# 2019 Subaru Outback 12V, Amps, Wattage, and Power Invertor **URL:** \ **Category:** Factual Questions\ **Created:** [October 23, 2020, 5:06am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651 "2020-10-23T05:06:59Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 23, 2020, 5:06am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/1 "2020-10-23T05:06:59Z")
Hello! I thought I could figure this out, but I need some help. I’ve purchased a 150w power invertor to run some LED lights (I’ve calculated I only need about 60w) through the cigarette lighter 12v power socket. I thought I was ok, but then I started reading that there are three 12v power sockets; one is 10a and the others are 20a. Can I use the 150w power invertor safely through the power socket (rated as 10a) in the front of my car without incident? Would it be safer to reconfigure the lights, so they’re all channeled to the 12v socket that’s 20a? I’m decorating for a drive-by Halloween parade and I’d prefer not to drive through on fire! Thanks! ---
**Author:** ![The\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_librarian/32/402_2.png) [@The\_Librarian](https://boards.straightdope.com/u/The_Librarian)\ **Post date:** [October 23, 2020, 6:10am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/2 "2020-10-23T06:10:26Z")
P = V\*A Power (in Watt) = Voltage (in Volt) \* Amperage (in Ampere) 150 W = 12 V \* ? A --\> ? A = 150/12 = 12.5 A The 20A sockets should do fine. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [October 23, 2020, 6:34am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/3 "2020-10-23T06:34:18Z")
But 150W is the _rating_ of the inverter, the maximum possible load. OP says the actual load is ~60W. So the current it’s drawing at 12V would be 60/12 = ~5A, or perhaps 6A allowing for inverter inefficiency. If the 60W estimate for load is reasonably accurate, the 10A socket will be fine. ---
**Author:** ![The\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/the_librarian/32/402_2.png) [@The\_Librarian](https://boards.straightdope.com/u/The_Librarian)\ **Post date:** [October 23, 2020, 6:41am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/4 "2020-10-23T06:41:39Z")
Pssst! ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 23, 2020, 4:24pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/5 "2020-10-23T16:24:14Z")
Thank you, Riemann and The\_Librarian! I hadn’t counted on having to take the amperage into consideration (well, actually, I wasn’t aware that I needed to), so I panicked a bit after reading a reference to it long after I had already set everything up. ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 23, 2020, 4:26pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/6 "2020-10-23T16:26:47Z")
Shhhh! ---
**Author:** ![iamthewalrus\_3](https://avatars.discourse-cdn.com/v4/letter/i/258eb7/32.png) [@iamthewalrus\_3](https://boards.straightdope.com/u/iamthewalrus_3)\ **Post date:** [October 23, 2020, 4:41pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/7 "2020-10-23T16:41:32Z")
LEDs run on DC and your cigarette lighter outputs DC, so a power inverter is going to be pretty wasteful, converting to AC and then something else (presumably the LED power supply) converting back to DC. You can likely get LEDs that run off of 12v input. You’d just need a plug that fit into the cigarette lighter. If you have LEDs that need some other voltage, you could just use something to step the voltage up/down and skip the DC-\>AC-\>DC conversion. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [October 23, 2020, 5:25pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/8 "2020-10-23T17:25:55Z")
True enough, if you were setting up some fancy permanent LED lighting for your car this is the right way to do it. But for a one-off Halloween parade, why worry about it. And a small inverter for a car is inexpensive and a useful thing to have (to charge a laptop, for example) so it’s probably better to spend a few bucks on this. ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 23, 2020, 10:58pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/9 "2020-10-23T22:58:44Z")
Indeed, as far as I can tell, this is the only time I’ll use the inverter. Although, these answers have brought up another similar question: when I was reading reviews of inverters on Amazon, several of them spoke about their purchases of 1000w or 1500w inverters that were capable of running multiple electrical appliances including small refrigerators. Is it possible that their cars’ 12v sockets are more than 20a? Not that I ever expect this scenario in my life – just curious. Thanks! ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [October 24, 2020, 12:31am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/10 "2020-10-24T00:31:25Z")
The 4Runner I used to drive had a 400W outlet, a small refrigerator would only be around 100W. I don’t have much knowledge beyond that. As to why people are buying 1000W+ inverters… it may be that the power rating is just indicative of a larger high-end inverter that’s efficient at a few hundred watts, rather than indicating any intention to use it near it maximum load. ---
**Author:** ![kanicbird](https://avatars.discourse-cdn.com/v4/letter/k/5f8ce5/32.png) [@kanicbird](https://boards.straightdope.com/u/kanicbird)\ **Post date:** [October 24, 2020, 2:16am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/11 "2020-10-24T02:16:14Z")
> [@Madam\_Librarian](#): > > Indeed, as far as I can tell, this is the only time I’ll use the inverter. > > Although, these answers have brought up another similar question: when I was reading reviews of inverters on Amazon, several of them spoke about their purchases of 1000w or 1500w inverters that were capable of running multiple electrical appliances including small refrigerators. Is it possible that their cars’ 12v sockets are more than 20a? > > Not that I ever expect this scenario in my life – just curious. > > Thanks! I got one to be able to run my furnace if power went out. (IIRC 1500W). No it would not be run off the 12V outlet, but clamped onto the battery. Now I may be able to run something like those 60W LED’s off if the 12V outlet, but that’s what I have the 150W inverter for. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [October 24, 2020, 3:21am UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/12 "2020-10-24T03:21:22Z")
Most of the wiring in your car is 5A. cigarette lighter sockets now often have dedicated wiring with a 20A fuse, any more than that would eventually blow the fuse and if the fuse was replaced with a nail 🙂 potentially burn out the wiring. Although the sockets aren’t really designed for very high currents, they aren’t specifically designed for only low currents either: the original application was a cigarette lighter, and those were hot, high current devices. The real limit is the wiring, which was never intended to be 1000W or 100A. Even a cigarette lighter was assumed to be off most of the time, giving everything a chance to cool down. ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 26, 2020, 5:44pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/13 "2020-10-26T17:44:18Z")
I wanted to share how I decorated my car, thanks to all of you! It was lots of fun on Saturday night – and I learned something about calculating amperage and that higher wattage power inverters should be run off one’s car battery, not from one’s cigarette lighter. Happy Halloween pictures: [Halloween Car! - Album on Imgur](https://imgur.com/a/Cu6DUcd) ---
**Author:** ![Cleophus](https://avatars.discourse-cdn.com/v4/letter/c/a88e57/32.png) [@Cleophus](https://boards.straightdope.com/u/Cleophus)\ **Post date:** [October 26, 2020, 6:54pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/14 "2020-10-26T18:54:37Z")
> [@Madam\_Librarian](#): > > Although, these answers have brought up another similar question: when I was reading reviews of inverters on Amazon, several of them spoke about their purchases of 1000w or 1500w inverters that were capable of running multiple electrical appliances including small refrigerators. Is it possible that their cars’ 12v sockets are more than 20a? These inverters are designed to be wired directly to the car battery and do not come with cigarette lighter plugs. ---
**Author:** ![Riemann](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/riemann/32/3133_2.png) [@Riemann](https://boards.straightdope.com/u/Riemann)\ **Post date:** [October 26, 2020, 7:01pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/15 "2020-10-26T19:01:19Z")
> [@Madam\_Librarian](#): > > Happy Halloween pictures: [https://imgur.com/a/Cu6DUcd](https://imgur.com/a/Cu6DUcd) That’s superb. So the skeleton is cooking in a cauldron inside a giant pumpkin, right? How did you get that effect of a translucent pumpkin so you can see the cauldron inside? ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 26, 2020, 10:11pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/16 "2020-10-26T22:11:24Z")
Aha! Ok, that makes sense. I did see some of them on Amazon with booster clamps, but they also came with all kinds of other goodies. I naively assumed they were similar to portable car jumpers. Thanks for putting them into context. ---
**Author:** ![Madam\_Librarian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/madam_librarian/32/3123_2.png) [@Madam\_Librarian](https://boards.straightdope.com/u/Madam_Librarian)\ **Post date:** [October 26, 2020, 10:28pm UTC](https://boards.straightdope.com/t/2019-subaru-outback-12v-amps-wattage-and-power-invertor/923651/17 "2020-10-26T22:28:03Z")
It’s actually two large lighted pumpkins up front and the cauldron with the skeleton in the back. **If you want all the boring details:** I took a thin piece of plywood-y stuff into which I drilled holes and then pushed little loops up through the holes created using zip ties. Then tied the pumpkins and cauldron down with fishing line and Velcro. A green LED light was placed in the cauldron along with the skeleton. Zip ties threaded through addition holes around the perimeter of the wood held the orange lights and leaves in place. Then, larger zip ties through strategically-placed holes lashed the wood platform to my roof rack. All lights were plugged into an extension cord in the cauldron that was fed through a small hole and down through a side window and into the cigarette lighter plug located under the armrest. It probably weighed less than twelve pounds, easy enough for two people to lift up to and down from the roof.