question about 12V power inverters & laptops

Only inverter I have ever used was the ones that plug into a cigarette lighter.You get what you pay for so I suggest don't buy the cheapest.Also don't buy it at a trk stop.I get mine at Walmart.They have like 3 different styles.

 

My guess is he put a much larger fuse in. That could cause a fire.

 

and your guess would be wrong.

never tampered with the system. just plug and go.

thjat walmart invertor had a gauge. it displated dc input volts. output wattage and ac volts. the meter never got higher then 180 watts with everything running. and that was with laptop being charged while being on.

most times the laptop was already charged. or turned off while being charged. so wattage would be less. printer only goes on when actually being used. so it's mostly turned off. tablet doesn't pull much and never leaves the outlet so it's always charged.

that only leaves the fan at night. and tv and satellite. when i'm awake.

 

Why not make one of the criteria for choosing a company to hire with be that their trucks have APU and inverter?? Then trying to figure voltage/amperage won't matter. And you can have a microwave and refrigerator.

 

I'm a sucker for over kill, I bought a cobra 2500 watt back in 99' never had any issues, ran everything from refrig, microwave, laptop, phone charger, I sold it Sept. of last year, and now heading back over the road, So went on line with Amazon, got a new cobra 2500 for 165.75 total, brand new, The new one I got has a USB port as well as 3 sockets, ordered it on Monday, the 1st, it was hear Wednesday the 3rd

 

A non gamin laptop pulls around 60-90 watts dc. After double conversion, it is at most 150watts. Now a gaming laptop will pull much more, but normal non dedicated graphic card laptops are relatively efficient. A small flat screen tv can use as little as 30 watts. Printer and fan doesn't use much. Your probably pulling less then 200 watts out of that 400 watt inverter. If you are using the full 400 watts, you must have replaced the fuse with one to big to be safe.

 

In most trucks, anything over 1500 watts is a waste. Lets do the math:

Depending on brand, your truck has an alternator that supplies between 100 and 200 amps at PEEK. Even at fast idle (1000 rpm) the alternator is only supplying half that. Depending on design and belts, most hit peek around 1600 engine rpm. So at fast idle we have a max of 100 Amps to work with. 100 Amps @ 14 volts is only 1400 watts. Now, inverters are rated at DC output and are generally 80% efficient. Now we only have 1120 watts to work with. The truth is, your 2500 watt inverter would have given you a brown out long before you ever got near 2500 watts.

Your fridge prob pulled 20 watts (more on start up). Microwave pulls around a 1000 when in use, depending on model. Phone charger is almost nothing and laptop pulls a max of 150 assuming it not a gaming laptop.

Now you may think the batts will save you, but consider this: Traditional starter batts are not designed to be drained repedialy. They are designed to discharge power quick, but not for long. You might get .5 kwh of useable storage. This means if your inverter was maxed out you would kill the batts to the point of not starting the truck in 12 min. Now lets assume you went out and bought some real nice AGM batts. You may have 2kwh of useable storage. Now you can run your 2500 watt inverter at max for about an hour, but the recharge will take a long time of running the truck. Truth is, a 2500 watt inverter is useless unless you have AGM batts that can support it. Even then, what do you have that will use that much power?

 

never used 400 watts. and NEVER changed the fuse.

the laptop charger says 65 watts wide range input. 100 volts @ 1.7 amps. output is 18v. @ 3.5 amps.

i don't think i've ever seen the walmart meter pass 235 watts.

but here's a question. what good would it do to change the fuse anyways>??????. I'D THINK THE HARBOR FREIGHT 6 FOOT EXTENSION WOULD MELT THE TRUCK DOWN. OR THE SOCKET PLUG and wiring on the invertor. cuz neither wiring is very thick.

 

My point.....changing the fuse is DANGEROUS and stupid. It asking for a fire. The wiring in your truck would fry to. Anyways, originally you said 400w and i didnt do the math to see your draw. Clearly you would be fine with a 200 watt inverter since you wont get much more then that out of the cigaret lighter anyway. Im glad you did not change your fuse so you get 400 out of your 400 watt inverter because thats asking for a fire.