Just noticed that lights and radio stay on whether I select battery 1 or 2 or both when I would have wanted them on only I selected battery 2 so as to preserve battery 1 exclusively for starting. What am I missing?
How does a battery selector switch work?
- Thread starter Ted10028
- Start date
I believe if your switch is correctly wired, when you select battery 1 your lights and radio are only running off battery 1. When you select battery 2 on the switch your lights and radio are only running off battery 2. When switched to all you are connected to both batteries. Of coures when switched to off nothing is on. Hopefully you are not crossed wired somewhere.
Read this article:
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
For the article dlochner posted.In short, the switch selects which battery powers all of the loads. Depending on how the wiring is configured it may also select where the charging current from the alternator goes. As a rule of thumb don’t stay on “both” if you’re running heavy loads for a long time, as you may discharge both batteries to the point where you can’t start the engine. Also don’t switch to Off while the engine is running or it might fry the diodes in your alternator (depending on how it’s wired).
So if I understand you this means that when you start your engine from, say, battery 1 selector switch position 1, you are using battery 1 to start your engine and to keep light and radio running? So then after you start your engine you have to go below to select position 2 to prevent battery 1 from being used for lights and radio and not being fully charged for next start?
guessing games are fun sometimes but no one but you can know how your boat is wired. It certainly sounds like someone screwed up yours. Nothing except bilge pumps should have power when the switch is off.
To be fair he said everything runs whether in position 1, 2, or both; but not that things run when it’s set to off.
interesting, the article above suggested everyone should check to see if bilge is running when battery selector is in off position.
I think I get how switch works now. So perhaps best strategy is to just use battery 1 for everything, and only switch to battery 2 if battery 1 lacks power to start. And use "both" occasionally to charge both batteries. Does that make sense?
So that begs the question, should I buy 2 deep cycle batteries, or 2 dual purpose. Guy at west marine suggested 2 AGM dual purpose batteries today. He said all West Marine AGMs are dual purpose. I'm thinking 2 deep cycle batteries makes more sense. My diesel is only 30HP. Probably generic West Marine batteries assume more cranking power is needed on average than is needed for my little Yanmar.
Never buy batteries from West Marine. They are made by East Penn and the identical batteries can be purchased at Sam’s Club, NAPA, Batteries Plus and dozens of other retailers for significantly less money. Many WalMart locations also have the East Penn product. I will never advise the East Penn AGM’s as they are not a deep cycle product. Their GEL batts are amazing but you need the charging infrastructure correct or you’ll ruin them…
If I compare West Marine Deep Cycle group 31 ( Wet versus AGM) specs look about the same; price too. What deep cycle AGM do you recommend and what specs in particular are you looking at.?
Well @Ted10028, you've just made the discovery about the 1+2+B switch that leads some of us to make a change! Yes, the 1 position and the 2 position are nothing more than 2 separate battery banks that energize everything exactly the same way. The B position does nothing more than combine the 2 battery banks in parallel. If you are going to buy 2 batteries that are exactly alike, you may as well just wire them in parallel and run them on just one bank. That way, you will have more capacity. But then, you're screwed if you run the bank down.
You could also get just one deep cycle grp 31 and put it on bank 1 and get a much smaller cranking battery just for starting the engine and put it on bank 2. Better yet, put 2 deep cycles on bank 1 (for the house load capacity that you probably need) and a small start battery on bank 2. You need minimal cranking for starting the small engine, so it doesn't really matter at all which bank you use when starting the engine. But if you decide you want to start your engine only with the small start battery, then you are switching back and forth between 1 & 2. Only fools use the C position, except when charging ... but most of us now have charging relays and never have to use the C position for charging. It's an antiquated method by now. I'll say that the 1+2+B switch is antiquated now, but that statement usually gets me in trouble around here!
Some (maybe many) of us have installed the DCP switch in combination with an ACR. That way, our start battery is used just for starting the engine (and nothing else) and the house bank is used just for house loads alone. We simply turn it on and both banks are energized simultaneously, but separately as well. This can be done with just 2 ON-OFF switches, but I prefer the DCP switch. It has a combined position, but that is only used under specific conditions that I'm not going to describe. Maine Sail's articles cover this topic, both the positives and the negatives, in very great detail.
Here, again, is one of those topics where you should do your homework. There is plenty of information, readily available, and interesting, too. You can easily waste your batteries if you don't arm yourself with knowledge, so we encourage you to learn the ins and outs of your electrical and switching systems so that you can decide on your own what is best for you.
You could also get just one deep cycle grp 31 and put it on bank 1 and get a much smaller cranking battery just for starting the engine and put it on bank 2. Better yet, put 2 deep cycles on bank 1 (for the house load capacity that you probably need) and a small start battery on bank 2. You need minimal cranking for starting the small engine, so it doesn't really matter at all which bank you use when starting the engine. But if you decide you want to start your engine only with the small start battery, then you are switching back and forth between 1 & 2. Only fools use the C position, except when charging ... but most of us now have charging relays and never have to use the C position for charging. It's an antiquated method by now. I'll say that the 1+2+B switch is antiquated now, but that statement usually gets me in trouble around here!
Some (maybe many) of us have installed the DCP switch in combination with an ACR. That way, our start battery is used just for starting the engine (and nothing else) and the house bank is used just for house loads alone. We simply turn it on and both banks are energized simultaneously, but separately as well. This can be done with just 2 ON-OFF switches, but I prefer the DCP switch. It has a combined position, but that is only used under specific conditions that I'm not going to describe. Maine Sail's articles cover this topic, both the positives and the negatives, in very great detail.
Here, again, is one of those topics where you should do your homework. There is plenty of information, readily available, and interesting, too. You can easily waste your batteries if you don't arm yourself with knowledge, so we encourage you to learn the ins and outs of your electrical and switching systems so that you can decide on your own what is best for you.
If I were buying AGM batteries, I would get Odyssey, Northstar, or X2Power (exclusively sold by Batteries Plus). They are identical batteries all made by ENERSYS. They are priced higher. If you are strictly shopping for price, you can make a bad decision ... but that's on you. I would never buy a battery that is described as "Dual Purpose". BTW, your bad decisions (in our eyes) may work out fine in the beginning or they may work out perfectly fine altogether. It's all up to you to determine what serves you best.
Becareful when buying Northstar Batteries and any TPPL batteries. Many of them are designed for use in stable platforms, which boats are not. From the Northstar Website:
In almost all of these applications the battery is connected to a charging system that keeps them fully charged or they are fully charged daily. As suggested by the applications, these batteries are for backup if there is a power outage and once power is restored, they are quickly recharged.
Recently there was a thread here where a member bought a boat that had Northstar batteries which had died after 2 years. The prior owner had installed high end Northstars specifically designed for the telecom industry keeping cell towers powered during outages.
AGM Thin Plate
Yes, I've read that article. Last summer, when I purchased an AGM battery, Northstar sold a battery that is identical to the Odyssey and X2Power batteries that are produced for marine & RV markets.Becareful when buying Northstar Batteries and any TPPL batteries. Many of them are designed for use in stable platforms, which boats are not. From the Northstar Website:
AGM Thin Plate
www.northstarbattery.com
I'm thinking that they have modified their product line. As said before, Northstar, Odyssey, X2Power are all produced by ENERSYS.
Now, in the Northstar line, if you click on "Transportation" you are linked to Odyssey batteries. Also, in various websites, the Northstar line has LiFePo4 batteries listed as replacements for their older AGM line of batteries.
I think Northstar has probably realized that LiFePo4 is the better product for marine market. Also, X2Power is now offering LiFePo4 batteries that they didn't have last year, if I'm not mistaken. I don't know about Odyssey, but it appears the writing is on the wall!
Scott…I wonder about their actions.
“I think Northstar has probably realized that LiFePo4 is the better product for marine market.“
Is it that they concluded it is a “Better” product?
Or that it is an easier product to sell given the current hype and market interests?
“I think Northstar has probably realized that LiFePo4 is the better product for marine market.“
Is it that they concluded it is a “Better” product?
Or that it is an easier product to sell given the current hype and market interests?
Maybe, but I read Maine Sails articles and he is pretty adamant that AGM's don't even come close to the same value as LiFePo4.
I think I am going to do a AGM and next time around try to do lithium and solve whatever problems it causes with the charger and alternator.