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View Full Version : What Wire Gauge for Hooking Two Batts in Parralel



cab13367
04-17-2011, 02:19 PM
So I bought two group 29 125AH batteries yesterday to power my stereo which I plan to wire in parallel as one 12V bank. My question is, is 2 gauge battery cable sufficient to connect the battery terminals together? If not, then what gauge should I use? The two batteries will be sitting right next to each other so the cable runs will be very short. The batts will be powering three amps - a JL M6600, an Exile SM600.1, and an Exile 1K Harpoon.

The batteries I bought are Group 29 Everlast Maxx Marine batteries from Walmart ($85/each) with an 18 month direct replacement (not prorated) warranty. I've been very happy with the Kirkland Group 27 I had from Costco so I figured these Walmart batts should do the job. The Group 29's have a little more amp hours than the Group 27's (125 vs 115). Any direct experience with the Everlast Maxx Marine, good or bad?

Thanks,

Al

ian ashton
04-17-2011, 03:16 PM
The bigger the better, but I'd feel perfectly comfortable with 2AWG connecting the two batteries, especially over such a short run.

Truth be told, I think mine are connected with 4awg right now - whatever size jumper they had at the store when I bought the batteries becuase I didn't feel like digging through the mountains of wire in my garage to find the proper connecters and length of 1/0. Since I've got it all already I plan to upgrade, but more so because I think the bigger wire and screw type terminals look cooler, lol.

mmandley
04-18-2011, 12:16 PM
2 gauge will be fine Al, You could get away with a 4 gauge but the issue lies when you need those as Starting batteries you will 1 heat those 4s up really fast and lost amperage to the starter.

I run 2 gauge as my jumper cables from battery to battery.

vandy654
04-18-2011, 01:09 PM
I'm in process of hooking up my dual batteries on my '02 LSV. The guy at West Marine questioned me when I told him my cable running from the starter battery to the starter was 2/0 gauge, they don't carry terminals in that size, I had to order them.

What are you guys running for cable size from the starter battery and stereo battery to the battery switch? Negative to Negative on the batteries? Is 2 AWG suffice? West Marine carries pre-made cables with the terminal ends in 2 AWG, they told me this is what a majority of people do. I just have seen posts with people running 2/0 cable from the batteries to the switch.

My cable runs from battery to battery is only a couple feet, and batteries to switch is less than 2'.

cab13367
04-18-2011, 09:10 PM
I'm in process of hooking up my dual batteries on my '02 LSV. The guy at West Marine questioned me when I told him my cable running from the starter battery to the starter was 2/0 gauge, they don't carry terminals in that size, I had to order them.

What are you guys running for cable size from the starter battery and stereo battery to the battery switch? Negative to Negative on the batteries? Is 2 AWG suffice? West Marine carries pre-made cables with the terminal ends in 2 AWG, they told me this is what a majority of people do. I just have seen posts with people running 2/0 cable from the batteries to the switch.

My cable runs from battery to battery is only a couple feet, and batteries to switch is less than 2'.

Here's a helpful table I found, except that I am running a total of 2050W RMS between my three amps and the table only goes up to 1400W RMS.

http://www.the12volt.com/info/recwirsz.asp

mmandley
04-18-2011, 10:38 PM
Vandy, 2/0 should be just fine for your starting line. Thats the standard size used in cars, and these boats for power and ground lines. The only time you really see 0 gauge is in stereo systems because the draw is Constant not short bursts like starting.

Even in my truck the starter cables are 2 gauge