dual battery help, best/easiest way - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cochino12 · 03-31-2009, 09:52 PM

I am running dual batteries in my plow truck and its staring to give me some problems. The previous owner installed dual batteries but there is no isolator for them and now I am having some electrical problems. Currently the batteries are just connected together with a 4 gauge wire +/- and the plow and accessories like radio...are run off the secondary battery. Earlier this week while I was on vacation after about 6 hours of plowing the plow stopped lifting and the radio shut off and the truck stayed running but only read 9 volts on the meter, after the truck was parked overnight the battery was dead.

So here are my questions.

1. What is the easiest way to isolate the batteries
2. Do I absolutely have to replace both batteries when I do it? they arent matching currently?

Thank for any help

powerdriver 1958 · 03-31-2009, 10:17 PM

sounds like the alternator died

cochino12 · 03-31-2009, 10:21 PM

Quote:

Originally Posted by powerdriver 1958

sounds like the alternator died

Thats what I originally thought too, I guess one of my guys pulled it out and took it to autozone to have it checked and they said it was good but the bearings were bad.

I figure I'll replace it too, I hate having electical problems

James McClure · 04-01-2009, 09:10 AM

Adam, you don't need an isolator. On dual setup's GM doesn't use one. The failure is in the charging circut not the batteries or electrical system. Check all the fuse links and all connections related to the charging circut, then replace the alternator and use matched batteries. Matched batteries aren't a necessity, but it's nice to know they are both new and of equal capability. Buy them bigger than you need and get the highest amperage alternator you can stuff in there. jim

03-31-2009, 09:52 PM	#1
cochino12 It followed me home? Join Date: Mar 2003 Location: Yup Posts: 5,751	dual battery help, best/easiest way I am running dual batteries in my plow truck and its staring to give me some problems. The previous owner installed dual batteries but there is no isolator for them and now I am having some electrical problems. Currently the batteries are just connected together with a 4 gauge wire +/- and the plow and accessories like radio...are run off the secondary battery. Earlier this week while I was on vacation after about 6 hours of plowing the plow stopped lifting and the radio shut off and the truck stayed running but only read 9 volts on the meter, after the truck was parked overnight the battery was dead. So here are my questions. 1. What is the easiest way to isolate the batteries 2. Do I absolutely have to replace both batteries when I do it? they arent matching currently? Thank for any help __________________ Adam That's why they call it a shortcut Kyle, if it was easy it would just be the way. 86 c-10 SWB 85 CCSB 90 GMC K30 Crew SRW 1985 C30 Dually Last edited by cochino12; 03-31-2009 at 10:20 PM.

03-31-2009, 10:17 PM	#2
powerdriver 1958 Kid's Mechanic Join Date: Nov 2006 Location: Kansas City Posts: 8,241	Re: dual battery help, best/easiest way sounds like the alternator died

04-01-2009, 09:10 AM	#4
James McClure One shot, one kill. Join Date: Dec 2007 Location: Saratoga Springs NY Posts: 859	Re: dual battery help, best/easiest way Adam, you don't need an isolator. On dual setup's GM doesn't use one. The failure is in the charging circut not the batteries or electrical system. Check all the fuse links and all connections related to the charging circut, then replace the alternator and use matched batteries. Matched batteries aren't a necessity, but it's nice to know they are both new and of equal capability. Buy them bigger than you need and get the highest amperage alternator you can stuff in there. jim __________________ 1984 K20 350M engine with 465,000 miles. Well, it's finally done!! Almost 2 years of work, but it was really worth the effort. Little stuff left to do is mount winch, wet sand & buff out and build belly pan\running boards. Body work takes lots and LOTS of beer!!!! God, Guts and Guns made America and God, Guts and Guns will preserve it! The worst thing you could do is get into my sights, but that don't matter, you'll never know it, cause you'll never hear the shotJim or Paladin whichever you choose.



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