Ag_F150

I am searching for an inverter to buy for a truck. My girlfriend puts LED Christmas lights on her truck during the month of December. Last year was the first year we had troubles where the lights went out or dimmed. I checked the strands, which were physically undamaged and the fuses were good. The 12 volt plug works with other units (like GPS), and those fuses are fine as well. Last year we tried replacing the inverter, and this worked for a little bit until the second strand of lights dimmed. I guess I have a few questions.
1. What could have been the problem last year- inverter, truck plug, or lights?

2. We got 2 strands of lights that are rated at 8.4 volts. How many watts should the inverter I get be rated for in order to get the lights to work? Do I even need to get a new inverter?

Any advice would be greatly appreciated.

chickenwire

I'm no EE, but here goes.

Assumptions. You're running an inverter to take your 12 volts DC to 115 volts AC.

You meant the LED strings are 8.4 WATTS not VOLTS. (Most 70 LED strings are 4.8 watts, not 8.4 watts). But in this case 16.8 watts divided by 120 volts = .14 amps. You're not going to tax any inverter out there at only .14 amps. (this is why you're told you can string a bajillion LED strings together.)

I suspect the issue you have is the inverter you are using. LED's can be very picky, are polarity dependent, etc. Many inexpensive inverters use a "modified sine wave" frequency that can cause LED's to wig out. A "true sine wave" inverter should work.

I discovered some of this with an in-wall timer switch for my outdoor Christmas lights. Worked fine for the old miniatures. When I plugged LED replacements in last year, some would like fine, others wouldn't. You need to check for "LED compatible" or the true sine wave.

chickenwire

Also be sure to remind your girlfriend that in many states blue lights are illegal (reserved for emergency vehicles in Michigan, for example.) If she's burning the lights while driving and a cop wants to do so, he/she can pull her over and ticket her.

chickenwire

Why not just buy 12 vdc LED lights?

Ag_F150

Chickenwire, your assumptions were right, I probably got side tracked while I was typing. Thank you for your help on this one. I'll have to look at the 12v dc lights. She just likes the Christmas lights just for the season, i think the 12vdc lights are too permanent for our situation.

Thanks again!

chickenwire

Dude - the 12 vdc lights are about as cheap at the 120 vac. Drop 20 bucks into them and be done with it!