Batteries and battery switch concerns

[DonC3222]

I just installed a new battery charger and 2 new batteries. I am unsure if I am using the battery switch properly.

2 questions:
1. Exactly when should I be using the switch on 1, 2 and/or both??? So far I normally just leave it on both for starting, cruising and charging. I imagine this is not how it should really be used. Can someone set me straight on how to use this properly.

2. I have one deep cell (flooded battery), and one maintenance free starter battery. They are hooked up in parallel off the charger. Should I have both batteries be the same type? If so, which one should I go with? I think I have to choose one or the other with my new ProMariner battery charger in its setup (flooded vs other battery types). I don't think the charger can do both at the same time, and I believe it matters in the life of the batteries. What do I do with this battery issue?

Thanks so much for the help.

 

[Stu Jackson]

1. Do some reading and find out how your boat is wired.

OEM 1-2-B Switch Wiring History http://c34.org/bbs/index.php/topic,4949.msg30101.html#msg30101

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: http://c34.org/bbs/index.php/topic,6604.0.html

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
http://forums.catalina.sailboatowners.com/showthread.php?t=137615


2. Maintenance free could also be flooded lead acid FLA. Usually not an issue. Since we can't see your batteries, and that's all you've told us, no way to know.

 

[Benny17441]

There seems to be different schools of thought as how to use the Battery switch. Nowadays some take as a given that any battery installation contains a dedicated starting battery which would render different recommendations on how to use the switch when compared to the traditional system of just having two batteries and a 1,2,all, off switch. Ay, Ay,Ay, I just finished reading the post and see that you have one starting battery and one deep cycle which are not really compatible to be combined unless in case of emergency. The starting battery has thin plates and is designed to provide large burst of power for a short duration and do not take kindly to deep discharges while the deep cycle battery has thicker plates and is designed to provide steady power over a longer duration and accept many cycles of charge/discharge. You could run them as having one starting battery and one small house bank but my recommendation would be to acquire a 2nd deep cycle battery compatible with the one you already have and connect them in parallel in essence doubling the size of your house bank and then dedicating the starting battery for just running the engine. What you may be looking for is redundancy in always having power in reserve to start the engine. If you use your current setup by combining both batteries you may run the risk of depleting them both due to usage or accident and be left with no adequate power to start the engine. I just had a friend that last week inquired about the same issue and when I asked him why did he purchase a starting battery for a two battery system he indicated it was recommended by an article and confirmed by another sailor. He was not too happy when I told him that he must have misinterpreted the article. I'll be brief, the old system consisted of two similar deep cycle batteries connected via a 1,2,all,off switch. These batteries were used both for starting the engine and for house duties. Their usage was alternated to always keep one in reserve for redundancy but the user always had the choice of combining them for a larger house bank. Do one outing on battery #1 and the next outing on Battery #2 etc. This is a very convenient system for day sailing and then when taking longer trips and having the need for a larger house bank you could always bring along a third battery or what we use which is a portable battery pack. Depending on your needs the current set up could be workable but I would refrain from combining both batteries unless you might need an emergency power boos. Use the starting battery for starting and after letting it charge back by the alternator switch to the deep cycle one. It is important to know that the position of the battery switch will indicate which battery is supplying power for the loads as well as receiving charge from the alternator. At some point you will likely want to recharge the deep cycle battery with the alternator which would mean you would have to place the switch to the desired position. Never cycle a switch through the off position while the engine is running or it could damage the alternator. Most modern switches are the "make before break" type which means they will secure a connection before releasing the prior one but there still might be some older switches out there. There are plenty of postings on the archives about the issue so you can do some homework. Hope this helps.

 

[DonC3222]

This helps a ton. So in summary, I should go get another deep cycle battery like one of the two I already bought. Hook them up in parallel, and try to use on for starting only, and one for house usage. If the house battery gets too low, I can switch to the other one as long as I am sure there is enough in it to start the engine.
When charging at shore, it sounds like I should place the switch to both so they both charge, as now they will be the same type of batteries. When using the engine, should I keep it on the house battery, since that starting battery probably won't be low, or place it on both, so they both charge?

Thanks again.

 

[Maine Sail]

This helps a ton. So in summary, I should go get another deep cycle battery like one of the two I already bought. Hook them up in parallel, and try to use on for starting only, and one for house usage. If the house battery gets too low, I can switch to the other one as long as I am sure there is enough in it to start the engine.
When charging at shore, it sounds like I should place the switch to both so they both charge, as now they will be the same type of batteries. When using the engine, should I keep it on the house battery, since that starting battery probably won't be low, or place it on both, so they both charge?

Thanks again.

You don't need to replace the start battery, if it is already healthy, but don't use it for house loads. You can combine the batteries for charging. So long as they charge at comparable voltages there is no problem charging these batteries in parallel.. They should be isolated during discharge though.

To keep it simple charge the start battery dock side and then let it sit there as your back up. When you go cruising just set your switch for the house battery and do everything with it. This will avoid needlessly touching the battery switch. If you ever kill the house bank simply switch to the starting battery and fire up the motor.

If you want to make charging the start battery seamless and fully automatic look into a Blue Sea ACR or a Yandina Combiner.....

 

[Benny17441]

This helps a ton. So in summary, I should go get another deep cycle battery like one of the two I already bought. Hook them up in parallel, and try to use on for starting only, and one for house usage. If the house battery gets too low, I can switch to the other one as long as I am sure there is enough in it to start the engine.
When charging at shore, it sounds like I should place the switch to both so they both charge, as now they will be the same type of batteries. When using the engine, should I keep it on the house battery, since that starting battery probably won't be low, or place it on both, so they both charge?

Thanks again.

You got it, just hook up the two deep cycle batteries in parallel as if they were a single battery to one of the switch positions and the single starting battery to the other position. For simplicity sake and to avoid mistakes and confusion like Maine suggests just place and keep the switch in the deep cycle batteries position and leave the starting battery as an emergency backup. Your deep cycles will be more than adequate to start the engine and provide house power and when motoring they will take charge from the alternator. Don't know what kind of battery charger you have installed but most will have 2 or 3 sets of output leads and if you connect a set to the starting battery and another set to the twin deep cycle batteries they will all take charge from shorepower irrespective of the position of the switch. The switch just controls which bank is supplying power to the loads and which bank may receive charge from the alternator. You could place the switch on the Both position if you want to charge both the starting and deep cycles from the alternator but if you just keep the starting battery as a backup there should be no need to recharge it as it will be getting its charge everytime you connect to shorepower. Just to clarify the starting battery goes to position #1 and the two deep cycles connected in parallel go to position #2 and when operating the boat just keep the switch in position #2. The two deep cycle batteries when connected in parallel in effect become a larger single battery and gets treated as one.

 

[Maine Sail]

Just to clarify the starting battery goes to position #1 and the two deep cycles connected in parallel go to position #2 and when operating the boat just keep the switch in position #2. The two deep cycle batteries when connected in parallel in effect become a larger single battery and gets treated as one.

Most pro's do it just the opposite and it has been this way for many years due to a few older products where the house bank/primary bank was considered the #1 battery. It requires no pass through BOTH and most find the term primary bank and secondary bank to line up well with the 1 & 2 positions. If you've always had house on #2 personal preference may win out but when using the batt switch as a House & Reserve or primary & secondary it makes sense to have the most used bank on the first position...