3amp accessory fuse on 12V Trunk Outlet - Higher amp fuse? - Please Advise.

[groundeffect]

I have a question.


I'm in the garage and noticed a tire is slightly below the recommend psi.

I connected a 12V air compressor to the 12V outlet in the truck, which is connected to the accessory 3-amp circuit.

With my Spyder off, the power is still going to the air compressor. Once I turned the 12V air compressor on, I heard a click, checked, and sure enough, the 3amp fuse in the front fuse box had blown. Clearly the air compressor I have pulls more then 3amps. I did check the model and documentation on it before hand, but no mention of amperage draw anywhere that I've looked.


I will be getting a replacement 3amp fuse for the one I've blown. However, I do have 5amp, 7.5amp, 10amp, 15amp, 20amp, 25amp and 30amp spare fuses here between what I have in my garage, and the spares on the backside of the cover of the front fuse box.



I DO NOT want to damage anything on my Spyder, but I was thinking of using a higher amperage fuse just to get my tire psi back up to spec.
My Question: If you temporarily use a 7.5amp, 10amp, or 15amp fuse in the accessory circuit in the front fuse box, will it damage anything on my Spyder?


Also, what determines the fuse limit on the circuits coming from the front fuse box? The size/limitation of the wires? Please advise.

Thank you.
Dean

 

[ataDude]

I have a question...

Fuses are generally sized to protect the wiring. I would not personally up the fuse on the stock outlet.

 

[MarkLawson]

Dean,

An alternate plan might be to either rewire the existing power plug straight to the battery with an in-line fuse (of your choosing), or add a second power plug that is wired straight to the battery. Either way, make sure your wire is sufficient to carry the load you need.

 

[retread]

Plan on an additional fuse block, where you can pick and choose what your requirements are. Most 12V compressors pull at least 5 amps, and something like Evoluzion's power buss or Eastern Beaver's PC-8 will give you a lot of leeway.

john

 

[NancysToy]

I agree that the best way to do this is connect the compressor to the jumper terminal under the seat, a battery charging pigtail (with the right connector), or another power outlet, properly wired and fused. An auxiliary fuse block like the Evoluzione, PC-8, or Centech is the best way to add extra wiring, beyond a simple, fused pigtail attached doirectly to the battery. Many small compressors, like the Slime, have a variety of attachment terminals.

The switched accessory circuit is fused at 3 amps to protect the 20 gauge wire. There are those that say DC wiring at 12 volts will take more amperage, but there are no commonly accepted DC standards, so the mandated AC rating of 3 amps is usually used. If you go larger, I would do it on a temporary basis only, while you are standing there, and I wouldn't go larger than 5 amps. There are some charts that say it could handle 10 amps, but who wants to take the chance of starting an electrical fire?

 

[groundeffect]

Ok, thanks for the comments, guys.

For the time being I'll wire something up outside the Spyder electrical system to get me by with powering my air compressor.

I will be wiring my GPS and Hot Hands directly to the battery at some point very soon - but both will have their own separate fuses, in-line. I may go to the powerbus solution later on if I need to add something else.

Cheers guys.
Dean

 

[groundeffect]

The switched accessory circuit is fused at 3 amps to protect the 20 gauge wire. There are those that say DC wiring at 12 volts will take more amperage, but there are no commonly accepted DC standards, so the mandated AC rating of 3 amps is usually used. If you go larger, I would do it on a temporary basis only, while you are standing there, and I wouldn't go larger than 5 amps. There are some charts that say it could handle 10 amps, but who wants to take the chance of starting an electrical fire?

Absolutely, great points, Scotty, as always, thank you.

I DO NOT want to risk fire, so I'll stay away from upsizing a fuse in this case.

A newbie like me appreciates the comments and direction.

Thank you again!
Dean

 

[NancysToy]

Absolutely, great points, Scotty, as always, thank you.

I DO NOT want to risk fire, so I'll stay away from upsizing a fuse in this case.

A newbie like me appreciates the comments and direction.

Thank you again!
Dean

I wouldn't worry if 5 amps will run your compressor, and you are not going to put anything bigger into the outlet, or anything for long, unattended periods. You could probably even get by with more amp draw for short periods, but this is tiny wire. Be careful of attaching too many things directly to the battery. Every extra terminal is a place for corrosion to start...and the screw length is limited, as is the space.

 

[groundeffect]

I wouldn't worry if 5 amps will run your compressor, and you are not going to put anything bigger into the outlet, or anything for long, unattended periods. You could probably even get by with more amp draw for short periods, but this is tiny wire. Be careful of attaching too many things directly to the battery. Every extra terminal is a place for corrosion to start...and the screw length is limited, as is the space.

Thanks, Scotty.

Every extra terminal is a place for corrosion to start...and the screw length is limited, as is the space.

The terminal ends on both my GPS and Hot Hands wires are pretty thin and I do not think it will be an issue, for these two items.

Actually, it is a perfect day for installing them, today. I'll get to it!
Cheers.
Dean

 

[Trickie Dick]

Why don't you just bite the bullet and install a fuse block and be done with it. That way you take care of your GPS. Hot hands and everything else. There is only so much room on those battery posts. IMO.

 

[WackyDan]

3 amps in 12volt circuit is 36 watts. Think about that.

5 amp would be 60 watts.

You'd have to go to a larger fuse than those to power a compressor.

Not a good idea to up the fuse size at all. You do not know what is downline on the circuit. Is it on a relay? Maybe... What is the relay rated for?

You are best off using the pigtail for a battery tender straight to your battery for a compressor.

Long term, yes think about a fuse block... Which you might need depending on future mods.

 

[bjt]

.......There are those that say DC wiring at 12 volts will take more amperage, but there are no commonly accepted DC standards, so the mandated AC rating of 3 amps is usually used. If you go larger, I would do it on a temporary basis only, while you are standing there, and I wouldn't go larger than 5 amps. There are some charts that say it could handle 10 amps, but who wants to take the chance of starting an electrical fire?

I found this and it seems like a very valid explanation.

The short answer is: the same if measured as amps RMS. Since AC current or voltage literally cycles between positive and negative, a current or voltage measurement value changes from moment to moment from its peak positive to its peak negative value and back again. The most common terms used in measuring voltage or current are peak, peak to peak, and RMS. Peak voltage or current is the maximum either positive or negative value while peak to peak is double peak values. RMS stands for Root Mean Square, a scary term but it can be thought of as a DC equivalent. An RMS voltage or current is peak voltage divided by the square root of two, or approximately 1.414.
Most AC voltage or current values are stated in RMS, here's an example. Normal United States house voltage is 120 volts AC RMS. This means the voltage actually swings from nearly 170 volts positive to 170 volts negative, or 340 volts peak to peak! A 100 watt, 120 volt light bulb draws just under one amp of current, 0.8333 amps RMS. You could use a 120 volt DC power source to run the same 100 watt bulb and it would still use 0.8333 DC amps.
Peak and peak to peak voltage and current measurements are important when dealing with electrical parts or component limitations. A part rated for 120 volts RMS can actually handle an instantaneous voltage of nearly 170 volts peak for example.

 

[MarkLawson]

I have a Slime compressor & haven't yet tried to use it. I have installed a couple of Gerbing heated clothing leads with 15 amp fuses. Seems like they would be a logical power source for mine...

 

[QuadManiac]

Although heating the wire and the potential for fire is an issue at the higher currents, another problem to be aware of is that of voltage drop.

Voltage drop is a function of the current passing through the wire times the resistance of that wire. Wire resistance is a function of the wire's length and diameter - smaller gauge wires have higher resistance per unit length than larger gauge wires. The longer the wire and the smaller the gauge, the higher the voltage drop will be across that wire - high current passing through a relatively long, relatively small gauge wire can result in a significant voltage drop.

Since the small gauge wire of the accessory socket has relatively high resistance, when passing higher than specified currents through these wires the voltage available at the socket will be somewhat lower than that suppled by the battery - sometimes too low for the accessory being used to operate properly.

 

[jgwoods]

I added a PC-8 fuse panel, go the one with the longest leads and wired from the battery to right up behind the instruments. I had them put the diode in the switched power wire so it never feeds back to the Can Am wiring in any way. To that I added my GPS, heated gear, and voltmeter. SO far so good.
It is easy to pop out the instruments and there is plenty of wire to draw out the fuse panel for additional work or adding more stuff, but most importantly I have not disturbed the Can Am wiring in any way so there can't be any warranty issues.

 

[groundeffect]

Thanks for the informative and suggestions, everyone.
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