BUS Bars and Dual Batteries

[Theryan]

I keep going back and forth on the idea of doing a dual battery setup and was watching the video that Bluesea has on their add-a-battery kit thing with the ACR and switch.

There's one thing that I'm trying to suss out and can't quite figure it out.

Are bus bars actually necessary? From what I can gather, they're only really used because they provide a convenient location to connect your +/- terminals to rather than having to connect them to the battery directly.

Is that accurate? Is there any actual requirement or benefit to using them, or could I run the positives and negatives directly to the posts on the battery and be done with it?

 

[Andisimose]

I bought a boat with the add-a-battery kit (switch and ACR) the previous owner had all leads connected either to the batteries or the Switch, there were no issues.

I just went through(yesterday) and added bus bars to clean it up a little and reduce the amount of connections on the batteries. It makes removing the batteries to charge/store a lot easier and I feel better because every connection is covered.

 

[Theryan]

I bought a boat with the add-a-battery kit (switch and ACR) the previous owner had all leads connected either to the batteries or the Switch, there were no issues.

I just went through(yesterday) and added bus bars to clean it up a little and reduce the amount of connections on the batteries. It makes removing the batteries to charge/store a lot easier and I feel better because every connection is covered.

Okay, that's what I assumed was the case. I've got an on-board charger that I just have to plug in, so luckily that isn't a huge issue.

Thanks for the insight!

 

[ctyke]

I just did the add a battery kit, went with a negative bus bar to limit battery connections. Make life easier when removing/installing batteries.

 

[Theryan]

I just did the add a battery kit, went with a negative bus bar to limit battery connections. Make life easier when removing/installing batteries.

Second question: for the add a battery kit, do I have to always turn the battery switch to "off" when not in use, or can I just leave it "on" at all times?

 

[Julian]

Second question: for the add a battery kit, do I have to always turn the battery switch to "off" when not in use, or can I just leave it "on" at all times?

Depends on if you have it connected to a trickle charger or not, and how long you will leave it "on" and the level of parasitic draw you have (radio, bilge pump etc).

I leave mine on all the time when it is in its slip because she is always connected to shore power.

Bus bars are definitely not required. They simply help with cleaning up the wiring to make removing and replacing the batteries a lot easier. The number of posts we have where someone misses a wire in the spring and can't figure out why something is not working is not insignificant. I have bus bars. Before I installed them I would use wire ties on my connections when I removed the batteries to keep all the wires together (I also labeled every wire-yes I'm anal...and have a label printer! LOL)

 

[Theryan]

Depends on if you have it connected to a trickle charger or not, and how long you will leave it "on" and the level of parasitic draw you have (radio, bilge pump etc).

I leave mine on all the time when it is in its slip because she is always connected to shore power.

Bus bars are definitely not required. They simply help with cleaning up the wiring to make removing and replacing the batteries a lot easier. The number of posts we have where someone misses a wire in the spring and can't figure out why something is not working is not insignificant. I have bus bars. Before I installed them I would use wire ties on my connections when I removed the batteries to keep all the wires together (I also labeled every wire-yes I'm anal...and have a label printer! LOL)

This is very good information, as always, Julian! Thanks!

I've got an onboard NOCO smart charger that stays connected at all times when it's in my garage (I tow) so I'm not too worried about decharging the batteries (only have a radio and bilge, so that shouldn't be too big).

 

[Andisimose]

The number of posts we have where someone misses a wire in the spring and can't figure out why something is not working is not insignificant.

This is why I went to bus bars this week. I missed a negative and just now noticed, 3 months into the year. Still need to trace it back and see what it went to.

 

[Julian]

This is very good information, as always, Julian! Thanks!

I've got an onboard NOCO smart charger that stays connected at all times when it's in my garage (I tow) so I'm not too worried about decharging the batteries (only have a radio and bilge, so that shouldn't be too big).

The only downside to this is if you have the backpressure bilge pump it will keep running every 2 minutes while the boat is "On". This will add a little wear to the pump. Of course in my situation....that is what I WANT.....because my boat is outside (on a lift) over the water....and I want the bilge running. If its in a garage....not needed...so I'd probably turn the batteries off in your situation....but not a big deal.

 

[Theryan]

The only downside to this is if you have the backpressure bilge pump it will keep running every 2 minutes while the boat is "On". This will add a little wear to the pump. Of course in my situation....that is what I WANT.....because my boat is outside (on a lift) over the water....and I want the bilge running. If its in a garage....not needed...so I'd probably turn the batteries off in your situation....but not a big deal.

So, in response to that one...

I've only got the one battery in my sx190 currently, and when the boat is in the garage it's all connected up but just turned off (engine, electronics). Would this be any different than having the battery switch on?

I guess I'm not totally sure I'm following what the point of turning it off (the battery switch) is, which is probably a dumb question but hey.

 

[IvanRZB]

Bus bars are great to keep things tidy. If you do use a bus bar remember to size the wire gauge connecting back to the battery so that it can handle the sum total of all the loads connected to the bus bar.

 

[IvanRZB]

I've only got the one battery in my sx190 currently, and when the boat is in the garage it's all connected up but just turned off (engine, electronics). Would this be any different than having the battery switch on?

I guess I'm not totally sure I'm following what the point of turning it off (the battery switch) is, which is probably a dumb question but hey.

Boat off is definitely different than battery disconnected. Things like stereo head units or GPS can still draw a current with the ignition in the off position--we ended up adding a battery switch to our SX190 because the battery would drain down just sitting in the garage.

 

[Theryan]

Boat off is definitely different than battery disconnected. Things like stereo head units or GPS can still draw a current with the ignition in the off position--we ended up adding a battery switch to our SX190 because the battery would drain down just sitting in the garage.

Does that matter a ton if it's always plugged into a charger, though?

 

[Julian]

So, in response to that one...

I've only got the one battery in my sx190 currently, and when the boat is in the garage it's all connected up but just turned off (engine, electronics). Would this be any different than having the battery switch on?

I guess I'm not totally sure I'm following what the point of turning it off (the battery switch) is, which is probably a dumb question but hey.

So it depends on your bilge pump type. In many (but not all boats) Yamaha used a back pressure bilge pump. The way that pump works is every 2 minutes the pump runs, and if it senses backpressure (water present) it runs until it doesn't feel back pressure (water not present). This is in comparison to a float switch bilge that only pumps if the float rises (like a sump pump in a house). I should probably get more details from Yamaha on WHEN they switched to the float switch pumps and if that was on ALL models at the same time.

So questions I have based on @IvanRZB posts are:

1. Do you have a battery switch?
2. Do you have a back pressure pump (way to tell is to look at the pump, or sit with the boat on and listen with the hatch open...if you hear a buzz every 2 min you have backpressure pump.)

If 1) Yes, and 2) Yes, I'd probably turn off the switch all the time to put less time on the pump. If 1) Yes, 2) No, I wouldn't bother turning it off as you are always charging and any parasitic draw wouldn't matter.

 

[ctyke]

Does that matter a ton if it's always plugged into a charger, though?

It doesn't matter a ton if you are only worried about battery drain. Other things can happen, shorts, equipment drain, pump wear, fire. I always turn it off and feel it is a good habit to get into, but I'm on a lift with no shore power.

 

[Theryan]

I was just thinking about something and wanted to see what you guys thought.

I realistically only will need a second battery if I put a bigger amp and speakers in. I am only out for like six hours at a time, and don't run the electrical/audio the whole time.

IF I install a second amp (only looking at like a 400-600w one) and speakers, is there any harm in adding a second battery specifically for said amp and not bothering with combining the batteries? Just connecting the battery to the amp and letting it run like that? It would only be used realistically for a few hours and not at full blast, then plugged back in when at home.

Is there any harm in running it that way? I may do a combined battery system in the future but I really don't need it right now for how little battery I use.

I was thinking I could also honestly just put an ACR in to connect the batteries and don't really need a switch since it seems a bit overkill.

Thoughts on that?

I also noticed that the person i bought my boat from has a deep cycle fleet farm battery installed as the only battery. Thinking I'm going to upgrade it to a dual purpose AGM and having it be a nicer one. Thoughts?

 

[tdonoughue]

My official thoughts:

1) On the bus bar (a bit late on this one), another benefit I found was that the post on the battery will, at a certain point, get crowded (or you will need to upgrade the wire and start running multiple items on one wire). A bus bar gives you the ability to hook many more individual wires than could fit on your battery.
2) Could you run your amp on a second battery disconnected from the charging capabilities of your boat? Sure. But, that battery would not charge while you are running the boat (and you would have to run it separately). And you would not be able to combine batteries and draw from that one in an emergency. So no harm, but you do lose a lot of useability, IMHO. If you don't do an ACR, you want to do a 1, 2, 1+2 battery switch, so that you can flip it to 2 when floating, then to 1 to start, and 1+2 when running (to charge both). Even if you keep that on 1 all the time until it runs dry and then switch to 2 to start and 1+2 to charge you will be better off. That is what I had for years before I upgraded to the ACR (which was a very good upgrade--it does it all automagically).

All that said, don't screw with it. Get a bus bar and and the ACR kit. You won't regret it.

3) I got two Marine Deep Cycle batteries from Costco to replace my 2 from the dealer after the 5th year. No regrets on the original or replacement batteries yet. And I didn't spend nearly as much as 1 AGM battery...

 

[Theryan]

This is very helpful.

So regarding the acr I think I decided I'll do the acr idea. I can run that without a switch, though, correct?

With how little I actually use the electrical when not running the engine (and that I charge it every day when I have it on the trailer) I don't think that I need the switch at all.

Any harm in that method?

Thanks for the insight and help!

 

[tdonoughue]

No harm, but not optimal.

Look into the Blue Sea Add-a-Battery Kit. Has the ACR and the switch in one pack (don't need the one that includes the charger in the same box, unless you want). Basically for not much more than an ACR you get the switch. And it is all designed to work together and make your life wonderful.

Again, no harm to not having a switch. But with the switch you can a) tie the batteries together to jump start in case your starting battery runs down for some reason and b) turn the electrical off to the boat (handy for those of us who store in a shed and not on the water--you flip the switch, cover it and leave--making sure that everything is off).

Edited to add: Mini Add-A-Battery Kit - 65A - Blue Sea Systems

 

[212s]

I don't think that I need the switch at all.

No harm, but not optimal.

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.