Jump to content

Adding a Dual Battery

bsprtsgrp
 Share

Recommended Posts

  • 10 months later...
  • Replies 127
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Popular Posts

tenscourts
tenscourts

I've gone through this entire process. See my build thread and pm me if you need additional info. BTW the OE battery size will not fit the second tray. Again, read my thread. I have part #s, pictures,

Vuk
Vuk

This is the battery tray, secondary auxiliary relay, and the optional 3 fuse box and cover for older model years if you want to replace the single fuse box on the aux battery harness:

Vuk
Vuk

My setup is complete now with nice factory-looking points to hook up an inverter. Should I ever need to jump start the primary battery, I can always run jump cables from aux battery to the primary.

Posted Images

jpinoy Enthusiast

jpinoy

Posted
Posted

So, as the parts came in, they sat around for a while(ok, a good while) finally got around to installing my dual setup. 

I picked up the Keyline Isolator 300amp(for future, friends trying to talk me into Overlanding.. haha) and AGM H6(Costco). The design for the battery terminal on the back of the isolator could use some redesign, or make it like their 140amp isolators.  If you buy their kit, you get the right terminals to fit from the looks of it. I bought some copper tubing and made my own lugs to fit correctly on the back terminals.. 😮‍💨

I used some red wire-loom for positive cables, but, I might switch it out with black. I picked up MTA 0300839 fuse block to use on it. I did pick up a 4 Relay/12 Fuse holder, just need to figure where to mount it, most likely in the corner next to the aux battery on that corner bracket. I'm going to re-wire it using the more flexible silicon wires. 

I did go the sensor route with the negative cable(used 2AWG). My old man gave me 1AWG red/black welding cable, so used the 1AWG for the positive. I connected some leads to the aux battery so I'm able to plug it into a maintainer, comes out by the bottom front grill. 

I left some of slack on the main cables if I need to move/route them. I used 2 fuse, between the isolator and main/aux battery. I ordered some wire loom mounting clips to clean up that side wiring/cabling. Most likely move the fuse onto the firewall for a cleaner look. 

427023302_1321708041837625_3864677358337896336_n.thumb.jpg.baabe8cac3e05913787e32e3703a660b.jpg

 

423944215_1508198366578786_3371667829314448957_n.thumb.jpg.4c876175fef3380f41fe0c2414d872c6.jpg

 

Don't mind that cable hanging down, it's going to get re-routed, it's for the LED strips.

423944205_737158188389924_1076121781060706663_n.thumb.jpg.cec127cc745a4ab5a627906c28998a4f.jpg

 

426829811_2636499233182697_3516004806779067301_n.thumb.jpg.30f159e2fca424ba9e2462ec708556ff.jpg

 

423944256_766047961697091_5723348345559009497_n.thumb.jpg.5c9b4fdab2011139c768ad3c76bbbc7a.jpg

 

426978189_1026673018437028_5882219932594468394_n.thumb.jpg.344af01aae936d63ca3db6e098895236.jpg

 

426828269_780489623968849_208218750770543542_n.thumb.jpg.1ea33ba3e6fc1ded6ae1f0139c2ac9d3.jpg

 

  • Like 1
  • 4 weeks later...
eurobound Enthusiast

eurobound

Posted
Posted

Some pics from factory 2nd battery installation. Works fine so far other than first 125 amp fuse provided was actually blown. Replaced it and it's worked solid for over a year now.

 

Buying the factory stuff was quite nice as it was totally plug and play with not much fuss. Wires fit perfectly and connectors to hold wires just snapped into place. Highly recommend going this route.

 

I also replaced both batteries at that time with AGM and so far no issues. 

20240225_162229.jpg

20240225_162232.jpg

20240225_162238.jpg

20240225_162244.jpg

  • Like 2
  • 7 months later...
BackRoadZ1 Enthusiast

BackRoadZ1

Posted
Posted
On 3/17/2024 at 11:13 AM, eurobound said:

Some pics from factory 2nd battery installation. Works fine so far other than first 125 amp fuse provided was actually blown. Replaced it and it's worked solid for over a year now.

 

Buying the factory stuff was quite nice as it was totally plug and play with not much fuss. Wires fit perfectly and connectors to hold wires just snapped into place. Highly recommend going this route.

 

I also replaced both batteries at that time with AGM and so far no issues. 

20240225_162229.jpg

20240225_162232.jpg

20240225_162238.jpg

20240225_162244.jpg

Do you have a parts list with part numbers for your kit?

  • 1 year later...
GraphiteSilveradoZ71 New Member

GraphiteSilveradoZ71

Posted
Posted
On 3/17/2024 at 11:13 AM, eurobound said:

Some pics from factory 2nd battery installation. Works fine so far other than first 125 amp fuse provided was actually blown. Replaced it and it's worked solid for over a year now.

 

Buying the factory stuff was quite nice as it was totally plug and play with not much fuss. Wires fit perfectly and connectors to hold wires just snapped into place. Highly recommend going this route.

 

I also replaced both batteries at that time with AGM and so far no issues. 

20240225_162229.jpg

20240225_162232.jpg

20240225_162238.jpg

20240225_162244.jpg

I came across this feed and something similar in another group. I’m looking to do the same if not similar on my 5.3L 1500.

Is this on a 5.3L/6.2L 1500 truck or 6.0L 2500/3500?

the black connector coming off of the grey relay, what does that connector go to? I’ve tried looking up the wiring diagram and have had no luck.

eurobound Enthusiast

eurobound

Posted
Posted (edited)
On 12/24/2025 at 6:05 PM, GraphiteSilveradoZ71 said:

I came across this feed and something similar in another group. I’m looking to do the same if not similar on my 5.3L 1500.

Is this on a 5.3L/6.2L 1500 truck or 6.0L 2500/3500?

the black connector coming off of the grey relay, what does that connector go to? I’ve tried looking up the wiring diagram and have had no luck.

It's been a while since I did this upgrade and don't remember much. I do know though that there were unused OEM connectors in the engine bay and this was just plug and play. Not sure if the extra pics will help. Good luck!

 

Edit: as per my signature, it's a 6.0L gas 3500HD

 

FWIW, It's been working well ever since I did it.

 

I personally would not mess around with aftermarket if I was given the chance to do it again unless for some reason I needed to upgrade the wiring. I have a nice aftermarket sound system installed with 1800 watts (2 Class A/B 900 watt amps at 4 ohm (6 x 150 per channel)) as well but as anyone will tell you the actual amp capacity needed to support even loud listening levels is well below the threshold of the alternator and wiring in this truck. This would be true except for SPL installs - that's a whole other animal. Just thought I'd throw that in there for anyone thinking they can't go with this OEM option as it won't be good enough for their car stereo system. 

20251226_092603.jpg

20251226_092554.jpg

Edited by eurobound

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing

  • Latest Articles

  • Posts

    • Another JR
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By Another JR · Posted

      Have considered installing a DC to DC charger in your camper to replace your isolator?  
    • newdude
      Gas fill door

      By newdude · Posted

      Common failure.  You need to replace the fuel door housing.   The painted cover transfers over to the new housing.  To remove the old one there is 4 spots where you poke the plastic to release it.  
    • newdude
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By newdude · Posted

      No such thing as regenerative braking on a pure ICE vehicle.     Regenerative braking is the re-capture of energy from electric motors and stores it in the battery pack.  So hybrids, PHEV and EVs have regenerative braking.     What you are seeing is the charging system changing modes is all.  Its likely entering charge mode for some sort of reason is all.  All of the charging modes will be listed below.   As for L10 vs D.  L10 turns off automatic grade braking.  L10 puts you in control of grade downshifts where in D it will automatically do it based on brake pedal position and other factors.  Otherwise L10 and D drive exactly the same aside from that one aspect.    Battery Sulfation Mode The BCM will enter this mode when the interpreted Generator output voltage is less than 13.2 V for 45 minutes. When this condition exists the BCM will enter Charge Mode for 2–3 minutes. The BCM will then determine which mode to enter depending on voltage requirements.   Charge Mode The BCM will enter Charge Mode when ever one of the following conditions are met:   Windshield wipers are ON for more than 3 s. Climate Control Voltage Boost Mode Request is true, as sensed by the HVAC control module via serial data. High speed cooling fan, rear defogger, and HVAC high speed blower operation can cause the BCM to enter the Charge Mode. The estimated battery temperature is less than 0°C (32°F). Battery State of Charge is less than 80%. Vehicle speed is greater than 145 km/h (90 mph) A current sensor malfunction exists. System voltage is determined to be below 12.56 V When any one of these conditions is met, the system will set targeted generator output voltage to a charging voltage between 13.9–15.5 V, depending on the battery state of charge and estimated battery temperature.   Fuel Economy Mode The BCM will enter Fuel Economy Mode when the estimated battery temperature is at least 0°C (32°F) but less than or equal to 80°C (176°F), the calculated battery current is less than 15 A and greater than −8 A, and the battery state-of-charge is greater than or equal to 80%. Its targeted generator output voltage is the open circuit voltage of the battery and can be between 12.5–13.1 V. When fuel economy mode is active, the generator is not charging, only maintaining open circuit battery voltage. The BCM will exit this mode and enter Charge Mode when any of the conditions described above are present.   Headlamp Mode The BCM will enter Headlamp Mode when ever the head lamps are ON (high or low beams). Voltage will be regulated between 13.9–14.5 V.   Start Up Mode When the engine is started the BCM sets a targeted generator output voltage of 14.5 V for 30 s.   Tow/Haul Mode (if applicable) Pressing the Tow/Haul Mode button located on the center stack, the vehicle system voltage is raised and the remote (non-vehicle) battery will be charged. Having the headlamps on will raise the system voltage and if the Tow/Haul button is applied it will not serve any purpose. The voltage is regulated between 13.9-14.5 V.      
    • jaszr2
      Active Grille Delete

      By jaszr2 · Posted

      Hello from Australia Just sharing that there is now a way to delete the active shutters entirely with just a plug in module. Opens up tons of room to light bars etc.
    • jake111
      Gasser Subforum Has Been Quiet - - So, Regenerative Braking and Using L10

      By jake111 · Posted

      I have an observation and a question... 1) I watch the voltage closely because I have had to dial in the cut-in/cut-out voltages of the battery separator to my camper.  The "smart" charging drives me nuts.  Anyway, I noticed that when coasting for a while, and especially if lightly using the brakes (though not necessary), the voltage goes up from mid/high-13 volts to mid/high-14 volts.  Then it drops back down after stopping or going again.  Consistently!   The only explanation I can come up with is REGENERATIVE BRAKING!  Well, maybe that's a little bit of an exaggeration, but it's certainly free extra battery charging.   2) Driving on mountain roads I will use L and vary the max gear.  Things straighten out and I end up in L10.  Sometimes I leave it there for a while.  Is there any difference between L10 and D?   

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...