries, the usage of the appliances it serves and the capacity of the recharging source. Any imbalance will reflect on battery longevity. It is best to start by conducting a power survey to determine the usage needs and properly size the Battery Bank(s). Once the ideal size of the battery banks has been established then you can determine the capacity requirements of the charging sources. After every use batteries should be promptly recharged to 100%. Battery chemistry requires that batteries receive adequate exercise in deep discharges and bulk charging. If the banks are too large for the usage the repeated shallow discharges are actually harmful. If the charger is too small, long periods of low current charges are not helpful. Primarily try to keep your batteries at 100% charge.

 

[Monheganlover]

Thanks for the feedback. What you and the previous respondent say makes sense. I was going to economize by getting a smaller, plug in charger to top off the batteries when I am in my slip. Generally, my solar panels keep them charged up. However, I see the logic of a hard wired charger that can meet 10 percent of the total amp hours of my combined banks. I see that installing a lower amperage plug-in charger was short-sighted as it could actually result in having to replace my batteries sooner and more expense than paying a few hundred more dollars now for the correctly sized charger.