Battery Question

[Ozdogg]

Hello CP Family,

I have a question that may be silly, but just wanted to make sure. I have two batteries on my 2120 and the power switch is on the stbd side. Here is my question. When I power my boat, should the switch be on 1, 2 or on both? What about when I'm in the marina and using shore power? Thanks for any feedback.

 

[Antidote]

A lot of people run out on 1 back on 2 to make sure both batteries are charged. Depending on your engine you can charge both with the Aux lead off your engine. When connected to shore power again it depends. Do you have an onboard battery charger? If so how is it connected? Directly to the batteries or to the selector switch. A more important question, is your boat properly grounded to prevent galvanic corrosion when you are connected to shore power?

 

[pelagic2530]

Think about it this way.

Whatever position you have the switch in, is what is powering not only your engine cranking, but also your house electrical load. However, it’s also the only thing getting charged by the alternator when the engine is running. So if only one battery is selected, the other one is isolated and remains in the charge state it started in. If “both” is selected, then both batteries are being charged, but both will also be drawn down if using power with the engine off, potentially leaving you without a sufficient charge to start the motor.

That said, there’s no major consensus on the right way to run that type of setup. The BEST option would likely be to start the motor on one battery, then switch to BOTH for the ride out to ensure both batteries are fully charged. Then, if you’re going to turn the motor off and drift while using electrical power, switch back to one battery while the engine is off. That way, no matter how discharged the online battery gets, the other battery is fully charged for engine cranking. Then, repeat the process when making the longer run in at the end of the day. For short start up and moves, I’d recommend keeping it on one battery- that way, that one battery is getting all of the charging current during the shorter engine run time.

As you can imagine, that can end up being a lot of battery switching back and forth, and if you forget a step somewhere you run the risk of two dead batteries and no way to crank the motor.

A far better solution is to simply separate your batteries into house and start circuits, using a BEP switch or another type of dual-circuit switch with a DVSR to charge both batteries. With that system, it’s just two switches on at the beginning of the day, two switches off at the end. No chance of a discharged cranking battery. That modification has been discussed at length here; a quick search should yield all the information you could want.

As an aside: do you know which of your batteries are designated 1 and 2? It doesn’t always line up with the switch dial positions. Probably worth taking the switch off the bulkhead and checking out which lead is on which terminal.

 

[tomc585]

The BEST option would likely be to start the motor on one battery, then switch to BOTH for the ride out to ensure both batteries are fully charged. Then, if you’re going to turn the motor off and drift while using electrical power, switch back to one battery while the engine is off. That way, no matter how discharged the online battery gets, the other battery is fully charged for engine cranking. Then, repeat the process when making the longer run in at the end of the day. For short start up and moves, I’d recommend keeping it on one battery- that way, that one battery is getting all of the charging current during the shorter engine run time.

As you can imagine, that can end up being a lot of battery switching back and forth, and if you forget a step somewhere you run the risk of two dead batteries and no way to crank the motor.

I do this without even thinking about it. It's just something you do.

 

[Ozdogg]

A lot of people run out on 1 back on 2 to make sure both batteries are charged. Depending on your engine you can charge both with the Aux lead off your engine. When connected to shore power again it depends. Do you have an onboard battery charger? If so how is it connected? Directly to the batteries or to the selector switch. A more important question, is your boat properly grounded to prevent galvanic corrosion when you are connected to shore power?

Hey Antidote,

Thanks for the response. I do have a dual bank battery charger, but not sure how it was set by the dealer where I purchased the boat. As far as being grounded and galvanic corrosion, how would I tell? I have a monthly service that comes out to scrub the bottom and they have never mentioned anything.

 

[Ozdogg]

Think about it this way.

Whatever position you have the switch in, is what is powering not only your engine cranking, but also your house electrical load. However, it’s also the only thing getting charged by the alternator when the engine is running. So if only one battery is selected, the other one is isolated and remains in the charge state it started in. If “both” is selected, then both batteries are being charged, but both will also be drawn down if using power with the engine off, potentially leaving you without a sufficient charge to start the motor.

That said, there’s no major consensus on the right way to run that type of setup. The BEST option would likely be to start the motor on one battery, then switch to BOTH for the ride out to ensure both batteries are fully charged. Then, if you’re going to turn the motor off and drift while using electrical power, switch back to one battery while the engine is off. That way, no matter how discharged the online battery gets, the other battery is fully charged for engine cranking. Then, repeat the process when making the longer run in at the end of the day. For short start up and moves, I’d recommend keeping it on one battery- that way, that one battery is getting all of the charging current during the shorter engine run time.

As you can imagine, that can end up being a lot of battery switching back and forth, and if you forget a step somewhere you run the risk of two dead batteries and no way to crank the motor.

A far better solution is to simply separate your batteries into house and start circuits, using a BEP switch or another type of dual-circuit switch with a DVSR to charge both batteries. With that system, it’s just two switches on at the beginning of the day, two switches off at the end. No chance of a discharged cranking battery. That modification has been discussed at length here; a quick search should yield all the information you could want.

As an aside: do you know which of your batteries are designated 1 and 2? It doesn’t always line up with the switch dial positions. Probably worth taking the switch off the bulkhead and checking out which lead is on which terminal.

Thank you for the valuable information! I will absolutely look into your recommendations.

 

[pelagic2530]

Hey Antidote,

Thanks for the response. I do have a dual bank battery charger, but not sure how it was set by the dealer where I purchased the boat. As far as being grounded and galvanic corrosion, how would I tell? I have a monthly service that comes out to scrub the bottom and they have never mentioned anything.

Does your battery charger have a plug that plugs directly into a standard extension cord?

If so, it’s a pre-wired, self contained charger. It doesn’t need to be tied in to the DC negative or bonding system; you really couldn’t do it if you tried. If the extent of your shore power system is plugging in a battery charger, galvanic isolation is essentially unnecessary in your case and would be difficult to accomplish anyway.

If you post a picture of your install, we should be able to tell you pretty quickly.

 

[pelagic2530]

I do this without even thinking about it. It's just something you do.

As do many, many others. It’s not wrong, but it does introduce the element of human error. All it takes is forgetting one time, to end up with a dead battery situation. Which is essentially impossible using a BEP switch setup. You also don’t get to take advantage of two different types of batteries with specialized constructions and sizes, to maximize the effectiveness of your system.

As long as you have a system and it’s working for you, keep on keepin’ on, brother I just like to point out that there is another way to do it, with distinct advantages.

 

[Ozdogg]

Does your battery charger have a plug that plugs directly into a standard extension cord?

If so, it’s a pre-wired, self contained charger. It doesn’t need to be tied in to the DC negative or bonding system; you really couldn’t do it if you tried. If the extent of your shore power system is plugging in a battery charger, galvanic isolation is essentially unnecessary in your case and would be difficult to accomplish anyway.

If you post a picture of your install, we should be able to tell you pretty quickly.

I'll post a pic of the install.

 

[Andy]

Hello CP Family,

I have a question that may be silly, but just wanted to make sure. I have two batteries on my 2120 and the power switch is on the stbd side. Here is my question. When I power my boat, should the switch be on 1, 2 or on both? What about when I'm in the marina and using shore power? Thanks for any feedback.

There are good answers by others here, but I have a different experience with how our battery switch operates. Background info; we have a 2013/2014 2520 XLD, 2014 300 Yamaha. Wired from the factory.
It does not matter if I chose #1 or #2. When I'm on #1, both #1 AND #2 are being charged by the engine. Same thing when I'm on #2. Both #2 AND #1 are being charged by the engine. I don't need to be on "Both" for both batteries to be charging.... I have proven this in a video I posted on Youtube, using all switch settings and showing the charge amount with my Fluke Volt/Ohm meter (aka Multi-meter) with each of the different options. (If anyone is interested, I'll post the link to that Youtube video here)..... By the way, this was NOT the case on my previous boat. It had six (yes, SIX) 4-D wet-cell truck batteries. Paired up to three (3) battery switches that were wired where I could control the usage of any of the six batteries. I also had a 170 amp alternator on the Diesel engine to accommodate the charging. The main point here is, I had to have the batteries on 'Both' for any of the three sets/banks of batteries to accept charge. If I was on #1, or #2, only that battery would charge.

 

[VCC]

Thanks Andy....mind posting the link...be interested in seeing it...thanks

 

[Ozdogg]

There are good answers by others here, but I have a different experience with how our battery switch operates. Background info; we have a 2013/2014 2520 XLD, 2014 300 Yamaha. Wired from the factory.
It does not matter if I chose #1 or #2. When I'm on #1, both #1 AND #2 are being charged by the engine. Same thing when I'm on #2. Both #2 AND #1 are being charged by the engine. I don't need to be on "Both" for both batteries to be charging.... I have proven this in a video I posted on Youtube, using all switch settings and showing the charge amount with my Fluke Volt/Ohm meter (aka Multi-meter) with each of the different options. (If anyone is interested, I'll post the link to that Youtube video here)..... By the way, this was NOT the case on my previous boat. It had six (yes, SIX) 4-D wet-cell truck batteries. Paired up to three (3) battery switches that were wired where I could control the usage of any of the six batteries. I also had a 170 amp alternator on the Diesel engine to accommodate the charging. The main point here is, I had to have the batteries on 'Both' for any of the three sets/banks of batteries to accept charge. If I was on #1, or #2, only that battery would charge.

Thanks Andy! Good information.

 

[Andy]

Thanks Andy....mind posting the link...be interested in seeing it...thanks

I'm almost embarrassed to post this here. But I did anyway (below). It's obvious I don't script, nor do I edit any of my videos. And along with me talking too loud (I'm nearly deaf) and mumbling with a speech-impediment, ☺☺, I got katty-wonkered in some of the things I was trying to say. In short, I was trying to suggest that a lot of the confusion exists because with most older boats (1970's-1980's-1990's ++??) and older people offering the 'advice' that applies to those older boats, you had/have to have the switch on 'Both' for both batteries to be charging. With the way our newer Parker is wired from the engine, both batteries are always charging no matter if you are switched to battery #1, #2 and/or 'Both'.... Another solution is to follow the advice of Warthog, Pelegic2530, and Mpellet, Antidote, and others and install a BEP Cluster. (That may be beyond my present skill-level, but I'd be happy to pay one of them to do it for me, if they ever decide to move to eastern NC ! ☺)

 

[pelagic2530]

I'm almost embarrassed to post this here. But I did anyway (below). It's obvious I don't script, nor do I edit any of my videos. And along with me talking too loud (I'm nearly deaf) and mumbling with a speech-impediment, ☺☺, I got katty-wonkered in some of the things I was trying to say. In short, I was trying to suggest that a lot of the confusion exists because with most older boats (1970's-1980's-1990's ++??) and older people offering the 'advice' that applies to those older boats, you had/have to have the switch on 'Both' for both batteries to be charging. With the way our newer Parker is wired from the engine, both batteries are always charging no matter if you are switched to battery #1, #2 and/or 'Both'.... Another solution is to follow the advice of Warthog, Pelegic2530, and Mpellet, Antidote, and others and install a BEP Cluster. (That may be beyond my present skill-level, but I'd be happy to pay one of them to do it for me, if they ever decide to move to eastern NC ! ☺)

@Andy, no need to be embarrassed. It takes a lot to put out genuine content on the internet showing clear, concise information and without spending half of the video begging for likes or subscribers.

Without knowing how your system is set up, and just catching glimpses of your system from the video, I’d be interested in seeing the specifics of how your cables are run. The fact that both batteries charge in either position is very interesting. Is your boat equipped with a VSR? With the engine off and the switch closed in the 1 and 2 positions, do you show continuity between the battery positive posts?

If you’ve got some pictures of your cabling, switches and breakers, I’d love to see them. Because at face value, nothing in your system seems to indicate a simultaneous charging ability. Which makes me wonder if your battery switch/overall setup is providing the type of battery isolation it’s supposed to.

 

[Andy]

@Andy, no need to be embarrassed. It takes a lot to put out genuine content on the internet showing clear, concise information and without spending half of the video begging for likes or subscribers.

Without knowing how your system is set up, and just catching glimpses of your system from the video, I’d be interested in seeing the specifics of how your cables are run. The fact that both batteries charge in either position is very interesting. Is your boat equipped with a VSR? With the engine off and the switch closed in the 1 and 2 positions, do you show continuity between the battery positive posts?

If you’ve got some pictures of your cabling, switches and breakers, I’d love to see them. Because at face value, nothing in your system seems to indicate a simultaneous charging ability. Which makes me wonder if your battery switch/overall setup is providing the type of battery isolation it’s supposed to.

Hi Pelegic, thank you! In the 'comment' section of the video a guy mentioned I have a 'combiner' installed that makes this happen. Here's his 'comment'.

Is the VSR you mentioned possibly the 'combiner' he mentioned? There is some kind of black electrical device installed beside/above the batteries, and is wired to the batteries. All of this was 'factory-installed' according to the original owner. I'll try to get a better picture of that device, and will post it here. Thank you once again!

Here's a not-great picture of it; I'll try to find a better one.

 

[Andy]

@Andy, no need to be embarrassed. It takes a lot to put out genuine content on the internet showing clear, concise information and without spending half of the video begging for likes or subscribers.

Without knowing how your system is set up, and just catching glimpses of your system from the video, I’d be interested in seeing the specifics of how your cables are run. The fact that both batteries charge in either position is very interesting. Is your boat equipped with a VSR? With the engine off and the switch closed in the 1 and 2 positions, do you show continuity between the battery positive posts?

If you’ve got some pictures of your cabling, switches and breakers, I’d love to see them. Because at face value, nothing in your system seems to indicate a simultaneous charging ability. Which makes me wonder if your battery switch/overall setup is providing the type of battery isolation it’s supposed to.

Hi Pelagic, Thank you once again!.... I posted a 'comment' from the video below about a 'combiner'. Here is another picture of it from a different angle; I'll also try to get a picture of the wire connections to the battery terminal posts....

 

[pelagic2530]

Hi Pelagic, Thank you once again!.... I posted a 'comment' from the video below about a 'combiner'. Here is another picture of it from a different angle; I'll also try to get a picture of the wire connections to the battery terminal posts....
View attachment 35982

That commenter is mistaking your two house power breakers (or possibly one house and one windlass? Unclear from the video) for a combiner. Those are the two small black devices to the right (aft) of your battery switch. A diode combiner looks similar at first glance, but that’s not what you have. It’s also far from “new” technology- in fact, where installed they should generally be replaced with a voltage sensitive combining relay (VSR) as the diode combiners tend to rob you of about a volt of charging potential. There is no “combiner” visible to my eye anywhere in your system.

The black and yellow box to the left (fwd) of your switch is another breaker. I suspect it’s for the aux. charging lead from your outboard. This is a separate charging feed from your alternator, giving you the ability to charge another battery back other than the one connected to your engine’s starter cable. I suspect that this is involved with your simultaneous charging ability; however I’d still like to see how it’s wired. Most commonly you see it simply wired to one of the batteries, especially if one is a bigger “house” bank. But if that were the case, in either position 1 or position 2, both alternator charging leads would be connected to the same battery- still leaving one without charging current. That’s clearly not the case.

 

[Blueghost93]

Not to get off topic but has anybody used a blue seas add a battery kit? It seems to solve the problem of the battery switch. My understanding is it isolates both batteries but can be charged at the same time. So when you crank your electronics don’t flicker or turn off.

https://www.westmarine.com/blue-sea...MYLbccXjLNRGuGg-gjxBLz7hczMhU3KYaAk6cEALw_wcB

 

[pelagic2530]

Not to get off topic but has anybody used a blue seas add a battery kit? It seems to solve the problem of the battery switch. My understanding is it isolates both batteries but can be charged at the same time. So when you crank your electronics don’t flicker or turn off.

https://www.westmarine.com/blue-sea...MYLbccXjLNRGuGg-gjxBLz7hczMhU3KYaAk6cEALw_wcB

It will work for that. It does the same thing as a BEP cluster, which also contains a DVSR for charging. The BEP cluster also has individual switches for house and start batteries, so one can be energized without the other, such as if you’re at the dock just using the house electrical system.

In my opinion the BEP cluster switch is a cleaner install with less exposed cabling. But this will serve essentially the same purpose.

 

[warthog5]

I suspect it’s for the aux. charging lead from your outboard. This is a separate charging feed from your alternator, giving you the ability to charge another battery

Winner Winner Chicken Diner.

Not to get off topic but has anybody used a blue seas add a battery kit?

Yes....1 Time, Before I discovered BEP Clusters. The Blue Seas Add-A- Battery takes up to much room. This is due to the radius of heavy cables.... You still don't really know which battery your sucking out of like you do with a BEB Cluster.
I've installed 58 BEP Clusters now.