Craig Maire II
I've noticed that even though I've recently purchased a new power inverter for my car when I use it to run my laptop I've been blowing fuses? Has anyone else had trouble like this and if so is there anything that can be done about it?
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Eric Whitehill
EF1
You might have a short somewhere, or you are overloading your electrical system. If you are popping fuses left and right, that's not good.
Most people hook their inverters up directly to the battery with a good ground. That eliminates many of the problems. Obviously, there is an inline fuse to prevent you from doing anything too bad or starting an electrical fire.
How much stuff do you have plugged into the Inverter? If you have a microwave and blender and hair dryer, yeah, you're going to blow it.
Typically, if you have a 400 watt inverter, you can plug your laptop (sans battery) into the inverter through your cigarette lighter without a problem. Once you start putting more than that, you can easily start to blow fuses.
HTH.
Most people hook their inverters up directly to the battery with a good ground. That eliminates many of the problems. Obviously, there is an inline fuse to prevent you from doing anything too bad or starting an electrical fire.
How much stuff do you have plugged into the Inverter? If you have a microwave and blender and hair dryer, yeah, you're going to blow it.
Typically, if you have a 400 watt inverter, you can plug your laptop (sans battery) into the inverter through your cigarette lighter without a problem. Once you start putting more than that, you can easily start to blow fuses.
HTH.
cdcollura
EF5
Good day,
There are three possibilities...
1). The inverter might be defective (possibly) or there is a short somewhere.
2). The laptop uses an exceptional amount of power (Sony Vaio can use 250 watts for example with that big "brick" power supply).
3). The fuses are not rated for the consumption (in watts) ... To find amps, take watts and divide by 12 volts.
For example, look on the power supply "brick" for your laptop computer. You should see the power consumption (in watts) on it, with voltage anywhere from 100 - 220 v.
The key here is the power, in watts. This is assuming 120 volts in, so 250 watts is about 2.2 amps. This is ohms / watts law (watts = voltage x amps).
The inverter is converting 12 volts to 120 volts. To get 250 watts out at 120 volts (2.2 amps), you need 12 volts in at 22 amps. I'll also add another 3 amps for heat dissapation, so at least 25 amps at 12 volts in is required.
Most cigarette lighters have 10 - 15 amp fuses. A 300 watt inverter does NOT put out 300 watts continuously. It pulls more current from the car battery depending on how much is plugged into it!
I would reccomend finding the fuse for the cigarette lighter and upgrading it to 20 amps (or even 30) ... I would NOT reccomend any more.
A final solution would be to set a dedicated 12 volt line straight from the car battery (if permanent). My HAM radio, car speaker audio amp, and inverter all use a dedicated 50-100 amp "monster" cable (with large inline fuse at tap of + battery terminal). The negative is vehicle (metal) ground. No cigarette lighter plugs here ;-)
I hope this information is useful...
There are three possibilities...
1). The inverter might be defective (possibly) or there is a short somewhere.
2). The laptop uses an exceptional amount of power (Sony Vaio can use 250 watts for example with that big "brick" power supply).
3). The fuses are not rated for the consumption (in watts) ... To find amps, take watts and divide by 12 volts.
For example, look on the power supply "brick" for your laptop computer. You should see the power consumption (in watts) on it, with voltage anywhere from 100 - 220 v.
The key here is the power, in watts. This is assuming 120 volts in, so 250 watts is about 2.2 amps. This is ohms / watts law (watts = voltage x amps).
The inverter is converting 12 volts to 120 volts. To get 250 watts out at 120 volts (2.2 amps), you need 12 volts in at 22 amps. I'll also add another 3 amps for heat dissapation, so at least 25 amps at 12 volts in is required.
Most cigarette lighters have 10 - 15 amp fuses. A 300 watt inverter does NOT put out 300 watts continuously. It pulls more current from the car battery depending on how much is plugged into it!
I would reccomend finding the fuse for the cigarette lighter and upgrading it to 20 amps (or even 30) ... I would NOT reccomend any more.
A final solution would be to set a dedicated 12 volt line straight from the car battery (if permanent). My HAM radio, car speaker audio amp, and inverter all use a dedicated 50-100 amp "monster" cable (with large inline fuse at tap of + battery terminal). The negative is vehicle (metal) ground. No cigarette lighter plugs here ;-)
I hope this information is useful...
Cris Schroeder
EF2
I have a 400W inverter that I use to power my laptop (or did, before it died; haven't tried the new one yet). The instruction manual notes that the 400W is only available if wired directly to the battery, which supports what Chris posted above...the current draw is too high for the cigarette lighter.
Oddly enough I can run the inverter from two of the three cigarette lighter jacks in the van. The third jack blows the aux fuse almost instantly with the inverter, but nothing else. It wouldn't hurt to check the connections on the jack to make sure you don't have dirty contacts or a short somewhere. I would be uncomfortable running a higher capacity fuse after looking at the wiring behind the jack.
Oddly enough I can run the inverter from two of the three cigarette lighter jacks in the van. The third jack blows the aux fuse almost instantly with the inverter, but nothing else. It wouldn't hurt to check the connections on the jack to make sure you don't have dirty contacts or a short somewhere. I would be uncomfortable running a higher capacity fuse after looking at the wiring behind the jack.
Roger Brown
EF0
More info would help narrow the problem down. As the other posters have stated, you have a short, or you are pulling too much current. How many watts is the inverter rated for (max, and continuous)? How many watts or amps is the device you are using need? How big is the fuse that is blowing? How far away from the battery is the outlet and what gauge wire supplies it (voltage drop)?
Chris, you may be experiencing voltage drop on the third outlet, since two others seem to be ok.
Roger
Chris, you may be experiencing voltage drop on the third outlet, since two others seem to be ok.
Roger
Robert Edmonds
EF5
I'm actually going to be trying this season to not use my inverter. Most laptops you can find a dc outlet adapter for, so I purchased one for my laptop. The GPS and WXWORX I use already have such adapters. I believe this will draw less power. Since I also carry a power pack (it's for a telescope, basically a battery with DC outlets), I hope to extend how long I can use this battery so I don't have to be near an outlet in a town or keep my car on so my battery doesn't drain (for when I'm sitting around waiting for the cap to break). With the inverter it would usually only last 2-3 hours, I believe I should now be able to get this to last much longer. I have to wait and see it will be here in about a week.
Anyhow, this may help if you're drawing too much power.
Anyhow, this may help if you're drawing too much power.
Are you blowing the fuse in the inverter, or a car fuse?
If it's a car fuse, then I'd suggest a direct connect like Eric mentioned. Otherwise, if it's the inverter fuse, then you need a bigger inverter.
The only thing I use an inverter for anymore is an emergency recharge of something. As far as my laptop and accessories, I've switched over to DC for all of them. I have a fused direct connect to the battery that I ran to the back of my vehicle which I then split out for my radios and inverter, and then a DC line for my laptop.
-John
Craig Maire II
Thanks for the replies! I will provide more info about my laptop and power converter tomorrow but I can say that it's the fuse in my car that keeps blowing.
Paul Knightley
EF5
I use a 350 watt inverter with a 240V UK output plugged into the power socket - I then plug a 4-way adapter in it, with vid cam, dig cam charger, and laptop plugged in...never had a prob with it.
Alan Broerse
EF2
fuses.wires and inverters
I use the cigarette lighter for my converter...the wires are gauged for at least 30 amps...and fused for the same......it runs a laptop and continuous charge video cam....not all power ports can boast that claim....as far as the ham radio, TV station VHF radio, siren/P.A. sytem and weather station display...they are direct wired with quick disconects from an 8 gauge copper wire to the battery.....I keep at least 1 powerport open for cell phone dedication....and 1 free as a backup........no problems blowing fuses.
I use the cigarette lighter for my converter...the wires are gauged for at least 30 amps...and fused for the same......it runs a laptop and continuous charge video cam....not all power ports can boast that claim....as far as the ham radio, TV station VHF radio, siren/P.A. sytem and weather station display...they are direct wired with quick disconects from an 8 gauge copper wire to the battery.....I keep at least 1 powerport open for cell phone dedication....and 1 free as a backup........no problems blowing fuses.
Tim Samaras
Guest
- Joined
- Dec 16, 2003
- Messages
- 173
Craig:
You've provided a key piece of information--blowing the fuze in your car.
Problem with running inverters from your (assumed) power outlet on the dash, is that the wire isn't likely heavy enough to handle the large current draw these inverters put out.
The difference is that the voltage drop across the wires causes the inverter to draw more current at a lower voltage. It has to-if you plugged in an appliance that ran 100 watts--thats .85 amps at 117 volts AC....or 8.3 amps at an assumed input voltage at 12.0 volts (also assuming a fictional 0% power loss through inverter which is impossible). Now, if the wiring dropped the DC voltage to 10.5 volts, the current goes UP to 9.52 amps (assuming the inverter maintains 117 volts at load).
Chris, and others have suggested a good hard-wired approach to wiring up these inverters..and this is ultimately your solution. If you're uncomfortable doing it...a competent car stereo shop can help you out. Just be sure you unplug all your goodies at the end of the day...or your battery will be dead the next morning of that hot moderate risk day.
If you choose this....ENSURE you have an in-line fuse NEXT to your battery (very important...DON'T locate this fuze downstream from the battery)! If not, you will have an excellent formula to start your car on fire.
Hope that helps!
Tim
You've provided a key piece of information--blowing the fuze in your car.
Problem with running inverters from your (assumed) power outlet on the dash, is that the wire isn't likely heavy enough to handle the large current draw these inverters put out.
The difference is that the voltage drop across the wires causes the inverter to draw more current at a lower voltage. It has to-if you plugged in an appliance that ran 100 watts--thats .85 amps at 117 volts AC....or 8.3 amps at an assumed input voltage at 12.0 volts (also assuming a fictional 0% power loss through inverter which is impossible). Now, if the wiring dropped the DC voltage to 10.5 volts, the current goes UP to 9.52 amps (assuming the inverter maintains 117 volts at load).
Chris, and others have suggested a good hard-wired approach to wiring up these inverters..and this is ultimately your solution. If you're uncomfortable doing it...a competent car stereo shop can help you out. Just be sure you unplug all your goodies at the end of the day...or your battery will be dead the next morning of that hot moderate risk day.
If you choose this....ENSURE you have an in-line fuse NEXT to your battery (very important...DON'T locate this fuze downstream from the battery)! If not, you will have an excellent formula to start your car on fire.
Hope that helps!
Tim
David Drummond
Member
Tim is 1000% right on this. This is the only proper way to run any inverter without potential issues aside from maybe those little tiny ones.
