Help with wiring in quick connectors to run portable compressor

[Draughon]

Scary that I’m doing this – but asking the greater hivemind as I am NOT an electrician and don’t want to start a fire under my hood.

Problem I’m trying to solve:

• Make electrical connections on my portable Thor’s Lightning approx. 4 feet longer for easier use.

Solution:

• Use a quick connect and permanently connect one end to battery.
• Attach perm connected end of the quick connector somewhere hidden either in the front bumper or grill for ease of use – that way I don’t need to have the hood up for air up / down.
• When I need to use the compressor, quick plug in and we’re good to go.

Questions:

• Thor’s Lightning sent me a quick connect kit – but the wire gauges are much much bigger than what my portable compressor uses – I believe the quick connections and wires are 6ga, and the alligator clips my compressor uses are more like 10ga (maybe 8ga?) . Will this mis-match in wires at the connector cause any foreseeable problems? Or should I just wire it up and send it?

It’s been recommended I put in an inline fuse – the compressor is rated for 90amps – should use a 120amp bladed fuse or do you think 100amps is enough for startup and heat? Also, it should be on the positive wire (indicated in the photo) – correct?

Photo

• B = path to car battery – 6ga wire
• C = path to compressor – 10ga (8ga?) wire
• X = where to cut alligator clips to crimp into connector
• 120 = approx. position of where to wire in inline fuse.

Does this look right and is it safe? Or should I be doing something else? The thought did occur to me to just open up the compressor and wire in some 8foot alligator clips but that seems daunting.

Compressor rating for reference:

What I'm trying to avoid is a repeat of something like this:

https://www.bronco6g.com/forum/thre...AE0Oza_Uv-_hMPFHKg_aem_jXXbDALBSo72dv30kgC6MQ

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[DuneRunner]

The difference in the wire gauge is fine in this application. The size of the load (how many amps you will draw) will determine the minimum wire gauge.
the picture you referenced is a bad install not bad components

if you want to use that connector to be able to plug in other things, you might like the flexibility of a 120 amp fuse. But don’t go larger than that on 6ga wire.
Couple of things you should always do

1. Have a fuse no more than 18” from the battery
2. Secure the wire feeding the fuse in a way that prevent shorts. I use hdpe cutting boards to make fuse holders and a safe spot to secure both sides of the wire. So if it comes loose of the holder it can’t move. They are cheap and easy to work with.
3. Put a switch and relay on your feed after the fuse. This will let you de-energize the connector for service or prevent shorts from water, etc.


you got this!

Post a picture when you done

 

[SierraBronco]

Am I reading this correctly? 90 amps through 10gauge? It seems you misread the cause of our fire. We have settled on the cause being a loose set screw connection. All the wiring was more than rated for the draw of our compressor. Remember-fuses are used to protect the circuit, your wires, not the device.

Look up the ampacity for 10G wires.

 

[SierraBronco]

The difference in the wire gauge is fine in this application. The size of the load (how many amps you will draw) will determine the minimum wire gauge.
the picture you referenced is a bad install not bad components

if you want to use that connector to be able to plug in other things, you might like the flexibility of a 120 amp fuse. But don’t go larger than that on 6ga wire.
Couple of things you should always do

1. Have a fuse no more than 18” from the battery
2. Secure the wire feeding the fuse in a way that prevent shorts. I use hdpe cutting boards to make fuse holders and a safe spot to secure both sides of the wire. So if it comes loose of the holder it can’t move. They are cheap and easy to work with.
3. Put a switch and relay on your feed after the fuse. This will let you de-energize the connector for service or prevent shorts from water, etc.


you got this!

Post a picture when you done

120amp fuse on 6g???

 

[Draughon]

If I'm understanding you correctly, the fuse should be on the 6ga positive wire (at the top of the photo) rather than the smaller wire below?

And no, this will be purely dedicated to the compressor, nothing else will be using this - so maybe 100amp fuse is fine?

Can you give me a link or example of what you're talking about here and where it should be wired in?

" Put a switch and relay on your feed after the fuse. This will let you de-energize the connector for service or prevent shorts from water, etc."

Thanks in advance!

The difference in the wire gauge is fine in this application. The size of the load (how many amps you will draw) will determine the minimum wire gauge.
the picture you referenced is a bad install not bad components

if you want to use that connector to be able to plug in other things, you might like the flexibility of a 120 amp fuse. But don’t go larger than that on 6ga wire.
Couple of things you should always do

1. Have a fuse no more than 18” from the battery
2. Secure the wire feeding the fuse in a way that prevent shorts. I use hdpe cutting boards to make fuse holders and a safe spot to secure both sides of the wire. So if it comes loose of the holder it can’t move. They are cheap and easy to work with.
3. Put a switch and relay on your feed after the fuse. This will let you de-energize the connector for service or prevent shorts from water, etc.


you got this!

Post a picture when you done

Scary that I’m doing this – but asking the greater hivemind as I am NOT an electrician and don’t want to start a fire under my hood.

Problem I’m trying to solve:

• Make electrical connections on my portable Thor’s Lightning approx. 4 feet longer for easier use.

Solution:

• Use a quick connect and permanently connect one end to battery.
• Attach perm connected end of the quick connector somewhere hidden either in the front bumper or grill for ease of use – that way I don’t need to have the hood up for air up / down.
• When I need to use the compressor, quick plug in and we’re good to go.

Questions:

• Thor’s Lightning sent me a quick connect kit – but the wire gauges are much much bigger than what my portable compressor uses – I believe the quick connections and wires are 6ga, and the alligator clips my compressor uses are more like 10ga. Will this mis-match in wires at the connector cause any foreseeable problems? Or should I just wire it up and send it?

It’s been recommended I put in an inline fuse – the compressor is rated for 90amps – should use a 120amp bladed fuse or do you think 100amps is enough for startup and heat? Also, it should be on the positive wire (indicated in the photo) – correct?

Photo

• B = path to car battery – 6ga wire
• C = path to compressor – 10ga wire
• X = where to cut alligator clips to crimp into connector
• 120 = approx. position of where to wire in inline fuse.

Does this look right and is it safe? Or should I be doing something else? The thought did occur to me to just open up the compressor and wire in some 8foot alligator clips but that seems daunting.

Compressor rating for reference:

What I'm trying to avoid is a repeat of something like this:

https://www.bronco6g.com/forum/thre...AE0Oza_Uv-_hMPFHKg_aem_jXXbDALBSo72dv30kgC6MQ

Am I reading this correctly? 90 amps through 10gauge? It seems you misread the cause of our fire. We have settled on the cause being a loose set screw connection. All the wiring was more than rated for the draw of our compressor. Remember-fuses are used to protect the circuit, your wires, not the device.

Look up the ampacity for 10G wires.

 

[Draughon]

The alligator "direct to battery" clips are much thinner (than the separate 6ga quick connect wiring kit) and came wired into the compressor that Thor's Lightning sells - the compressor is rated at 90amps, so assuming that's fine since it's their product.

Am I reading this correctly? 90 amps through 10gauge? It seems you misread the cause of our fire. We have settled on the cause being a loose set screw connection. All the wiring was more than rated for the draw of our compressor. Remember-fuses are used to protect the circuit, your wires, not the device.

Look up the ampacity for 10G wires.

 

[DuneRunner]

Am I reading this correctly? 90 amps through 10gauge? It seems you misread the cause of our fire. We have settled on the cause being a loose set screw connection. All the wiring was more than rated for the draw of our compressor. Remember-fuses are used to protect the circuit, your wires, not the device.

Look up the ampacity for 10G wires.

My point was the multiple paths for wringing combined with an install that allowed for a dead short on the unfused leg is a bad install.

 

[DuneRunner]

@Draughon i am traveling this week so I can’t send you pics of my install, but the guys at car audio fabrication on YouTube have done great videos on wiring, I will try find something specific and post here

 

[Draughon]

I'm very open to doing this safely and correctly - if anyone can draw me a "idiot proof" diagram I can use to create this please let me know!

 

[SierraBronco]

The alligator "direct to battery" clips are much thinner (than the separate 6ga quick connect wiring kit) and came wired into the compressor that Thor's Lightning sells - the compressor is rated at 90amps, so assuming that's fine since it's their product.

Why do people so often avoid shit they don’t want an answer to? Must we learn the hard way that these companies don’t give a shit and will cut corners to save a couple bucks?

 

[Draughon]

Thanks! That would be a huge help.

@Draughon i am traveling this week so I can’t send you pics of my install, but the guys at car audio fabrication on YouTube have done great videos on wiring, I will try find something specific and post here

 

[Brian_B]

It’s another case of manufacturers not following ampacity charts inside the black box of their product. They can get away from it because (presumably) they test their product and can prove that the wire doesn’t overheat or break under their rated use conditions. Sometimes those conditions are very specific and not what people do in the real world though.

Wire gauge has to deal with both amps and distance (voltage drop).

In this particular application, I would cut those alligator clip leads back as close to the compressor as you can work with. #6 sounds reasonable for a under hood installation — I would go #4 if you are running back to the tailgate though. Fuses at 120A sounds about right too.

Those pins on the connector are fine so long as you get the crimps done well and correctly. Usually there is a special crimp tool: if you don’t have that I would solder the wiring in. They do make connectors like that for #6, although I would recommend just using a terminal bolt style distribution block with crimped ring lugs — it still connects and disconnects easily (with a wrench) and is much more secure and less prone to issues / more bullet proof. Those crimps are hard to do correctly and get harder with bigger gauge wire.

Did you have a relay in here for the switch, or using an actual 100A switch?

@DuneRunner has a great post.

 

[DuneRunner]

120amp fuse on 6g???

It will vary by length but I can’t imagine a reason to run the connector more than 4ft away from the battery
https://jascoautomotive.com/automotive-wire-amperage-capacity-chart/

 

[SierraBronco]

It will vary by length but I can’t imagine a reason to run the connector more than 4ft away from the battery
https://jascoautomotive.com/automotive-wire-amperage-capacity-chart/

Right. And the thing you shared shows a max suggested current of 30 amps at 7.8 ft. So let's say 40 amps through four feet?

5 AMPS	10 AMPS	15 AMPS	20 AMPS	25 AMPS	30 AMPS

10g 46.8 ft 23.4 ft 15.6 ft 11.7 ft 9.4 ft 7.8 ft

 

[Brian_B]

It will vary by length but I can’t imagine a reason to run the connector more than 4ft away from the battery
https://jascoautomotive.com/automotive-wire-amperage-capacity-chart/

Yup. Distance plays a big part in automotive wiring, since the voltage is so low. Copper can carry a lot of current, and if you can keep the runs short, that keeps the internal resistance low (which is what causes them to heat up and fail).

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