Cig Lighter watts / amps

[270S]

On a typical RV, what is the dash cigarette lighter fused at?
What is the most anyone has used it safely - without popping a cb or fuse? Where is the fuse for this item located?
Going to use (plug in) a small Inverter for minor 120Vac use while travelling.

[A32Deuce]

If you want to do that, then run a dedicated line for a 12 volt outlet with rather the proper sized fuse or a circuit breaker.

[Dan_M]

Watts = Volts * Amps (P=IV)

So, 12VDC, 20 Amp Fuse will give you 240 Watts.

[rsdata]

I think that most cig lighter fuses are 10 amps.

If you are going to do an inverter, you will be limited to about 100 watts without changing the fuse.

[babock]

Read the manual. There is no typical size.

If no manual , just look at the fuse in the fuse box.

[msm1827]

10 amp fuse. My leveler control is on the same fuse as the cig. lighter.

[rockfordroo]

I believe most vehicles use a 20 amp fuse for their 12VDC power plugs/cigarette lighters. At least all my GM vehicles do. I'd assume the same for RV's, but don't know.

Look in your fuse box and you'll know for sure.

[UT_Grandpa]

The fuse is only a minor component as to how much power can be drawn from a Cig lighter. Remember the fuse is there to protect the WIRING not the device. The smaller the wire, the smaller the fuse.

Generally speaking you should not try to draw more than 10 Amps (previously mentioned) from this outlet. The problem is the button on the end of the plug is normally Chrome plated and a poor conductor. It will heat up and perhaps melt the socket insulator.

I run an inverter from the one near the Murphy bed and pull about 9 Amps with no issues. Need more power than this? Run a fused connection to your battery or to your switch panel.

[A32Deuce]

Originally Posted by rockfordroo

I believe most vehicles use a 20 amp fuse for their 12VDC power plugs/cigarette lighters. At least all my GM vehicles do. I'd assume the same for RV's, but don't know.

Look in your fuse box and you'll know for sure.

Oops, assume will get you in trouble!

[A32Deuce]

Lighters may be 15 amp. Power ports maybe 20 amps. Any more amps then what the fuse is rated for will require heavier wire to feed the outlet.

[veepapa]

Yes 10 amps is what my Georgetown Xl is fused at. Also what I did was I used the same line and installed two more outlets on the dash, one on the passenger side and one more on the driver side. Keeping in mind that they are all good for 10 amps I use for my two GPSs and my Garmin road camera. All below 10 amps just a lot more convenient rather that having long cables all over the dash.

[270S]

Thanks all, I do electrical design and manufacturing, but I wanted to know what size the fuse is & where it is located vs a cloud electrical discussion. I'll track it down myself; I just thought I would ask if anyone knew because my RV is in the shop for a windshield leak and I do not currently have access to it for tracking it down.

Update, I tracked down an online copy of the F53 manual. Page 67 labels position 22 (under dash) as a 20amp CIGAR fuse vs Cigarette - that is why I missed it and had to ask - see first picture.

That's the answer I was looking for. 'hope this helps someone else. BTW, 20 amps means apx 264 watts may be pulled before the fuse will blow. However, knowing the RV industry the wire is more than likely undersized and more amps/watts will be drawn than should be by the load due to inefficiencies of the undersized wire. Just a pic (second one) from the webpage is here - see the webpage (FAQ - Wire sizing) to determine correct wire size for proper loading. It explains it all.

[Underdog]

The cig plug by the dinette in my Sunseeker must have such tiny wiring and/or poor contacts that it has a huge voltage drop with a 150 watt inverter and an inverter alarms and shuts down for low voltage. I never tried the cab cig lighter. I hard wired an 1100 watt inverter to the coach batteries and that will even power a coffee maker.

[wrapperman]

My cigarette lighter fuse was only a 7.5 amp. Had to replace it because I used a small 100 watt inverter. It is an inline fuse just a few inches behind the lighter itself. I pulled the front console panel to change it. You might be able to reach it from behind the console.

[babock]

Some inverters like mine have a tough time even starting up without a load through a cigarette lighter outlet. I have to start the engine up to overcome the voltage drop. All I charge are a couple Li batteries for my mountain bike.

[markb422]

I use a 120 watt pure sine wave inverter plugged into the 12 volt outlet at the antenna booster to power the TV and Direct TV receiver. The TV is 40 watts and the receiver is 60 watts. Works great. The booster amp and outlet is fused at 10 amps. 10 amps X 12 volts = 120 watts.

[McCormickJim]

My Georgetown 31L5 "cigarette lighter" socket is fused at 7.5 amps.

As stated by babock, "There is no typical size." You need to either LOOK at it or find it in your manual.

Reading your manual may help, but the manual for the 31L5 is generic and does not mention the fuse or its location.

The fuse on your unit may be like mine. Mine is not on a fuse block, it is an in-line fuse. To find an in-line fuse, look at the wiring for the 12v socket. The in-line fuse will be within 10 inches of the socket.

Here is how I found the fuse and the size; I got on the FR website and wrote a note to Customer Service on their provided contact form. I asked where the fuse block is located for the socket and which fuse is it on the block.

Instead of writing back, Customer Service CALLED me. Told me everything I needed to know and kept me a very happy customer. They even told me how to locate the in-line fuse and the amperage. The only thing they didn't know was whether the fuse is a glass or automotive fuse. I found the fuse exactly where they said it would be and replaced it. Yeah Forest River !!

[jimmoore13]

You likely have the right answer from other respondents, but, you truly need to familiarize yourself with the vehicle's owner's manual. You also NEED to know where all the fuse blocks are (most vehicles have several) and what's fused where. While you're at it, you NEED to know if you have spare fuses stashed in the fuse blocks, and you NEED to lay in a supply of spares...for your glove box or console storage. For $10 there's no reason to not have what you need: https://smile.amazon.com/s/ref=nb_sb...use+assortment


Once you've answered your question to your own satisfaction, then you can choose a small cigarette lighter-powered inverter, or you can step up to something more capable.
https://smile.amazon.com/s/ref=nb_sb...+volt+inverter Bestek and others have cigarette lighter-powered inverters up to 300 watts, but their power demands could exceed your cigarette lighter circuit's capacity. Once again, all in your owner's manual.

Ideally, you'll bite the bullet and install a truly adequately sized inverter powered directly from your vehicle's starting battery. Something in the 750 watts range will probably be the "Goldilocks" size (just right), and allow you to charge a laptop and run a couple of small devices while running down the road....and NOT require upgrading your alternator to accommodate the huge power consumption of a larger draw.

This handy-dandy calculator will help you understand the power demands on a 12 volt system imposed by a 750 watt, 120 volt draw - 62.5 AMPS per hour!! Allowing for inefficiencies in the inverter, that's more like 70 amps. Your stock alternator may struggle to keep up once you also add in other electric power demands such as headlights, running lights, electronics, stereo, and, and, and.

Voltage current resistance and electric power general basic electrical formulas mathematical calculations calculator formula for power calculating energy work equation power law watts understandimg general electrical pie chart electricity calculation
So, plug in 12 volts and 750 watts, and the calculator does the rest. You're using 12 volts (not 120) because that is the true source of your power...the battery.

Going back to your question, if you plug into the calculator 12 volts and 300 watts (largest cigarette lighter style inverter), you get 25 AMPS! That had better be one hell of a cigarette lighter!! More likely, you'll need to settle for a 150 or 100 watt inverter, and a good supply of replacement fuses, because you'll be on the ragged edge of what that cigarette lighter circuit will tolerate.



P.S. Today's vehicles often have several cigarette lighter sockets. Some are hot all the time, and some are switched. I have one in the fold-down console arm rest and two on my dash. Rest assured, not all cigarette lighter sockets are the same. The one in my MOVABLE console arm rest is very unlikely to be the right choice for ANY inverter. It's there to charge a device like a phone, not run a coffee pot. The one on my dash that is powered continuously would be a bad choice for an inverter, because if you leave a 25 amp draw powered up and running while you go in for lunch on the road, you might well need a jump start when you come out.

Investigate EACH cigarette' lighter's capacity for power delivery, and, IF POSSIBLE, choose the switched lighter socket for your inverter. This way, no dead battery surprises. If you hard-wire a larger inverter, you'd damned well better remember to turn it off when you turn off the engine, or you're walkin'!

[DSurette]

There are two accessory outlets on the dash of our Encounter. Each one is protected by a 5A fuse. I run a GPS and the TST507 TPMS on one and a dash cam on the other.

[270S]

If you've seen some of my earlier posts, my Class A is 100% off-grid capable. It has a 3Kw I/C, Solar, Gens, ... My original question was not about inverters, .... just the cig fuse size - btw, solved. I can turn on my large I/CX when moving if desired, but sometimes, I just want a small amount of 120Vac to power a pc or camera. 'didn't mean to open a can pf worms. If people would stick to the thread's subject and not digress, it may be less problematic for all. If you do not know, don't guess or suppose - that is not really being helpful.

Some of my other stuff and pic of fuses 20Amp in #22