Battery Isolator

[Crackerbox]

I recently bought a boat and it has a four position battery isolator. My last boat did too. I always ran it on just one in case the stereo ran it down. But it got me wondering.......if it's just set to one, will it still charge the other one or is that one "isolated" from draw (and thus charging)? If so should you always run on both but when you shut off and float or fish or camp, switch it to one or the other?

 

[sirbob]

I might - depends how its wired .

Usually not however has been my experience. If I want to charge all the batteries on mine I switch to "all"

 

[Crackerbox]

I might - depends how its wired .

Usually not however has been my experience. If I want to charge all the batteries on mine I switch to "all"

Thank you.

 

[Singleton]

I run mine on all.
when beached, switch moves to 2 (dedicated stereo battery).
time to leave, move to ALL and go about my day.

switch only moves to 1, when boat is on trailer and I need to open hatch, turn on lights, etc.

 

[Crackerbox]

Thank you for the replies. I'll make sure to switch it when I stop.

 

[Shlbyntro]

If you have something like this the answer is yes. If just a switch, then what @sirbob said

 

[Crackerbox]

If you have something like this the answer is yes. If just a switch, then what @sirbob said View attachment 934030

It looks like this:

 

[FUN4ME]

SI-ACR Automatic Charging Relay - 12/24V DC 120A - Blue Sea Systems

Automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

www.bluesea.com

take a look at this, it will charge the second battery while the boat is running

 

[RiverDave]

You know I have always wondered about this.. They put a battery "Isolator" in my Offroad cars, and they always told me you can run the stereo till it won't play anymore, and then when you go to start it, it will start on the good battery, but it will charge both when the alternator is working or you plug it into the wall?

I have never run the battery dry to find out, but it didn't sound right to me>?

RD

 

[sirbob]

Also note - I have 2 kinds of batteries. A high cranking amp for starting (1 switch ) and 2 deep cell batteries (switch 2) for when parked for music etc.

 

[mesquito_creek]

You know I have always wondered about this.. They put a battery "Isolator" in my Offroad cars, and they always told me you can run the stereo till it won't play anymore, and then when you go to start it, it will start on the good battery, but it will charge both when the alternator is working or you plug it into the wall?

I have never run the battery dry to find out, but it didn't sound right to me>?

RD

You are dead on with this... The manual perko type battery switch are so out dated. Just put one of these on and forget about it and never worry again. The main battery is for starting only and the second acts as a house for everything else. The house battery will never run down the starting battery and once the starting battery is at full charge from the alternator, the switch closes and starts charging the house while under way... I am going to remove my perkos and just install one of these marine grade smart isolators.

 

[Justsomeguy]

I do the same. Run on All switch to 1 when stopped. I always wondered if it would charge both. But was always taught to do it this way. So, that's the way I have always done it.

 

[Shlbyntro]

You know I have always wondered about this.. They put a battery "Isolator" in my Offroad cars, and they always told me you can run the stereo till it won't play anymore, and then when you go to start it, it will start on the good battery, but it will charge both when the alternator is working or you plug it into the wall?

I have never run the battery dry to find out, but it didn't sound right to me>?

RD

I will take a picture of my Ultra for you guys when I get home, I have my boat wired like this.

2x 31s only feed the stereo,
1x 24 feeds the rest of the boat systems.
And 1x battery switch turns on both electrical systems independant of eachother but does have an emergency parallel should I ever need it. The alternator charges all 3 batteries when the engine is running via an isolator. In addition to keeping the systems isolated, an isolator also aids in keeping the alternator from overcurrenting and burning up in a multi battery system, to an extent of course.

It looks like this:

View attachment 934092

Ya thats just a 2 bank battery switch. What @sirbob said is how I operate a boat with one of these as well

 

[Flyinbowtie]

I've wired up a couple of boats and a couple of SXS with the isolator/combiner from these guys in the past, and will use them again.
Good gear.

https://hellroaring.com/

 

[Crackerbox]

You are dead on with this... The manual perko type battery switch are so out dated. Just put one of these on and forget about it and never worry again. The main battery is for starting only and the second acts as a house for everything else. The house battery will never run down the starting battery and once the starting battery is at full charge from the alternator, the switch closes and starts charging the house while under way... I am going to remove my perkos and just install one of these marine grade smart isolators.


View attachment 934120

That's pretty cool. I'll have to look into one of those thank you.

 

[GETBOATS]

Blue Sea ACR and forget it,

What is an ACR, and how does it work?

• What is an ACR?
  An ACR parallels (combines) batteries during charging, and isolates them when charging has stopped and after battery voltage has fallen. An ACR is intended to keep a load from discharging both of the batteries.
• How does an ACR work?
  An ACR senses when the voltage of either of the batteries rises to a level indicating that a charge source is active (13.0V for 2 minutes). The ACR′s contacts then connect and the ACR applies the charge to both batteries. If the voltage on both of the batteries subsequently drops to 12.75V for 30 seconds, the ACR will disconnect, isolating the batteries.
• Why do I need an ACR?
  An ACR allows two battery banks to be connected so that they can share the output of a single charge source, allowing the user to charge more battery banks than the number of charging outputs. For example, an ACR can be used with a single-output charger, resulting in a simpler system at lower cost than a dual-output charger.
• How many ACRs do I need?
  To combine two battery banks, one ACR is needed; to combine three battery banks, two ACRs are required.

What are some features of ACRs?

• What does “Dual Sensing” mean?
  A dual-sensing ACR will sense an active charge source on one or both batteries and not solely on a designated battery. The ACR will operate if the measured voltage on either of the terminals is of a level to initiate a connection or disconnection.
• How does an ACR differ from a battery isolator?
  Battery isolators use one-way electrical check valves called diodes that allow current to flow to, but not from, the battery. ACRs use a relay combined with a circuit that senses when a charging source is being applied to either battery. ACRs are more efficient than battery isolators because they create little heat and consume minimal charging energy.
• Will an ACR manage the charge of my individual battery banks?
  An ACR does not direct the charge to the battery that “needs it the most” or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries.
• What Charge Sources will an ACR work with?
  An ACR will work with all charge sources, including an alternator, AC charger, or solar panel. However, low current charge sources might not produce the voltage rise required to force the ACR to combine.

What else do I need to know about my ACR?

• What are the minimum number of connections I need to make my ACR work?
  Three: One wire to each battery, and one for a ground (GND) connection. For safety reasons, remember to disconnect the negative battery connections before beginning any ACR installation. See this article for more information on selecting the right fuses for Blue Sea Systems ACRs: See Selecting the Appropriate Fuse Rating When Installing the 120A SI ACR
• What does “Undervoltage Lockout” mean?
  As a safety feature, some ACRs prevent combining into a severely discharged battery. A dual-sensing ACR will monitor the voltage on both batteries and will not connect if either battery is below the undervoltage lockout level. Use caution when combining into a battery with extremely low voltage, because this might represent a faulty battery or a problem elsewhere in the system.
• Why doesn't my ACR automatically combine every time my engine is running?
  For an ACR to automatically combine the batteries, voltage and time thresholds must be reached. Although these numbers vary somewhat from one ACR product to another, if ACR terminal voltage is greater than 13.0V for 2 minutes, the ACR should combine.

 

[Taboma]

I will take a picture of my Ultra for you guys when I get home, I have my boat wired like this.

2x 31s only feed the stereo,
1x 24 feeds the rest of the boat systems.
And 1x battery switch turns on both electrical systems independant of eachother but does have an emergency parallel should I ever need it. The alternator charges all 3 batteries when the engine is running via an isolator. In addition to keeping the systems isolated, an isolator also aids in keeping the alternator from overcurrenting and burning up in a multi battery system, to an extent of course.


Ya thats just a 2 bank battery switch. What @sirbob said is how I operate a boat with one of these as well

Running such varied sizes, do you have any independent state of charge regulation other than the alternating view all three as one jumbo battery ??
This being a problem I see with many of these charge isolators or ACR relays, with varying battery types and ampacities.

 

[GETBOATS]

actually I'm using these in my boats and fifth wheel, you'll never think about battery life again.

BEP Battery Distribution Cluster for Single Engine with Two Battery BanksPart # 714-140A-DVSR

The 714-140A-DVSR uses a dual sensing DVSR (710-140A). This system ensures that you will always have a fully charged reserve battery. When the switch is in position one, battery one becomes the sensing battery for the VSR. Battery two, which is in isolation, is charged through the VSR when the engine is running to ensure that it is always fully charged. When the switch is in position two, battery two becomes the sensing battery and battery one is charged through the VSR. The fact that there is always a fully charged battery in reserve is a huge safety benefit

 

[Crackerbox]

I have a question on both the Smart Battery isolator that Mesquite_Creek mentioned and the ACR that Getboats mentioned. I don't get to get out in the boat too often and that probably won't change until I retire. It's nice to just click the isolator to off and forget about any drain. This thing has a decent stereo with a big amp and a MinKota I drive ulterra and a Hummingbird fishfinder and who knows how the previous owner has everything wired. It all works. So with these other two systems what keeps it from drawing down? Reading through the ACR info it sounds like once it gets to a certain low voltage it isolates but isn't it better to be able to shut it off after running while it's charged up and not worry about it draining down? I don't see anything in the picture of the smart battery one that would let you disconnect either. Just wondering. Both systems seem way better for keeping things charged when you are running.

 

[Taboma]

actually I'm using these in my boats and fifth wheel, you'll never think about battery life again.

BEP Battery Distribution Cluster for Single Engine with Two Battery BanksPart # 714-140A-DVSR

The 714-140A-DVSR uses a dual sensing DVSR (710-140A). This system ensures that you will always have a fully charged reserve battery. When the switch is in position one, battery one becomes the sensing battery for the VSR. Battery two, which is in isolation, is charged through the VSR when the engine is running to ensure that it is always fully charged. When the switch is in position two, battery two becomes the sensing battery and battery one is charged through the VSR. The fact that there is always a fully charged battery in reserve is a huge safety benefit

What I'm not reading and perhaps I'm not fully grasping the marketing lingo --- is the charge rate for each battery independently regulated while charging from one source ?

 

[Taboma]

You are dead on with this... The manual perko type battery switch are so out dated. Just put one of these on and forget about it and never worry again. The main battery is for starting only and the second acts as a house for everything else. The house battery will never run down the starting battery and once the starting battery is at full charge from the alternator, the switch closes and starts charging the house while under way... I am going to remove my perkos and just install one of these marine grade smart isolators.


View attachment 934120

Sounds good, so long as you run long enough to recharge the starting battery, so it will switch and start charging the house battery. Is that switch CG approved Marine Rated ? It appears to be in a vehicle.

 

[ElAzul]

If you guys are really worried about having a dead battery in the middle of the lake or desert there is also a change guard. I use them on public safety stuff everyday it simply cuts off whatever is wired to it when a set time or voltage is reached. So most cop/fire/rescue vehi I will install one and set it to like 10.2 volts. It will isolate and turn off toys/lights etc and shut that circuit down so you can still start. Works like a charm and no weird charging issues or wiring magic

 

[mesquito_creek]

The way I see it is that the ACR is a bit "smarter" in that its basically a two way switch. The true battery isolator is a one way Master/Slave relationship. Having said that, nothing stops you from wiring the smart batter isolator behind the perko switch so that you can cut off the batteries via the switch. BUT if you have things like power amps or accessories wired directly to a battery you are already violating the perko switch.

 

[GETBOATS]

I have a question on both the Smart Battery isolator that Mesquite_Creek mentioned and the ACR that Getboats mentioned. I don't get to get out in the boat too often and that probably won't change until I retire. It's nice to just click the isolator to off and forget about any drain. This thing has a decent stereo with a big amp and a MinKota I drive ulterra and a Hummingbird fishfinder and who knows how the previous owner has everything wired. It all works. So with these other two systems what keeps it from drawing down? Reading through the ACR info it sounds like once it gets to a certain low voltage it isolates but isn't it better to be able to shut it off after running while it's charged up and not worry about it draining down? I don't see anything in the picture of the smart battery one that would let you disconnect either. Just wondering. Both systems seem way better for keeping things charged when you are running.

A big mistake many installers make is not running ALL sources of battery use to the common terminal of the battery switch, so when its off, its off. no drain whatsoever. with the only exception of a bilge pump float switch if the boat is so equipped. go around the switch say for a stereo and you have potential of being stranded with a dead battery.

 

[mesquito_creek]

Sounds good, so long as you run long enough to recharge the starting battery, so it will switch and start charging the house battery. Is that switch CG approved Marine Rated ? It appears to be in a vehicle.

According to the manufacture it is marine rated... But yes, I have one installed in a vehicle in the picture.

 

[Taboma]

According to the manufacture it is marine rated... But yes, I have one installed in a vehicle in the picture.

I know Blue Seas and ProMariner make multi-battery ACRs, that do provide independent charge regulation, including dual alternator, multiple batteries. When we had our Sports fisher with dual alternators and a system of cranking batteries and 8-D house batteries, I had multiple Perko switches so I could obtain numerous charging and output configurations if needed while underway, but no fancy regulation, just winged it.

 

[CoolCruzin]

Cobra installed this “blue sea system “
Battery isolation
I never worry about it .
The led tells you if your under voltage.
Turn it to on and never think about it .
Off for storage

 

[mesquito_creek]

I know Blue Seas and ProMariner make multi-battery ACRs, that do provide independent charge regulation, including dual alternator, multiple batteries. When we had our Sports fisher with dual alternators and a system of cranking batteries and 8-D house batteries, I had multiple Perko switches so I could obtain numerous charging and output configurations if needed while underway, but no fancy regulation, just winged it.

I should have qualified that I use the simple true battery isolator on a dual battery setup with two matched group 27 marine deep cycle batteries. It’s basically just a second battery for the stereo.

In my cruiser with multiple batteries I have a C-charger wired to each battery in a more complicated setup with a generator involved and solar etc... And I do not leverage a smart isolator at all in that setup. The generator has its own starting battery and as long as that starts all your other problems magically go away.

 

[Cole Canadian]

Have a bucket van that is electric over hydraulic, that use's it's own battery system. Original had a starter relay that was activated by a low voltage relay when the ignition key was turned on, thereby isolating the lift battery. I decided to update the system to the new isolators and then it shorted out??? (started draining coach battery also).
Dealer replaced it for free, and that one also went bad, took it back and dealer said draw to high (140amp unit) for it and no refund.
Went back to original basic system (just have to listen for the click) and no issues.
Could be an easy isolator fix for marine use?

 

[Shlbyntro]

Running such varied sizes, do you have any independent state of charge regulation other than the alternating view all three as one jumbo battery ??
This being a problem I see with many of these charge isolators or ACR relays, with varying battery types and ampacities.

When using the isolator, you have to disconnect the main charging lead from the alternator thats part of the OEM wiring harness and run a new lead from the alternator directly to the isolator. I used an 8 gauge. Then the output terminals will get wired directly to each independant bank (as i have it pictured below, they are connected directly to the independant banks on the back side of the battery switch) but you can also run leads direct to the battery banks

The battery switch I used is made by Blue Sea and has 4 posts on the back, 2 independant banks that are energized independently of each other when you switch the battery switch to the on position. Both get switched off when the single battery switch is in the off position. The battery switch also has a parallel position for emergency starts in the event that the engine battery bank goes dead.

One bank (24) is dedicated engine and boat systems, the other bank (2x 31s) is dedicated stereo. EVERYTHING electric on the boat with the exception of the stereo memory and the float switch are powered through the single battery switch via their dedicated banks. The stereo memory is wired direct to the stereo battery bank.

To answer your question, electricity will flow in the path of least resistance. In the case of an engine charging circuit, to the battery/battery bank that needs it most. The current moves as it sees fit so to speak and I have yet to see any issues with uneven charging in any boat utilizing an isolator system.

In an isolator setup, it is important to recognize that an isolator will slow the rate of charge vs not having one at all and different isolators have different amp ratings which you want to match to your alternator(s) as closely as possible so as not to allow one to overpower the other. In my experience, a stock alternator can charge up to 3 wet celled batteries safely and without issue so long as the batteries are healthy and were not talking about 4Ds or 8Ds. With a properly installed isolator, I have felt comfortable with 4 batteries not being an issue so long as they are arranged in a 2+2 configuration.

There are many isolators out there varying in amp ratings and number of charging banks as well as battery banks. I have seen everywhere from 1 charging/2 load(mine) - to - 2 charging/4 load.

 

[bocco]

Pic is a little blurry but this is what I have. The alternator hot goes to the terminal on the right. The other two terminals charge each battery. I never set my switch to all. Both batteries get charges when the motor is running.

 

[checkrd past]

Just adding what I've been told . I have a perko with the dual battery set up. Don't laugh but was told to never run on both becauce it was too much for the alterator to handle . anyone else hear such a thing..This has been a fine read,Thanks

 

[Shlbyntro]

Just adding what I've been told . I have a perko with the dual battery set up. Don't laugh but was told to never run on both becauce it was too much for the alterator to handle . anyone else hear such a thing..This has been a fine read,Thanks

It depends on how many batteries you have and on your alternator. Most boat engine's alternators can handle 2 wet batteries no problem, 3 batteries if you keep them healthy. If one of the 3 is not quite up to snuff then it will fry the alternator. Agm, gel, and lithium are a different story and you want to run on an even more conservative program.

A lot of new boats now (especially the wakey ones) are coming stock with 100+ amp alternators and can handle bigger battery loads.

 

[checkrd past]

It depends on how many batteries you have and on your alternator. Most boat engine's alternators can handle 2 wet batteries no problem, 3 batteries if you keep them healthy. If one of the 3 is not quite up to snuff then it will fry the alternator. Agm, gel, and lithium are a different story and you want to run on an even more conservative program.

A lot of new boats now (especially the wakey ones) are coming stock with 100+ amp alternators and can handle bigger battery loads.

I just have 2, Thanks