15 amp fuse for accessory socket

[shermanc]

My spouse has a power converter for mobile work; it's output is 120V AC, for a laptop. When plugged into the "accessory socket" (which routes thru slot/fuse 3, 15 amp), the fuse has blown twice in about 2 months. The power converter unit recommneds "auto fuse, 20 Amp". Is it safe to use a 20 amp fuse in slot 3, if it's only powering this device?

 

[ziddey]

Obviously at your own risk, but it'll probably be fine. As it is, 15A is already extreme for a laptop.. What model? Perhaps better to get a DC-DC charger for it.

 

[shermanc]

Obviously at your own risk, but it'll probably be fine. As it is, 15A is already extreme for a laptop.. What model? Perhaps better to get a DC-DC charger for it.

It's a "power inverter", that provides a place to plug in a regular 120-volt plug (that powers a laptop power supply). There's a 20-amp fuse in the back of the unit, as well.

 

[mrplt]

12V battery, 15A fuse, you'll blow out the fuse at ~180 watts.
How many watts does the laptop charger draw? Are you sure the power inverter is working properly?

It's a "power inverter", that provides a place to plug in a regular 120-volt plug (that powers a laptop power supply). There's a 20-amp fuse in the back of the unit, as well.

The 20-amp fuse on the back of the unit won't do anything in this case, as the 15A fuse will blow first. Do NOT swap the 15A fuse with a 20A one, as the wiring behind that fuse probably is probably not suitable for 20A.

 

[shermanc]

12V battery, 15A fuse, you'll blow out the fuse at ~180 watts.
How many watts does the laptop charger draw? Are you sure the power inverter is working properly?

The 20-amp fuse on the back of the unit won't do anything in this case, as the 15A fuse will blow first. Do NOT swap the 15A fuse with a 20A one, as the wiring behind that fuse probably is probably not suitable for 20A.

Any ideas on how to prevent the 15 amp fuse from blowing again? Power supply for laptop (HP) is 65W. Power inverter (Tripp-Lite) is 150W.

 

[mrplt]

Any ideas on how to prevent the 15 amp fuse from blowing again? Power supply for laptop (HP) is 65W. Power inverter (Tripp-Lite) is 150W.

So the inverter is rated at 150W but it can do 300W peak (I don't know how, as 12V*20A = 240 watts is the maximum it can do without tripping the internal fuse)
If there are other devices connected to the same fuse, they might be going over 15 amps combined.
Otherwise, I don't see how a 65-watt charger can pull more than 180 watts, even instantaneously. So I wouldn't blame the charger.
It's possible that the inverter for some reason pulls more than 180 watts for a split second (could be a capacitor issue, bad connection etc.) Although very unlikely, it could be because the 12V plug (or the 110V one) isn't fully plugged, acting almost like an open circuit.

 

[ziddey]

Any ideas on how to prevent the 15 amp fuse from blowing again? Power supply for laptop (HP) is 65W. Power inverter (Tripp-Lite) is 150W.

Perhaps better to get a DC-DC charger for it.

 

[theblooms]

They make lighter socket laptop adapters. That way you don't need to use an inverter. Go that route.

 

[shermanc]

The power inverter being used is supplied by the employer, who also owns the laptop, so I'm sure it's not allowed. Just need a way to make this setup work, w/o blowing the fuse.

 

[mrplt]

They make lighter socket laptop adapters. That way you don't need to use an inverter. Go that route.
View attachment 312372

This makes much more sense than an inverter. I don’t see why it would be mandatory to use an inverter instead of a charger like this. I’m not surprised that it blows a 15A fuse with the inefficiency here. 12V DC to 110V AC, then back to ~12V (depends on the computer) DC.

 

[theblooms]

The power inverter being used is supplied by the employer, who also owns the laptop, so I'm sure it's not allowed. Just need a way to make this setup work, w/o blowing the fuse.

There's no way that it's not allowed. Not gonna happen.