Power Inverter problems

[donnygs]

Hi all,

I am having a problem getting my laptop to charge in my work truck.

I am using:
-2011 Dodge Ram 3500 with a diesel engine. (Had the exact same problem with a 2010 Ford F-350 gas engine)

-Wagan Smart AC 120W USB Inverter (has a 3 prong outlet for my laptop cord to plug into)

-Samsung RV515 laptop

The problem I am having is the laptop wont charge (doesn't matter if the laptop is on of off) while the truck is running. But if I turn the truck off and rotate the key to the "Accessory" position it works.

My truck is equipped with a MTC (Medical Treatment Centre) which is basically a cap mounted in the bed that is used to transport and treat patients. I don't have any of the lights or heaters turned on in the MTC when I experience this problem.

So why does my laptop only charge when my truck is off?

Thanks all!!

[Mussels]

the voltage from the socket must be too low or too high, for the laptop charger to use.

[Sinzia]

That sounds more like an alternator issue... when its in the accessory position its running off the 12 volt battery, but when the truck's running its getting the power from the alternator.

[white phantom]

yeah defo far from a mechanic but i agree with what mussels n sinzia are both saying it sounds like a problem with the voltage getting to the socket when the trucks running since it works when the engines off rules out a dodgey socket

[donnygs]

hmmm... I like the idea of power coming from the alternator vs. coming from the battery. That must be it. It can't be the socket because I have 4 sockets to choose from in this truck, 3 sockets in the Ford and they all have the same result. The battery power must be different than the alternator power. I wonder how I can fix this problem...

[Mussels]

Originally Posted by donnygs

hmmm... I like the idea of power coming from the alternator vs. coming from the battery. That must be it. It can't be the socket because I have 4 sockets to choose from in this truck, 3 sockets in the Ford and they all have the same result. The battery power must be different than the alternator power. I wonder how I can fix this problem...

better altenator, or better inverter.

[Sinzia]

Alternators run around 14 volts, the battery's at 12 volts... that's why all car electronics have a power supply built in somewhere that will run from 11-14 volts.

Does something like a radar detector or some other piece of electronics work? nothing like a light, but something that's more complicated work? If not, then I'd have your alternator looked at.

[Mussels]

a better inverter might be the best solution, one that can handle the higher voltage while the alternator is providing power, smoothing it down for the laptops charger to handle it.


cheaper and easier than testing/replacing the alternator in multiple vehicles.

[Jstn7477]

Since it happens in 2 different vehicles, your power inverter's overvoltage protection circuit may be broken or out of calibration, causing the power inverter to shut down thinking the line voltage is too high. A fully charged (and unloaded) car battery usually has a voltage of about 12.8V, and the alternator outputs roughly 14V, depending on engine RPM and the amount of accessories or lights engaged. The power inverter should accept an input voltage of about 10-16V DC.

Are there any status lights on the inverter. For instance, when it works, is there a green light, and if there is a low battery/fault light, does that turn on when the power inverter fails to operate?

[donnygs]

I can charge my android cell phone multiple ways. I can charge my cell phone using a car charger and using the same inverter with the wall outlet charger that came with the phone. There is also a 2 prong outlet in the dash of this truck that will charge my cell phone no problem.

My buddy also charge its tablet PC directly from the 2 prong outlet in the dash.

I don't think there is a problem with my alternator since this happens in two completely different trucks.

Thanks everybody for the ideas

[donnygs]

sorry I didn't see the two last comments there. There is a blue light on my inverter. its blue when the truck is off and supplying power to the laptop and its blue when the truck is on and not supplying power.

I checked the fuse and its fine.

here are some stats on my inverter.

True-rated™ Power: 120W Continuous
Peak Surge Power: 300W
AC Voltage Output: 110V ± 5V AC RMS
USB Output: 0.5A
Optimum Efficiency: 90%
Input Voltage Range: 10V to 15V DC
No Load Current Draw: 0.15A
Low Battery Alarm: 10.5V ± 0.5V DC
Low Battery Auto Shutdown: 9.5V ± 0.5V DC
Cooling Fan: Yes
AC Outlet: Single
USB Power Port: Single
Net Weight: 3.4 oz (97 g)
Gross Weight (with adapters): 5.5 oz (156 g)
Dimensions: 2.8 in. x 3.7 in. x 0.8 in.
(7.0 cm x 9.4 cm x 2.1 cm)
UPC: 084367-02382-7

I think I agree with the census saying that I need a better inverter

[donnygs]

in my manual it says if the light is solid blue I have 120 watt of power source. If it is blue and blinking the power source is getting deprived. It's always been solid blue

[Mussels]

Originally Posted by donnygs

in my manual it says if the light is solid blue I have 120 watt of power source. If it is blue and blinking the power source is getting deprived. It's always been solid blue

doesnt mean it cant be outputting too high a voltage for the laptop brick to handle.

[donnygs]

ok I turned on all lights in the truck and in the mtc, have heat in the truck and in the mtc on. Radio is on. There is also a Motorola car phone and a Kenwood land mobile radio hardwired into the trucks power source. everything is on, Wouldn't that draw down my voltage A LOT?