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Dual battery wiring diagram

JetDrew1332

Member
Messages
13
Reaction score
5
Points
12
Boat Make
Yamaha
Year
2014
Boat Model
212X
Boat Length
21
Hello everyone. I purchased a 2014 yamaha 212X last summer and the original owner(s) had a yamaha dual battery kit installed. Part # SBT-DUALB-AT-08.
I checked all the literature he gave me but I could not find anything on the dual battery kit. I've tried searching the internet for the instructions/wiring diagram for the kit but have had no luck. I'm believe it's installed correctly because the boat ran fine and the aftermarket sound system had no issues. But I did find a 10 year old leaking starter battery when I winterized it. Because of that I'm trying to check everything to make sure it's wired correctly. First time boat owner and learning as I go. Any input on this would be greatly appreciated!
 
Does that help at all? This is from my 2020 boat..

624F5A21-C39B-40E7-8A64-6DC5D9C65FB1.jpeg
 
Does that help at all? This is from my 2020 boat..

View attachment 232575
Thank you for the diagram! It does help but instead of 3 individual switches i have 1. It's a 4 position: OFF, BAT 1, BOTH BAT, and BAT 2. Since i posted this I've done quite a bit of digging into other setups on all kinds of boats and with a better understanding of certain builds the picture is getting clearer. I'll attach a picture and link of the particular dual battery kit installed currently have installed.

 

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I should have posted this picture as well… this is what the switch looks like and came as OEM in my boat.

57C52431-B5AF-48F3-8847-E7AA78ECEA3A.jpeg
Since that battery kit you have includes a DVSR charge relay I’m going to assume that both batteries get charged by the engines no matter if only Batt 1 or Batt 2 is selected. This also means that by having Batt 1 selected, Batt 2 is isolated while floating and can be selected if Batt 1 is too low to start the engines and or Batt 1&2 can be selected to parallel.

The DVSR will close once voltage reaches 13.4 volts paralleling the two batteries, and will open when the voltage drops to 12.7 separating them.
 
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I should have posted this picture as well… this is what the switch looks like and came as OEM in my boat.

View attachment 232584
Since that battery kit you have includes a DVSR charge relay I’m going to assume that both batteries get charged by the engines no matter if only Batt 1 or Batt 2 is selected. This also means that by having Batt 1 selected, Batt 2 is isolated while floating and can be selected if Batt 1 is too low to start the engines and or Batt 1&2 can be selected to parallel.

The DVSR will close once voltage reaches 13.4 volts paralleling the two batteries, and will open when the voltage drops to 12.7 separating them.
This image is the closest thing I could find searching BEP dual battery switch wiring diagram on Google images. In my case I have 2 engines. Between your help and this diagram and some other info I found, I should be able to ensure wiring is correct. I was hoping for a direct diagram for my particular setup but just can't find one. I plan on adding bus bars, fuses, and Noco gen5 X2 charger. The previous owner had installed a new Kenwood 8 speaker sound system with amp and sub throughout the interior of the boat and 2 wet sounds tower speakers with their own amp. Needless to say the wiring was a bit messy and I'm starting at the batteries and working my way through the entire boat to make sure everything is correct. Then diving into some cable management to clean things up. Thank you for taking the take to help! It's much appreciated!
 

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BEP marine changed their website a while back to a “better” format and it’s hard for me at least to find what I’m looking for now, so great job on finding that diagram! Since you found it via google I was determined to find the diagram on BEP’s site, I did find it and linked it below, the image is a bit brighter. I also found the link to the DVSR, how it operates and such and is linked below as well.



The image you posted is how I imagined it would look, I wish there was a diagram that showed the moveable contacts in the 1, 2, 1&2 switch. Without seeing how the moveable contacts are configured and a description of whether or not they are a make then break, or a break then make configuration, I do not think you should ever operate this switch whilst the engines are running. If it is a break then make and the engines are running you could destroy your rectifier / regulators, I saw a mention of that in another switch cluster on BEP’s site. You can test this of course with a continuity meter to be sure. While the engines are running they need to be connected to a battery. I suppose that is the advantage of the 714 model switch that has separate switches for the house and start and a separate emergency parallel switch plus the DVSR in that both the start and house battery switches are always on whilst running the boat.

This is a nice compact little switch that will make sure that both your batteries get charged when the engine is running.

The DVSR can be configured to be fully automatic in that the DVSR is always sensing voltage from either battery and will close the switch as soon as it sees 13.4 volts from either battery, or in storage mode which means the DVSR is inactive until an ignition hot / run hot supplies control power to the DVSR. This storage mode is optimal for when the boat is not in use and or the batteries are being charged from an on board charger. This will enable your smart charger to charge the batteries independently assuring proper charging of each battery. This accomplished by cutting the little red wire on the back of the DVSR and is attached to the activation source of your choice-see the instructions in the second linked description of the DVSR operation. It appears with the single dual pole switch you have the little red wire could be attached to the COM so that the DVSR is activated when either battery is selected. Some folks have attached the DVSR red wire to the positive of one of the fuel pump hot wires but that is mainly for people running a LFP / LizfePO4 house battery.

The NOCO charger is used by a lot of folks on this website with great success but I’d recommend a 10x2 charger. Lead acid batteries need a charger that is 10-13% of their am hour rating to properly charge them. If you have a 75Ah battery 13% is 9.75 amps. And speaking of batteries you’ll want to have dual purpose batteries, Start / Deep cycle batteries.

Your plan of cleaning up the battery and house wiring by placing them on buss bars is excellent!

You’re welcome for the help! It was fun learning how the single switch and DVSR switch operates.
 
BEP marine changed their website a while back to a “better” format and it’s hard for me at least to find what I’m looking for now, so great job on finding that diagram! Since you found it via google I was determined to find the diagram on BEP’s site, I did find it and linked it below, the image is a bit brighter. I also found the link to the DVSR, how it operates and such and is linked below as well.



The image you posted is how I imagined it would look, I wish there was a diagram that showed the moveable contacts in the 1, 2, 1&2 switch. Without seeing how the moveable contacts are configured and a description of whether or not they are a make then break, or a break then make configuration, I do not think you should ever operate this switch whilst the engines are running. If it is a break then make and the engines are running you could destroy your rectifier / regulators, I saw a mention of that in another switch cluster on BEP’s site. You can test this of course with a continuity meter to be sure. While the engines are running they need to be connected to a battery. I suppose that is the advantage of the 714 model switch that has separate switches for the house and start and a separate emergency parallel switch plus the DVSR in that both the start and house battery switches are always on whilst running the boat.

This is a nice compact little switch that will make sure that both your batteries get charged when the engine is running.

The DVSR can be configured to be fully automatic in that the DVSR is always sensing voltage from either battery and will close the switch as soon as it sees 13.4 volts from either battery, or in storage mode which means the DVSR is inactive until an ignition hot / run hot supplies control power to the DVSR. This storage mode is optimal for when the boat is not in use and or the batteries are being charged from an on board charger. This will enable your smart charger to charge the batteries independently assuring proper charging of each battery. This accomplished by cutting the little red wire on the back of the DVSR and is attached to the activation source of your choice-see the instructions in the second linked description of the DVSR operation. It appears with the single dual pole switch you have the little red wire could be attached to the COM so that the DVSR is activated when either battery is selected. Some folks have attached the DVSR red wire to the positive of one of the fuel pump hot wires but that is mainly for people running a LFP / LizfePO4 house battery.

The NOCO charger is used by a lot of folks on this website with great success but I’d recommend a 10x2 charger. Lead acid batteries need a charger that is 10-13% of their am hour rating to properly charge them. If you have a 75Ah battery 13% is 9.75 amps. And speaking of batteries you’ll want to have dual purpose batteries, Start / Deep cycle batteries.

Your plan of cleaning up the battery and house wiring by placing them on buss bars is excellent!

You’re welcome for the help! It was fun learning how the single switch and DVSR switch operates.
Boy am I glad you mentioned the batteries! I opted for group 27 instead of the group 24 that were in there due to the sound system and our boating habits. But if you advise in sticking with group 24, i will follow. We like to beach and jam out to music for extended periods of time. And most of the time we are on small lakes or short stretches of river. We also do alot of wakeboarding and tubing which helps with recharge. I'll attach the pics of the batteries I bought and tell me what you think. Kinda on a budget so I went with Interstate brand. The Interstate SRM-27 is described as a dual purpose battery on Interstate's website, ill attach that link as well. With you advising to go with 2 dual purpose, I'll have to see if I can exchange the starter battery (should be able to, I bought it from an actual Interstate store locally a couple weeks ago and hasn't been used).


With what you mentioned about the Noco charger, I'll definitely be underrated. The Gen5x2 is only rated for 5A per bank.

I still have time for the battery exchange but I've been long out of time for the charger return at Amazon. Wish I would've started here before just winging my purchases.
 

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Update: I did some more digging on the Noco gen5x2 on their website and this charger i capable of charging up to 120ah but it takes quite some time. Their graph shows how long in hours it takes to charge different ah batteries. I'm hoping to still use this charger as it cannot be returned. What do you think? The attached link will show a user guide and data sheet. Again thank you for all your help! I feel like I'm almost their thanks to you.

 
No worries on the battery charger.. as you mentioned it is the time, and the only time you will feel a pinch here is if you are really pulling the batteries down and don’t have enough time for the charge cycle to complete before the next outing.

I will suggest you get a hydrometer and check the gravity on the batteries regularly until you can bench mark how they are doing. What you will be looking for is overall specific gravity, and a balance between the cells. At least once a month you will want to run an equalizing charge on your batteries, in the noco manual it is called repair mode, this will correct the main problem you will have which is stratified electrolyte, this mode will not only increase the overall gravity but will balance the cells. I’ve seen a lot of people not do equalizing charges on their FLA batteries and then complain there is not enough capacity and add more batteries (huge weight gain) and still not have the capacity they are looking for. Fun fact, FLA deep cycle batteries typically need about 8-12 cycles from new before they reach full capacity. You will also notice in the fine print of the noco charger user guide it mentions a “typical” discharge which is 50% or rated capacity, so a 100Ah battery is only capable of 50Ah of discharge without degridating the life span of the battery. Typical life span of a FLA battery is 500 cycles. Again, this gravity / equalizing charge can be bench marked and you can develop a schedule over time to how often you need to do it.

The batteries; I think if you can change out that start only battery to the SRM-27 battery that you bought it would be good. Our engines don’t draw a lot of cranking amps in the first place and the specs on the SRM 27 (stick with the group 27’s) look pretty good, 88 Ah rating so you’ll have 44Ah’s for each battery. Be sure and pick up a jump starter pack to keep on board just in case you or someone else needs it. I only run a group 24 start battery because it is a dedicated start battery, your situation is a bit different though and you may want to alternate your batteries for deep cycle usage.

In addition, I’d put one of these smart shunts on each of your house batteries, they’re about $100 bucks and are configurable to any battery chemistry and Ah rating, then you will know for sure how much power is left in each battery SOC or state of charge, how many Ah’s & KWh’s you have used, and voltage of the battery etc. They are very small and connect via the Bluetooth Victron app which is free. And you will see current flow in each direction in real time, so when you are at the sand bar / beach you will see negative or minus current and when you are underway you will see current without a — in front of it meaning current flowing into your battery from the engines, and the SOC will update in real time. I know you are on a budget, but these things are priceless in that you will KNOW how much battery power you are using. I suppose you could put just one of them on the main ground between the batteries and ground, as long as you just were to use one battery you’d know what you did to that battery without having to guesstimate the useage of the other battery if you switch over to it. Myself, I want to have one battery that is reserved for engine starting only.

This information will be valuable down the road if you ever decide you need more capacity, your usage sounds like you might be a candidate for a LFP battery which are expensive but well worth the performance and weight savings. But that is well down the road.
 
No worries on the battery charger.. as you mentioned it is the time, and the only time you will feel a pinch here is if you are really pulling the batteries down and don’t have enough time for the charge cycle to complete before the next outing.

I will suggest you get a hydrometer and check the gravity on the batteries regularly until you can bench mark how they are doing. What you will be looking for is overall specific gravity, and a balance between the cells. At least once a month you will want to run an equalizing charge on your batteries, in the noco manual it is called repair mode, this will correct the main problem you will have which is stratified electrolyte, this mode will not only increase the overall gravity but will balance the cells. I’ve seen a lot of people not do equalizing charges on their FLA batteries and then complain there is not enough capacity and add more batteries (huge weight gain) and still not have the capacity they are looking for. Fun fact, FLA deep cycle batteries typically need about 8-12 cycles from new before they reach full capacity. You will also notice in the fine print of the noco charger user guide it mentions a “typical” discharge which is 50% or rated capacity, so a 100Ah battery is only capable of 50Ah of discharge without degridating the life span of the battery. Typical life span of a FLA battery is 500 cycles. Again, this gravity / equalizing charge can be bench marked and you can develop a schedule over time to how often you need to do it.

The batteries; I think if you can change out that start only battery to the SRM-27 battery that you bought it would be good. Our engines don’t draw a lot of cranking amps in the first place and the specs on the SRM 27 (stick with the group 27’s) look pretty good, 88 Ah rating so you’ll have 44Ah’s for each battery. Be sure and pick up a jump starter pack to keep on board just in case you or someone else needs it. I only run a group 24 start battery because it is a dedicated start battery, your situation is a bit different though and you may want to alternate your batteries for deep cycle usage.

In addition, I’d put one of these smart shunts on each of your house batteries, they’re about $100 bucks and are configurable to any battery chemistry and Ah rating, then you will know for sure how much power is left in each battery SOC or state of charge, how many Ah’s & KWh’s you have used, and voltage of the battery etc. They are very small and connect via the Bluetooth Victron app which is free. And you will see current flow in each direction in real time, so when you are at the sand bar / beach you will see negative or minus current and when you are underway you will see current without a — in front of it meaning current flowing into your battery from the engines, and the SOC will update in real time. I know you are on a budget, but these things are priceless in that you will KNOW how much battery power you are using. I suppose you could put just one of them on the main ground between the batteries and ground, as long as you just were to use one battery you’d know what you did to that battery without having to guesstimate the useage of the other battery if you switch over to it. Myself, I want to have one battery that is reserved for engine starting only.

This information will be valuable down the road if you ever decide you need more capacity, your usage sounds like you might be a candidate for a LFP battery which are expensive but well worth the performance and weight savings. But that is well down the road.
I truly appreciate the time you took to educate me on this subject. It means alot! When I get the install done and tested i will definitely take the time to take pictures and upload to the group.
 
I truly appreciate the time you took to educate me on this subject. It means alot! When I get the install done and tested i will definitely take the time to take pictures and upload to the group.
You are welcome! I’m sure we would all like to see the finished project!

These things here are pretty cool, I think they take a #4 wood screw??? Can’t remember the size but they sure make running wires and such neat and tidy..
 
Boy am I glad you mentioned the batteries! I opted for group 27 instead of the group 24 that were in there due to the sound system and our boating habits. But if you advise in sticking with group 24, i will follow. We like to beach and jam out to music for extended periods of time. And most of the time we are on small lakes or short stretches of river. We also do alot of wakeboarding and tubing which helps with recharge. I'll attach the pics of the batteries I bought and tell me what you think. Kinda on a budget so I went with Interstate brand. The Interstate SRM-27 is described as a dual purpose battery on Interstate's website, ill attach that link as well. With you advising to go with 2 dual purpose, I'll have to see if I can exchange the starter battery (should be able to, I bought it from an actual Interstate store locally a couple weeks ago and hasn't been used).


With what you mentioned about the Noco charger, I'll definitely be underrated. The Gen5x2 is only rated for 5A per bank.

I still have time for the battery exchange but I've been long out of time for the charger return at Amazon. Wish I would've started here before just winging my purchases.
The 5a is perfect for that setup, don't change it. I have the same starting battery with a noco 5x3, I am using x2 lithium batteries on a separate perko switch and its a fantastic setup, low amp charging is always best unless you need a quick turnaround. The shunt is not completely necessary IMO since you are not using lithium so running your battery low, although not ideal, isn't the end of the world but it is nice to know how much power you draw. Just wire it into the negative wire from your house battery. After I get home and wash the boat I plug it in overnight and its always good to go.
 
Here’s a great link to battery maintenance;

I wrote to interstate this morning and asked what their recommendation for charge rates are on their flooded lead acid batteries

4EC90589-A5A2-475B-93E4-9A93BBC26FB6.jpeg


is and this was the response I received from the lab manager.

F4073A66-1A62-4A0D-B13B-90CFF2550E87.jpeg

Will a 5A work? Yes, it will just take twice as long to charge the battery. I forgot to mention before to not let your partially discharged battery sit for any longer than you can get it on a charger.
 
Great news! That will be just fine. I really only boat on the weekends and I always trailor to and from spots. There's only 1 time a year I take it to a lake where I moor for around 8 days but like I mentioned before we are always tubing and wakeboarding.

I did think more about how the Noco charger should be wired to everything. Should I run the a negative from each battery to the bus bar instead of bridging the 2? And should I land the battery charger leads directly to the battery posts or the the bus bars? Is it ok the leave the charger leads always connected to said points (not plugged into power of course)? And when the charger is in use, of course have the battery switch to off but does the negative need to break somewhere? These were all questions that popped up yesterday when thinking more about it. I definitely could be over thinking the whole thing.
 
Connect the NOCO charger leads directly to the batteries and leave them connected.
Connect the positives from the engines directly to the starter and or battery #1. Let the DVSR tie them together for engine based charging.
If you are going to use positive buss bars for each battery be sure they are separate from each other, again, let the dvsr tie them together for engine based charging. This is a great idea for the house / accessory loads in that each load wire has a separate connection to the positive buss bar E.G. no stacking of connectors.

Landing the battery grounds and the other grounds on a common ground bus is a great idea. Leaving them tied tougher is fine.
 
Connect the NOCO charger leads directly to the batteries and leave them connected.
Connect the positives from the engines directly to the starter and or battery #1. Let the DVSR tie them together for engine based charging.
If you are going to use positive buss bars for each battery be sure they are separate from each other, again, let the dvsr tie them together for engine based charging. This is a great idea for the house / accessory loads in that each load wire has a separate connection to the positive buss bar E.G. no stacking of connectors.

Landing the battery grounds and the other grounds on a common ground bus is a great idea. Leaving them tied tougher is fine.
Got it. Will do. Good news! I have a friend of mine I haven't talked to in years reach out to me and help me with the batteries/wiring, as well as the sound system. He used to do it for a living. So bewltween your advise and his experience I'm sure this will be done correctly. Thanks again!
 
Got it. Will do. Good news! I have a friend of mine I haven't talked to in years reach out to me and help me with the batteries/wiring, as well as the sound system. He used to do it for a living. So bewltween your advise and his experience I'm sure this will be done correctly. Thanks again!
Awesome things are lining up nicely for a great boating season!
 
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