what gauge battery wire
 

have have 69 gmc with a 350 and a red top optima
i was wondering what gauge wire i should use for the battery
i didnt know if the better battery or any would need different gauge
the battery will be under the hood

I would use 2ga for under the hood. Bigger than stock but not crazy big. I have bought it at Oreilly's before by the foot.

return the red top if you can..
get a normal lead/acid battery..
we've had to warranty every red/yellow top battery we've sold..
if you run the battery down you have to trickle charge it.. letting the alt recharge it. will kill it..
they are great for racing, no chance of acid leaking.. but normal use. they are crap.. if you ever run them down.. slow charge on a trickle charger or battery tender like charger..

red and yellow top batteries
 

very expensive learning curve for my boat batteries

X2 on the Red top, 6 mo old let it run dead 2 amp charged it....... never would hold a charge after that.

X2 I am on my third one replaced under warranty. It now stays on the trickle charger.

Vince

I've had trouble with every Optima I've owned over the last 15 years (4). I'll never buy them or recommend them to anyone for any purpose.

As far as cables go, If I am upgrading or installing any cables going forward in any vehicle I truely care about I will be using welding cable. Preferably 1-0. It conducts better, it's much more flexible and far more resiliant to damage and heat. Whenever I terminate new cables I solder them with a torch and it's amazing how well the jacket on the cable holds up to direct flame without melting.

It's a bit more money, but well spent IMO.

I used 1/0 welding cable on my sedan, but my battery is in the back, not under the hood. I think 2 gauge would be fine, but bigger never hurts (for cables). I believe in over-kill - I crimp, solder, then cover with shrink tube.

Spend some time reading the tech section at MadElectrical.com. They have some really helpful diagrams and explanations about charging systems.

what ever size you use, make sure the ground strap is as big too.
12v- to block and to the body. no sense upgrading the +cable if your still using the light weight oem braided ground.

I've been using this technique on the general wiring on my project. Very time consuming, but also very reassuring. How do you crimp the lugs on heavy cables? Is there a special tool you'd recommend? Do you recommend just using a vice? Inquiring minds want to know. Thanks in advance.

Pat

There is a tool if you are crimping a lot of them. Here: Heavy Duty Hammer Crimper

You can also use a 1/4" round steel rod and a vise - better than just smashing them with the vice - use the steel rod to focus the crimp. For large cast lugs, I usually drill a small hole in the end and use that to solder the connection.

When I can, I use adhesive-lined shrink tube - makes the connection waterproof. I buy the clear shrink tube - when it's sealed up, you can clearly see the connection and the wire color. (like the connections on the right in the picture).

Use welding cables. They work the best(by far). Go down to your local welding supply store and ask for welding leads. Then just buy the end terminals and the bolts. I like the quick disconnect switches like the ones below.(you can get these through jegs or any aftermarket parts place)

http://i50.tinypic.com/30siwcx.jpg

For those who want the ultimate in battery cables, there is marine grade cable - fine wire cable like welding cable, but tinned the full length for additional corrosion resistance. Be prepared to pay a bunch!

Finally, someone got it right. It's not the gauge of the cable, it's the number of strands in the cable. A fine wire cable will carry a current load better than a coarse wire cable.