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Big 3 upgrade

SS FORCE

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Thread starter #1
Hello all,

I am currently working on doing the big 3 upgrade on my 06 LBZ.

I bought Knukonceptz kolossus flex 1/0 OFC, ring terminals, wire loom and a fuse for the alt portion to complete the task. In looking at the stock wiring setup though I think I'll end up rewiring all the battery connections. Currently the alt wire goes to the distribution block on the side of the engine block. I have read to leave this one in place and run the additional 1/0 wire to the + side battery. Can I just get rid of this connection entirely during my rewire and run 2 cables, one to the + of each battery? Or do I only need to do one? Is there any reason to leave the stock alt cable in place?

I don't like how the wiring between the batteries was run on these trucks. Seems they had it setup much simpler on my old 97 6.5TD. The 06 has wires running from one battery to the other by way of going under the front of the engine.

Anyone on here done this and have any feedback on a better way? Do I leave the distribution block and just add the second + alt charge wire?
 

WarWagon

Well it hits on 7 of 8...
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#3
So the big three needs to be grounds: 1) frame to engine, 2) body to engine, and 3) body to frame. You don't see a positive connection in the description. :stop: Let me expand on this:

Dealing with current ANY length of wire introduces resistance and resistance means voltage drop. Voltage drop means the minor 0.X volts difference can overcharge one battery and undercharge the other battery. Current? At the minimum figure 6 amps per battery and some AGM batteries can take 100% of the alternator output - the wiring becomes the limit or GM's firecracker (poor hot running design) alternators simply lets the magic smoke out. Yes, AGM's can and will take all 140 Amps if they are discharged enough.

Simply put the positive connection design on 1997 6.5TD and all the 6.X diesels before it SUCKED! GM terminals are weaker than the top post... But more important is it's a long run to the other battery on the positive cable with 2 iffy connections. The long cable run alone works the other battery harder and less voltage to charge the other battery. Simple, but, SUCKED!

So you want the ground cables and positive cables to be the same length for each battery. The Duramax brings both batteries positive cables to a common point then to the starter. I don't recall if it was the jumper cable connection or on the starter offhand. Maybe varied by the years.

I digress... Forget about the batteries except to start the engine and then a parasitic 6A load.

One more time with feeling: Don't hook up anything new to the batteries.

You create ground loops and other small diameter wires that the huge starter and glow plug current attempts to travel through. Then there is a mere 6A current to charge them. Everything after engine start is alternator powered so again the batteries are useless at this point. The starter is asking for 600+ Amps making the large cables small and sneaking lots of current through every other cable hooked on the battery. A 2 volt drop to the starter is acceptable over battery cables, eh. That's a 2 volt dead short across any other ground wire to the frame or body from the battery. I am aware the Bean Counters at General Fukup Motors like to give you a ground loop from the factory to save on Bean Counter's wire. Aka battery to body connection rather than a separate frame to engine strap GM used to have on older models. GM had a model called Blazer for a reason and Trailblazers notably had this OEM BeanCounter Fukup. Go ahead and disconnect the main negative cable from the engine say with corrosion, loose bolt, etc. and hit the starter. The small ground wires will burn off and/or you will be arc welding bearings between the body and engine.

The above said be careful making new connections to the alternator from the batteries. Same thing of current loops during starting. Further alt diodes do short out and the the fusible link doesn't blow (say because it's doubled up with two links/fuses instead of just one) it's an insurance claim from a burned to the ground vehicle. So you can replace the existing wires with thicker wires, but, DO NOT DOUBLE THEM UP ON THE POSITIVE SIDE! Any wire going to the positive terminal on the battery is asking to be hit with the 600A from the starter esp. if you are running new wires to the side of the engine from each battery. Again connection failure from the big battery cable dumps the 600A into the little cable. Doubled up makes the resistance values different and the same charging/work issues between the batteries. The current can run through the alternator battery connection back to the other battery then starter depending on what battery is bad or connection is loose/bad.

Even if the new bigger wire can take the starter load... You see the problems with two current paths.
 

SS FORCE

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Thread starter #4
Thank you WarWagon that makes sense.

In doing reading some sources said just to leave the original charge wire in place and add another run. Makes sense not to now. Also, if I am understanding what you said, maybe its best I leave the wire routing and endpoints stock and just upgrade the gauge of wire?

The ground coming off the driver side battery to the frame is a puny little thing. I'll be putting subs in the truck that will be wired with thicker gauge.

Thanks for your help
 

WarWagon

Well it hits on 7 of 8...
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#5
Thank you WarWagon that makes sense.

In doing reading some sources said just to leave the original charge wire in place and add another run. Makes sense not to now. Also, if I am understanding what you said, maybe its best I leave the wire routing and endpoints stock and just upgrade the gauge of wire?

The ground coming off the driver side battery to the frame is a puny little thing. I'll be putting subs in the truck that will be wired with thicker gauge.

Thanks for your help
'The ground coming off the driver side battery to the frame is a puny little thing.' GM Bean counter ground loop garbage. Cut battery to frame off and replace it with frame to engine ground strap. This is part of the ABS ground. ABS, Frame, Battery, Engine, Alternator. Cut the battery loop out of it by going direct to engine.

Yes, upgrade the gauge of wire. Reuse existing ground points where possible. Do not add a strap to an existing ground location (bolt) as this can introduce 'noise' into the other items grounded there.
 

Will L.

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#8
My 0.02

The “best” spot is closest to the largest electrical draw.
So starter housing.

Now the quailty of the starter carrying ground through the block to the alternator and the multiple ground wires on the engine comes into play. IF that starter mount to block is weak ground and couldn’t carry the ground to the engine, then should you connect to the block and not to the starter to ensure the good ground to electronics? Not really. Because the need for the high amperage at the starter, if there is the bad connection, it simply wouldn’t crank so the electronics never come in to play.

If you don’t care about money invested and will deal with the annoyance of it- the best theoretical method would be a ground bar coming off the battery. Then ground ar feeding 1 wire to each component: starter; alternator; each grounding point. Both on the engine, and the body. They would in theory to stop all noise and safely not allow under grounding need to all be the size of the largest amperage draw. So if you use #2, you should have multiple #2 grounds running all over the place.

As for the interference from alternator: dc current only travels one direction so it can’t backfeed in the closed loop system. However the alternator is an ac circuit that is converted to dc. So a capacitor to absorb the fluctuations that occur there. Many alternators have one on it since the addition of fm radio just for eliminating the alternator whine in the radio.

So that falls to the electrical rule of being 100%. But it is so rediculously over kill to do it that way, no one does it. If every wire is sized only to it’s ampacity, and the large ground wire fails, the tiny wire to something else will try to carry the load and fail in a nice smoke show. But it is impractical and expensive. The odds of loosing contact that way is crazy rare. Simply having clean quality connections through the block is usually a better answer. Going to a dry hole as pointed out is key. Hit the block with a roloc disk or something that takes it to bare metal. A key thingI do is clean the block face well where the starter mounts to the block.

An interesting thing that any guys who work on semis or yellow iron, they will point out both positive and negative battery cables both go to the starter. Then they have secondary cables that go to the chassis ground and to the body system. They have to. The amperage draw of those huge starters will arc enough to weld cast iron if the ground connections become weak from starter to block.

I don’t bother with that on my rigs. I run to the block, then bounce from there to frame and body. To annoying to fight it on the small starter.
 

THEFERMANATOR

FRANKENBURBAN
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Staff #9
The factory battery cables run 1 battery cable from each battery to the starter. The cable running under the front of the engine does connect the batteries, but if you look at the starter you will see there is a cable from EACH battery connecting to the battery post. This is a SUPERIOR design to the 6.5's cables in EVERY way. Then you have each batteries ground connecting to the front lower block where all the harness grounds hook to the block. I don't see ANY reason myself to "upgrade" the cables on a DURAMAX. They already use a low current draw permanent magnet gear reduction starter, carbon pile glow plugs that only draw high amperage for a few seconds then taper off, and the intake heater only runs when the engine is running IIRC. Battery cables have never been an issue on the DURAMAX to my knowledge. Even those going to only 1 battery for twin/triple turbo setups normally keep the stock cables, and just remove the passenger side one.
 

Will L.

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#11
Idk if it is a dry heat thing or what- but in the southwest, guys are beefing them up a bit in size to eextend battery life.
The factory set up works, but when they upgrade tha cables, wet battery life goes from 2.5 to 4 years. Carrying charge load and having less voltage drop adds up to helping the system, but I was surprised to hear this big a jump from the dmax friends here in Vegas area.

I always just figured they were copying issues popping up in rust belt loosing grounds just incase.

But heck yeah- GM made improvements on the dmax rigs from the idi errors.
 

FellowTraveler

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#12
Idk if it is a dry heat thing or what- but in the southwest, guys are beefing them up a bit in size to eextend battery life.
The factory set up works, but when they upgrade tha cables, wet battery life goes from 2.5 to 4 years. Carrying charge load and having less voltage drop adds up to helping the system, but I was surprised to hear this big a jump from the dmax friends here in Vegas area.

I always just figured they were copying issues popping up in rust belt loosing grounds just incase.

But heck yeah- GM made improvements on the dmax rigs from the idi errors.
I have taken to using NORD LOK washers on my battery cables keeping the bolts nice and tight to the cables.
 

Will L.

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#13
Nordloc washers are hands down the best antivibration dvice ever made. They come factory on hmmwv/hummers where the cv axle mounts through the disk brake and into the differential output flange. They are reuseable for something like 50 uses iirc. So yeah- I’m a fan of them.

However if it is a sidepost battery, the bolt locked against the terminal ring still doesn’t stop the terminal ring from pivoting.
I hate sideposts. I feel it is something that never should have been invented. If they had done it like a marine battery where there is a 3/8” threaded rod and a 5/8” plate surface coming out of it, it would have been better- But still not desired.
 

THEFERMANATOR

FRANKENBURBAN
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@THEFERMANATOR is a body or frame to engine ground cable add-on of any use on a Duramax? The ABS frame ground was a problem on my 2005.
It can't hurt, but it was almost a 6 guage ground strap that runs from the back of the block to the firewall. I definately retained it plus all my stock grounds when I did my swap, and grounds at the engine have never been an issue. That abs ground is an issue on all gmt-800 trucks. GM's bright idea to ground the abs where it is subject to dirt, salt, and everything else was a dumb idea.
 

THEFERMANATOR

FRANKENBURBAN
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Staff #15
Idk if it is a dry heat thing or what- but in the southwest, guys are beefing them up a bit in size to eextend battery life.
The factory set up works, but when they upgrade tha cables, wet battery life goes from 2.5 to 4 years. Carrying charge load and having less voltage drop adds up to helping the system, but I was surprised to hear this big a jump from the dmax friends here in Vegas area.

I always just figured they were copying issues popping up in rust belt loosing grounds just incase.

But heck yeah- GM made improvements on the dmax rigs from the idi errors.
I find this hard to believe. It's heat and over charging that kills the passenger side battery in my experience. Both times my batts have gone, it's been the passenger side, and it's been BALOONED when I change them. I've seen 15.8 volts out of mine on a cold start after the glow plugs cycle off, and it will stay over 15 volts for AWHILE. Heat under the hood has always been an issue, and I credit GM for the heat issue with there t-stat temp's being so high before they open, the fan clutch not kicking in until it's up there, and running the turbo so hot before the coolant flows through it. Then again, still to this day GM dropped the ball on the heater coolant return which leads to trans overheating coming down a long steep grade.
 

Will L.

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#16
Your closer to the issue than you realize. That higher voltage and an unbalanced charge to the two batteries is proof of the issue. It gets hard to understand for most automotive guys. Like, if you say to them run 2 cables both 4 gauge from point a to point be to help the voltage drop but keeping the resistance down.

Commercial and industrial electricians have to deal with the issue all the time. In high power circuits like 400 hp electric motors in parallel runs. To have a single wire big enough to withstand the load, it would have to be the size of your thigh. But running 2 wires LESS than half the size gets it done. But having the parallel wires EXACTLY the same length is crucial. When one wire gets 2% longer than the other, it overheats one wire from imbalances, thermal changes greatly enhance the effect. Energy efficiency goes out the window, failures increase, etc. This is a big reason why I just got my cert as a thermographer- the whole electrical, controls, and hvac dept just did because the cost long term is massive.

Anyways, is there a difference in the battery cable length going to the 2 batteries of more than 2%? Of course! So “proper sizing” according to the normal lock rotor amp draw X 1.25% rule goes out the window on the starter.

Now the overcharge issue. Why does it charge so crazy high? The alt “reads” the load as a combined unit. Remember voltage is consistant but ohms add up (being dc it isn’t exact, but the rule of thumb mind you- Thevenin is the accurate description but harder to remember). So it shoves out power at a high level from the measured resistance. But all that power gets to one battery before the other.
While the voltage will equalize between the two batteries, the amperage is not. The EMF is WAY out. This is a perfect “how not to” instruction for Thevinin’s therom and Kirchof’s laws. And back to the ac current and interfering issue for the alternator WarWagon brought up- that is because an alternator is ac power that is converted to dc. And ac power is directly determined in ohms, where as the dc power has more reactive than resistance impedence. This is why we use ac alternators instead of dc generators like in the 1950’s.

Idk how well that translates to non sparkys. I learned car electrical before high voltage, and it confused me at first.

So another way to say it to exaggerate it. Imagine starter and alternator on the engine, and one battery only 3’ away. The second battery is 30’ away. Use 2 gauge battery cables. When nothing is on, the batteries will equalize power. Then crank the engine over without fuel until it wont crank. Disconnect the batteries. The close battery will be at say 9 volts and the far battery will have 10 volts. Because the far battery has so much reactive current and emf to fight through, it will not be able to discharge as fast as the other battery.

Now give the engine fuel and use the dyno built in starter and battery to start it. So now the engine alternator is charging the 2 batteries with the same supply of electricity. But the battery that is more dead at 9 volts will take in more electrical charge than the 10 volt for 2 reasons.
One: Delta variance. Easier to understand is Newrons law of cooling saying the bigger the difference in temperature the faster the heat loss occurs- electrically same thing. The more discharged a battery the faster it can soak it in. This is a bad thing btw. Why you should not charge a completely dead battery on 500 amp booster charge. A slow trickle makes the battery last longer.
Two: the longer cable still has all the resistave impedance it did before, even though now the electrical draw is less there by lowering the reactive impedance.
So even if you took out the two crappy batteries and put in two iden new batteries, the far away battery will get less juice- a slower charge improving its lifespan.

This is why all semi trucks, heavy equipment, military vehicles, etc that use more than 1 battery always have the batteries next to each other, connected to each other primarily- then have all the power come out of one location, regardless is there are parallel power and parallel ground cables.

It is simply better electrical engineering. Of which- no surprise here- GM is amazingly horrible at. They make up their own rules as to what to do based on production costs- not sound electrical mathematics.

So back to the 3’ vs 30’. Replace the tiny cables with 750 mcm control feed wire. The reactive resistance is so low in that wire that you need a $50,000 meter to read the difference even though one is 10 tomes the length. The resistance impedance will be exactly 10 times higher. But collectively the big honkin wire will allow the far battery to discharge and almost the same rate. It will also allow it to charge at almost the same rate. So the life of the close battery gets extended in the short term. And since the far battery isn’t constantly draining into the close battery whenever the engine is off just resting, now the life of the far battery does better because it now has proper rest periods instead of always charging or discharging.

Away from the electrical possibility, some people consider the heat on the batteries and rotate them extending the life a little- but not just the heat gets spread more evenly- that electrical indifference is still in play- they just don’t know how much it is helping. And back to Newtons law- keeping that battery at a more stable temperature is always going to extend its life. A good example is Tesla batteries. The batteries that don’t get the cooling system serviced die so much faster. The folks that get them serviced on time get long lifespan. Because the coolant degradation can’t keep temperatures even enough.

I hope I explained that ok. Anyone here an EE or better at explaining the process than me? Please speak up if so.
 

THEFERMANATOR

FRANKENBURBAN
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I know several have moved the passenger battery down under the cab, used the same cables, and battery life goes up. And I'm pretty sure the passenger side battety has more cable than the drivers side, but they are pretty dang close to each other in length with how GM routed them to even things up, but the charge distance from where the alternator connects is right next to the drivers side battery. So if I understand your theory correctly, this should cook the drivers side battery since it only has about 3 feet of wire to it vs the almost 10 feet to the passenger side battery. But as far as battery to starter, the cables are pretty dang close in length.
 

FellowTraveler

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#18
I'm in the final leg of my conversion and 'will use only one (1) AGM battery for now' because of radiator occupying space on driver side.
The Cummins has less compression and starts effortlessly on one battery at the touch of the switch however; I hope to find a way to install both under the chassis some how at a later date.
 

Will L.

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#19
I helped do 1 dmax cable swap, but his cables were toated anyways. I didn’t pay attention to length that came out. Haven’t really watched or tried to pay alot of attention to this, just a thing the local folks are doing, and I get questioned on because of both truck wrenching history and since I’m an electrician.

On the “my theory” part- to clarify- not mine and no theory. I understand it because of need to for the job, and it is long proven physics.

The 3’ vs 30’ thing was an example to try conveying a complicated combination of electrical factors and formulas. You cant really do those examples in real life and use a dmm to measure and see the differences. It’s a combination of phenomenons occuring, that some basic rules to follow just get applied in the electrical world and all is fine.

The balanced length is 1 part of the equation. How the cable puls from 2 different sources is another. It’s actually quite large. Seriously stupid not having the 2 batteries next to each other.

Enlarging the size of the wires, especially where the wires get hot, is another massive part of the equation. You can think of it another way- turbos.

The 6.5 (we can all relate there) has the tiny turbo which works and helps over n/a application. That is the tiny wires. Now go to the ATT or hx40. It is bigger, so it breathes easier. It takes a hair more umff to light it off, but end results are better. The larger wire has slightly more material the electrical currnt has to travel. So that takes the little more umff. But once the current is flowing- it breathes better, or should say carries more electrons to the load. Where the bigger turbo doesn’t light off at the lower rpm, the electrons don’t carry the same on bigger wire at micro voltages. But when you hit the key to crank the starter - the electrical turbo lag only lasts a couple nano seconds before you are at full boost.

There is a point of diminishing returns, too large of wire. 4/0. Just like too big of turbo. Some argue ATT and hx40 are too big and should use the hx40ii. That would be 2/0.

There are crappy version turbos with junk flowing housings that even though same wheel sizes just cant perform the same. That’s generic welding cable instead of the proper cable- same size but won’t carry current the same and insulation not rated for oils and heat. But are cheaper so some people try them with negative results then blame the concept instead of the actual error of wrong part.

Like mentioned, GM breaks all kinds of common sense rules in the name of profit. In the electrical world they are equivalent to the crack addict alcoholic that huffs paint with CTE. Yes, they are really that bad with doing things like seperating batteries, a million grounding locations on engine, trans, and body. Hummer ds4 electrical systems have the same crappy engine grounding problems- they copied how and where gm grounds mount. The don’t have the in cab/ dash issues- ever. Why? They used an actual Electrical Engineer who ran the ground wires to ajoing proper sized wires, and carry it all the way back to the batteries through the harness. There is no body grounds in a hmmwv/hummer- because that is just stupid to do. But the COMPLETE electrical harness costs more $ to make. Civilian Hummers using same engine and same batteries, next to each other, have stock battery cables that are 2/0 marine rated fine strand. Why? Because less than that is wrong. Electrically wrong.

Right now there is a guy on hummer forum with blower resistor/ controls issue. Why? Civi Hummers used gmt400 a/c electrical components. GM ate all the warranty- not AM General. Because AM General knew the engineering was wrong from day one.

I step aside to your far superior knowledge on many things on rigs. Overall, I trust your judgment on rigs more than my own- you win hands down if it were a contest. But on the electrical side? Sorry it is not me your disagreement is with. It’s Nikoli Tesla Max Plank, Albert Einstein, Gustav Kirchof,Robert Bunsen, Joesph Fourier, Issac Newton, and George Ohm. There is probably more on that list, but the formulas I memorized and work with all have their names attached- all as laws not theories except one - Einstein- he has the theory that is NEVER going to be a law- E=mc2 has a flaw. The c isn’t c. But until someone understands what Tesla trued to explian or a new super genius figures it out- it’s the closest we have to right. Then Einstein will fade from fame. But thats a worse side track...
 

Will L.

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#20
Something hit me, I get amzing results from optima batteries, even red tops and many don't. I always mount the batteries next to each other, run 2/0 or 4/0 marine rated cables, and add increased frame, engine, body grounds. My alternators tend to runnthe life of the rig. Correlation doesn’t equal causation- but better electrical design is probably why so many spend more money long term than I do.
I talk too much and this subject is ALWAYS a huge argument with great mechanics because they usually go with “well the mfr says...” ignoring the avalanche of errors and short cuts they know the mfr takes in other places. So i just tell people how I suggest it.
Top post only used, optima, mounted together, proper cable sizes, adding solenoids or relays where appropriate, and if you are adding large electrical draws- get a re-engineered alternator not just a bigger one or multiples.

I am simply not smart enough to explain the hows and whys.

@SS FORCE (wow that types out bad) sorry for the side mess here. I don’t know the harness enough to give the best answers here to your specific questions. You should have only one charge wire. If you have multiple positive cables they should be exact same length and 2/0 marine rated fine strand if you have no extra electrical draws like winches, sound system, inverters for power tools, etc. if you do run them, get 4/0. Modify what you need to in order to make the batteries next to each other. Connect them with 1each 4/0 wire. Then come off that assembly with your cables. The charge wire is best connected at this same junction point. You may need to increase this wire. Talk to the engineers at powermaster for the wire size and alternator you should have for your application instead of the factory stuff. What you have may suffice.

Run the same battery cable spec for the ground wire. Batteries together. Then cable to starter (block is excuseable option) then from that same connector to frame and body.

And back to your normally scheduled program after this last side track.
When Einstein was asked what is like to be the smartest man in the world, he replied – I don’t know you would have to ask Nikolai Tesla that. When tesla was asked about E=MC2 and the effects and study of the theory of relativity, he replied it’s a neat trick with numbers that almost all add up, But it is wrong because the speed of light is not constant.
 
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