Help with wiring house and starting bateries

[captainfrank]

I need to replace my batteries (group 27) which now are wired as bank one and bank two through a three postion switch. I would like to create a system which keeps the two group 27 batteries for house use and add a dedicated starting battery. I'm not sure on how to wire the starting battery into the system. Can I simply connect the two group 27's as bank one and setup the new starting battery as bank two? If so, how does the starting battery get charged? I now charge with the switch on both. Is this ok with these different kind of batteries? Any feedback will be greatly appreciated.

[sailingdog]

CaptainFrank-

My recommendation to solve your problem is to get a BlueSea Dual Circuit Plus battery switch and either an ACR or an Echo charger.

Connect the two house batteries in parallel and connect them to the #1 side of the DCP switch. Connect the main DC panel feed on the other post of the #1 side. Connect the starting battery to the #2 side of the switch, and the lead to the starter motor to the other post of the #2 side.

Connect the alternator output to the house bank. Connect the AC charger to the house bank. Connect the ACR or echo charger to the house and starting banks. Either of these will connect and charge the starting battery whenever there is a charging level voltage on the house side.

Do not mix battery chemistries... ie, if your house bank is wet-cell, your starting bank should also be wet-cell.

[Rockter]

Yes, that will work. It's what I have. Starting batteries are not expensive.
If your battery switch has a field wire interruptor on it, you can start on the start battery, then switch to house batteries.
If your battery switch does not have an interruptor on it, you can wire one in manually, but you must remember to throw it to off (the field wire interruptor switch) before switching the battery master.
With practice, you remember.

[sailingdog]

Rockter-

The nice thing about the Dual Circuit Plus is that the switch isolates the start battery and house batteries in the "ON" position, and allows you to start your engine off the starting battery while protecting the house loads from the dropout/surges caused by starting the engine, unless the banks are COMBINED.

Using this with an ACR or Echo Charger is really the best setup IMHO for a boat with dedicated start and house banks.

[chucklesR]

Go with 3 Group 27 Optima Spiral top deep cycle AGM's and you have a respectable 2 battery house bank (140ah) and a starting battery that is the same, and has the cranking power.

I have the set up above (Blue Sea, ACR etc..) except I have 4 batteries. Works like a champ, and if any battery fails I have an exact replacement on hand by simply changing wires.

[camaraderie]

All of the above will work but if you just want a quick fix...remove the battery you now have on #2 and place the new starting battery there. Take the removed battery and wire it in parallel to your #1 battery. (Minus to minus, plus to plus)
Switch the batt switch to "Both" when you want to charge all of them at the same time.
As long as the batteries are all the same type...(i.e. flooded, AGM or Gel) it does not matter that they are deep cycle vs. start construction.

[sander06]

I've got my starting battery in the #1 position and three house batteries wired into the #2 position. All of the batteries can be charged by our Xantrex battery charger, but only the starting battery and one of the house batteries is charged by the engine alternator. If I hooked up all of the house batteries in parallel, wouldn't the engine be able to charge the whole shooting-match? Also, does the battery select switch determine what battery /battery bank is actually being charged at any given moment. I got the impression that the Xantrex charger charged everything no matter what the selector switch was set for, while the batteries being charged by the alternator was actually determined by the selector switch position. Is that true?

Boat batteries and switches and charging make me dizzy!!!!

[sailingdog]

Sander-

It depends on how the charger is wired. If it is wired downstream of the battery switch, then it the switch position can be off... and it wouldn't matter... if it is upstream of the switch—ie, the switch is between it and the batteries—then the position of the switch may determine what gets charged.

HOw is it that you can only charge only one of the house batteries? Aren't they wired in parallel? If not, how are they wired??

[sander06]

Of the three house batteries, one is a stand alone used for the electronics, lights, etc. on the boat. When the PO's added a refrigerator to the boat they put in a couple of house batteries wired in parallel for just the cooling unit. All of the three house batteries are so wired that they can all be charged by the Xantrex. However, for whatever reason, only the original stand-alone battery is hooked up to the alternator for charging. Hence, the refrigerator batteries can't be charged by the alternator. I'm just wondering if I can overcome the whole hootenanny by wiring all of the house batteries together in parallel and call it good. I guess I'd need to disconnect one of the Xantrex house battery connections since currently the unit is charging the starting battery, the stand-alone house battery, and the refrigerator batteries as three separate batteries.

What I'm thinking is that the refrigerator batteries aren't even hooked into the battery selector switch at all since they only planned on using the refrigerator while they were tied up at the dock and had no intention of ever using it while anchored out. That means I would have the starting battery as #1 and the three house batteries wired in parallel as #2.

[Cerveza]

A lot of people like the idea of having fancy charge controllers and voltage sensitive relays. I feel the more basic and simple the setup is, the more reliable it will be. I'm planning on a setup like this. I have maximum redundancy and the only moving parts is the main battery switches.



This is my battery isolator.