BUS Bars and Dual Batteries

[Theryan]

I agree, a switch cuts off the battery connection for safety. I don't need to charge on weekends as I'm using the boat, but plug in the on-board charger if I'm not using the boat for a couple days or more - like during the week - to keep everything topped up and ready for the next outing. A switch ensures there is no battery drain in the event you forget to charge or don't need to charge every day like me.

My charging system will top back up to full on both the start and house batteries if I run at cruising speed for 15-20mins after hours of floating (figure about 30 amps total available to charge), but I'm only running a digital amp (JL Audio MX500/4) added on to the stock Fusion and Connext 6-speaker system - it doesn't draw that much unless we're really pounding the tunes, and most of the time we're on or near the boat so we don't have it cranked. Some times we're very close to the ramp and it won't get topped up, and on those days I'll plug in the charger to make sure they're good, but most days we're a bit further and the batteries hit 14.2v or more by the time we're back at the ramp. Once the engines are off, surface voltage is 12.7v which is perfect for turning off the switches as the batteries are at 100%.

A critical part is ensuring you have a good multi-stage smart charger as well. A good one is marine certified and ignition protected so you have no worries of sparking the hydrogen gas if the batteries vent (sealed batteries typically don't vent with these chargers). And the multi-stage will top them up and maintain them at 100% by cycling on and off to keep them topped up without worrying about over-charging.

Yeah, I've got a nice Noco smart dual bank charger.

Realistically, not feeling like doing the switch also comes from feeling like I don't want to spend the time doing it if I don't need it.

The ACR should allow the stator to maintain the charges (I don't believe that our boats actually charger like an alternator, but rather just maintain where it's at, but keep me honest if I'm wrong).

I always plug in and leave my plugged in when at home, so it's never a big issue.

I also honestly have fears of hooking up the switch incorrectly and don't want to have to get a bunch of new wire, etc. to do it if it isn't necessary.

 

[212s]

Realistically, not feeling like doing the switch also comes from feeling like I don't want to spend the time doing it if I don't need it.

Not sure what's involved, but if you have to remove the battery cables to wire in the ACR, you might as well put the switch in. But that's up to you.

The ACR should allow the stator to maintain the charges (I don't believe that our boats actually charger like an alternator, but rather just maintain where it's at, but keep me honest if I'm wrong).

A stator is what's inside an alternator to generate current, so essentially the same thing. However, since our engines are small with less torque than a car engine, the stators are small, so they produce about 25 amps each of current at max output which is plenty to run the boat and charge the batteries under typical conditions (typical vehicle alternator is 85-150 amps depending on vehicle). My boat has twin engines so produces about 50 amps to run and charge the batteries.

If you're adding more batteries and amplifiers to your boat, then you're going to need to charge them up with an auxiliary power source when not in use like an on-board charger. For those of us in winter climates, a charger is required to maintain the batteries during the off season too. This isn't new or unique to boats though - car stereo enthusiasts are often required to upgrade their alternators to higher output and/or add second and third batteries to drive their 1000w+ systems, and sometimes they use battery chargers at home.

I always plug in and leave my plugged in when at home, so it's never a big issue.
I also honestly have fears of hooking up the switch incorrectly and don't want to have to get a bunch of new wire, etc. to do it if it isn't necessary.

I understand that...no matter what you choose, make sure you triple-check all the connections so you don't do any damage. It's not really that hard to do something like this, but it's easy to misplace a wire. Let us know how it works out.

 

[Theryan]

So, the more I'm thinking about it you guys have convinced me to just do the full add a battery kit.

I was reading the other threads on the install, and I have the general idea of how to install them, but there is some confusion.

Being that I will be using a dual bank on board charger...

Should i be installing the ACR on the load side?
And I can't for the life of me figure out which fuses I should be using for these. Any advice?

Thanks for all of the help, guys. I'll post pictures when it's done eventually!

 

[tdonoughue]

http://assets.bluesea.com/files/resources/instructions/990310020.pdf

This is the instructions from Blue Sea (which are quite good). Go to page 2, left side. Note that the gray wires are optional--so I would just not worry about them. Only difference is that you will have 2 engines, so 2 wires from the starters rather than the 1 shown. They even show you the negative bus bar, in case you get one...

 

[ctyke]

And I can't for the life of me figure out which fuses I should be using for these. Any advice?

Thanks for all of the help, guys. I'll post pictures when it's done eventually!

here is what I got to hook up the acr.
InstallGear 8 Gauge AWG 1ft Power... Amazon.com: InstallGear 8 Gauge AWG 1ft Power Wire with 60A AGU Fuse Holder - 99.9% Oxygen-Free Copper: Car Electronics
And bought some more 8 gauge to run directly to the battery. Some run them to the switch. Also you need to run a negative to the negative bus bar.

 

[Theryan]

http://assets.bluesea.com/files/resources/instructions/990310020.pdf

This is the instructions from Blue Sea (which are quite good). Go to page 2, left side. Note that the gray wires are optional--so I would just not worry about them. Only difference is that you will have 2 engines, so 2 wires from the starters rather than the 1 shown. They even show you the negative bus bar, in case you get one...

I've only got one engine in my boat, so no modifying it there.

Now the question, and what I posted in another thread, is that I just need to figure out the following:

-Which size fuse I need.
-Do I need to install the ACR on the battery side, or the load side, considering i have a dual bank battery charger (the answers on this one vary, so I'm not positive which way to go).

Thanks for the help!

 

[Theryan]

here is what I got to hook up the acr.
InstallGear 8 Gauge AWG 1ft Power... Amazon.com: InstallGear 8 Gauge AWG 1ft Power Wire with 60A AGU Fuse Holder - 99.9% Oxygen-Free Copper: Car Electronics
And bought some more 8 gauge to run directly to the battery. Some run them to the switch. Also you need to run a negative to the negative bus bar.

Oh, that fuse holder is exactly what I've been looking for! I was looking at the ones from amplifier companies, but this one would work great. Was 60 amp what you went with for the fuse?

 

[ctyke]

I went with the 60 AMP fuses.
So, I didn't mess with the OEM wiring, one of those wires is what charges the starting battery. I simply moved all the red one to the new switch. I added the ACR, one red wire to each battery and a smaller ground wire to the ground block. When the engines are running, they supply voltage back to the battery, the ACR senses that and supplies voltage to both batteries. No need to run additional wires back from the engine(s). I also didn't add in the starter isolation.

 

[tdonoughue]

I think I went with 100A, but other than that, exactly what he said...

 

[djtech2k]

I just got my boat and it has a dual battery setup but it has 2 switches attached. I do not understand why. The radio also stays on even with the switches turned off. So I definitely want to rewire mine.

My question is about bus bars. I want to use them but what size did you guys use? I just ordered and received some from amazon but they are HUGE. I think it says its 5/16" but the bolts/posts are very big. I have glanced at the batteries in the boat so I do not know what size connections are there.

What did you guys use?

On a side note, I bought the Noco Genius dual battery charger. It is the 4amp version. After using my boat for the first time Saturday, I hooked up the charger. Battery 2 turned green within 1 day. Battery 1 is still showing red on the charger. I looked and both batteries have a sticker from 2019, so they look pretty new. I have powered down the charger and hooked it back up 2x but no change from red. Has anyone experienced this?

 

[Theryan]

That's the same charger that I have. It's a slow charging guy, so check on it again periodically. If your battery was really discharged then it'll take some time to get it back to full, as the charger adjusts itself to what the battery needs.

 

[tdonoughue]

As to the bus bar, I don't remember what amperage either of mine are, but Amazon does.

For the negative back by the battery I got a 150A with 1/4" studs (Blue Sea 2307).
For the positive back by the battery I got a fuse block (Blue Sea 5029)
For up by the helm, I got a Blue Sea Dualbus 5x8-32 100A (and then connected it to the fuse block and bus bar.

Seems to be working for me...

On the charger, sounds like you just need to leave that puppy plugged in longer. After the batteries are charged, leave it plugged in to maintain them.

 

[djtech2k]

As to the bus bar, I don't remember what amperage either of mine are, but Amazon does.

For the negative back by the battery I got a 150A with 1/4" studs (Blue Sea 2307).
For the positive back by the battery I got a fuse block (Blue Sea 5029)
For up by the helm, I got a Blue Sea Dualbus 5x8-32 100A (and then connected it to the fuse block and bus bar.

Seems to be working for me...

On the charger, sounds like you just need to leave that puppy plugged in longer. After the batteries are charged, leave it plugged in to maintain them.

Thanks.

I don't have any extra audio or electronics installed right now, but do plan to add some. The bus bars I got are just so big that it doesn't seem like the cable ends will be big enough to fit on them. I have not verified, but I am pretty sure. I assume the cables to the motors will be the biggest cable I have right now.

I will check out those models. So I guess 1/4" is will fit the engine cables and the helm/electronics.

For the charger, I checked it last night and batt 1 was still red light. It has been charging non-stop since Saturday or Sunday.

 

[djtech2k]

Ok so I finally got the chance to get back in the boat. I wanted to document how it is wired with the 2 switches so that I could re-wire it properly with the single switch. I cannot figure out how to get the cover off of the switches. There are 4 screws/bolts hold it to the board/wall. I could reach my hand behind 1 of them and think I felt a nut holding it on. My issue is that I do not know how to get behind this board/wall. Does it come out somehow? I will post a picture of it below. I am sure this is simple, but I could not find how to get behind it.

On the other note, battery 1 is still red on the charger. Its been charging since Sat/Sun. Just to test, I flipped the outputs on the charger to see if it reads the same way and it does. Battery 1 is still showing red light, which means charging. There is now way it should need 6 days to charge. Any ideas?

 

[ctyke]

Ok so I finally got the chance to get back in the boat. I wanted to document how it is wired with the 2 switches so that I could re-wire it properly with the single switch. I cannot figure out how to get the cover off of the switches. There are 4 screws/bolts hold it to the board/wall. I could reach my hand behind 1 of them and think I felt a nut holding it on. My issue is that I do not know how to get behind this board/wall. Does it come out somehow? I will post a picture of it below. I am sure this is simple, but I could not find how to get behind it.

On the other note, battery 1 is still red on the charger. Its been charging since Sat/Sun. Just to test, I flipped the outputs on the charger to see if it reads the same way and it does. Battery 1 is still showing red light, which means charging. There is now way it should need 6 days to charge. Any ideas?

Check out Perko for wiring diagrams, looks like its just the 4 screws that hold it to the wall, so remove those and it should come off.

PERKO Inc. - Catalog - Battery Switches - Medium Duty Battery Selector Switch [8501]

PERKO Figure No. 8501 Medium Duty Battery Selector Switch [8501DP, 8501, battery switch]

www.perko.com

As for your battery, sounds like it could be bad, I would disconnect everything and try charging it and bring it in to have it tested.

I personally don't like everything connected to the batteries, makes it rather hard to remove and connect everything back up and can lead to battery drain. So I use bus bars and fuse panels.

 

[djtech2k]

Thanks.

So I followed the link and looked at the install instructions. I’m assuming mine are the same switches. Anyway, the wiring diagrams show 2 switches with 2 batteries and 2 engines. I do not know why it would do that. Wouldn’t you want 1 switch with 2 batteries?

 

[tdonoughue]

That is the weirdest thing I have seen in awhile.

So, to pull the connectors off the switches, pull the switch off the wall by undoing the 4 screws. Then you can flip the switch over and see the connections on the back side.

Your two switches are both A, B, A+B switches. You should only need 1 of them. You wire A to one battery, B to the other battery. Then you put everything on the other side of the switch. When you are starting, put it on A (start battery). While you are running, put it on ALL. When you are floating (listening to the radio and whatnot), put it on B.

I have no idea why someone wired 2 of those type of switches in your boat. The labeling on them is equally confusing to me. All I can figure is that they only wired A on either of them an are ignoring the entire other post of the switch...

 

[djtech2k]

That is the weirdest thing I have seen in awhile.

So, to pull the connectors off the switches, pull the switch off the wall by undoing the 4 screws. Then you can flip the switch over and see the connections on the back side.

Your two switches are both A, B, A+B switches. You should only need 1 of them. You wire A to one battery, B to the other battery. Then you put everything on the other side of the switch. When you are starting, put it on A (start battery). While you are running, put it on ALL. When you are floating (listening to the radio and whatnot), put it on B.

I have no idea why someone wired 2 of those type of switches in your boat. The labeling on them is equally confusing to me. All I can figure is that they only wired A on either of them an are ignoring the entire other post of the switch...

I totally agree with you. What makes it even more strange is if you look at the Perko wiring diagram from their website. In the 2 engines with 2 batteries scenarios, they all have 2 switches. At a glance, I think the boat is wired like their diagram.

I need to look at it closer but Perko does show using 2 switches. It’s a strange setup too because mine has power cables that run from switch 1 to switch 2. Again I think it’s from the diagram.

I think 1 switch makes more sense but they are saying to use 2 for some reason. I wish I could see the wiring on my switches without having to take them off the wall/board. I did write down what I see on the wiring. For example, there’s no bus bars and there’s some smaller wires going directly to the battery so they must not be run thru the switches. I know the radio stays hot even with the switches both off. I definitely want to change all that. I just want to get it right the first time but this setup has me scratching my head.

 

[djtech2k]

Is anyone familiar with the wiring that perko shows? Is that how I should keep it or would it be better to go with 1 switch as discussed?

 

[ctyke]

Is anyone familiar with the wiring that perko shows? Is that how I should keep it or would it be better to go with 1 switch as discussed?

If you look at the labels on the switches they are labeled port and starboard, the PO wired it like the Perco instructions, one battery/switch per engine. Then they cross over to supply power to each other in the event a battery dies. Weird setup, but maybe on bigger boats this is what they do?

If it was me, I would get a BlueSeas add a battery kit and re-wire that mess. One battery for the engines, the other for the house stuff.