Running on 1 battery VS 2?

[Harry]

2000 262
7.4 DP

[Bfun220]

I have a question about the ACR dual battery switch that came as an option on my 2013 273.

One time I forgot to turn the battery switch off and some how a few interior lights we left on, as well. I was away from the boat for about a week and when I returned nothing would work and the engine would not crank on start. I was new to ACR and didn't realize there was a position on the switch for "both" batteries until I revisited the owners manual. Once I selected "both" batteries, I was able to start engine started.

I understand that the system prevented both batteries from going dead, but why wasn't I able to start the engine without switching to "both" batteries?
Was it because the system cut off both batteries when they were drawn down to the low voltage threshold and there was only enough power to start the engine when both batteries were combined?

I would guess you have everything running off the same battery. So when your lights drained battery 1 it didnt have anything to start the engine. When you switched to both battery 2 provided power. If you can look at the back of your switch, see if your only connected to 3 posts.
The system can not cut off power being supplied to your boat. It will just lockout power between the batteries.

[iboatmon]

I would guess you have everything running off the same battery. So when your lights drained battery 1 it didnt have anything to start the engine. When you switched to both battery 2 provided power. If you can look at the back of your switch, see if your only connected to 3 posts.
The system can not cut off power being supplied to your boat. It will just lockout power between the batteries.

So I guess what you are saying is that the ACR "isolated" battery 2 when battery 1 went below a certain voltage. This prevented both batteries from being depleted, saving battery 2 for engine starting. It seems to me that it should have been able to use the isolated battery for starting without me having to switch to "both" batteries. I am sure my switch wiring is the original factory wiring, so it shouldn't be wired as a standard dual battery switch. as you suggest.

[Bfun220]

So I guess what you are saying is that the ACR "isolated" battery 2 when battery 1 went below a certain voltage. This prevented both batteries from being depleted, saving battery 2 for engine starting. It seems to me that it should have been able to use the isolated battery for starting without me having to switch to "both" batteries. I am sure my switch wiring is the original factory wiring, so it shouldn't be wired as a standard dual battery switch. as you suggest.

Yes, the ACR "isolated" battery 2 from being depleted.

And yes, you should not have to switch to both for starting. This is why I suggested checking the wires on the back of the switch. Or you could check to make sure the contacts are all working.

I can disconnect and remove my house battery and start the engine with my switch in the on position.

[Bobo87]

[quote=Bobo87 post_id=36430

So, if I understand your question correctly you actually are asking about tuning 3 batteries?

Also, what is the year and middle of your boat.

Bobo glad your finally speaking Pot the Jus with me
[/quote]

Yes sir! Figured sine I gotta head to New Orleans next week for work I should brush up on my Cajun.

[Wes]

blue sea acr load side wiring.jpg

Thought I would add a diagram of how to wire the Blue Sea ACR so that the ACR would not drain batteries as described on page 5 post by Photo_G on Aug 13 2018. I have this system installed in my Cobalt 242. Super simply on/off operation. Protects sensitive electronics from surges when starting boat. Don’t have to worry about running down starting battery when anchored listening to the radio, running anchor lights, etc. Both batteries always charged automatically. I have the remote indicator light mounted on the dash, so I can see when batteries are combined and charging. Great system.

[Bobo87]

Yep. That is the diagram I used for my installation, Wes. Curios. How do you lIke the remote light?

[Wes]

I have a small light mounted just to the right of the ignition switch. Reassuring to see the normal charge light from time to time. Although I haven’t had a voltage caused lockout from the ACR, it’s also reassuring to know I will see the flashing light sequence that will tell me something is wrong with one of the batteries. Well worth running the wiring to the front panel.

[Bobo87]

Wes - Did you get the light from Blue Sea or something else? A picture would be helpful if you don't mind.

[Wes]

I ordered the light from West Marine. It is a Blue Sea Systems LED Indicator light, Model #343725, Mfg #8033. Cost was $3.99. Don’t have a picture of my installed light, but you can see it on the West Marine online site.

[Wes]

On the West Marine website search “Blue Se Systems LED Indicator Light” to find it.

[Bobo87]

Will do. Thank you Wes.

[NautiGirl]

blue sea acr load side wiring.jpg

Thought I would add a diagram of how to wire the Blue Sea ACR so that the ACR would not drain batteries as described on page 5 post by Photo_G on Aug 13 2018. I have this system installed in my Cobalt 242. Super simply on/off operation. Protects sensitive electronics from surges when starting boat. Don’t have to worry about running down starting battery when anchored listening to the radio, running anchor lights, etc. Both batteries always charged automatically. I have the remote indicator light mounted on the dash, so I can see when batteries are combined and charging. Great system.

Hey Wes / others who have done this - couple questions. Did you install fuses between the ACR and the Switch in this configuration? I have seen people on other sites say since the wires are so short when you wire to the load side of the switch that fuses are really not needed.

Along the same lines what size wire did you use to put this together? If I am reading the diagram correctly the wires to the ACR should only have to handle the charging current of the Alternator so I would think 6GA would be plenty?

We should have some 4GA wire and battery lugs leftover from our stereo install - could be a really good time to bite the bullet and do an ACR while I have everything torn apart anyway.

[Bfun220]

I installed one of these on my boat and I won't install it without something protecting the wire. Never heard if you run a wire short enough that it doesn't need a fuse/breaker. Short wires can still overload, get hot, melt stuff and cause fires.
As for sizing, here is a chart with what they recommend.

[NautiGirl]

I installed one of these on my boat and I won't install it without something protecting the wire. Never heard if you run a wire short enough that it doesn't need a fuse/breaker. Short wires can still overload, get hot, melt stuff and cause fires.
As for sizing, here is a chart with what they recommend.

Yeah - you are right do it correctly the first time. I was trying to get cheap as the fuse and fuse holders cost more than the switch and ACR.