Dumb automotive question

[Grant Lamontagne]

I have this really great tire pump for filling up truck tires but it has one significant problem- it keeps blowing the fuse in my Jeep.  I pumped up two tires today and blew my last two 20 amp fuses.  This thing is also known for blowing fuses- if you read the reviews for it you see a bunch of people complaining about it:

http://www.canadiantire.ca/AST/browse/4/Auto/AutoTools/AirPumpsCompressors/PRD~0095079P/Heavy-duty+Air+Compressor.jsp?locale=en

I have another compressor that I keep in the car but it takes longer to fill a small car tire than this "Red Monster" takes to fill a 30" Jeep tire.

So my question is this- can I (safely) replace the 20 amp cigarette lighter fuse with a 30 amp one?  Will there be any significant problems if I do?  I also use the 12V plug for my cell phone, laptop, inverter and occasionally a roof light that I should always use at work but rarely do.  If I change the fuse will it cause problems for any of them?

When it comes to electricity I'm pretty clueless.  I can do anything straightforward, but if I venture off the path I'm probably going to need my fire extinguisher.

Def

[jerseydevil]

I don't think that would be a good idea, boss.  You're risking a fire doing that.  The wiring leading to the fuze wouldn't be rated for 30 amps, and you risk a meltdown.  I'm not 100% certain of this, but I'm pretty sure.

[stressmaster5000]

I don't think that would be a good idea, boss.  You're risking a fire doing that.  The wiring leading to the fuze wouldn't be rated for 30 amps, and you risk a meltdown.  I'm not 100% certain of this, but I'm pretty sure.

I gotta agree with JD here about the wiring being rated and potential meltdown and fire thing happening. A pretty straightforward go around would be to run a wire right from the battery and use an inline fuse holder to power that pump. Just make sure everything on that line is rated for 30 amps, ie the power socket and any other attachments you would use.

[Grant Lamontagne]

You guys make it sound like a car fire is a bad thing.... 

Thanks for the info- I bought a couple more 20's today when I was out and replaced it with a 20 so I'm safe for now. 

My other plan was to use a household 12V adaptor I have- I can plug in an extension cord, then the adaptor and the compressor into that, and if I trip a breaker in the house it's a lot easier to reset than it is to pull the glove compartment out of the Jeep each time.

Def

[jzmtl]

Those 110 to 12 v adapter typically don't put out more than 10 amps, make sure yours can supply enough power.

[Santos]

I don't think that would be a good idea, boss.  You're risking a fire doing that.  The wiring leading to the fuze wouldn't be rated for 30 amps, and you risk a meltdown.  I'm not 100% certain of this, but I'm pretty sure.

I gotta agree with JD here about the wiring being rated and potential meltdown and fire thing happening. A pretty straightforward go around would be to run a wire right from the battery and use an inline fuse holder to power that pump. Just make sure everything on that line is rated for 30 amps, ie the power socket and any other attachments you would use.

Generally auto wiring has a safety margin in it... like if it has a 10 amp fuse then its probably a 15a wire. The fuse needs to be considerably weaker to guarantee it goes... not the wire. Also the wire usually is of all the same thickness in the loom as its more economical ie you have 10 amp fuse but the wire is the same as 15 amp fuse. From experience generally its not good to exceed the highest rated fuse in the fusebox not counting the headlights (eg in my case 15)

I think stressmaster is spot on. Just get sump heavy gauge autowire at an electronig store coupled with some aligator clips and inline fuse (25/30A) and run it straight from the battery, if away from civilisation remember to do it with the

You can also get resetable blade Fuses, i've been meaning to get one in 10A & 15A for trouble shooting electrical faults on the trail. Blowing 15 fuses or more to find an earth leak to get you home isnt really eco friendly... even if i get 100 plus fuses for under $10 of the on the resetable fuse. No need to run all that expensive equipment from the home power point

Another cool idea is the Endless Air set up, basically a engine driven compressor, many convert them out of aircon units but their is a commercial one available. If you got room amongst your aircon, power steer and alternator for one more cylindrical accessory it is ideal. doesn't take up cargo space, always there and lives the electricity for the battery.

Lastly try filling up the tyres OFF the vehicle. If the fuse sometimes blows its probably just the strain from the weight pushing on the tyre. Jacking up the vehicle like you would change a tyre fill it up, rinse and repeat. I dont know what type of jack comes with the jeeps but my suzuki has a time consuming scissor jack so i keep a second small hydrolic bottle jack from a comercial van (think it was mitsibishi) which is rated at 2t and is not much bigger than 600ml coke bottle.


wohooo i spelt tyre with a y.... how british   

[turnsouth]

I don't think that would be a good idea, boss.  You're risking a fire doing that.  The wiring leading to the fuze wouldn't be rated for 30 amps, and you risk a meltdown.  I'm not 100% certain of this, but I'm pretty sure.

Exactly correct. Fuses are used in automobiles to protect the wiring, and this has never been more important than in the last 20 years. The main reason being is that the auto makers use the minimum amount of conductor in the wire to save money, this not only reduces production costs (number one importance) but it also reduces weight (for fuel mileage). So if a circuit is rated at 20 amps it likely has only a 10% tolerance above that.

A good example of this is the Ford speed control deactivation switch recall of the last few years. What happens is that the hydraulic pressure switch in the brake system starts to leak, which in itself isn't the big issue, most electro/mechanical switch eventually fail, the problem comes because the brake fluid creeps though the wiring into the cruise servo and creates low resistance which blows the fuse. Now normally an automotive company could care less about an issue like this, at least for a car out of warranty, but what was happening was that customers were putting larger fuses in the circuit which basically turned the whole segment of wiring into a 12 volt heater. And of course enough heat + hydraulic fluid = fire. Had to rewire a few of them that had burned down.

[badwolf]

As already mentioned and what I've done with mine, is to wire directly to the battery with its own 30amp fuse. My current and previous vehicles cigarette lighter sockets use 30amp rated fuses and my compressor ran fine with no problems but I just wanted it wired permanently. My compressor came with jump and cigarette leads. This is the one I have

Mine is not this noisy, I think its vibrating on the chair


ps. So, don't upgrade the fuse in the cigarette socket, do connect directly to the battery with its own 30amp fuse

[turnsouth]

I thinking that what you need is a proper upgrade:



 

[Grant Lamontagne]

I thinking that what you need is a proper upgrade:



 

That thing is sweet, but would probably double the value of my Jeep! 

Ok, so I got the message loud and clear that putting a bigger fuse in is a bad thing.  I won't do that.

But, it leads me to think about another project I had in mind, and that's to wire in a few other 12v sockets since I usually want to plug in more than one thing.  If I understand you all right then it should be fine as long as it's a) independent of the current cigarette lighter wiring and b) has heavy enough wire to handle additional power.

Would that be an accurate assumption?

Def

[AimlessWanderer]

Sounds good to me. I'd pull it straight from the battery if possible. I would also put a fuse holder in with a larger fuse rated for the cable and total socket consumption, then secondary fuses for each socket. Check the ratings of the sockets too, I've been caught out with beefing up everything bar the socket itself before. If you need to shop around for higher rated cable, make sure you get multi-strand and not simple 7 strand (lots of fine copper not a few thicker bits) or you'll end up with breaks and overheating as the cable is subject to vibrations

The next week link in the chain would be the supply, ensuring your alternator is rated above maximum socket consumption if you are using these with the engine running, or looking to include a split charging relay and leisure (deep cycle) battery with suitable capacity elsewhere in the vehicle if you want to use them without the engine going. Flat batteries aren't fun  You're probably not going to want to replace your alternator, so just make sure you're not setting up to pull 100A at the sockets with only a 35A alternator 

[AimlessWanderer]

Also ... if you're thinking of running high amp power from the front to rear of the car, increase the sizes of the cables further. Lost voltage over the distance will heat the cables, increasing the resistance, heating them more ..... It depends on the actual distance travelled as you weave the cable through wherever it needs to go, but there are guide charts available online which tell you what size cable to use, for what amps, over what distance.

Google 12v marine systems cable selection (or something similar) and you should find what you need. If not, drop me a PM with what you need it to do (and which system Canada rates cables on - CSA or SWG etc) and I'll give you a hand 

[turnsouth]

If I understand you all right then it should be fine as long as it's a) independent of the current cigarette lighter wiring and b) has heavy enough wire to handle additional power.

Would that be an accurate assumption?

Def

Yes, just make sure that the fuse you use is rated somewhat below the capacity of the wiring.

Some other considerations:

• If you add a pre-made "bank" of lighter sockets check the individual rating of each outlet. While something like that may be rated at say 40 amps for four outlets, the manufacture might have come to that number by designing it at 10 amps per outlet
• Always check the duty cycle of the accessory you have plugged into the power outlets, some are not meant to run too long. I've seen where a fellow plugged in his compressor to fill his air mattress, and came back 30 minutes latter to find the cord he had draped across his leather seat had burned right through the cover...

[turnsouth]

Also ... if you're thinking of running high amp power from the front to rear of the car, increase the sizes of the cables further.

Good point .

[AimlessWanderer]

If you add a pre-made "bank" of lighter sockets check the individual rating of each outlet. While something like that may be rated at say 40 amps for four outlets, the manufacture might have come to that number by designing it at 10 amps per outlet

... and you might see something like 10A per socket but 25A overall due the common components not being rated for operating all sockets at capacity. This is similar to what I'm suggesting if you go for individual sockets in different areas - one fuse per socket, but another fuse/breaker for the lot. Breakers are easier as you if you do trip it by running too many sockets at capacity at once, just push a button and you're back up and running 

[turnsouth]

Breakers are easier as you if you do trip it by running too many sockets at capacity at once, just push a button and you're back up and running 

Yes, a push button, or one that will not reset unless the load is removed from the circuit.

The automatic self resetting breakers, while convenient keep trying and trying to reset -- wires get warm -- trying and trying -- wires get hot -- trying and trying -- insulation begins to melt -- trying and trying -- smoke -- trying and trying -- flame...

[AimlessWanderer]

  I bet Grant's brain feels like that right now 

[Sparky415]

I agree with everything everyone above has said 

Now check if the compressor has its own inbuilt fuse?
If it has....
Cut the cigaret plug off the lead, strip the wires back a bit and connect up to man sized crock clips
Then clip straight on to the battery terminals 

You can sort out your wiring another day 

[Grant Lamontagne]

I agree with everything everyone above has said 

Now check if the compressor has its own inbuilt fuse?
If it has....
Cut the cigaret plug off the lead, strip the wires back a bit and connect up to man sized crock clips
Then clip straight on to the battery terminals 

You can sort out your wiring another day 

I think the fuse is built into the cigarette plug.

Def

[turnsouth]

Something you can do Boss, if you are not going to need the outlet on a permanent basis, is along the lines of what Terry and Al have said. You could get a heavy duty marine outlet, add a nice length cord to it with alligator clips and an inline fuse. This way it can be as long and as heavy duty as you want, then when you are not using it you can roll it up and keep it in your tool box.

Handy if you need power outside of the Jeep too

[Sparky415]

Something you can do Boss, if you are not going to need the outlet on a permanent basis, is along the lines of what Terry and Al have said. You could get a heavy duty marine outlet, add a nice length cord to it with alligator clips and an inline fuse. This way it can be as long and as heavy duty as you want, then when you are not using it you can roll it up and keep it in your tool box.

Handy if you need power outside of the Jeep too

+1 Sorted 

[Grant Lamontagne]

Something you can do Boss, if you are not going to need the outlet on a permanent basis, is along the lines of what Terry and Al have said. You could get a heavy duty marine outlet, add a nice length cord to it with alligator clips and an inline fuse. This way it can be as long and as heavy duty as you want, then when you are not using it you can roll it up and keep it in your tool box.

Handy if you need power outside of the Jeep too

That is more or less what I was planning, only I figured I would mount the plug inside the Jeep somewhere.  In fact, I'd sort of planned to do a few of them like that, only not alligator clipping them, but wiring them directly to the battery.

Def

[Carlos]

Getting back to the original problem, here's my take: you have 20amp rated fuses that blows at a given point, but you have a considerable amount of runtime both before that happened and after (with the new fuse, of course). This indicates your compressor has a sustained current consumption under 20A, with sporadic higher peaks.

Here's two choices to consider:

1. use slow-blow fuses instead of normal ones. Slow fuses can take more current than the rated one, but only for a small fraction of time. They are used on equipments that operate under a given consumption, but has short higher peaks, which seems to be the case of your compressor. Microwaves usually carry these kind of fuses also.

Having said that, I don't even know if there are slow-blow fuse versions for what you want (I don't know that much about cars  ).

2. the other option is to consider a 30A rated car UPS (uninterruptible power supply): you connect the lighter to the UPS input, and the compressor to the UPS output. The UPS will drain normally from the car outlet, but when the current demand increases, it uses its internal batteries and capacitors to feed that extra supply (only for a short period).

[Grant Lamontagne]

Well I tried running the Jeep while filling up the third tire today (got two done yesterday before I ran out of fuses!) and there wasn't an issue.  Now it's too small a sample size to consider it a definite result, but it is promising.

Def

[Chako]

I wouldn't even be playing with this at all. Def, upgrade to a standalone garage air compressor with a tire gauge fitting at the end of an air hose.

http://www.canadiantire.ca/AST/browse/6/Tools/1/CompressorsAirTools/Compressors.jsp

Pack a few fuses with your portable fuse eater for emergency only situations.

[Grant Lamontagne]

The funny thing about garages is that they have this funny way of not being handy when you aren't at home.  I like to be more or less prepared wherever I go, which is why I have this quiet fascination (no one really knows this so please don't tell anyone) with Swiss Army Knives and multitools.

Def

[Santos]

In fact, I'd sort of planned to do a few of them like that, only not alligator clipping them, but wiring them directly to the battery.

Def

Just be mindful that a power leak can occur with this set up even with nothing connected, at very least have a manual operated battery isolator switch inline of this set up.. If you want to get fancy google dual battery circuits (the can work even with 1 battery)

[turnsouth]

Just be mindful that a power leak can occur with this set up even with nothing connected...

This won't be a issue if the outlets are installed correctly

[Santos]

Just be mindful that a power leak can occur with this set up even with nothing connected...

This won't be a issue if the outlets are installed correctly

yeah but some one who asks if he is allowed to use 30a fuses instead of 20A is guaranteed for 100% workmanship 

Canada is cold, you want to give a cranking battery every chance  can get, any bit of moisture seeping along the circuit is enough to cause a power leak. Even with it 100% correct a isolator switch is a recommended failsafe. 

[Grant Lamontagne]

Ok, now I'm thinking I may as well just put a lightning rod on the roof and only pump up my tires during a storm...

Def