ACR questions...

[ReelSlim]

First off I read through quite a few old threads but haven’t got the answers I’m looking for. I just ordered a Blue Seas ACR add a battery kit. Basically it’s the rotary switch and the ACR unit. I looked at a lot of wiring diagrams and watched a few you tube videos as well. I have twin outboards and a kicker with a two battery system. I see that you can hook up a wire from the start position on your ignition that will isolate the house from start batteries if they happen to be connected at the time you start the mains. Do you need to run a wire from each ignition switch or will it really matter once the first motor is running before starting the second one.

 

[bigbruce]

First off I read through quite a few old threads but haven’t got the answers I’m looking for. I just ordered a Blue Seas ACR add a battery kit. Basically it’s the rotary switch and the ACR unit. I looked at a lot of wiring diagrams and watched a few you tube videos as well. I have twin outboards and a kicker with a two battery system. I see that you can hook up a wire from the start position on your ignition that will isolate the house from start batteries if they happen to be connected at the time you start the mains. Do you need to run a wire from each ignition switch or will it really matter once the first motor is running before starting the second one.

Can't answer your question - but suggest you shoot a note to the Blue Seas folks. I had a question for them when I was installing mine and they were quick to respond.

 

[noluck]

reelslim can you post the diagram you are talking about?

 

[ReelSlim]

reelslim can you post the diagram you are talking about?

The first picture shows the set up with a single outboard and ties the ignition wire back to sense the start voltage and isolates the house from the start battery. The only pictures I find with twin outboards tend to leave that connection out for some reason. The is the biggest reason I want the ACR is during start up and not pulling my electronics down off my house battery. I can do it with a proper 4 terminal Manual isolation switch but thought I would try one of these since I'm going to modify how the builder wired up the existing switch.

 

[noluck]

i have always wired them like diagram 2

 

[ReelSlim]

I just got a reply back from a contact that @CIVANO posted last year. Kevin the rep got back to me right away with a better diagram and an additional required part that I just ordered on-line. Basically I just need to wire in a bridge rectifier that will only send the ignition start voltage to the ACR and not back feed to the other ignition switch from the second motor. I kind of was thinking about using diodes but the part he suggested was like $5.oo and can easily be mounted behind my dash and then I just need to run a single wire back to the ACR.

 

[ReelSlim]

His response...


When starting engines, house and engine battery banks should be isolated to protect house circuits from starting transients. The new 120 Amp SI (Starting Isolation) ACR, part number 7610, from Blue Sea Systems is designed specifically to do so, as well as provide combining and normal isolation functions. Starting Isolation automatically isolates the house battery bank from the engine battery bank when the starting circuit is engaged.

When the start key switch is closed to start either engine, the signal to the starter solenoid is sent to the Starting Isolation circuit. This circuit opens the ACR before either starter is engaged.

With two engines, install a diode bridge to activate Starting Isolation from either start key switch. A diode bridge will accept a signal from either engine but keep the start signals isolated. A diode bridge looks like a diode isolator in reverse. Only two of the diodes in the bridge are used; the other two diodes can be ignored. Although only two of the diodes are used in this application, a diode bridge is inexpensive and provides a more convenient package. Fully molded diode bridges with terminations are more rugged and easier to work with than individual diodes. A diode bridge suitable for this application is GBPC2504-E4/51GI-ND available from www.digikey.com, a mail order electronics distributor.

 

[ReelSlim]

i have always wired them like diagram 2

There is a good You Tube video from Portland Marine and shows why the SI or start interrupter option is wired from the ignition switches. Basically if you are running along the ACR is most likely charging both the house and the start battery. All of a sudden you pick up some kelp or debris so you slow down shut off you motors and raise them up to clear it. In that short time both batteries are most likely equal so the ACR is still sitting in the Both position essentially. So now when you start the main motor you we be pulling load on your house battery and not isolating it from the start battery and dropping your electronics etc down. For me that is the issue I am trying to solve with the ACR.

 

[noluck]

i have never found that issue, if both engines are off and nothing is charging the batteries are isolated. the only time the house and starting batteries are ever connected is if you move the battery switch from on to combine in a emergency situation. the arc only switches your charge wire to maintain proper charge state of all battery banks. nothing to due with load

 

[ReelSlim]

No they are connected during charging as well. After a bit of time they will not be combined when the motors are off. If its like the example I used there is a good chance they are not isolated from each other for up to 30secs after the voltage drops to 12.75V according to the Blue Seas website. (Possibly up to 2 minutes) That is why they have the SI option on them and makes sure you are not combined if some instances. It may of never been an issue but it can be is all I'm saying. The load I was referring to is the draw from starting your main motors.