Dual Batter Charger - 1997 Explorer 215

[CLM65]

Thanks CB, putting the ACR on the load side of the battery switch certainly would take it out of the equation.  Prior to your post, all of the literature I saw from Blue Sea said that the ACR should be wired directly to the battery to minimize voltage drop since the ACR makes decisions based on the sensed voltage.

[Capt. Bob]

The key to this whole thing is the dual circuit plus switch. You'll need that to replace the ol' 1,2, Both, Off switch.

https://www.bluesea.com/resources/68

Keep diggin' in that wallet.

[CLM65]

Yea, that's not gonna happen.  I don't like that you only have the option of battery "1" or "both" with that switch.  I prefer to be able to pick either battery.  So I have a 1/2/both switch and an on/off switch.  Overkill, maybe, but gives me more options.

[RickK]

Looks like my setup except I can turn them on individually and then combine them if needed.  Like when we go camping I will leave the house on and turn off the starting, leaving it off most of the time.  With that switch they're either both on or off.

[Capt. Bob]

I have a 1/2/both switch and an on/off switch.

How is that wired?

[CLM65]

I don't have a sketch, so I'll try a brief description.  The house battery feeds a simple on/off battery switch (SW1).  The load side of SW1 has a lead to the house loads.  There is also a lead from the load side of SW1 to position “2” on the 1/2/both battery switch (SW2).  The starting battery feeds position “1” on SW2.  So normally SW1 will be on, feeding the house loads, and SW2 will be in position “1”, for starting the engine.  If I want to combine the batteries, SW2 gets changed to “both”.  If I only want to use the house battery for everything, SW2 gets changed to “2”.

Why would I do it this way you ask?  Well, on numerous occasions I have experienced shorted/dead batteries that are so drained that they would not even take a jump start.  So I figure combining the batteries is much like jump starting, and may have the same problems.  With my setup, it gives me a little more flexibility.

Let me know if you see flaws in this logic.

[Capt. Bob]

I understand your description but I'm still working through the logic.

I'm correct in thinking that the common post in SW2 feeds only your engine, yes?

You could supply the house loads with the starter battery (if for some reason) by placing SW2 in the both position and SW1 in the open correct?
 
Interesting thoughts on a rainy afternoon.

[Capt. Bob]

OK I see it now.

Tell me, how will you wire in the ACR (on your rebuild correct?) or will you use a different switching setup similar to Rick's?

[CLM65]

Yes, this will be on the rebuild.  I was planning to connect the ACR to the line side of each battery switch.  But now I'm wondering if I should change that based on your diagram from BS.

[czizza]

WOW this is a lot of different information then I had. Strange thing is if you go to the BlueSea website it still has the ACR in the battery side and not the load side.

https://www.bluesea.com/products/7650/Add-A-Battery_Kit_-_120A

Here is the instruction and they also say ACR is on battery side:

http://assets.bluesea.com/files/resources/instructions/990310020.pdf

... And if you look at the link ... it shows a single battery charger connected to the house battery and explains it.

https://www.bluesea.com/support/articles/57/Automatic_Charging_Relay_-_An_Alternative_to_Multiple_Output_Charging_Systems

I think the issue is because I have an SI-ACR and the one in the picture from RickK is the CL-ACR ... I guess I am going to have to call them.

Here is the kit I have:

[CLM65]

If you are going to contact them, you may also want to ask them about the undervoltage lockout.  If I understand it correctly, if either battery is less than 9.5 volts, the ACR will not combine the batteries.  So if your single bank charger is connected to battery 1, and battery 2 was drained down to 9 volts because you left the stereo on, then the ACR will not allow the charger to charge battery 2.

[Capt. Bob]

OK czizza,
Remember what's happening here with the ACR.
First, forget the dedicated battery charger for a moment.

It's allowing the charging system of the engine to supply all your power sources (in this case both the house and start batteries) with juice. The Dual Circuit switch allows you use both house and start batteries for their designated purpose (at the same time) and also allows you to use the ACR to properly distribute the charging to each battery. In this situation, there is no additional battery charger to provide energy while the boat is at rest (think trailer/slip).

The ACR can also use a "single bank" battery charger (remember, this is what your engine is also) and allow it (again just as it does with the engine charging circuit) to charge both batteries. No need to upgrade to a "dual bank" charger. This is the diagram you first posted above.

Now, if you have/want a dedicated dual bank charger for shore use, you would wire it directly to each battery. You would use the switch to "remove" it from the load while charging (switch in the off position). Once you disconnect from shore power and launch, you turn the switch on to use your batteries for their intended purpose and the ACR handles the engine charging distribution. That would be the diagram I posted (which is the "add a battery" one). In that diagram a shore charger is not shown but is understood (at least by me) to be wired directly to each battery as you normally would. Again, charge on shore, switch off. Underway, switch on.

Here's the real concern and it may best be directed at the charger manufacturer.

Will the use of the ACR, which now feeds the engine charge back to the batteries, affect their charger?
Well, since many users have dedicated chargers already wired into their systems and receive power underway from their engine circuits back to their battery with no problems, I see no reason to think it would be any different with an ACR in place. I'm thinking that the charger has built in circuits that prohibit the backflow from the engine to affect the charger circuits. Just a guess but Blue Sea tech support agrees so....

If you use what you have shown (dual circuit switch and the ACR) plus a dedicated dual bank charger to handle shore charging, no problems.

Good luck.

[Capt. Bob]

If you are going to contact them, you may also want to ask them about the undervoltage lockout.  If I understand it correctly, if either battery is less than 9.5 volts, the ACR will not combine the batteries.  So if your single bank charger is connected to battery 1, and battery 2 was drained down to 9 volts because you left the stereo on, then the ACR will not allow the charger to charge battery 2.

Good point.

All the more reason to use a dual bank dedicated shore charger and taking the ACR out of the loop.
Allow the ACR to perform it's intended function of charge distribution while underway and the battery charger to do the same while on shore. Yes, you will need to spend more if you don't have a dual bank charger.

In Craig's case, (if I have the diagram right in my mind) he would wire the ACR between position 1 and 2 on SW2 (SW1 would need to be in the on position and SW2 in position 1; as in normal operation). When he wanted to charge on shore, both SW1 and SW2 would be in the off position.

[czizza]

Now, if you have/want a dedicated dual bank charger for shore use, you would wire it directly to each battery. You would use the switch to "remove" it from the load while charging (switch in the off position). Once you disconnect from shore power and launch, you turn the switch on to use your batteries for their intended purpose and the ACR handles the engine charging distribution. That would be the diagram I posted (which is the "add a battery" one). In that diagram a shore charger is not shown but is understood (at least by me) to be wired directly to each battery as you normally would. Again, charge on shore, switch off. Underway, switch on.

Here's the real concern and it may best be directed at the charger manufacturer.

Will the use of the ACR, which now feeds the engine charge back to the batteries, affect their charger?
Well, since many users have dedicated chargers already wired into their systems and receive power underway from their engine circuits back to their battery with no problems, I see no reason to think it would be any different with an ACR in place. I'm thinking that the charger has built in circuits that prohibit the backflow from the engine to affect the charger circuits. Just a guess but Blue Sea tech support agrees so....

If you use what you have shown (dual circuit switch and the ACR) plus a dedicated dual bank charger to handle shore charging, no problems.

Good luck.

I saw your drawing and that makes sense ... Isolate the ACR for when the engine is running ... this avoids the 9.5volt issue and get a dual charger for when the trailer is on land.

Any issues with me putting the power receptacle, here, obviously as high as possible:



-Melo
 

[RickK]

Nope, mine is mounted in the same location and they have a cover that snaps in.