Help Adding 2nd Batt

[walkychalky 10+ year member]

so i have a 220 amp alt and yellow top under the hood right now runnin my orion 2500d but i wanna add a second batt in the back jus to be safe......i wanna move the yellow top to my trunk and run my amp off of it and put a red top under the hood.........so how do i hook it up?.....do i need to hook it to the alt or do i jus run wire from + to + and - to - on the batts??....or what? any help is appreciated

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[iamamp3pimp 5,000+ posts]

Hook up the redtop as normal. put the yellow top in the back. Remove the wire from your amp, and connect it to your positive lead on the yellow top. Fuse both ends, as now both sides are powered, and if anything happens, your ride will burn to the ground. Ground your yellowtop in the back. All is well.

If you plan to run your system with the car off, on the second battery, then you need an isolator, but its not necesary.

 

[walkychalky 10+ year member]

Hook up the redtop as normal. put the yellow top in the back. Remove the wire from your amp, and connect it to your positive lead on the yellow top. Fuse both ends, as now both sides are powered, and if anything happens, your ride will burn to the ground. Ground your yellowtop in the back. All is well.
If you plan to run your system with the car off, on the second battery, then you need an isolator, but its not necesary.

so do i run wire from the + on the red top to the + on the yellow top and from the - on the red to the - on the yellow.......and what do mean fuse both ends?.....fuse both ends of what?

 

[knukonceptz 10+ year member]

Ground Red top under the hood to chassis, ground Yellow top in rear to chassis.

------Battery+++_FUSE1_++++++++++++++++++++_FUSE2_+++Battery-----

Properly wired required 2 fuses, because with one fuse you have power still at both sides of the holder with fuse removed. So either do no inline fuses or do two inline fuses (correct)

 

[walkychalky 10+ year member]

Ground Red top under the hood to chassis, ground Yellow top in rear to chassis.
------Battery+++_FUSE1_++++++++++++++++++++_FUSE2_+++Battery-----

Properly wired required 2 fuses, because with one fuse you have power still at both sides of the holder with fuse removed. So either do no inline fuses or do two inline fuses (correct)

iC......thanx for clearin that up

but is my ride really gonna burn to the ground?? //content.invisioncic.com/y282845/emoticons/eek.gif.771b7a90cf45cabdc554ff1121c21c4a.gif

 

[knukonceptz 10+ year member]

Not without some help, if you go the no fuse route and you are rear ended or T-boned you have power from two 800+ amp batteries live in your car's interior where sparks can lead to fire. This is why you fuse both ends 12-18" from the battery making any chance of a dead short to a minimum.

I have seen a not so well secured battery make a dead short to chassis when it fell over in a trunk and smoke filled most of the car rapidly, made a nice weld mark too

 

[walkychalky 10+ year member]

Not without some help, if you go the no fuse route and you are rear ended or T-boned you have power from two 800+ amp batteries live in your car's interior where sparks can lead to fire. This is why you fuse both ends 12-18" from the battery making any chance of a dead short to a minimum.
I have seen a not so well secured battery make a dead short to chassis when it fell over in a trunk and smoke filled most of the car rapidly, made a nice weld mark too

yah i'll def be fusing both ends and securing the batt....thanks for u help

 

[XaznKewLguyX 10+ year member]

sweet i've always wondered but never wanted to ask lol.

 

[revrider1 5,000+ posts]

That is what I am currently working on //content.invisioncic.com/y282845/emoticons/up2something.gif.dd110ecf3ae4b76050d87598f2f8de7c.gif

 

[irnotfob 10+ year member]

and this can happen if you do not have a fused distribution block as well? or if you change wire sizes and don't fuse there is a chance your car will burn down?

 

[revrider1 5,000+ posts]

and this can happen if you do not have a fused distribution block as well? or if you change wire sizes and don't fuse there is a chance your car will burn down?

Um yeh, we know that

 

[cjj2d 10+ year member]

so you don't have to connect the battery in the trunk to the alt???

 

[knukonceptz 10+ year member]

No, you connect to the front battery and the charge goes from the ALT to both batteries by means of the Main power wire. As a side note, you should charge both batteries prior to installation. A battery could be sitting on a shelf for months sometimes and need a good over night charge for best performance.

 

[MegaHurtz 10+ year member]

The front and rear batteries need to be isolated. This can be done with a number of ways. The way that I recommend is to use an RV solenoid. There are other isolators, some of which can lose up to a full volt across the terminals, RV solenoids are supposed to be very efficient, or so I am told. There is a connection on the isolator for a wire that would become hot when the car is running (the isolator is essentially a high amperage SPST relay). Car turns on, coil energizes, current flows throughout the system, rear battery charges. The reason that you have to use an isolator is that the batteries will not be perfectly equal. When wired in parallel, they will attempt to level themselves off, resulting eventually in both of them being drained. The way to work around this, is to buy 2 identical batteries at the same time, but it doesn't sound like this is what you are going to do. Definitely fuse both batteries 18" from the positive terminal, this is not a should do, this is a MUST do.

 

[knukonceptz 10+ year member]

No isolater or solenoid required, using those two in audio applications defeats the purpose of the added reserve capacity. How can two batteries drain themselves dead? - why do you think I said to charge both first. If the two are equal in charge to begin with and are connected in the same circuit, how is one going to be lower then the second if they are connected? IF you have a bad battery - YES it will eventually kill the second. Two good working batteries of different size will work together just fine.

We need a Battery sticky as we have gone over and over on this topic of multiple batteries killing your ALT, Isolators needed.... and other comments that are just not factual.