12V battery system - adding ACR

[SlipperyOar]

I am looking into adding an ACR or an 1/2/B switch to my current electrical system. I've been reading lots into the BlueSea ACR system and the ease of installation and reliability behind it. I've also seen how a make-before-break 1/2/B switch can do the same job, with the risk of forgetting to turn off the Both connection before starting and risk of the switch become faulty with a broken connection before going to both batteries. My rectified regulator on my E100TLCSC is the CDI 193-3408 with 10 amp charging and automatically regulates the voltage, stopping charging at 14.1 volts which only will recharge my starter battery.

My question is, if i were to add the ACR into my system, do i need to disconnect the MinnKota 2-bank battery charger to my house battery and allow the charging to happen through the starter battery and ACR to charge both batteries? What is the best method to recharge my house and starter while underway.

I am mainly interested in having the most reliable, safe, issue free way to maintain the house battery while i am out fishing. My starter battery charges nearly instantly back to full voltage but my house battery becomes weaker as the day goes on. I always leave my MinnKota plugged in while my boat is parked. My plan would be to periodically start my main motor while trolling on my kicker to recharge my house battery or allow all the short hops i do while jigging to do the trick.

I have attached my current battery setup, and how i would integrate the ACR system and 1/2/Both switch.

 

[dingbat]

I have attached my current battery setup, and how i would integrate the ACR system and 1/2/Both switch.

If you get the full Blue Seas kit, it comes with a Off/ON/Combine

Turn switch to On when using the boat. Turn it Off when leaving the boat. It’s that easy.

Should the starting battery get weak or fail, you switch to Combine which parallels the batteries to provide power to start the boat.

Should the starting battery short, you pull the positive cable off the start battery then flip switch to Combine

 

[ESGWheel]

Love the diagrams and clearly you have put a lot of good thought into this. I too have been looking for reliability and simplicity for charging a house battery, albeit for different reasons, the end goal is the same.

Here is something that you may not have considered with adding an ACR coupled with the MinnKota charger: how does the ACR respond to it? Let me explain > I suspect the Blue Sea ACR will close a relay and connect the two banks under conditions that will be achieved while charging with the MinnKota. As you have read the ACR will combine the two banks when it senses 13.6V for 30 sec or 13.0 for 2 min (on either bank). I assume that will be achieved with the MinnKota and it may not like being connected together given it’s a ‘two bank’ type charger. You can confirm this suspicion with Blue Sea tech support > I have found them very helpful and responsive.

But the good news is the ACR can be deactivated by opening its ground. See pic below from their installation instructions.

Thus, if this switch is installed and then opened prior to plugging in the MinnKota, the ACR is effectively deactivated and all charging should occur as expected > just like there was not an ACR installed. And you get the benefit of the ACR to help maintain the house batteries as you desire. But again suggest validating with Tech Support.

More:
it’s possible to wire up a relay to open this ground circuit thus one less switch to remember to throw and with possible detrimental impact to the MinnKota if not opened when plugging in.

Here is a great article on ACRs if you have not read it already: link,

Good luck and please post what you end up doing for the benefit of all.

 

[ESGWheel]

As a follow up: the Blue Sea ACR has a ‘start isolation’ feature that you show using in your diagram. Its purpose is “Allows temporary isolation of house loads from engine circuit during engine cranking to protect sensitive electronics.” While best to check with Tech Support, I suspect this feature temporary disables the ACR same as disconnecting its ground would do as shown in the pic in post #3.

If that is the case you can save some wiring by installing a Normally Open (NO) relay on that ground wire that closes only when key is the “Run” position. That way you get a twofer: no extra switch to flip prior to plugging in and will also provide the ‘start isolation’ feature. Neat. (if need help with what that relay set up looks like, let me know.)

Also, I just noticed your 12-amp fuse size from the ACR to the batteries. This is not enough. There is a table in the instructions (attached below) that has a minimum of 75A rating. Think of it this way: the full charging current of your motor needs to be able to pass thru the ACR, thus the cables and fuses are quite large and not like a typical trickle 110VAC charger.

More: while electrically I do not see an issue with the idea of retaining your current On/Off Start Battey Switch along with the House Accessories switch as shown in your diagram, you are still faced with turning off two switches (will be three without the ground relay mentioned above Thus as Dingbat mentioned by instead using the Blue Sea switch, life cannot get easier. Tougher to get all set up, but in the long run simple to operate and now have the flexibility to combine batts if needed.

 

[ESGWheel]

@SlipperyOar: I was reviewing some of my notes and posts on ACRs and realized that I made a mistake in my post #4. I had assumed your engine's alternator output well exceeded 12 amps, hence my comment / concern. I now see you originally posted the output of it is a max of 10A which I missed before. Sorry for my mistake.

And if you have a few, what was the outcome of your install? Thanks.