Battery 1, 2 or Both?

[Seafarer_Bob]

I did a lot of reading on this and here's one thing I know. The Blue Sea ACR is installed between the voltage regulator and the battery so it combines both batteries when it detects a positive charge coming from the alternator and disconnects them when there's no charge detected. The Yamaha isolator cable comes directly from the voltage regulator so it charges the second battery completely independent from the main charging cable.

The big difference (for me anyway) is using the Blue Sea ACR the batteries should be exactly the same, with the Yamaha isolator the batteries can be different.

 

[Joe317]

Thanks for all the replies. I finally found Gradys take on the issue.

Why Not Run Engine with Battery Switch on

I would like to know why not run engine with battery switch on

www.gradywhite.com

 

[Blaugrana]

On this topic I have already ordered a blue sea add a kit, and what this will do able to charge both batteries ,when starting battery get up to a certain amperage also able to use both battery to start in emergencies, also if electronics are on it will isolate it so you don’t have to turn your electronics off on starting Your engine

https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A
Also are you the code to get 15% off at West Marine MK57356
I saw the code on the hull truth
And used it 4 days ago and it worked for me

If your engine has an Aux charging cable, you do not need the kit just the battery switch.

e-Series Dual Circuit Plus™ Battery Switch - Blue Sea Systems

350 Amps continuous rating for inboard gasoline or diesel engines.

www.bluesea.com

 

[SkunkBoat]

The Aux charging is built into the rectifier/regulator on every yamaha and suzuki and probably others. You just have to connect the cable and feed it thru the wire harness.
It is simply a diode that allows charging current to flow but prevent "starter" current from being drawn. It also isolates the batteries from each other.
There have been aftermarket versions of diode "Isolators" for decades.

It is there to allow simultaneous charging of two batteries. It is in the Yamaha manuals somewhere. They did that just for you!
For some reason dealers never connect it and never tell you about it.

Boats that are wired with a Off-1-Both-2 without aux charge have the "House" (your fuse panel & switches) connected to the common terminal of the switch (the one that goes to the motor).
This means your House always runs on the same battery that is starting the motor and the other battery is doing NOTHING.
In this configuration you have to rotate the use of batteries. In this case there is is no designated "Start" battery and "House" battery.

The big advantage of using the aux charging is that you can move your house feed from the common terminal of the switch to the House +
You have the Aux to the House + to charge the "House Battery". It is isolated from the "start" battery. Your "Start" battery (usually configure as #1) only starts the motor and recharges thru the starter cable. Nothing electric runs off it (maybe bilge pump auto). It just sits there charging and waiting for the next time you need to start.
The House (#2) runs everything and recharges thru the Aux cable.

Using the existing switch, it stays on #1 (or Off ) all the time unless you need to use the House battery to start

You would need another switch in the House circiut because the exsisting switch will not shut off the house. This can be done by getting rid of the stupid red button breaker and using a switchable breaker. Or replace the existing switch with another type of Blue Seas switch that is a Dual Cutoff with Combine feature.

This can also be done using two motors and 3 or 4 batteries.

You can accomplish much the same with an ACR if thats the route you take...

 

[seasick]

Skunkboat,
The servers must have liked your response, they posted it 4 times
I know you didn't do that based on message count.
There was some sort of forum software issue yesterday and I supposed that might be related to the multiple posts.
On a positive note; I got your message!

 

[Rustygaff]

I have a single F300 and 2 group 31 AGM's. Last year I installed a Yandina combiner so the unselected battery will get a charge when the selected battery is topped off. I also rotate by odd/even calendar days which battery I select for that particular day's use.

 

[blindmullet]

On one of my boats with Merc Optis, I usually run each motor on a separate battery BUT, 9 out of 10 times when first starting those motors, I can't get them to fire unless I select BOTH. I gave up trying to figure out why that is but Optis are quite particular about voltage at the motor when crankng.

The Opti requires over a 1000MCA and most marine batteries can't accommodate. If I remember correctly the coils run basically run off the battery. I chased a bad coil for weeks!

 

[Fishtales]

On one of my boats with Merc Optis, I usually run each motor on a separate battery BUT, 9 out of 10 times when first starting those motors, I can't get them to fire unless I select BOTH. I gave up trying to figure out why that is but Optis are quite particular about voltage at the motor when crankng.

Interesting. Never had that issue. I think GW recommends one bank per engine to eliminate two motors charging the same batteries (could be wrong here)...