Adding second battery

[ejschultz 10+ year member]

If the front and rear battery are not identical, I would recommend using a battery isolator. Having different batteries will cause the lives of both of them to be shortened. An isolator will fix this issue. I personally prefer diode type isolators. Solenoid isolators take up a little bit of current so they pose a little bit of a bigger load on your alternator. Diode isolators absorb a little bit of voltage, but not much (about .4 volts). Diode isolators are also much more dependable. Solenoids have about a 10,000 cycle life while diodes have essentially infinite lifespans, as long as you don't get them overly hot (hundreds of degrees). If the batteries are the same, run a run of positive and ground the rear battery to the chassis. If you get an alternator whine with it grounded to the chassis, run a ground up front. Also, a fuse will be needed within 18 inches of both batteries between the batteries. One of the pictures only had a fuse up by the front battery. If something up front shorts out, it's going to draw a lot of current from the rear battery too and all of your wire is going to burn up inside the car or wherever you put it, potentially starting a fire. Two fuses will protect you from this. Also, obviously fuse the power wire from the rear battery to the amp(s).

 

[basscort2009 5,000+ posts]

same = same
and yes, you want them to be equal. thats why i wouldnt recommend upgrading to 2 runs pos and still running the neg thru chassis. that creates a bottle-neck. if you want to run one pos run, and ground to the chassis, that is (generally) ok. but more pos runs means you need more ground to complete the circuit. so (IMHO) if you run 2+ pos runs, you should do the same for the ground

thats a decent way to do it as well. i dont see why u wanna run more than one in any situation except usaci stock or whatever class where u can only have one battery, then its cool. buti have had 3 batts in the back and all i did was one runj one pos to the back and just ground all the batts to the chassis and it did fine

either way is good though

 

[basscort2009 5,000+ posts]

If the front and rear battery are not identical, I would recommend using a battery isolator. Having different batteries will cause the lives of both of them to be shortened. An isolator will fix this issue. I personally prefer diode type isolators. Solenoid isolators take up a little bit of current so they pose a little bit of a bigger load on your alternator. Diode isolators absorb a little bit of voltage, but not much (about .4 volts). Diode isolators are also much more dependable. Solenoids have about a 10,000 cycle life while diodes have essentially infinite lifespans, as long as you don't get them overly hot (hundreds of degrees). If the batteries are the same, run a run of positive and ground the rear battery to the chassis. If you get an alternator whine with it grounded to the chassis, run a ground up front. Also, a fuse will be needed within 18 inches of both batteries between the batteries. One of the pictures only had a fuse up by the front battery. If something up front shorts out, it's going to draw a lot of current from the rear battery too and all of your wire is going to burn up inside the car or wherever you put it, potentially starting a fire. Two fuses will protect you from this. Also, obviously fuse the power wire from the rear battery to the amp(s).

u only need one fuse between the batts. it protects current going either way. and ACTUALLY, i get hell for this but i dont run fuses at all. they get in my way and its just more crimp points where tenths of dbs can be lost. i have one run of UNfused 4/0 going to my back battery lol

 

[jco1385 5,000+ posts]

u only need one fuse between the batts. it protects current going either way. and ACTUALLY, i get hell for this but i dont run fuses at all. they get in my way and its just more crimp points where tenths of dbs can be lost. i have one run of UNfused 4/0 going to my back battery lol

negative. there's still power on both sides if it blows. if there are 2 then they will isolate the wire between the batteries, and keep the power within 18" of either battery

 

[basscort2009 5,000+ posts]

i have 1000 volt ul rated wire. its not gonna burn up. (most wire rated at 600 volts ul)

 

[basscort2009 5,000+ posts]

but to give good advise, YES it is probly the best idea to do 2 fuses

 

[jco1385 5,000+ posts]

but to give good advise, YES it is probly the best idea to do 2 fuses

//content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif

we're talking to everyday people, with the normal products. so yes, 2 fuses are recommended.

 

[basscort2009 5,000+ posts]

lol yea.

 

[basscort2009 5,000+ posts]

This is the correct way to wire up another battery right? Is the 2nd fuse necessary? I dont have the ground the second battery again, it will ground out through the other battery?

back to bobby32, sry bro lol

either one of the pics that i and u drew would work as long as u ADD one fuse to either picture

 

[ejschultz 10+ year member]

i have 1000 volt ul rated wire. its not gonna burn up. (most wire rated at 600 volts ul)

This isn't true. Voltage will not burn up wire, current will. Fuses protect against high amounts of current that can damage wiring and equipment. In any case, if you're running 4/0, you're probably okay to not have a fuse in there, but if that power wire comes unattached from anything and grounds itself, you're f*cked. I'd strongly recommend fusing at both ends to prevent any instances that could possibly result of a connection coming loose and grounding. You're always better safe than sorry.

 

[basscort2009 5,000+ posts]

This isn't true. Voltage will not burn up wire, current will. Fuses protect against high amounts of current that can damage wiring and equipment. In any case, if you're running 4/0, you're probably okay to not have a fuse in there, but if that power wire comes unattached from anything and grounds itself, you're f*cked. I'd strongly recommend fusing at both ends to prevent any instances that could possibly result of a connection coming loose and grounding. You're always better safe than sorry.

it took me 2 and half hours to install one amp, (run 4/0 and ground back battery)

I AM ALWAYS VERY SAFE, thats why im not sry lol

 

[ejschultz 10+ year member]

it took me 2 and half hours to install one amp, (run 4/0 and ground back battery)
I AM ALWAYS VERY SAFE, thats why im not sry lol

I guess it is hard to find a 4/0 fuse holder.

 

[basscort2009 5,000+ posts]

I guess it is hard to find a 4/0 fuse holder.

//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif:uhoh: yea thats why it took so long.....

 

[jco1385 5,000+ posts]

make one //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[Bobby322 10+ year member]

Okaaay so the guy who thread jacked me really got this off topic. I'm guessing my picture will work but I need to add a fuse from the amp to the rear battery? I probally will just ground the second battery to save wire, if I can find a good grounding spot