Moving battery to back, thanks everyone, especially gp1138-think problem solved

[dohc v6]

I have been having trouble starting my car since I relocated the battery to the trunk. I talked to shane(redzmonte) and timg, both said they have the same problem. So tomorrow I am going to put the battery where the computer is and hopefully move the computer just to the side of the battery. Has anyone ever done this swap?

[Crazy K]

yeah.... didn't GM do the same on the second gen cars???

[z34Phoenix]

second gen they put the pcm on the drv side and the bat on passanger side... i was told the reason they are seprate is the current being pulled thru the alt wires to the bad was not good for the pcm. you consider mounting the battery in the fender well? the do this on the intrepids and some other dodge products. will also give a lower CG lol

[Pontiac6KSTEAWD]

I personally would only consider putting the bat next to the ECM if the bat was gel filled. Battery acid is mean to electronics...

 

I have heard a rumor, that you can put a farad cap nearer the engine bay/in the engine bay, and it will aleviate the problems or a remote battery. I dont personally know this, but it seems to make sense.

[toms92gpse]

I've had my battery in my trunk for about 3 years and have yet to have a starting issue other then the few times I've ran my battery dead leaving my inside lights on overnight.

[dohc v6]

Not me, I guess its the turbo, but all of our cars have a hard time starting. The engine cranks awesome, but just does not start good, and when it does it dumps fuel and runs like shit for the first 20 sec or so. Where can I mount it in the bumper?

[Schurkey]

Not me, I guess its the turbo, but all of our cars have a hard time starting. The engine cranks awesome, but just does not start good, and when it does it dumps fuel and runs like shit for the first 20 sec or so.

That hardly makes sense. You could mount the battery on the moon if you used large enough cables to prevent excess voltage drop. The starter and computer don't know where the battery is. What they know is that they're getting--or not getting--enough current/voltage to work properly.

 

If you were in my driveway, I'd be checking voltage at the computer and at the starter. Somewhere you have a voltage drop; and if the starter is cranking good, I bet the computer is under-volted until the alternator starts putting out enough to supply the computer.

 

Or--the engine just runs bad for some other reason besides the location of the battery; and moving the battery won't help or hurt the way the engine runs.

[dohc v6]

Umm, ok. I am going to move the battery, temporarly and see if it starts easier. I get 11.9 volts with the car off at the starter.

[dohc v6]

Got a site for that capacitor fix? I would like to keep the battery in the trunk as it freees up space. If you can get me the link. I want to get this thing fixed this weekend.

[Pontiac6KSTEAWD]

Asking me a big question there. That was some time ago that i read that on some website, But you did raise a good point on something else...

 

How do you have your remote battery grounded? 11.9V is low, it should be about 12.2 or 12.3. Last time I ran a remote battery, I had the same problem. I ended up taking changing how the ground wire was grounded. I originally started by grounding it to the frame of the car by the trunk. I had the problems, so I ran a 8 guage ground wire from the battery back to the engine itself. And this solved my problem.

[dohc v6]

I have my ground to the strut tower frame

[dohc v6]

i am thinking thats my problem then. Why does the strut tower not work?

[Pontiac6KSTEAWD]

No clue. I know W-bodys have always had issues with grounding wires, but I know you fixed those when you did your engine swap. So the only thing left is the way the current is carried thru the body.

 

Where do you have the positive wire going also?

[dohc v6]

I have my positive wire goring from my battery to the started directly, then a wire from the AUX post to the starter. The ground I have from the battery to the strut tower bar plate, they are unplated, but I never sanded off the paint underneath the mount. I am going to try some things tomorrow, thanks

[Schurkey]

I get 11.9 volts with the car off at the starter.

With no load? Damn!

 

A fully-charged battery should have 12.6--12.7 volts with no load. A battery showing 12.2 volts is HALF DEAD. At 11.9, you have real problems.

 

What's the voltage AT THE BATTERY?

 

First Guess: If the electricity can't go forward to power the starter/computer efficiently; it also can't get back to the battery from the alternator efficiently.

 

I suggest doing some voltage drop tests UNDER LOAD to see whether the positive side (insulated circuit) or negative side (un-insulated circuit) or both are at fault. With the battery in the back, you're gonna need about 20 feet of ~12 gauge wire to make the connections to your voltmeter.

 

You'll connect your long jumper wire to the battery + or - terminal. On a side terminal battery, you can't connect to the terminal itself, you have to connect to the terminal bolt head--so--take the terminals off to be sure the terminals are bright and shiny; and then securely tighten, before you start. Drag the free end of the jumper wire forward so you can make voltmeter connections to the jumper wire AND the starter and alternator at the front of the car. For the purposes of the voltage drop tests, a connection to the battery + means a connection to the jumper wire, which then connects to the battery + post; while a connection to the battery - means a connection to the jumper wire which is then connected to battery - post.

 

Connect voltmeter + to battery +. Connect voltmeter - to starter + post. Disable ignition. Have a helper crank the engine while you watch the voltmeter. With the engine cranking, you should have LESS than 1/2 (0.5) volts showing on the meter. More voltage means high resistance in the positive cable from battery to starter. Fix this before continuing.

 

Connect voltmeter - to battery -. Connect voltmeter + to engine ground. Ignition still disabled. Have a helper crank the engine while you watch the voltmeter. With engine cranking, you should have LESS than 1/2 (0.5) volts showing on the meter. More voltage means high resistance in the GROUND side of the circuit. Fix this before continuing.

 

Connect voltmeter + to alternator + (the output terminal.) Connect voltmeter - to battery + post. Start engine, run at ~2000 rpm with the headlights on, heater fan on high, wipers on, radio on. Voltmeter should show LESS than 1/4 (0.25) volts. More voltage means high resistance in the charging system insulated circuit. Fix this before continuing.

 

Connect voltmeter + to battery -. Connect voltmeter - to alternator case. Start engine, run at ~2000 rpm with the accessories running just like previous test. Voltmeter should show LESS than 1/4 (0.25) volts. More voltage means high resistance in the charging system ground circuit. Fix as needed.

 

I expect this will take care of things--but--you probably should check to see that proper voltage is getting to the computer; and that it's suitably grounded.

 

If you thought the starter cranked good at 12 volts OCV, just wait 'til you get the electrical system sorted out...

[dohc v6]

OK I checked it again, it is 12.7 at the aux post. So thats good. I took the battery out and moved it to the front and found out that the car start perfect with the battery hooked up in front. So I found a site that says all about voltage drop and the wire to use for remote battery reloactions. So I put 15ft in, with 150 amp and see that I need a minimum of 1/0 wire. So I am running 2ga wire now. So I am going to leave the postive wire thats running the car now and use that as my new ground and get some 2/0 wire and that should sove my problem.

[Schurkey]

OK I checked it again, it is 12.7 at the aux post. So thats good. I took the battery out and moved it to the front and found out that the car start perfect with the battery hooked up in front. So I found a site that says all about voltage drop and the wire to use for remote battery reloactions. So I put 15ft in, with 150 amp and see that I need a minimum of 1/0 wire. So I am running 2ga wire now. So I am going to leave the postive wire thats running the car now and use that as my new ground and get some 2/0 wire and that should sove my problem.

So you've determined that you need 1/0 gauge wire, but you're still going to use 2 gauge for the ground? Is this in addition to the body ground, or instead of the body ground?

 

Sounds like you may still be shy of enough conductor for the ground side of the circuit.

[dohc v6]

I was told that another member used 8ga wire for the ground, so I thought that 2ga would be perfect.Should I used 1/0 wire for the ground as well. Ald

[toms92gpse]

I'm running 2 gauge if i rember right, and I just got it grounded to my truck floor where i stripped the paint off.

[slick]

Whatever you do, your ground needs to be ATLEAST as big as your power cable, if not larger.

[dohc v6]

What I am going to do is ground it at the block and ground it at the rear strut tower as well.

[dohc v6]

Whats the minimum voltage for the computer and starter?

[slick]

Voltage is usually 10.5V. Amperage would be more of a concern, IMO.

[Pontiac6KSTEAWD]

I was the one grounding with the 6 guage wire (posted earlier it was 8, and I was wrong). Yes you could ground with a 1/0 guage. I didnt. There are enough grounding straps, and whatever else the engine uses to pass the ground along. At this point you are just trying to complete a circuit that was removed during the transfer of the battery. If you were using this battery as a connection for some serious amps, and stereo equipment, then I would say go with the 0/1. I am not running a whole bunch of equipment, and as long as you have upgraded all the other "big 3", then I dont see a 6 guage wiring being added to compliment the circuit being a problem. It worked for me at anyrate.

 

The Maximum amps for current flow on 6 guage wire is 101 amps. 1 guage is 211, and 0 is 245. Your maximum output from your alternator is roughly 105 posted amps. which can increase to 150-180 amps. But none of this really ever makes it to the battery because the diode is seeing the draw, and creating more amps for the system to use. Your battery draws, after initial cold start, 15-20 amps to recharge from the starter (for aproxamately 30-45 mins). Your starter draws roughly 175 amps from the battery on startup. Going thru the engine straps/ground strap for a ground on the motor, and the 4-6 guage wire from the battery to the postive starter post. Since electricity can loose its conductivity over length, in this case a car (trunk to engine compartment), even thou you technically have a lower point then 4/0 wire being the whole car is steel. The energy is dispersed thru every other electronic, connecting weld, spot weld, electrical short, light, and whatever else as well.

 

So to sum up. Electricity follows the path of lease resistance. A wire, going directly from the battery, to the starter chasis, or if you like, engine block, this then becomes the path of lease resistence since its a direct connection. And since you are still getting a negative current from the ground straps, this just enhances the effect.

 

I used 6 guage wire, and I didnt have a problem. But I also didnt have electricly powered brakes, and I had a 63amp alternator. So find a guage you are comfortable with.

 

http://www.powerstream.com/Wire_Size.htm (for house wiring, but the same principals apply)

 

Looking over your car, you have added HID headlights, a vacume/exhaust powered turbo (not one of those ebay leave blowers), a vacume operated braking system (I assume with no ABS), a aftermarket headunit (using pics from your cardomain), and i dont know about any "other" stereo equipment. So it looks like you should go with 3 or 4 guage (knowing GM electrical systems). 2 guage if you are really concerned. The rest is way overkill.

 

Thats my 2 cents.

[Dark Ride]

I'm looking to eventually move my battery to the trunk to make room for the cold air intake. I plan on using 2 guage jumper cable wire. I was curious if you guys would post what yours looked liked, did any of you guys use a battery box, or how did you mount it? Pictures would be cool.