Charging system question

Dec 27, 2012
587
Precision Precision 28 St Augustine
The Charger (unknown brand) on my boat has a internal float. When I plug into shore power the charger either goes into float mode or charges depending on the battery power level. My question is, should my charger be wired to a switch on the panel allowing the option to bypass it when on shore power? My batteries have the standard on/off,1,2,all switch but that doesn’t do anything for the charger. It seems whenever I search this topic I only come up with the battery switch.

The only thing I power on shore power is a small refrigerator that can be powered on AC or DC. While at the dock I switch to AC.
 
Dec 27, 2012
587
Precision Precision 28 St Augustine
I don’t have a switch on the panel. Maybe I’m wrong but at dock nothing is drawing dc power so other then the times the batts need charged I don’t see the need to keep the charger on. I realize the charger has a float but not sure if I should always trust it.

The only potential dc draw at dock is the bilge pump and that kicks on probably once every few weeks.
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
I don’t have a switch on the panel.Maybe I’m wrong but at dock nothing is drawing dc power so other then the times the batts need charged I don’t see the need to keep the charger on.
Couple of questions.

  1. How do you turn on the charger if there is not a switch?
  2. You are correct you only need the charger to maintain the battery charge, what happens if the batteries fail?
  3. Are you frequently at the boat to monitor the battery charge levels?
  4. It would help to know the name and model of the charger, some have a feature of providing DC power to the boat if the battery fails or is missing
As a start. There are times when the batteries get drawn down by on board DC loads. For example a pump with a stuck bilge switch. Is there a solution on your boat?
 
May 17, 2004
5,032
Beneteau Oceanis 37 Havre de Grace
There are times when the batteries get drawn down by on board DC loads. For example a pump with a stuck bilge switch. Is there a solution on your boat?
This.

Even if there are no usual DC loads the bilge pump could still run, there could be some unknown parasitic loads, or the batteries could self discharge slightly if left for extended periods, especially if in warmer temperatures. It would be good to have a switch, or better a circuit breaker, dedicated to the charger, but I wouldn’t be afraid to leave the charger on float for extended periods. As long as the float voltage is correct and the batteries start with the right amount of water no damage should be done.
 
Dec 27, 2012
587
Precision Precision 28 St Augustine
Im going to add a switch but continue to keep the charger on. A mechanic at the marina advised that the charger should not be kept on. I didnt tell him it has a internal float.
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
Keep an eye on that boat. It helps with “hydro therapy “.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
There should be some circuit protection for the charger, typically a circuit breaker on the AC panel. Some boat owners use a plug in type of charger and just use an available outlet for the charger. This is not a good practice as the plug can come loose and is subject to corrosion. If the plug was installed by a previous owner, it should be inspected to make sure it is ABYC compliant.

So while you're doing the investigation, figure out what kind of charger you have. It may be in the best interests of your batteries to update the charger to a modern three stage charger like the Sterling/ProMariner chargers.

Since my refrigerator runs on DC I leave the charger on all the time. With a good charger and proper installation there should be no danger to doing this. I even leave the charger on when sailing so I don't forget to turn it on when I get back to the dock. (Been there, done that, bad for the batteries!).
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
I don't have a switch for my charger either. I'f I'm plugged into shore power, my charger is either floating or charging.
 
Sep 25, 2008
7,077
Alden 50 Sarasota, Florida
Im going to add a switch but continue to keep the charger on. A mechanic at the marina advised that the charger should not be kept on. I didnt tell him it has a internal float.
All multi-stage chargers have a float cycle. That’s a reason to leave it on, not off, especially if any DC stuff can draw from the batteries while you aren’t aboard. Regardless, having a means to shut off a charger is good but not for the reason your yard guy said.
 
Jan 19, 2010
12,362
Hobie 16 & Rhodes 22 Skeeter Charleston
So if you need to turn your charger off for some reason, can't you just use the circuit breaker? Or unplug from shore power. I'm trying to do the cost/benefit analysis here.
 
Nov 13, 2013
723
Catalina 34 Tacoma
I don't have a switch for my charger either. I'f I'm plugged into shore power, my charger is either floating or charging.
I would not feel comfortable leaving the charger on 24/7. I've heard to many charger failure stories that lead to cooked batteries. Add a decent voltmeter like the Victon and charge when needed for a 24 hr period. My batteries are in year 7. I do have a breaker on the AC panel that turns the charger on/off when connected to shore power. I use the charger to power lights, water pressure, comm, when on the boat.
 
Jan 21, 2018
78
Hunter P42 Ft Lauderdale
My charger/inverter has been on shore power for two decades without an issue. Your results may vary. The last time I returned to the boat the main AC breaker had popped. Either something I did on leaving, or while I was away. Batteries were way down.

Important note: The bilge pump is not there to run once a week. It is there for when it needs to run every five minutes or less. And it needs the DC power to do that.
 
May 24, 2004
7,129
CC 30 South Florida
You got a shore power inlet so you should have a 120V ac panel or at minimum a section in the panel dedicated for 120V ac power. Your battery charger is powered by 120V and in most installations there is a dedicated breaker switch for the battery charger. This is in addition to a Master 120V breaker switch that can be use to shut off power to all appliances and receptacles. It is likely that your battery charger may have been installed by a previous owner so you need to find out how it was wired. 1) Do a test by shutting down the master breaker to the 120V panel. Your charger as well as your refrigerator should turn off. If they don't then it means they were hardwired into the shore power inlet circuit and are bypassing the panel. This could point to a possible hazard if the circuit is not properly fused. If you determine that the charger has been hardwired I would suggest you get an electrician to connect it to a circuit breaker switch in the panel for safety and the convenience of being able to turn it On and Off. Sometimes previous owners will do the easy install instead of the proper install and other times a breakers witch goes bad and a replacement cannot be found and would require a new panel so it is bypassed. Single breaker switches and boxes can be purchased and installed in case there is none available in the panel or replacements cannot be found. Good luck.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
I would not feel comfortable leaving the charger on 24/7. I've heard to many charger failure stories that lead to cooked batteries. Add a decent voltmeter like the Victon and charge when needed for a 24 hr period. My batteries are in year 7. I do have a breaker on the AC panel that turns the charger on/off when connected to shore power. I use the charger to power lights, water pressure, comm, when on the boat.
An important consideration is the age of the charger and the kind of charger, all chargers are not alike. I would not leave an old ferro-resonant charger plugged in unless I was on the boat. However, the newer chargers are much safer.
 
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Oct 9, 2020
2
CAL 20 USA
The Charger (unknown brand) on my boat has a internal float. When I plug into shore power the charger either goes into float mode or charges depending on the battery power level. My question is, should my charger be wired to a switch on the panel allowing the option to bypass it when on shore power? My batteries have the standard on/off,1,2,all switch but that doesn’t do anything for the charger. It seems whenever I search this topic I only come up with the battery switch.

The only thing I power on shore power is a small refrigerator that can be powered on AC or DC. While at the dock I switch to AC.
I think the way you have it is good it should be on with shore power so it may float charge . Good luck Bill
 
Mar 20, 2016
594
Beneteau 351 WYC Whitby
Newer chargers are the way to go like Sterling or pronautic these charge the batteries go to float and when something like the the fridge kicks in supplies the amps not the batteries . You can actually unhook the batteries and they will supply the 12v for your boat .They are world voltage plug in to 120 or 220 they don't care and have programs to charge lead acid, gel, agm, or lithium ion
 
Oct 24, 2010
2,405
Hunter 30 Everett, WA
Im going to add a switch but continue to keep the charger on. A mechanic at the marina advised that the charger should not be kept on. I didnt tell him it has a internal float.
Hearing a flat statement like that tells me the mechanic may have no clue what he's talking about (unless he knows about a problem with your specific charger.) Most boats leave their chargers on full time. A problem with a charger would be much rarer than a battery damaged by inadequate charging. Look at your model of the charger and find a manual for it. If it's a working 3 stage charger you should be good to go. If not, replace it.

Ken
 
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