Dual Battery Wiring Help

[Simpleman04]

I want to install a second battery. I already have a deep cycle battery for free that I want to install. Can I hook em both to the alternator and then ground separatly. Im not sure because one is deep cycle the other is optima red top 34/78
Any advice?

[Shawn]

use the search feature for "dual battery" alot of info out there already.

In a dual battery setup, the batts should be equal - the same make/model/size/ect.

[enine]

If you wire two straight together they should be the same, since you have different then you should probably isolate them. You can do this with a relay or a diode isolator, each has advantages and disadvantages.

[Mattman24]

i have a 200amp stinger relay isolator works fine, havent had and problems

Matt

[enine]

You just have to be careful with the relay "isolotor" since it doesn't isolate when connected so you could have a dead second battery load down the starting battery to where you can't get the truck started. I wanted to be able to run my second down so I used the true isolator (diode) to keep them seperate even when charging.

[Simpleman04]

i appreciate the help guys. Im going to the marina tomorrow they have all sorts of different kinds of isolators. I will set them up to charge separatly.