two batteries

i want to install another battery in my car i have everything i need to do it just need to double check to make sure it's hooked up right.  if it's big it's ok, if it's shinny it's better. if it's loud, it kicks. the louder the better

make sure the 2 batts match....ive had problems with the charging systems not charging 1 batt fully if they didnt match.  something to look for. and dont forget to fuse the rear batt also.   XS

You should use a PAC-200 Relay to isolate the batteries from each other. 

Can you list the items you have for this 2 battery setup? just to make sure you got everything. There really isnt much. Your alternator should produce enough amps to charge both batteries. I am not sure why people say the batteries should be identical, I don't think they need to be identical. I am in a similar predicament whereby I purchased all the items I think I need. Just need to hook it up. Also like mentionned above, make sure you have a isolator relay and fuse for each battery. I put fuses for every device as well. Having extra fuses dont harm, but having too few is cause for burning up something. mark

what happens if you hook up 2 new batteries to a 100amp alternator?    that is all my stock nissan alternator puts out and i have a new red top and yellow top optima i want to install into my maxima?

what u need 2 batterries for?

t0mmyr, think if it this way. A battery is basically like a bank, where you keep putting $1 every millisesecond (the alternator storing some current to the extra-battery). Once in a whiles (each time your subwoofer is hitting a powerfuil bass note) you need more power whereby the current is being provided from the extra battery. Like withdrawing $100 from the bank. Even though you are withdrawing $100, it is still nothing compared to what you saved by adding $1 every millisecond. Now havin 2 batteries would be like having 2 banks. You will surely be putting little bit of power in each battery, but I havent seen anyone yet with 2 batteries. Are you sure you need 2? What made you decide on 2 batteries? That might give us clues. Also what power amps and speakers are you using?   I am sorry if I bored you with the bank analogy, but I just thought it might be helpful for some. Mark

A extra batt only helps if you plan on playing your system with the motor off. It will let you play longer. that's it. It will not make a bit of differance if your car is running. That is when your alt is powering your system. and charging both batts. Make sure you have a ho alt. (extra batt=extra load) start with 2 new identical batts. I don't use isolators myself. Some one is sure to argue that with me. I have been running dual batts for years never had a isolator, no troubles. Big Dave