Adding a Dual Battery

[davester]

Are you sure 250A fuses are enough for your inverter?  With no conversion loss, it needs the full 250A to provide 3000W output power.

 

And having two wires going to the inverter instead isn't the way to go, as you can't control how much current each wire passes...

[Vuk]

The installation manual for the inverter says to run two 00 gauge lines that are fused with 250Amp fuses each. I think that if you keep the length of the two wires close to identical, there should be no issues.

[davester]

To me, that seems very odd.

 

From a wiring safety standpoint, parallel power wires are either 100% overkill or a fire hazard, as you have to (or rather should) treat it as if either wire will fail/break, so only one of the wires will wind up having to pass all the current needed for the inverter (so both a single wire and fuse can handle all the power to the inverter).

 

The only way having 2 parallel power wires makes sense, is if the inverter is really 2 independent 1500W inverters, and each wire powers one side.

[Vuk]

Inverters with two sets of 12V screw terminals appear to be common in the range above 2000W. I suppose that if say one fused link fails, the other fuse would blow quickly as, like you said, it cannot handle that load all alone.

[Contra]

On 7/5/2017 at 4:23 PM, bsprtsgrp said:

Installed....

where did you go through the firewall for the ACC remote signal

[Vuk]

I did not wire into the cab - just tapped into the engine/body harness connector (the big one right there next to the aux battery).

[Vuk]

Violet/brown; check my post on previous page, that's where it goes factory but many other signals will work.

 

What's the make/model of that isolator?

[Vuk]

I had something very important pointed out by J_Mas6.2 member and I think this is understated in most topics pertaining to custom dual battery setups, and especially lengthy ones where it becomes hard to read every single post (there are some notes on this on earlier pages of this topic). The negative lead of the aux battery should be looped through the current sensor measuring current through the negative leads of the primary battery. It should be looped through from top to down (just like leads from the primary battery), to ensure correct current measurement, or simply connected directly to the primary battery terminal (that way all drawn from both batteries will flow through the existing ground leads to the primary battery). However, I would recommend running additional leads to the ground (through the sensor), from the aux battery. This is essential for correct operation of the charging system.

 

The builder's manual is not very helpful when it comes to this detail. In the schematics there, the current sensor measures current through ground circuits marked # 250 and 450, while the aux battery ground (circuit # 350) does not appear to loop through the current sensor. However, not all truck/engine configurations have the current sensor, which is where the builder's manual is short.

 

For trucks that do have current sensors, this also invalidates (I believe) all negative terminal part numbers listed in this topic - I have seen none that are long enough to actually run to the primary battery.

 

Note that one could relatively easily make a circuit that will take information from two current sensors, "combine" them, and send that info to the BCM. A small microcontroller could do this as the signal coming out of the current sensor is nothing but a pulse width-modulated pulse train of a specific frequency. However, the hard part is programming the microcontroller to properly respond to the BCM diagnostic actions - the builder's manual states that the pulse width range 5-95% is meant to be proportional to the current being drawn out of the battery, while 0-5% and 95-100% are meant for diagnostic purposes. Specification on what exactly is being done here is omitted, which makes a correct design with two current sensors quite impossible.

Edited January 3, 2020 by Vuk
Reference to earlier posts added

[h1000101b]

I've read this thread, read other threads (also from other sites), spoke with people etc.

 

I'M POSTING HERE B/C THIS THREAD PERTAINS TO THIS SITUATION - I CAN POST ELSEWHERE, BUT THIS WHOLE DISCUSSION WOULD BE LOST.  MY MAIN GOAL OF THIS POST IS TO SEE IF ANYONE HAS ANY COMMENTS OR SUGGESTIONS ON MY WIRE DIAGRAM BEFORE I PULL MY TRUCK APART. THANK YOU

 

My goal is to add the following:

 

1. High Output Alternator (320A Iraggi)

2. Add Second Battery (Optima Yellow Group Size D34-78)

3. Upgrade All Charging wires to 1/0 Gauge (GP car Audio Power Wire w/Big 3 kit)

 

From what I gather, The route that i'm going to take is as follows:

 

1. Install the Alternator

2. Run 1/0 Gauge Ground from (-) of Alternator to Frame (Leave factory wire connected) and to (-) of Factory Battery

3. Run 1/0 Gauge Power from (+) of Alternator to (+) of Factory Battery (fused @ 320A)

4. Run 1/0 Gauge Power from (-) of Factory Battery to (-) of Second Battery and to Body Ground

5. Run 1/0 Gauge Power from (+) of Factory Battery (fused @ 320A) to (+) of Second Battery (fused @ 320A)

6. From there all Power needed for AUX Equipment (Amps, Rock Lights, Inverters, etc) will Run from the (+) of the Second Battery (Fused appropriately)

 

I did a lot of research into this and the only things that had any second thoughts on were if I should run a relay or not and if i should run the 1/0 gauge wire through the current sensor. (not sure if it would even fit).

 

I decided not to do either.

 

The first of which I chose not to do, mainly for the fact that the relay has a voltage drop of its own (minor), but also, it's removal has been the fix for many people in car audio  to reduce lights from flickering.  The amount of battery capacity that I have won't have issues with me needing to isolate my batteries.

 

The second of which I chose not to do, was only because I read a lot of posts (mainly in car audio forums) that didn't do this and had no issues.  I feel that the current wire that is running through the sensor must suffice.  I'm still a bit on the fence on this one.  But, I could only find maybe 1 or 2 instances where people did this modification and it was for much smaller rated systems. Neither seemed to have any problems. I just tend to follow the majority of examples that don't have issues.

 

I'm attaching my general wire layout. If anyone sees something or could have a rational discussion, please do. I'm all ears.

 

 

 

Edited May 2, 2020 by h1000101b

[Jcota1117]

On 6/27/2017 at 5:59 PM, tenscourts said:

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, and videos.

 

Sent from my Pixel XL using Tapatalk. My build thread: http://www.gm-trucks.com/forums/index.php?/topic/192614-Tenscourts'-2016-LTZ/Z71-CCSB-4WD-Silverado

Hey bud, I’m looking to do this set up can you send me a link to the videos and pictures. I can’t seem to find it on your page. Thank you!

[jpinoy]

On 12/6/2019 at 2:11 PM, Vuk said:

I picked up a 48PG battery today and installed my three-fuse modification. The original negative auxiliary battery cable 84354708 seems like it would never be delivered, so I picked up 22846471 (at about the same price) and removed the sensor. This one gives an additional ground lead of decent gauge that can be used for accessories, which is even better.

 

I've replaced the 175A fuses with 250A as a preparation for a 3000W inverter running off of the aux battery. I will post pics once the battery lays down in the next couple of days.

 

 

 

 

 

Where did you get that battery post like that? I ordered that same top fuse box and wondered how how you have it attached to the post clamp. Or is that part of your three-fuse modification you mentioned.   Trying to get my dual battery setup going.

[Vuk]

That battery post is the original on 23273450 GM dual battery harness, with the exception that it connects to a single fuse holder. The height and angles work for this fuse box, too.

[jpinoy]

That battery post is the original on 23273450 GM dual battery harness, with the exception that it connects to a single fuse holder. The height and angles work for this fuse box, too.

Nice, thank you! Working on getting my parts together as well. Saw a couple cables online that had that style after asking you in here. I'll look up that part number.

Sent from my SM-N986U1 using Tapatalk

[Mark 27]

I would look for an alternator repair shop, if you can find one.

[Lews 2018]

Good Day Good People

 

I have been following various forums looking for the right dual battery solution. Since I didnt want to trust an aftermarket solution, I went to the dealer and had them retro fit the complete wiring for the 2500 series silverado. Everything went in and appears as a stock solution but there is a flaw.

 

There is no way to send the signal to open/close the relay to charge the second battery. The mechanic gave me 2 options;

 

connect the power cables bypassing the relay (one power cable goes to the alternator the other goes to the second battery)

put a on/off switch inline with the harness (see attached image) along with an amp gauge to monitor usage.

 

Any other options? Thanks for the assist..