Help!! - I need help with mounting battery in trunk.

[wetumpka]

Can someone tell, or better yet, show me how I should mount my battery in the trunk? Every since I moved it to the trunk ('74 duster) I've had nothing but problems. My new battery drains after a few minutes of constant cranking. I don't think that I have something wired right.

The car is primarily a street car that will see some time at the track. What is the right way to hook the battery up?

Right now I have a negative cable going from the battery to a body support in the trunk near the tail light and a negative cable going from the battery to a hole in the driver side cylinder head. Both are 2 ga. wire. I have the positive wire tied into where I cut the terminal from the old positive terminal.

The car will turn and try to start. Sometimes it will start sometimes it won't. When the battery was under the hood it ran perfect.

 

[moparstuart]

pictures of how you have it mounted ???

 

[Meep-Meep]

Did you double up on the positive cable (i.e. two standard size cables in parallel) or use a single BIG cable? Your battery is probably not dead - it's just fighting the resistance of the small wire. Rule of thumb is the longer you go the bigger you go. If the cable turns into a heater while you are cranking then that's the issue.

 

[scotts74birds]

I dont know what the current draw of your starter is, but I am assuming 90 amps? Using an on-line voltage drop calculator, estimated 28ft round trip of wire between batt and starter, #2 wire, your voltage drop is about .405 v. or 3.38%. Not too bad. Do you have access to a DC ammeter to verify what is actually happening in the wire? Source: http://www.powerstream.com/Wire_Size.htm Its near the bottom of the page. Scotty

 

[5.7 hemi]

Negative should go to the frame, negative from the head to the frame. Positive should be 0 in size, multipule stand. Hope this helps.

 

[daredevil]

Negative should go to the frame, negative from the head to the frame. Positive should be 0 in size, multipule stand. Hope this helps.

beat me to it. good cable aint cheap.

 

[69HEMICORONETR/TCONV]

Something that works very good if you have access to it is old welding cable. Most industry has a rule to follow that more than 3 holes in the insulation (even if taped) within about a 10 ft length requires the cable to be replaced. Odds are you can get a good length of unbroken cable when they replace the leads. That's fine strand, large guage wire which will give you even less resistance than a larger strand wire.

:yes: I get large lengths all the time from my job when these no long meet code and it also makes GREAT jumper cables too !

 

[RGAZ]

Make sure the ground connection for the negative in the trunk is not through paint or primer. It must be metal to metal contact. Do NOT depend on the bolt to conduct. Be sure to protect it from corrosion after connection. Be sure to bolt the connection tightly.

Be sure the battery cannot move. I have seen trunk batteries that touch other areas of the trunk and they short out.

Lastly, Be sure the location you chose is not limited by a small weld connection to the rest of the body. With the mopar uni-body design not all steel frame points are created equal.

Good luck,
Randy

 

[Revhendo]

I've always used 2 gauge without any problems. The key is the grounds. I usually will weld a stud to the rear frame section (longitudinal), and then after the cable is attatched, I primer over it to prevent rust and corosion. (You don't have to get carried away with the Krylon here.) I also will run a 2 gauge cable from the head to the front frame section. It doesn't hurt to run a 6 gauge ground to the body from the head, either.
When it comes down to it, my motto is "More grounds than dirt."

 

[1969 b5blue]

I used 1 gauge welding wire and wired it straight to the starter.

 

[moparstuart]

have you had good luck with that optima battery ? I have heard night mare stories that they are junk ??

 

[1969 b5blue]

no trouble at all. had it in the car for three years now.

 

[Revhendo]

That's about four more years than I have ever got out of an Optima....:rolling:

 

[moparstuart]

That's about four more years than I have ever got out of an Optima....:rolling:

thats what i heard too, that they last about a year at most ?????

 

[69HEMICORONETR/TCONV]

Never had any dealings with them , but never heard anything good about them either.

 

[wetumpka]

Thanks guys for the info. I didn't want ya'll to think that I posted a problem and abandoned it. I've been trying to respond but wasn't able to do so for sme reason. Anyway, I'm going to try some of your recommendations as soon as I can. I sent my Holley 750 DP out to california to the Carb Shop to be rebuilt and blueprinted.

 

[wetumpka]

Thanks, I have one 2 ga. for the positive and one 2 ga. negative. I realized that I didn't have the engine grounded to the frame.

 

[Revhendo]

Thanks, I have one 2 ga. for the positive and one 2 ga. negative. I realized that I didn't have the engine grounded to the frame.

Oh that will do it. I built a car one time that I didn't ground the engine to the chassis well enough. Every time you started that pig it would try and find a ground through one of the steel braided power steering lines. Quite the spark show.
Other little known fact. Second gen Camaros weren't always grounded the best and would try and ground themselves through the shift cables. It often resulted in stranded drivers with oddly burned out shift cables.

 

[wetumpka]

Thanks Revhendo.

 

[Revhendo]

[/QUOTE]

Dude, have you considered a proper battery box for that bad boy? I've seen some pretty nasty things happed when batteries get loose.