adding a second battery

[inferno]

o i just installed and optima red top up front and now want to install a yellow top in the trunk for my system.

now do i just connect the power wire from the front battery to the second or is there something i have to install in between. I remember reading before that an isolator was to be used. but im not positive on this. so any help would be appreciated.

i have 4ga ran to the trunk that i was using for my amp. could i use that for my battery then run a higher gauge from that battery to the amps?

[dmbprep69]

OK well really u should just use another redtop, but if u already have the second yellow top then u need an isloator, and ur gonna need at least 2 ga wiring from batt to batt and then use ur 4 ga to the amps. Well good luck!
Peace,
Andrew

[nineteen88ga]

Look for an Orion MBR70 same thing as a battery isolator, but looks better then a big relay.

[inferno]

why should i get another red top? and why 2 ga?

not trying to be smart just asking questions. this is all going to be run inside the car so i just need to know how much space im going to have for stuff. with a 2ga or higher im going to need to make a new hole in the firewall for this.

[red98grandamse]

Gabe, youll want a new hole in the firewall no matter what. But you need 2 guage, because you are running the wire over a much longer distance than whats under your hood. Also, make sure you get a grommet for the hole you put through the firewall :), you dont need the metal cutting into the wire you run.

[inferno]

well im just wondering cause i already have the 4ga going thru the firewall and im kinda being lazy in having to remove it but i guess i can use whats left for the big3 :)

where can i find 2ga wire? and where can i find the orion thing?

[red98grandamse]

I just did a search for it, out of curiosity as to wtf it was, and found one on ebay for 100 buy it now. as far as 2 guage wire, Ive no idea, never had to buy any, so hopefully someone else knows for ya. And if steve comes back on he should definately know... but maybe the audio section in circuit city for their installs?

[inferno]

i saw the ebay one and its used and he has modified it. ive i get it i want a brand new one that i know hasnt been tampered with. and i read the manual for it and it only requires a 4ga wire with 2 circuit breakers

[red98grandamse]

Ahh ok, I dont know much about that particular piece, as well as not knowing too much about wiring other than what i read. did you see if you can pick one up local, like circuit city or a car audio place? It wont be as cheap as finding one online, but they may have one if you need/want it now.

[inferno]

well i still have to get my car fix. im looking online for some 0 gauge wire and some 2 guage and knukoncepts is the cheapest place i find it at 1.85/ft for 0 guage

[red98grandamse]

that doesnt sound too bad 15 feet ought to be enough, but Ive never worked it out. Id be interested in figuring it out though, as Im hoping to move my battery to the trunk sometime this spring.

[tenspeed]

Gabe, check out the electrical supply houses in Rochester. Maynards and Rero come to mind.

Another place would be one of the electrical contractors. Billitier used to have a small room at their shop on Glide Street where they kept scraps from wire pulls. I used to fill a truck, take it to metal salvage and come back with coffee money.

[quadkid]

if you want some cheap wire, look into getting some welders wire. Its not as pretty as stereo wire, but it works just as well.

[matts]

the welders wire will work, good cheap alternative. first time i've heard it in a while, i had forgotten about it.

in my opinion the 4 gauge you're using will work. that's what i've got going from 1 battery to the other in my GA. works fine, has worked fine for a couple years now. 2 gauge wouldn't hurt, bigger wire never hurt anything when it comes to electric. but since you've already got the 4 i think you'll be fine.

the isolator is a 50/50 deal. some say you need it and some say it's a waste of money. i've got one on my setup. got a pic of it posted around here somewhere. it's a stinger 200 amp i believe. i picked mine up for $20, but i think they usually list for about $50. i look at it like bigger wire, it may not be necissary, but it won't hurt anything either.

some people say you need 2 identical batteries when you install them in a vehicle, but i think that's more applicable if you're not using a isolator. i've got a die hard or something, i can't remember, under the hood of the GA, and a stinger dry cell in the trunk. definately not the same battery and again, it's been working like a charm the past couple years.

one thing that everyone seems to agree upon is that you definately want to have the 2nd battery FULLY charged when you put it in. all you gotta do is throw it on a battery charger and make sure it's charged before you put it in.

hooking it up is easy, pos to pos and then a short piece of ground wire going to some metal. now if you dont have any extra 4 ga. wire for the ground and you have to buy some i would go ahead and go with a 2 ga. or bigger.

[tenspeed]

Originally posted by quadkid
if you want some cheap wire, look into getting some welders wire. Its not as pretty as stereo wire, but it works just as well.

You don't need stereo wire for power. The welding cables we have at work are 2 gauge. Welding wire has a soft but thick insulation and is multi stranded.

The regular wire has less strands, is less flexable but it has a hard insulation around it. It is harder to work with but it should be better for connecting two batteries together. There will be less of a chance of cutting the insulation.

[nineteen88ga]

I think the differnece between welding cable and car audio power cable was discussed a while back, and you definately want an isolator of some sort being a 200 amp relay or an MBR70. Just don't do what this kid did when I sold an old bandpass box......

he had 2 batteries in his trunk, and one amp was hooked directly to one, and his other amp was hooked directly to the other. thats it. no was was it linked to the charging system in the car. lol

[inferno]

well thanks guys for the input. I think i will just use the 4ga that i already have run to the trunk. I will add an isolator and will probably just buy some more 4ga wire because that what my amp can take in if i remember correctly and remove all the 8ga wires in my trunk and upgrade to 4ga.

I will also do the Big3 and this should help me some. but as stated i still need to get my car fixed

i want to put a yellow top in the trunk but i dont know if i wanna go and spend $170 on that battery when i just bought my red top for 130 but ill see when i get there. im going to be stocking up on parts

then i have to make a plan on how im going to install everything in my car

2subs,2amp,isolator,battery,xbox,tv lots of thing with a little trunk

[matts]

a 2nd red top would be up to the task IMO. since you've got the 2nd battery in the trunk i wouldn't upgrade all the wire in the trunk to 4 ga. now if you've got a big honkin sub amp that has input for 4 gauge it won't hurt to use it there. but if it's an amp for your mids/highs the 8 ga will work fine.


here's a pic of my isolator in the trunk. it's little, but makes a noticable "click" when you turn the car on/off. it's small enough and doesn't make any kind of heat or anything, so it shouldn't be a problem to hide it out of the way. just make sure the wires dont touch anything :lol:

[inferno]

hmm that is pretty small. you dont have anything holding down the battery?

[nineteen88ga]

ohh yeah good point. The MBR70 is a little more safe as far as having the wires covered. all isolators I've seen (200amp relays) have open terminals.

[inferno]

what a good and inexpensive battery?

[matts]

yeah, the battery is actually in a little sleeve type thing. the battery slides out and the sleeve has several screws holding it still

[ramairgt2]

what about your alternator? I have a 105 amp in my car. Wouldn't you want a higher rated one for charging two batteries instead of one battery? Atleast thats how most of the systems are done that i have seen. Oh btw I hope you still plan on using a lightning cap too or Farad Cap as they are known

[matts]

i dont remember what amp the alternator is........it's been beefed up a little. the cap i have is really more for looks than function. it's hooked up and works,but the battery is my main workhorse

[inferno]

i have a cap already and a HO alt

[AmIGrand]

4 awg will be fine, it only needs to carry the charging current to the 2nd battery.

Mixing and matching battery types is OK for the most part, people who say differently have never proven anything like a point. Hell, Optima even RECOMENDS a Red up front and a Yellow in back.

The 200A relay will work just fine - though I would've put it under the hood rather than in back. It has an ignition switch that opens the relay when the motor is off, isolating the rear battery from teh rest of the car. When the ignition comes on, the relay closes and both batteries are seeing the alternator. Alternatively, you could run a constant wire to the relay and put in a switch to manually open/close it. Either way, it works great, usually cheaper than an isolator.

Make sure there is a fuse or circuit breaker within 18" of EACH batteries positive terminal. Otherwise, things'll get real intersting if that power wire ever gets cut or pinched.... You want those fuses to be rated very close to the alternators output, i.e., 100 amps or so.

Make sure you upgrade all the ground straps under the hood. Make sure you ground the rear battery very well indeed.

Wire the cap in if it makes you feel better, but it's not going to help much.

[matts]

i use my cap because of the cool looking voltage display

[inferno]

i got my stinger relay today from oznium . so now i have to get my car running.

question... How do i wire the relay? theres no instructions

[matts]

oh, i dont remember exactly. have you went to stingers website and checked?

[inferno]

what exactly is true ignition?

[inferno]

another question would be is it better to have high amp wire or high volt?

[inferno]

BUMP E BUMP.

what exactly is true ignition?

[Bumpin1OHM]

in reference to what?

[inferno]

that what the instruction for the relay says.

one of the points is pose to be connect to "true ignition". im guessing acc would work.

another question would be would my remote wire from the amp work?

[Bumpin1OHM]

yea that would be any wire that has power only when the key is on accessory or the car is running

[inferno]

so remote wire will work?

[dandragonrage]

So... Why are you guys recommending JUST relays? You'd want diodes to isolate a battery... In fact, if you threw diodes in front of both batteries, you wouldn't need a relay at all...

[inferno]

well i already have the relay now so ima use it

[Bumpin1OHM]

Originally posted by dandragonrage
So... Why are you guys recommending JUST relays? You'd want diodes to isolate a battery... In fact, if you threw diodes in front of both batteries, you wouldn't need a relay at all... or he could just use an isolator/relay pack and be safe and not wake up one day to find his car burnt down to the frame from an electrical fire

[inferno]

yea yo. anyways. can i use the remote wire or do i have to run another acc line?

[Bumpin1OHM]

u can use ur exsisting remote wire

[inferno]

aight. im just trying to get everything done for the impala so i can have my system back.