[RCA]

All fair points. The good news is that the ID system is water cooled and as has been demonstrated elsewhere in these forums that the 12v battery is constantly being charged by the HV battery. As such it is quite different situation than “depleting” your Jeep battery while running your gear. Instead it would be more akin to you running the Jeep’s diesel motor while using your electric loads — I suspect in such a case your battery would have fared quite well.

Actually the Jeep was running all the time that I was drawing power for the equipment. I think the issue is sustained high current charging versus "topping up". In looking at my Car Scanner data, the 12 volt battery voltage in the ID.4 varies, and the charger appears to kick in only on an "as needed" basis once the voltage hits a lower limit. When it's charging, the voltage peaks at around 15 volts.

 

[MJSullivan56]

Actually the Jeep was running all the time that I was drawing power for the equipment. I think the issue is sustained high current charging versus "topping up". In looking at my Car Scanner data, the 12 volt battery voltage in the ID.4 varies, and the charger appears to kick in only on an "as needed" basis once the voltage hits a lower limit. When it's charging, the voltage peaks at around 15 volts.

Well, guess I’m just going to have to find out (eventually)

 

[MJSullivan56]

And here is my first attempt at a layout. I think everything will clear as well as not get in the way of servicing the vehicle.

 

[Atlant]

Right. But I was asking about the primary cable from the battery to the bus bar. Is it 2/0?

The bus bar bolts directly to the battery's positive terminal, no? Photos of this have been posted here within the last few days.

 

[SunWizard]

It appears from my measurements that the primary 12v cable is 1 gauge. Ergo, there is no reason to use any greater than that for my 12v to 120v inverter project. Does that make sense?

Yes the bus bar is bolted directly to the battery + so that wire size does not matter for this. There are nice threaded connections under the red and black caps labeled + and - for jump starting, and that is the best connection point as shown in the previous big inverter thread here:

https://www.vwidtalk.com/posts/170658/

 

[MJSullivan56]

Yes the bus bar is bolted directly to the battery + so that wire size does not matter for this. There are nice threaded connections under the red and black caps labeled + and - for jump starting, and that is the best connection point as shown in the previous big inverter thread here:

https://www.vwidtalk.com/posts/170658/

I think it does matter — there is no point in drawing more from the battery than what the HV is capable of replenishing. I.e. I believe that the OEM red wire represents the limiting factor as to how much you can reasonably draw from the 12v subsystem over an extended amount of time.

 

[waldo22]

1AWG copper maxes at 145A, so that's just over 2kW at 14V and ~1.7kW at 12V.

Your reasoning makes sense based on what's feeding the battery to keep it charged, but it may still make sense to go a bit larger to allow you to pull larger loads directly from the battery.

I wouldn't pull larger loads than probably 1,500W with 1AWG cable.

 

[MJSullivan56]

1AWG copper maxes at 145A, so that's just over 2kW at 14V and ~1.7kW at 12V.

Your reasoning makes sense based on what's feeding the battery to keep it charged, but it may still make sense to go a bit larger to allow you to pull larger loads directly from the battery.

I wouldn't pull larger loads than probably 1,500W with 1AWG cable.

That’s the goal. Basically to have an “emergency” 15A 120V outlet.

 

[SunWizard]

I believe that the OEM red wire represents the limiting factor as to how much you can reasonably draw from the 12v subsystem over an extended amount of time.

The size of the wire coming from the DC converter to the bus on mine (not red) measures 1/2" which is at least 2/0, maybe 3/0 depending on insulation thickness. This makes sense because it needs to be able to handle the 3000w continuous that the DC converter can output.

Edit: what measurement were you using to come up with 1 gauge?

 

[MJSullivan56]

The size of the wire coming from the DC converter to the bus on mine (not red) measures 1/2" which is at least 2/0, maybe 3/0 depending on insulation thickness. This makes sense because it needs to be able to handle the 3000w continuous that the DC converter can output.

Edit: what measurement were you using to come up with 1 gauge?

Mine measures 0.445” diameter using a caliper. As per WireAndCableYourWay.com, 1 gauge is the appropriate size for that value. See attached screenshot.

 

[SunWizard]

Mine measures 0.445” diameter using a caliper. As per WireAndCableYourWay.com, 1 gauge is the appropriate size for that value.

That spec is probably for a thicker insulation than this wire has, and they don't list the thickness. Its strange that yours is smaller than mine. But either way, it has to handle the full 3000w continuous that the DC converter can output or we would be having melting insulation.

 

[MJSullivan56]

That spec is probably for a thicker insulation than this wire has, and they don't list the thickness. Its strange that yours is smaller than mine. But either way, it has to handle the full 3000w continuous that the DC converter can output or we would be having melting insulation.

Mine’s a 2021, German made of course.

 

[CroFab]

It appears from my measurements that the primary 12v cable is 1 gauge. Ergo, there is no reason to use any greater than that for my 12v to 120v inverter project. Does that make sense?

View attachment 37826

Unless you can measure the actual core wire diameter, The sheath/ covering can vary substantially from supplier to supplier.

 

[MJSullivan56]

Well looking at price of stuff I might go with 1/0 gauge since Amazon offers that for less than 1gauge from a reputable source. Gosh I hate giving them my money.

 

[waldo22]

Well looking at price of stuff I might go with 1/0 gauge since Amazon offers that for less than 1gauge from a reputable source.

This is why I cut all my cable from DC fast chargers. And usually by the time I go back there again, they've already grown back!

 

[MJSullivan56]

This is why I cut all my cable from DC fast chargers. And usually by the time I go back there again, they've already grown back!

AFAIK, harvesting copper is generally the domain of crack heads. Just sayin’

 

[Annotribe]

You should either size up your connector or size down your breaker. You want the breaker to trip before you melt your connector.

Edit: Nevermind, I see you are using a 150A breaker in your mockup picture.

 

[MJSullivan56]

So this is the inverter I purchased for this project.
I'm wondering if I should now go with a 200A breaker together with 1/0 cable?

Giandel 2000W Inverter Review

 

[MJSullivan56]

Progress so far (waiting on the wire and connectors):

 

[MJSullivan56]

Ok, who here said I need at least 1/0 gauge for this project? This stuff is significantly bigger than anything that our ID.4s use. Not complaining but it does seem like overkill. I guess I can always claim bragging rights.