How to add a 3rd Battery

I know there have been past posts on this but i couldnt find my exact answer. Right now I have 2 batteries and an isolator.

Question 1: if i want to add a 3rd battery, do i just hook the + and the + together and the - and - together between the 2nd and 3rd batteries (both stereo batteries)?

Question 2: if that is correct, will the 3rd battery still charge while the boat is running?

Question 3: when i want to charge the batteries at night, do i need to charge all 3 seperatley? unhook them and get 3 chargers?

thanks for the help. like i said, i know there have been tons of posts on batteries, so sorry if i didnt find what i was looking for.

Buy an identical battery to your second battery, run it in parallel to the second battery. It will receive charge the same way the #2 battery does. It is important that the battery be the same type size and age, but since they'll only run the stereo, it is not as critical as it is with parallel starting batteries.

I charge my system by putting the charger on my starting battery. When it approaches full charge, the isolator allows current to flow to my Optimas. It takes longer this way but it's simple.

So, question 1 is the way I'd do it.

than you psyclone - i did not realize that if i put a charger on my starting battery, that once it gets fully charged, my other battery would beging to charge.

any other opinions?

anyone????

Question 1: if i want to add a 3rd battery, do i just hook the + and the + together and the - and - together between the 2nd and 3rd batteries (both stereo batteries)? YES
Question 2: if that is correct, will the 3rd battery still charge while the boat is running?

YES

Question 3: when i want to charge the batteries at night, do i need to charge all 3 seperatley? unhook them and get 3 chargers?

YES

Grant with respect I have to disagree with you . I have a 3 bank charger the will charge each one at the same time with 15 amps going to each. It is 3 bank PRO charger that does great.http://www.dualpro.com/productframeset.htm
here is the web site. It is made for bass boats but charges the batts. just fine.
Later

Shawn: With no respect to you and both of your alternators I disagree with you, LOL J/K you are correct you can do it with one charger

Im assuming that the Isolater that he has switches from battery bank A to battery bank B electronicly and if he was to attach a charger to lets say battery bank A the charge would not travel to battery bank B, Because the isolater would not let it,

Disclamer: I could be wrong, LOL Who knows how his set boat is set up. But if the Isolator is set up right you would need a leed going to each battery either threw 1 charger with a charging leed for each battery or 3 diffrent battery chargers.

It is 3 seperate chargers in one case. It has 3 sets of leads and can charge each battery independently. that way if you have an isolator it will charge both sides at the same time. Your work on the MC is looking great. I cant wait to get started on my new BU. NOt a crazy as the superair but still loud!! hahahah

Shawn, Hummm. So you want to play Battery charger poker! OK Ill see your tiny 3 battery charger and raise you with this 4 battery charger, LOL

hahaah I looked at that one. But since I only have 3 batterys mine works great. I'll rely on the alternators to keep it up while riding. We NEVER park

1.25 amps?? and only 3 lbs for the unit?? kinda wimpy!! mine is 15 amps per and 22lbs. Just kidding, they are both nice chargers (more than 1 way to skin a cat). But Like I said before we live right on the lake with the boat ramp in our back yard so we never just park and listen to the radio. we just put it up and hang out in the hot tub over looking the lake. hahah Have a good night.\

thanks for the help guys. i will look through that site and see if i cant order one. if i cant order one, maybe i will just buy a house with a hot tub like shawn and not worry about parking and running down the batteries

Grant,
A hellroaring senses the charge going to the primary battery, when it exceeds 13.3vdc, meaning that the primary battery is near full charge, it passes current to the secondary batteries. Diode isolators work similarly, with a .6 vdc drop. Since you use a relay, you have to energize the relay to pass current from your charger to your secondary batteries, so you need more than one charger. It's a lot faster that way and you have a pantload of batteries, different for you. I guess I shoulda been more specific about my setup. Hellroaring is the way to go. Relays are good but the contacts will still drop voltage and the current can pass both ways. If your alternator dies while you are out pimpin', you will discharge all batteries with no isolation and you won't know it until you shut off your boat and try to restart. Probably won't happen, and you have gobs of batteries, but I only have three and crap always happens to me, so Hellroaring it is

Psyclone,

I believe the stinger isolator/relay works the same wayas the hellroaring. I see no voltage drop with mine.

Shawn,

Not to hijack here but where exactly do you guys live on Texoma? Did you build or buy an existing home?

We are on the little mineral side. Just south of grand pappys. We bought an older house 5 bed 5 bath and 5500sqf. I gutted it to the studs and remodeled it through out. It is over looking the lake. We have a boat ramp in the back yard and ride about 1/2 mile form the house. Do you come up this way much??