View Full Version : Dual batteries

11-10-2000, 08:48 AM
I am considering putting dual batteries in my truck. I have a '78 Chevy K10. It is currently a single battery setup. Does anyone have any experience with this? Besides getting an extra battery tray, what else do I need? How do you get the cables to connect the batteries? How do you connect the batteries? My whole reason for doing this is because I plow with the truck.

John DiMartino
11-10-2000, 04:33 PM
I just put dual batterys in both my 89GMC,and my 91 GMC.It wasnt to bad,and boy do they crank fast now-wow it spins it like its warm before when its 25 degrees out now.I used top/side mount batterys in both trucks.The ideal thing is to find a wrecked 6.2 diesel in the wrecking yard and rob the cables and tray,from both batterys.If you cant do that your best way is to go to an auto parts store and buy a made up cable for the ground on the aux. battery.Measure the lenth needed,from the engine block or accesory bracket,to the - side of the battery,then add about 6" to give it room to move.The positive side can be done a few ways,one is to just make a long ,heavy cable to connect the 2 together in parallel,which is what I did,since GM does it this way on the diesels.You might be able to buy one,if not,buy universal new ends and make one up from one to the other.i have a friend that puts his plow pump motor on the 2nd battery,and uses a battery isolator to keep them separate,this means his main lights never flicker,but it costs more and your plow wont cycle as fast as with 2 batterys.

11-10-2000, 06:48 PM
Thanks for the help John. Looks like I might get to do my favorite "junkyard pickin". Hopefully I can find one. Otherwise I will just get a new tray and make my own cables. If I do, do I just hook positive to positive on the batteries, and then ground each battery? Does that give me 24 volts? That's the part I don't understand.

11-10-2000, 08:30 PM
i hooked mine up in parrallel as mentioned by john but i put positive to positive and negative to negative

also you need two batteries in the same conditiion preferably new
i was told that if one is old and weaker the newerone will draw it down i am not a battery expert but i have always followed this

John DiMartino
11-10-2000, 08:50 PM
I took the 2+ terminals and connected them together in parallel.This gives you 12 volts,but double the reserve capacity,and cranking amps-it will make the plow so much faster and the motor will last a lot longer too.I bought 2 brand new Interstate Mega-tron 725CCA batteries,put them both at the same time.My plow flies back and forth now,and hardly any dimming of the lights when lifting/angling.I got my + cable from my Dad's 1980 Caprice Wagon,it was a diesel new,and its had a gas motor in it for 15 yrs now,so it has only had one battery in it,I just pulled the thick cable that went from one batt to the other,it fit great,I just secured it to the radiator shroud and it looks like the factory did it.I used the - terminal from that car too-since it was just dangling.It cost me 37 for the tray,brand new at GMC dealer.My total cost with 2 new batteries was about 160,not bad considering how much it'll help while plowing.

11-11-2000, 04:31 PM
Thanks for all you input guys!! I think I know exactly now what I need to do. I'm running an older Meyers E47, so a speed increase would be great. I was wanting to do it just for the extra lights and cold starts, extra speed is just a bonus. Thanks again for your help. You guys are great!!