On-Board Charger,Battery Switch, and Automatic Charging Relay

[Trapper John]

The present battery system in my 1992 Seaswirl 250 SWL is a typical Rube Goldberg slice and splice nightmare. I intend to replace the battery charger and switch and to install busbars to eliminate the rat nests presently found at the battery terminals.
The switch replacement that I have in mind is the Blue Sea Systems dual circuit battery switch and its companion ACR.

Where I get confused is at the charger/switch interface. Since I am going to run two battery banks, do I need a dual bank charger as well, or do I simply connect a single output charger to the battery switch? No matter how hard I look at the manufacturer?s wiring diagrams I can?t sniff out the answer, so I am obviously flunking wiring 101.

 

[captain zac]

Re: On-Board Charger,Battery Switch, and Automatic Charging Relay

I would go with a 2 bank smart charger but would consider a 3 bank if I ever decide to have 3 bats
not much price difference

 

[Silvertip]

Re: On-Board Charger,Battery Switch, and Automatic Charging Relay

You can use a single bank charger and connect it to the COM terminal on the switch. But what that means is that the switch must be left in the BOTH position when charging (or 1 or 2 if you want to charge individual batteries). If you install a dual bank, each output on the charger goes directly to the battery. This allows turning the switch OFF to ensure nothing on the boat stays powered when the boat is docked or stored. I also question the need for BOTH the ACR and the switch. You can certainly do that, but I just question the need. Learn to use the switch to your advantage and you don't need the ACR. Or use the ACR and eliminate the switch. Any of the three works.

 

[Trapper John]

Re: On-Board Charger,Battery Switch, and Automatic Charging Relay

Thanks to both Cap"t Zac and Silvertip for the advice. The price differential between the two and three bank chargers is $10 (for 20a). By eliminating the ACR, which I understand to be redundant, shaves another $80 from my initial plan. Sounds like I owe you guys a Salmon fishing trip if you're ever out this way.

 

[bruceb58]

Re: On-Board Charger,Battery Switch, and Automatic Charging Relay

Personally, I use the switch and the ACR. The reason you want the switch in addition to the ACR is that if you get into a situation where both batteries are run down, You can put them in the "both" position and start up. Some would say that if you have the switch, you can do away with the ACR but with the ACR, you can just leave the switch in one position and never have to move it. If you leave the switch in "both" to charge both the batteries, you run the risk of accidentally leaving it that way and running down both batteries.

As far as charging with the ACR, be aware that when either battery has a charger on it, its going to combine the two batteries. Personally, I have an ACR and a two bank charger and the ACR does connect them both together. There is an option to disable the ACR so while charging, your two bank charger can independently charge both batteries if you desire.