Author Topic: 86 c20 wiring up a dual battery  (Read 6965 times)

Offline Cowman85

  • Registered Users
  • *
  • Posts: 121
86 c20 wiring up a dual battery
« on: February 19, 2009, 01:09:05 PM »
the guy i bought the truck off of had removed the second battery for some reason. There is some kind of amp looking type box for "load sensing alternator" hook up (i hope i remembered right), everything was cut off of that and just one battery running on the front passengers side.
question is how do i hook up a second battery to this truck? the one i am using right now will be the lead, the secondary is older so i figured it better that way.
right now i think the only wire on the drivers side is the negetive battery terminal.
86 C20 350/TH400 LWB
80 C2500 350/Muncie SM465 *gone to heaven* LWB
98 Malibu 3.1 V6
86 S10 L99/4L60E

Offline 808SS

  • Newbie
  • Posts: 52
Re: 86 c20 wiring up a dual battery
« Reply #1 on: February 19, 2009, 01:12:42 PM »
Do you need the second battery?
1979 C10, airride, 20" rims, and lots of rust
1994 Impala SS, under construction, LSX, 4L80E, 4.10 gears, sound system, 20" rims up front and 22" rims rear

Offline Cowman85

  • Registered Users
  • *
  • Posts: 121
Re: 86 c20 wiring up a dual battery
« Reply #2 on: February 19, 2009, 01:26:17 PM »
i am running a 450watt system right now and without that she could only crank over 4 times or so before the battery would start to slow, i am planning on installing more lights and accessories so it would be beneficial to the life of the first, not to mention the knowledge cant hurt.
i think i only need to know where to tie in a positive lead for the secondary battery, but i would like to know what the load sensing unit it that was hooked up before.
86 C20 350/TH400 LWB
80 C2500 350/Muncie SM465 *gone to heaven* LWB
98 Malibu 3.1 V6
86 S10 L99/4L60E

Offline choptop

  • Senior Member
  • ****
  • Posts: 2476
  • Extended cab fanatic
    • conversiontrucks
Re: 86 c20 wiring up a dual battery
« Reply #3 on: February 19, 2009, 03:33:14 PM »
Ive got a 1000 watt system in the wifes 81 c20 and only one battery. Sounds like you need a newer, bigger battery. I have run a similar system in this truck with 8 KC Highlighters and never needed 2 batteries.
76 C10 Choptop,76 C10 Swb
85 C10, 85 K10, 85 K20,86 C10,86 K10 (all extended cabs)
86 C30 extended crewcab

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19022
Re: 86 c20 wiring up a dual battery
« Reply #4 on: February 19, 2009, 04:56:19 PM »
If you are going to run dual batteries ideally they should both be in the same state of health. It's real simple to wire up. It needs to be in parallel. I'll post a pic in a minute
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19022
Re: 86 c20 wiring up a dual battery
« Reply #5 on: February 19, 2009, 05:06:58 PM »
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10

Offline Cowman85

  • Registered Users
  • *
  • Posts: 121
Re: 86 c20 wiring up a dual battery
« Reply #6 on: February 19, 2009, 06:54:50 PM »
thanks a million VileZambonie, thats exactly what i was looking for  :)
86 C20 350/TH400 LWB
80 C2500 350/Muncie SM465 *gone to heaven* LWB
98 Malibu 3.1 V6
86 S10 L99/4L60E

Offline Combatmp29r

  • New Users
  • Posts: 1
  • Newbie
Re: 86 c20 wiring up a dual battery
« Reply #7 on: December 01, 2013, 09:20:51 PM »
VileZambonie your a life saver. Ive been looking for the factory dual battery diagram for months. Even my my local dealership couldnt find it. I have a 85 K30 that came with dual batteries and has all the pieces still on the inner fenders but no wires. I will soon remedy that :)