claytonjn

iTrader: (5)

Ok, so I'm planning on installing a second battery. My plan is to install an Optima Yellow Top in the spare tire well using the BMR Battery Relocation Kit. Rather than a battery isolator, I got an "Automatic Charging Relay" from a company called Blue Sea Systems. Basically, when it detects the alternator is putting out a charge it connects the batteries in parallel, when the alternator isn't charging, it disconnects the positive cables which isolates the batteries.

I'm pretty sure I have all this stuff figured out. I'm planning on getting an amp so that I can use my Bose Factory Headunit with aftermarket speakers, so as far as I know I can connect the amp directly to the Yellow Top. I'm also going to install a carputer, which will run off the Yellow Top.

What I need help with is this - I want to run some of the factory things off the Yellow Top. I have found absolutely NO advice, instructions, guides, etc about this. I haven't found anybody else even asking about doing anything like this. I want everything for starting, ECU, VATS, and my alarm off the normal battery under the hood. I want my interior lights/trunk lights, headlights, door locks, trunk latch, radio, and power (cigarette) outlets on the Yellow Top battery.

What I was thinking of doing is cutting the power to the fuses for the things I want the Yellow Top powering and then running a cable from the Yellow Top to the fuses I disconnected from the hood battery. I think this is how I would break up the fuses:

Hood battery:

• ECM (I'm assuming this is the engine computer?)
• INJ#1 (fuel injectors?)
• FAN (radiator fan?)
• TURN B/U (turn signals/back up lights?)
• INJ#2 (fuel injectors?)
• HTR-A/C (heater/air conditioning?)
• GAGES (gauges?)
• SIR (airbag?)
• WDO (window motors?)
• INST LPS (instrument lights?)
• WPR (windshield wipers?)
• STOP HAZ (hazard lights?)
• VATS (vats?)
• CRK (crank?)

Yellow Top:

• LID (trunk latch motor?)
• ACC (interior lights, outlets, power mirrors?)
• RADIO (radio?)
• PWR ACC (no clue...)
• TAIL (tail lights?)
• ARC (radio memory?)
• FOG LPS (fog lights?)
• DRL (running lights?)
• Headlights (it looks like these come straight from the battery with a fusible link?)

I'm pretty sure I have everything figured out, but I'd like some reassurance, advice, opinions, anything. I don't want to get into if I do/don't need a second battery, etc, just advice on how to go about doing it. I'd especially like advice for if my plan for splitting the fuses, and which to split, is good.

BTW, my car is a '92 Camaro (Convertible) RS - 5.0L TBI.


Thanks!

1ADan

iTrader: (4)

sounds quite involved, curious as to why you'd be looking to do such an involved rewire? as for tips, you're gonna want to go over the wiring diagrams here (a big favorite of mine these days) and see what circuits have what features you want moved. From there, just remove the ones you don't want in the factory box and build a new one with the power source coming from the yellow top

claytonjn

iTrader: (5)

I'd like to be able to go to the drive-in, camping, etc and listen to the radio without the car running or having to worry about starting it - that's the main reason, plus when I install a carputer, I want it to be always on so I can use my phone to remotely control some car features.

That website is where I've gotten all the info I have about the wiring in the Camaro, it has been a great help.

Stock Car Racer

Back in the day when the cars used a internal regulated Alternator - not computerized, - it was possible to take the alternator to a electrical shop and have them rebuild it so it would run automatically when the car was running and hop it up to about 160 Amps.
The Caddillac alternators back then - you could get a 120 amp....

You could then run a double ought copper wire from the post on the back of the alternator to the rear battery.
Leave the original factory wiring harness intact and run the car and the stereo off both batteries.

I had several Orion amplifiers, I ran that set up with two batteries in the trunk.
There is no room in the fenderwell in the trunk area of a Camaro for two batteries, two or three amplifiers and a set of 10 inch subs...

My Monte Carlo SS was a much better platform for that.

Back in the day - when you did not have to have emissions connected to your vehicle.
We would remove the smog pump and put a second alternator in place of the smog pump with auto start - and connect it to the batteries in the trunk.

The problem with trying to do that with a later generation of the 82 - 92 Camaro is that the later versions used a computer controlled alternator and it monitored all the electrical systems and it would have conflicts if you tried to run different parts of the car off two different electrical systems.

claytonjn

iTrader: (5)

So you're saying it can't be done? Wouldn't running some of the stuff off the rear battery be the same as if the fuse was blown for those things? I wouldn't think it would make a bit of difference in terms of how the car runs/performs if my radio fuse blows for example...

1ADan

iTrader: (4)

unless you're looking to rewire most of the car, I would stick with just doing the dual battery setup the simple way (charging relay, isolator, whatever). other than the stereo and carputer (maybe), there's not that big of a draw on the electrical system to make the headache worthwhile. use the 2nd battery for your amps and carputer, leave the other stuff as is.

claytonjn

iTrader: (5)

would I have to rrewire the whole car though? Why couldn't I just run one 1/0 cable to the fuse box and hook the stuff up to that before it gets to the fuse box..

1ADan

iTrader: (4)

circuits are shared by multiple things, so unless you know exactly is on which fuse, you could be causing more headaches. some fuses are responsible for sending power to up to a dozen different things

claytonjn

iTrader: (5)

Yea, well as far as I know splitting up the fuses as I outlined above would give the results I want. My biggest concern is I don't know if there's anything between the alternator/battery and the fuse box (like a voltage regulator or some such?) There are a few wires coming out of the alternator - I know one goes straight to the battery but I don't know where the others go and if the stuff in the car is powered off one of the different ones if the electricity is different in any way, like a pulsed signal or something I don't have an oscilloscope to test, only a DMM. The way I'm thinking about hooking stuff up the power would come straight from the alternator to the fuse box, and I don't know if that would be a problem.

Oh and btw now that I'm not at work and am actually thinking about it better, everything would still be powered off the alternator. It would just be a different cable powering them but it would be the same as if I just spliced a second line from the alternator and sent it to the fuses I want to put on the second battery. While the car is running the batteries are in parallel so it would be the same as if I just hooked positive to positive and did nothing else. The fuses would only be different when the alternator isn't running, so it shouldn't matter if it's computerized or whatever or not.

claytonjn

iTrader: (5)

Just to update, I got everything set up and has been working wonderfully for months. I have an optima yellow top in the trunk, 0 gauge all around, and a ACR that connects when it senses 13+ DC volts and disconnects when it drops below 12V. It also has a manual override so I can jump one battery from the other.

I have half the stock stuff on the back and half on the front. It wasn't really that much work and WELL worth it. I haven't needed a jump since I finished the setup and it's nice being able to listen the the radio, work on the car, etc without having to worry about the battery dying. Another nice thing is that I changed some stuff to not be controlled by the key (I can do windows/radio without the key in)