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Post by bushwacker on Oct 9, 2017 21:35:04 GMT -5
I have ended up getting a 2nd battery for the boat. I already have a switch installed that came with the boat. It has positions 1,2,both,off. I am wanting to make sure the existing wiring is right. As of now with a single battery. The positive from the engine is on the common post on the switch. The Alternator positive is there as well as the a positive wire going to my house circuit breaker. The negative from engine is on the negative post to the battery. The positive on the battery is connected to position 1 on the switch. (Not connected) There is another positive wire connected to position 2 now. I know it will go on the 2nd battery. There are also 2 negative leads connected to the negative buss bar. When I install the 2nd battery should I put the negative from the engine to the buss bar and connect each of the existing leads to each negative post on the batteries? Here's what I am thinking. Thanks for any help.  |
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Post by mwardncsu on Oct 9, 2017 21:52:38 GMT -5
Hard to answer without more details on the wire size(s), specifics of the bus bar (size / rating) etc.
I’m not a fan of those setups as you are using a cranking batt for cranking but also constant draw purposes (which should be fed from a deep cycle).
I prefer a three switch setup - one each between a battery and the load(s) - so a cranking batt with the switch on the positive lead to the motor, and then a switch between a deep cycle and a fuse panel where the loads are distributed. Then, a third switch can bridge the two batteries for emergency parallel if your cranking batt goes out and you need to help boost it to from the deep cycle to get back home.
I general what you’ve drawn looks correct for that type of setup but I’d want to know more on the wire gauges, the bus bar rating size, the cranking motor draw, etc before saying you’re fine
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Post by bushwacker on Oct 10, 2017 7:16:55 GMT -5
2 ga. From motor positive and negitive. 6 ga. Positive and negitive from switch and negitive buss bar. I have ran the boat on this single battery for over a year now. That battery powers everything. Just looking to add a battery for peace of mind when out on long trips. Thinking of switching batteries every other time out to keep them consistent.
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Post by mwardncsu on Oct 10, 2017 8:41:23 GMT -5
I'm confused on what the 6ga is connected to - but 6ga is not likely enough to be a connection path for your motor - it's fine for the feed to your panel for lights, fish finder, etc, etc.
Not sure what the "POS Circuit" box in your drawing is - I assume this is the fuse panel/switch block/etc for your lights, pumps, etc? Need to know the total current draw that could come from this.
Again, I'm not wild on using cranking batts for my constant loads as you WILL prematurely kill your cranking batteries - they are designed for high-current, short-burst loads. Constant draws need deep-cycle batteries which are designed for steady supply of current but not necessarily in high-burst.
As to switching back in forth between trips - if you go with this setup then yes, do that - but I'd also suggest a two-bank charger connected to the two batteries to keep them topped up / maintained when not on the water - especially since you will be pulling on them with your constant source feeds?
For the setup as you have wired above, I would have 2ga wire going from the motor to the common on the switch, and from "1" on the switch to Battery 1's Postive - and also from "2" on the switch to Battery 2's positive terminal. Then, for the ground path, you should be using 2 Ga also from the motor and from the negative terminals on each battery. Not knowing the specs on you bus-bar and it's current ratings, I would suggest you connect these three 2 ga wires together on one terminal post - that way they are all together and current runs between then - not across the bus-bar which may or may not be rated for it. If you know the specs on the bus-bar are rated for the current draw of the motor + your constant sources, then you could distribute the connections across your bus-bar.
As to the constant source connected to your fuse block/panel/switches, etc - connect the 6 ga wire from the common terminal on the battery switch to the panel feed. Either home run all your grounds from your lights, pumps, fish-finder, etc to your bus bar, or have those go to a common ground connection and then run a 6 ga back from that to the bus-bar in your diagram.
Also - you should have a fuse on each battery within 7" in-line of the positive wire off the battery's positive terminal. Often the cranking motor itself is not fused when it is connected directly to a cranking battery. At a minimum you should have a fuse on the 6 ga wire immediately after the switch to protect that wire (fuses protect the wire from overload in the event of a short and then fire - not the device connected...)
Hope some of this makes sense and helps...... it is not terribly complex, but there is a bit of engineering that needs to go into the design of a safe power system for boat... last thing you want is a fire when you're out on the water....
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Post by mwardncsu on Oct 10, 2017 8:48:21 GMT -5
Also - forgot to mention but with most motors you do NOT want to turn the switch from 1 to Off to 2 with the motor running. If your switch is actually a 1/2/1+2/Off then you can turn it through 1 to 1+2 to 2 but not from 1 to off to 2 (or vice-versa of course)
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Post by bushwacker on Oct 10, 2017 9:39:36 GMT -5
Also - forgot to mention but with most motors you do NOT want to turn the switch from 1 to Off to 2 with the motor running. If your switch is actually a 1/2/1+2/Off then you can turn it through 1 to 1+2 to 2 but not from 1 to off to 2 (or vice-versa of course)  This is my switch. |
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Post by mwardncsu on Oct 10, 2017 9:43:38 GMT -5
gotcha - so just be careful in not switching from 1 to Off to 2 (or vice-versa) if the motor is running.... (guess the switch says that too  ) |
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Post by bushwacker on Oct 10, 2017 9:52:30 GMT -5
gotcha - so just be careful in not switching from 1 to Off to 2 (or vice-versa) if the motor is running.... (guess the switch says that too )  This diagram is what I am seeing most common. Where the engine neg. comes into batt. 1 then batt 1 neg. connected to battery 2 neg then a neg. from 2 going to the neg buss bar. |
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Post by mwardncsu on Oct 10, 2017 9:56:07 GMT -5
A bus bar is just a common connection point - this is the same thing without the bus-bar - the main thing is the negative cable has to be able to carry all the same current as the positive side - hence my comments on needing to know the rating of the bus-bar you have.
In the pic above it does not matter if the negative from the motor connects to the negative from Batt 1, Batt 2 or if it went to a bus-bar and the neg from batt 1 and batt 2 also connect to the bus-bar (assuming the bus-bar is rated for the appropriate amperage). The important thing is all the ground sides are connected together to a common ground potential.
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Post by mwardncsu on Oct 10, 2017 10:02:32 GMT -5
The diagram above shows now fuses on the larger cables - as I mentioned often the motor is not fused - with the logic that the high amp draw is usually short - unless the started "sticks" and keeps running and could create an overlay situation - then you can throw the switch to kill the circuit..... you definitely want a fuse on the smaller gauge wire that comes off the commmon that feeds the constant load panels - it should be side to something a below the carrying capacity of that wire (6 ga can carry up to 100-120A). The safest is to all up all the loads that is supplies - that may be overkill as often not all the loads will be on at the same time - but they might.
In the diagram above, they are using a distribution fuse box that also has a ground "bus bar" integrated for the smaller loads - you connect the grounds of your pumps, lights, fish finder, etc to that - then you need a ground wire large enough to carry the current for anything connected to that ground back to the battery or the main common bus-bar - use the same gauge as the positive that supplies and you should be fine
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Yam
New Member
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Post by Yam on Oct 11, 2017 6:32:09 GMT -5
Hi Bush. I can tell you that one of the best things I have done for my boat is to use an ACR switch (Google: Blue Sea 7650). This is a smart switch that automatically isolates your batteries from each other when you are using your house battery. What this means is that when you are trolling, battery power is only sucked from your house and your starting battery is left alone. Once you start your engine, both batteries are then connected together and charged from the alternator. Additionally, the power draw from starting the engine will not be seen in all of your other stuff such as your expensive electronics. I use a deep cycle for my house and a regular starting battery for my engine. Trust me.... It's worth understanding, buying and using. All of my power issues were immediately solved with this little gadget!
The whole 2 battery switch with two starter batteries that typically come with a boat makes zero sense to me. Starter batteries are not meant to be drawn down and will die quickly if exposed to what we do as striper fishermen. And if you run the basic switch with a deep cycle and a starter, then you will always have to turn the switch each time you start trolling and each time you start up or you will most definitely kill your starter battery.
With the system above, I have been using the same batteries since 2013 and have overcome many obstacles that have left others dead in the water.
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Post by smlfishing on Oct 11, 2017 7:36:14 GMT -5
Sounds like some solid advice. One thing to remember is to make sure your bilge pump is hooked up so it retains power even if you turn your batteries off.
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Post by mwardncsu on Oct 11, 2017 8:14:15 GMT -5
Sounds like some solid advice. One thing to remember is to make sure your bilge pump is hooked up so it retains power even if you turn your batteries off. This is a good point - the bilge should be directly connected to one of the batteries, with a in-line fuse on the positive lead to the pump. |
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Post by bushwacker on Oct 11, 2017 14:18:56 GMT -5
Hi Bush. I can tell you that one of the best things I have done for my boat is to use an ACR switch (Google: Blue Sea 7650). This is a smart switch that automatically isolates your batteries from each other when you are using your house battery. What this means is that when you are trolling, battery power is only sucked from your house and your starting battery is left alone. Once you start your engine, both batteries are then connected together and charged from the alternator. Additionally, the power draw from starting the engine will not be seen in all of your other stuff such as your expensive electronics. I use a deep cycle for my house and a regular starting battery for my engine. Trust me.... It's worth understanding, buying and using. All of my power issues were immediately solved with this little gadget! The whole 2 battery switch with two starter batteries that typically come with a boat makes zero sense to me. Starter batteries are not meant to be drawn down and will die quickly if exposed to what we do as striper fishermen. And if you run the basic switch with a deep cycle and a starter, then you will always have to turn the switch each time you start trolling and each time you start up or you will most definitely kill your starter battery. With the system above, I have been using the same batteries since 2013 and have overcome many obstacles that have left others dead in the water. Yam thanks for the input. What does your charging setup look like for these 2 batteries. Do you have a duel charger or do you just charge your house battery over night. Seems like the starting battery would hold up pretty good only being used to start the engine and then being charged while driving. |
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Yam
New Member
Posts: 585
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Post by Yam on Oct 11, 2017 14:28:52 GMT -5
Hi Bush. I can tell you that one of the best things I have done for my boat is to use an ACR switch (Google: Blue Sea 7650). This is a smart switch that automatically isolates your batteries from each other when you are using your house battery. What this means is that when you are trolling, battery power is only sucked from your house and your starting battery is left alone. Once you start your engine, both batteries are then connected together and charged from the alternator. Additionally, the power draw from starting the engine will not be seen in all of your other stuff such as your expensive electronics. I use a deep cycle for my house and a regular starting battery for my engine. Trust me.... It's worth understanding, buying and using. All of my power issues were immediately solved with this little gadget! The whole 2 battery switch with two starter batteries that typically come with a boat makes zero sense to me. Starter batteries are not meant to be drawn down and will die quickly if exposed to what we do as striper fishermen. And if you run the basic switch with a deep cycle and a starter, then you will always have to turn the switch each time you start trolling and each time you start up or you will most definitely kill your starter battery. With the system above, I have been using the same batteries since 2013 and have overcome many obstacles that have left others dead in the water. Yam thanks for the input. What does your charging setup look like for these 2 batteries. Do you have a duel charger or do you just charge your house battery over night. Seems like the starting battery would hold up pretty good only being used to start the engine and then being charged while driving. I originally had a dual charger so I just use it. As you said, my cranking battery never really needs it. A single charger will work and I'm pretty sure that if you turn the switch to combine, that charging your deep cycle would charge your cranking battery although it would increase the time taken to fully charge the deep cycle. |
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