Adding 12v accessory (cigarette) outlets

DaveInDenver

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Gee, pretty affordable too.
So Dave, how would you size them?
I don't have my NEC book with me, so I'd only be able to guess. But if memory serves (and see the Monday night radio thread to judge my memory), I wouldn't have guessed 1/0 cable to be good to 300A for any sort of length. So I'd probably fuse the battery side to limit the current through those cables to around that, probably something like a 250A time delay.

FYI, read following at risk of headache.

The code approaches fusing differently. You calculate the load, take some margin factor and size the fuse. Then you use cable sufficiently sized for that fused load. So you'd need to know the stalled motor current for your winch plus anticipated load and that will give you a value. My guess is the stall current is gonna be like 225A (around 4.25HP stalled) and so I would take 150% of that value plus the expected continuous loads like ECU, ignition, radios, etc. at 125%. So say 330A + 20A = 350A. I would use a regular blow fuse. If you have electric fans, I would call those a continuous load during wheeling, so take their max current at 125%. You can take non-continuous loads at 100%, so headlights for example could be included at 100% of max.

But I'm almost 100% certain 1/0 cable can't safely take 350A+ over 20 feet. So I would fuse at the 40C capacity for 1/0 and deal with nuisance tripping. I can get back to you with the ampacity of 1/0 for different ambient temps and insulation types tonight or tomorrow.
 

Red_Chili

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I am running about 10' of fine braid welding cable (copper), one per battery hot, to the engine bay. Winch usage would be the highest load. You know what, I keep saying 1/0 but there ain't no stinkin' way it is only 8.25mm in diameter. I gotta check that. :doh:
 

DaveInDenver

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I am running about 10' of fine braid welding cable (copper), one per battery hot, to the engine bay. Winch usage would be the highest load. You know what, I keep saying 1/0 but there ain't no stinkin' way it is only 8.25mm in diameter. I gotta check that. :doh:
It all depends on the insulation. Flipping through the Coleman Cable catalog, looks like 1/0AWG, 1064-stand, CPE-insulation welding cable is rated to 260A using the NEC method (90C conductor temp, 40C ambient). I'd probably use a 200A or 225A Bussman ANL (#2024). They should tolerate <300A for winch pulls but will melt in few seconds above 400A.

http://www.colemancable.com
 
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Hants

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Ok, Dave, now you have me a bit worried.

I'm planning to run 1/0 fine-strand, tinned cable for my winch. Stall is 440A. Stock, it comes with 2 gauge cables.

Should I be running 2/0 instead (less than 10' total circuit length)? I figured 2 sizes larger would be sufficient.

Are they really delivering barely-within-ampacity cable?
 

Red_Chili

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I run the cable that came with my winch. Meh.
 

DaveInDenver

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Ok, Dave, now you have me a bit worried.

I'm planning to run 1/0 fine-strand, tinned cable for my winch. Stall is 440A. Stock, it comes with 2 gauge cables.

Should I be running 2/0 instead (less than 10' total circuit length)? I figured 2 sizes larger would be sufficient.

Are they really delivering barely-within-ampacity cable?
I'd be very surprised if they really drew >5kW. It might be 440A at some seriously depressed voltage. With the engine running and assuming a voltage dip to 12V, I'd expect more like ~250A tops going into a regular 8,000 or 9,000 lbs winch. Maybe a 15,000 lbs winch with a monster motor could be looking at those kind of currents. Measure the winding resistance, that's what you need to find the true stall current of a DC motor is. If they rate the motor at 4.6HP, that is at the max torque and by definition that will be stall speed at zero RPM. That 4.6HP is 3.43kW and at 12V you are looking at 286A. Wire sizing also needs to capture how long the expected current is going to happen and temp rise. The cables are cold at ambient, say 25C, and will work for a few minutes and cool down again. It's different than if a 5HP motor is working constantly in a steel foundry...

If Warn is using 2AWG cables, it's for just a few feet and I bet the insulation is 105C. I would personally run one size bigger cables from the engine bay battery and that's mostly so I could use 90C insulation (but if the cables they give you are long enough, use them). For Bill's installation the length of the wires would concern me from a voltage drop and heating at full current standpoint, but size-wise 1/0AWG itself wouldn't bother me much with fuses at the batteries. If you are being conservative, go ahead and assume the engine is dead and you are doing a dead pull, the battery is depressed to 9V and it's a full current pull. That's 3.4kW/9V = 377A. What am I missing to get 440A? Are these motors series or shunt (or maybe compound) wound? If they are true series wound, there can be significant current through the stator, but that's not proportional and should be constant. I wouldn't expect that to be very high, what 30A, 40A? There's a point where the battery is too flat to energize the field and so it won't matter how much current you have in theory, the motor will not operate anyway.
 
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Corbet

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Did you installed switched and non-switched power to the fuse block? I also like the idea of the circuit breaker (I assume in lieu of a fuse?).

Everything is wired hot all the time. The circuit breaker also works like a master switch if need be. I thought about doing some circuits ignition switched, but realized 90% of everything I would ever want to add would be just fine always on. So I followed the KISS theory.
 

Hants

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Corbet

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Old thread but logical place to add this.

After 15 years with the Engle fridge plugged into my rear 12v cigarette style outlets I purchased a larger National Luna fridge last year. Ever since I’ve had issues with it tripping the low voltage protection and turning off.

The National Luna came with a Hella style 12v plug which I hate and the Blue Sea outlets hate them too. It wouldn’t even stay plugged in. So I ordered Equipt’s in-house made cord with a more traditional style 12v plug. That stayed in the outlet but I started having this voltage issue.

Voltage always tested fine on the meter so it had to be an amperage issue. I dove into the circuit last week and found this inside the plug.

IMG_8592.jpeg


The spring that keeps pressure on the positive pin of the plug has obviously seen some heat and I’m assuming arcing. So I ordered up some Anderson Powerpole connectors and got to work today with the install.

IMG_8647.jpeg


So far everything has been working as it should. These connectors “click” in and are rated to 30 amps with the pins I installed.
 

DaveInDenver

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Did the same, 100% agree it's the better way. I ended up wtih a single cigar outlet (handy for a USB adapter, so I left it) and two doubles like you used in back, fuse block behind and had Kurt send me the replacement cord from an Engel MT60.

IMG_2356_mid.png


IMG_2350_mid.png
 
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