Shore power battery settings

[CFitz]

We just purchased a 1994 Catalina 28.
We are new to this and want to make sure we fully understand the way the battery system works when connected to shore power as we see many differing opinions about it.
So when on shore power and away from the boat do we set the battery switch to OFF or to ALL?
Will the battery charger charge the batteries in either position?
When connected to shore power and on the boat do you need to have your battery switch to ALL? The cabin lights do not work when in OFF position. Why do you need batteries on to run cabin lights when connected to shore power?
Thanks in advance
Carol

 

[kloudie1]

I don't know exactly how your boat is wired, and with it having gone through a couple of owners, someone may have rewired stuff. In general, the battery switch should be in the "OFF" position when you aren't there or using 12Volt systems.. Usually, the bilge pump is wired "hot" to a battery (one and not both) so that it works with the 12V master switch turned off. Usually, the battery charger is wired directly to the individual batteries from the charger so the batteries will charge if connected to shore power, and the 120Volt power is switched on to the charger; usually, master on and charger switch on. The only time the battery switch should be on "BOTH" is when you are charging with your propulsion engine..
The lights are powered by the batteries only since they have to work when sailing at night with the engine off..
Happy Sailing !!

 

[Justin_NSA]

Part of it depends on whether the ABC switch is in front of or behind the batteries.
I wired my system so the charger goes to the battery buss and they are always charging when shore power is plugged in and charger is on. My ABC switch is after the battery bank so the setting determines where the DC system gets power: shore, start or all

 

[CFitz]

I don't know exactly how your boat is wired, and with it having gone through a couple of owners, someone may have rewired stuff. In general, the battery switch should be in the "OFF" position when you aren't there or using 12Volt systems.. Usually, the bilge pump is wired "hot" to a battery (one and not both) so that it works with the 12V master switch turned off. Usually, the battery charger is wired directly to the individual batteries from the charger so the batteries will charge if connected to shore power, and the 120Volt power is switched on to the charger; usually, master on and charger switch on. The only time the battery switch should be on "BOTH" is when you are charging with your propulsion engine..
The lights are powered by the batteries only since they have to work when sailing at night with the engine off..
Happy Sailing !!

 

[Justin_NSA]

R C has a very thorough article on this.

1/2/BOTH Switch Considerations

1/2/BOTH Battery Switch Considerations - Ever wonder how to make the 1/2/BOTH switch easier to use, let this article explain how to do that.

marinehowto.com

 

[jssailem]

Hi Carol.. I see you found a Catalina. Are your still on the hard or are you now in the water and tied to a slip?

Boat power systems can be mysterious but fear not. Once you gain an awareness you will feel much more comfortable.

Lets first divide the systems. AC this is power from a plug on shore (or in the case your boat has a generator the power coming from the generator). This is just like the power you have at home. Your boat has a "Charger" to convert the AC power to DC (battery power). DC makes up the #2 system on the boat .

AC. You tie up in a slip and you plug the boat into "Shore Power". Now you can run those things that have switches on the AC Panel. Thinks like a water heater, a refrigerator, a microwave, a coffee maker, and a battery charger. You may also have some plugs on the boat that are just like home. They provide AC power to run lights, computers, etc. When you go out sailing and unplug the boat from shore power these things all go away, unless you have a DC option for these "loads" (for example a refrigerator is an electrical load). Now if you have a generator you can power it up and listen to the motor running driving the generator and providing AC power to your boat. Many sailors sail so they do not have to listen to a motor. It is all personal choice.

On the other side you have your Batteries. DC power. If you charged them while at the slip (plugged into shore power and you flipped the switch labeled Charger to on) then you have a source of DC power supporting all of the loads you have that run on DC power. As an example, your lights, sometimes you refrigerator, your navigational electronics etc. These all run silently drawing down the power you have stored in the batteries.

Your boat and your system is likely as described in your boat manual. There is one caveat to that statement, "as long as a previous owner has not altered the electrical system".

This is why it is a bit awkward for someone who has not inspected your boats systems to give you reliable answers. If this boat and sail boating in general is totally new and baffling I would encourage you to get professional help to go over your systems and point out any thing out of the ordinary. You might find a boating neighbor with a lot of experience, a professional boat worker in your local marina, or you might resort to studying the many books that are excellent sources for a new person to acquaint them with their boat systems.

With regard to electrical, Nigel Calder has an excellent book on electrical systems for the boat owner.

Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems: Calder, Nigel, Calder Nigel: 9780071432382: Amazon.com: Books

Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's Essential Systems [Calder, Nigel, Calder Nigel] on Amazon.com. *FREE* shipping on qualifying offers. Boatowner's Mechanical and Electrical Manual: How to Maintain, Repair, and Improve Your Boat's...

www.amazon.com

Or our local expert.. MaineSail is an excellent source. Marine How To - DIY for Boaters - Marine How To

Good luck and be safe.

 

[CFitz]

Yes she is now at dock plugged in to shore power.
Mast went up yesterday and we have returned home to retrieve the sails and cushions etc. and will return in a couple of days.
We left the power on ALL while plugged in but after reading and getting a little more familiar we have someone switching it to OFF for us today. We have 2 new batteries on board (after launch finding out the ones we had were dead, and yes they worked a few days before but where at end of their lives)
The switch for battery charger has always been left to ON and all others on DC panel like cabin lights, nav etc off while not using (when left on ALL) .... We now think that when left on OFF but battery charger on and plugged into shore power the batteries will be charged and also the bilge on auto is hardwired to batteries ... So I think that while we are on the boat using shore power we will have it on ALL to run cabin lights etc? But the outlets should still work on OFF when connected to shore power?
Then when we start the engine on ALL .. turn off engine and then return to 1 (on odd # days) and 2 (on even # days) to return to shore?
Does this make sense?
Plus we will check under lazzerette where the charger is, when main switch in OFF position and connected to shore power to see if there are lights indicating it's charging (just so we can fully understand for our non electrician brains)
Does this make sense? We could essentially use solar powered LUCI lights and always be in OFF and still plug things in and batteries will still be charging. What about the water pump/pressure tho? Hmmm guess when we go back to boat we check this?
Learning curve here ..
Next week we take boat for sail for first time without someone telling us what to do... That should be fun

 

[Benny17441]

You need to follow the output leads of your inboard battery charger to see how it is wired. In most installations the output leads are connected directly to the batteries and independently from the battery switch, in which case all you would have to do is power the charger. There might be a breaker switch in the 120V panel to power the charger after you have connected the power cord to shorepower. On the other question, most boats are not equiped with a 120V/12V converter so all the 12V power needs are supplied by the batteries. The way it works when on shorepower is the batteries supply power for the cabin lights, water pump, radios, phone chargers and 12v fans and the 120V battery charger replenishes that power used to the batteries. Now the battery switch is used when charging the batteries with the engine running and the alternator and you can select which battery or battery bank you want to direct the charge to. Now you can simultaneously charge your batteries from shore power and from the alternator. There are no benefits to doing this but you are not going to damage anything if you run the engine while connected to shorepower. What most people do is if they are in the boat they will turn the battery switch on to have power for the lights and appliances and when they leave they will turn the switch off and leave the batteries to charge on their own. The recommended method is to charge batteries every time after the boat is used. I and many others will keep the battery charger on 24/7. Some advocate that keeping them on maintenance (trickle) charge for too long has a small detrimental effect but the way I see it convenience trumps any small loss of battery useful life. Of utmost importance is to keep the batteries watered, check them every two weeks and add distilled water as needed. The learning curve on the electrical systems of a boat is long so I would recommend a book like "Sailboat Electrics Simplified" by Don Casey.

 

[CFitz]

You need to follow the output leads of your inboard battery charger to see how it is wired. In most installations the output leads are connected directly to the batteries and independently from the battery switch, in which case all you would have to do is power the charger. There might be a breaker switch in the 120V panel to power the charger after you have connected the power cord to shorepower. On the other question, most boats are not equiped with a 120V/12V converter so all the 12V power needs are supplied by the batteries. The way it works when on shorepower is the batteries supply power for the cabin lights, water pump, radios, phone chargers and 12v fans and the 120V battery charger replenishes that power used to the batteries. Now the battery switch is used when charging the batteries with the engine running and the alternator and you can select which battery or battery bank you want to direct the charge to. Now you can simultaneously charge your batteries from shore power and from the alternator. There are no benefits to doing this but you are not going to damage anything if you run the engine while connected to shorepower. What most people do is if they are in the boat they will turn the battery switch on to have power for the lights and appliances and when they leave they will turn the switch off and leave the batteries to charge on their own. The recommended method is to charge batteries every time after the boat is used. I and many others will keep the battery charger on 24/7. Some advocate that keeping them on maintenance (trickle) charge for too long has a small detrimental effect but the way I see it convenience trumps any small loss of battery useful life. Of utmost importance is to keep the batteries watered, check them every two weeks and add distilled water as needed. The learning curve on the electrical systems of a boat is long so I would recommend a book like "Sailboat Electrics Simplified" by Don Casey.

thankyou
by the way our batteries are deep cycle group 31
thanks for the book recommendation too

 

[Benny17441]

Then when we start the engine on ALL .. turn off engine and then return to 1 (on odd # days) and 2 (on even # days) to return to shore?

What you are doing is alternating batteries for two purposes 1) for redundancy, you keep a battery in reserve to maintain emergency power. 2) Deep cycle batteries have a limited number of cycles so the idea of using both batteries is to try and match the useful life of the pair. Also batteries need exercise, they need to be periodically deeply discharged so the charger can help clean the battery plates. Do not discharge batteries beyond 50% of their capacity unless in an emergency as at that level their useful life is disproportionally shortened. A battery bank can be composed of one battery or more. In your current setup you have two banks when the switch is set to either A or B (1 or 2) but when you switch to All you only have one larger but single bank. No need to start engine on ALL unless the battery in use is weak. This way you can direct all the alternator charge to the battery used to start. It is sad when someone forgets to switch back from ALL and the refrigerator kills both batteries. Now there is more than one way to skin a cat. If you carry an automotive battery pack that will provide your needed redundancy to start the engine and you can combine your two banks into one and have more house power at your disposal. See what I meant about a long learning curve. Batteries is just one single topic.

 

[Maine Sail]

As others have said the only way to know how the charger is wired is to physically trace it. Typically Catalina ran to the banks but a PO could have changed that.

To Test:

1- With the battery switch OFF, check the battery bank voltages with a volt meter & write them down
2- Plug into shore power and turn on the battery charger via the AC panel.
3- Leave battery switch set to OFF
4- Wait a few minutes and test the bank voltages with a volt meter & write them down.
5- Were there any increases in bank voltage? If yes on both banks the charger is working.
6- If there were no voltage changes, repeat the test with the switch on #1, then #2, then BOTH/COMBINE.

A properly wired battery charger will not require you to leave the battery switch set to ON or BOTH when you leave the boat. Of course there are many improperly wired chargers out there so always test & confirm.

 

[Stu Jackson]

As you get further into your new boat (Congratulations!!!), this may be of interest to you:

Electrical Systems 101 Electrical Systems 101

 

[jviss]

I love these battery and battery selector switch threads. New ones pop up frequently. It's like jazz, the repetition is appealing. Also, there's a "call and response" aspect, bad information followed by corrections. The trick is to recognize the bad info, which is nearly impossible for beginners. My recommendation is to go with recognized experts. And even though I'm an electrical engineer, you can't trust me, as I haven't posted my degree, and you still wouldn't know my specialty! So, go with Maine Sail, Nigel Calder, et.al.

That said, although it was standard practice going back perhaps a 100 years, the idea of alternating two lead acid batteries is considered by many experts now to be inferior to simply creating one large bank. With one bank of two batteries you won't be discharging either battery as deeply, and this prolongs their life.

Second, it is not necessary to deeply discharge lead acid batteries periodically to "keep the plates clean." This won't clean the plates, only a controlled over-charge can do that. (The trick is to avoid sulfation entirely.) The way you avoid the sulfate on the plates is to keep them as fully charged as possible for as much of the time as possible. Lead acid batteries don't have a memory like nickle-cadmium and some other chemistries (although new lead acid batteries will "break in" in the first few cycles when new - an advanced topic).

The best set-up is to rewire the OFF-A-B-BOTH switch so that in normal operation it is on OFF when you are not on the boat, or A when you are operating the boat, connecting the parallel connected batteries of Bank 1 to the panel that feeds the house loads. (The "A" terminal to the bank, the "C" (common) terminal to the house panel.) The alternator output is connected directly to this bank. If there's no other battery, so is the starter. I highly recommend having a separate engine starting battery. If you do, you will have a disconnect switch, too, and in normal operation the disconnect will be closed, connecting the starting battery to the starter. Other engine electrical systems will likely be connected to the starting battery, but not always. The Starter will also be connected to the "B" terminal of the OFF-A-B-BOTH switch. With this arrangement you can power the house from the main bank or starter battery and start the engine from the starting battery or main bank. The starting battery will be charged by either an echo charger or combining relay. If this fails, the starting battery can be charged from the alternator. This is covered quite well in Maine Sail's thread on the topic.

By the way, your original question, about the charger: it's connected to each battery; if two channels, both to the main bank.

 

[CFitz]

I love these battery and battery selector switch threads. New ones pop up frequently. It's like jazz, the repetition is appealing. Also, there's a "call and response" aspect, bad information followed by corrections. The trick is to recognize the bad info, which is nearly impossible for beginners. My recommendation is to go with recognized experts. And even though I'm an electrical engineer, you can't trust me, as I haven't posted my degree, and you still wouldn't know my specialty! So, go with Maine Sail, Nigel Calder, et.al.

That said, although it was standard practice going back perhaps a 100 years, the idea of alternating two lead acid batteries is considered by many experts now to be inferior to simply creating one large bank. With one bank of two batteries you won't be discharging either battery as deeply, and this prolongs their life.

Second, it is not necessary to deeply discharge lead acid batteries periodically to "keep the plates clean." This won't clean the plates, only a controlled over-charge can do that. (The trick is to avoid sulfation entirely.) The way you avoid the sulfate on the plates is to keep them as fully charged as possible for as much of the time as possible. Lead acid batteries don't have a memory like nickle-cadmium and some other chemistries (although new lead acid batteries will "break in" in the first few cycles when new - an advanced topic).

The best set-up is to rewire the OFF-A-B-BOTH switch so that in normal operation it is on OFF when you are not on the boat, or A when you are operating the boat, connecting the parallel connected batteries of Bank 1 to the panel that feeds the house loads. (The "A" terminal to the bank, the "C" (common) terminal to the house panel.) The alternator output is connected directly to this bank. If there's no other battery, so is the starter. I highly recommend having a separate engine starting battery. If you do, you will have a disconnect switch, too, and in normal operation the disconnect will be closed, connecting the starting battery to the starter. Other engine electrical systems will likely be connected to the starting battery, but not always. The Starter will also be connected to the "B" terminal of the OFF-A-B-BOTH switch. With this arrangement you can power the house from the main bank or starter battery and start the engine from the starting battery or main bank. The starting battery will be charged by either an echo charger or combining relay. If this fails, the starting battery can be charged from the alternator. This is covered quite well in Maine Sail's thread on the topic.

By the way, your original question, about the charger: it's connected to each battery; if two channels, both to the main bank.