Is grounding 230 amps through the tub a bad idea?

toximus

toximus

I live in my Jeep
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I previously ran all aftermarket grounds back to the battery. But now I'm realizing that I'd have much better packaging if I just grounded to the tub.

When I calculate out everything aftermarket that could be running at the same time, I come up with 230a (electric fan and dual ARB doesn't help).

If I ground the battery to the tub with a 1/0 strap, would the fire wall area of the tub be good enough quality for that much energy to transfer across?
 
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I'm also running a 240a alternator. Should I ground the engine to the tub with 1/0 and to the battery with 1/0 or can I get by with only 1/0 engine to tub and 4ga engine to battery?
 
I much prefer to run high amperage gear right to the battery or a bus bar near the battery. However, it will work..

With such a high output alternator I would upgrade the block to battery ground cable if you expect to use all 240 amps.
 
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Seems like a really high amount of draw. However, your plan should work ok on 1/0. Cables might be a beating to route neatly being so large. Definitely upgrade the block to battery ground or else if the 4ga isn't enough, you might have problems there since the alternator grounds through the block and that cable.

Upgrade the battery charge wire and fuse or fusible link it too if you haven't already.

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machoheadgames said:
Seems like a really high amount of draw.
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Oops. I think I counted something twice.

40a ARB #1
40a ARB #2
30a Light bar
40a fan (still waiting to hear back with a final number on this)
15a rock lights
15a back up lights
40a speaker amp
40a subwoofer amp

Speakers and ARB would never be on at the same time.
 
toximus said:
Oops. I think I counted something twice.

40a ARB #1
40a ARB #2
30a Light bar
40a fan (still waiting to hear back with a final number on this)
15a rock lights
15a back up lights
40a speaker amp
40a subwoofer amp

Speakers and ARB would never be on at the same time.
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Those amp ratings are not continuous, those are peak loads. Definitely ground anything that can generate continuous high amp draws, like a winch, directly to the battery.
 
toximus said:
Oops. I think I counted something twice.

40a ARB #1
40a ARB #2
30a Light bar
40a fan (still waiting to hear back with a final number on this)
15a rock lights
15a back up lights
40a speaker amp
40a subwoofer amp

Speakers and ARB would never be on at the same time.
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Looks like 180 if speakers aren't running, and 260 if everything is going? 180 is better than 240 at least.

Damn, 15A rock lights and another 15 for backups? What lights are you running? Seems high, I've used some crazy bright rigid backups in the past and even they were like 2A per light, and 3200 lm each.

Also curious what the fans are with the e-fan? You working on something custom?
 
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I'm going to say the exact opposite of Jerry with conditions: Ground it to the chassis. Two caveats: 1) Your battery to tub/chassis grounding strap/wire/cable must be up to the task, and 2) All ground connections must be good ones and capable of staying that way. If either of these aren't true, yes - you're better of running a cable back to the battery negative. But if they are true, the ground path through the chassis/tub is far lower impedance than ANY cable you could run in a practical sense.

Now in the case of my winch - I did both. I grounded through the frame, AND I installed beefed up grounding cables from the battery. I also installed a huge jumper at one of the motor mounts as the frame is apparently only grounded to the rest of the Jeep through the brake lines from what @mrblaine was able to determine. However, if any of these ground connections go south - where the winch itself is grounded is of most concern as its exposed to the weather - than this won't work too well. So I ran the standard negative cable back to the battery as well for reliability. Best of both worlds.

YMMV and all that...
 
You should be fine to use the body for the grounds since that's all peak power and some of those numbers seem pretty high to me anyway (like top volume, top gain, etc). Also if you're blasting music on the trails constantly you're probably in a side by side and none of it matters anyway ;).

However I generally prefer my aux fuse block for my runs (aside from my winch). It's currently grounded by the headlight, but if this becomes an issue I'll run the ground direct to the battery.

You could ground some loops independently to cut down that load pretty quickly, such as grounding the fan to the block, making it mostly something to not even consider.
 
machoheadgames said:
Damn, 15A rock lights and another 15 for backups? What lights are you running? Seems high, I've used some crazy bright rigid backups in the past and even they were like 2A per light, and 3200 lm each.
Click to expand...

If I remember correctly, I just used the same fuses that came with it.

machoheadgames said:
Also curious what the fans are with the e-fan? You working on something custom?
Click to expand...

You could say that...

20220227_164316.jpg
 
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toximus said:
If I remember correctly, I just used the same fuses that came with it.



You could say that...

View attachment 313529
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Ah…if you’re basing it off the fuse it came with, then that’s overestimating it quite a bit. Not that that’s a bad thing. I think the sets of Rigids I’ve bought usually have 15A fuses even though only draw a few amps total. One set of Rigids I bought had a 40A fuse. Those still only were like 6A total load.

Forgot you’re part of the V8 world. Nice, carry on.
 
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Here's the diagram.

So, thoughts on the only battery grounds going to the winch, firewall, PDC, and engine block (just like factory)? All of the additional grounds would be interior except for the fan, dual ARB, and rock lights.

For everything on block 3 and 4, I could place a busbar with a single grounding wire to the firewall.

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Edit - I don't know why I placed the starter so far away from the engine. It's 100% attached. Lol.
 
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I was able to clean it up a ton. Should be much cleaner under the hood this way too. I'm open to feedback.

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Might help with your calculations. The fuses you're basing you amp draw from are there to protect the wires (or should be). Your rock lights are LED, I assume. I'd be real surprised if they pull more than 5 amps, for example.

If you really want to know your current draw, you'll need to look up all your accessories and sum them.

If you can't look them up, hook up the accessory to a battery (fully charged) and put your meter in line on the one of the leads. Measure directly. Most meters only go to 10 amps though, so watch those compressors and amps. Note, you'll also be building in a little safety factor with the method. Power=voltage x current. If your accessories are connected to 12V, they will pull more current to get the right power. In the vehicle, with the engine running, you should have 14 + volts, which will reduce the current required.

240 is a lot... Like more than most of the welders we have in our garages. If your building for that much current, you're oversizing all your main wires, and copper is really expensive.
 
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