Charging Two Batteries ?? Connecting the Charger

[melbourne]

Two 12volt batteries wired parallel.The battery system has the 1,2,or both switch.

How do I manually charge this dual battery system at shore??

Do i connect the charger to a single battery and throw the switch to both??

Battery 1: Exide Deep Cycle Nautilus Gold (NG-27)
675 MCA
550 CCA
182 RC
105 Amps per Hour

Battery 2:
Exide Dual Purpose Nautilus (NG-24)
625 MCA
500 CCA
120 RC
70 Amp Per Hour.

I have a Battery Tender Plus - The Battery Tender Plus is a 1.25 amp battery charger designed to fully charge a battery and maintain it at proper storage voltage without the damaging effects caused by trickle chargers. Included is a quick connect harness for hard to reach areas.

Temperature compensated to ensure optimum charge voltage according to ambient temperature.
Automatically switches from full charge to float charging mode.
Battery Tender at 1.25 amps will charge as fast or faster than any 3 amp charger available.
Reverse Polarity Protection to ensure user safety. Red & Green Lights Alternately Flash in this condition.
Complete 4-step charging program (Initialization, Bulk Charge, Absorption Mode, Float Mode).

 

[Silvertip]

Re: Charging Two Batteries ?? Connecting the Charger

You can do this in a number of ways but the simplest is to connect it to the COM terminal of the switch. If you want to charge both batteries, set the switch to BOTH. If just BAT 1, set it to BAT 1, or the same for just BAT 2. The switch does the same thing for your charger as it does for the engine charging system. It is a simple matter of setting the switch to the battery(ies) you want to charge.

 

[melbourne]

Re: Charging Two Batteries ?? Connecting the Charger

Thanks SilverTip,

I'll look underneath the cover of the dual battery switch.

I am assuming the Common Connectors on the switch has a positive and negative lead??

 

[Silvertip]

Re: Charging Two Batteries ?? Connecting the Charger

NO! The switch has only POSITIVE connections. Negative for your charger goes to the negative terminal on either battery. You do have a jumper between the negatives of the two batteries don't you?

 

[melbourne]

Re: Charging Two Batteries ?? Connecting the Charger

Yes, I have a jumper between the negative leads on both batteries. I need to take the cover off of the switch to determine where "common" is. I will assume it's the "both" switch position or it's clearly identified as "common" or "COM"..

With this configuration will I charge both batteries at once using the "both" position or would you suggest I charge one battery at a time using the "1" or "2" position????

BTW...I am grateful for your guidance.

 

[Chris1956]

Re: Charging Two Batteries ?? Connecting the Charger

Actually, it is easier than that. Set the switch to both. Connect the charger red lead to the positive post of either battery. Connect the black charger lead to the negative post of either battery. Since thebatteries are conected at the switch, you will charge both at the same time.

 

[melbourne]

Re: Charging Two Batteries ?? Connecting the Charger

Does it matter if the batteries are different????

Battery 1: Exide Deep Cycle Nautilus Gold (NG-27)
675 MCA
550 CCA
182 RC
105 Amps per Hour

Battery 2:
Exide Dual Purpose Nautilus (NG-24)
625 MCA
500 CCA
120 RC
70 Amp Per Hour.

 

[Chris1956]

Re: Charging Two Batteries ?? Connecting the Charger

As long as the batteries are both 12V, they will charge fine. One will charge up a bit faster, and then the second will catch up.

 

[melbourne]

Re: Charging Two Batteries ?? Connecting the Charger

Thanks Captain !!

 

[Silvertip]

Re: Charging Two Batteries ?? Connecting the Charger

There are three big posts on a dual battery switch. BAT 1 POS connects to one post. BAT 2 POS connects to the Bat 2 post. COM is the OUTPUT of the switch. It has voltage from either BAT 1, BAT 2 or BOTH depending on how you have the switch set. The COM terminal feeds the circuits connected to it.

 

[Dodger1234]

Re: Charging Two Batteries ?? Connecting the Charger

Hello Chris1956, on your above comment are you saying hook up the charger to any battery then put the switch to both and your good to for charging both. Thanks for helping the electrically handicapped.
Dodger123.

 

[bowman316]

Re: Charging Two Batteries ?? Connecting the Charger

The wire going to the comm terminal is touching the positive terminal, so hooking the charger up the the positive terminal is like hooking up the the com too. that is how i see it anyway.

 

[Chris1956]

Re: Charging Two Batteries ?? Connecting the Charger

Bowman is correct. If you want to charge a single battery, you will need to connect the charger to the positive post of that battery, and the neg post of either battery and set the switch to off.

 

[bowman316]

Re: Charging Two Batteries ?? Connecting the Charger

I can still run other wires to one battery, and not have them involved what so ever in the switch, Even when the switch is off, these wires are still hot.
They are not touching the com wire, they are on the srews, next to the terminal.