12v Outlet

[Comodave]

Originally Posted by tpbrady

Look at a trolling motor socket and connector. They can handle the amperage and waterproof.

Tom

Good idea. Since I don’t fish I never thought about that.

[Bacchus]

I put one similar to this before we did an extended cruise where we would be "off grid" much of the time. Worked great for phone, tablet & laptop charging w/o the need for an inverter but that is still possible if desired or needed (most laptops have 12V chargers as an accy)
https://www.amazon.com/Blue-Sea-Syst...a-887099168800

[O C Diver]

Cigarette lighter sockets would be my last choice for devices needing amperage. What you want to use are Anderson Power Pole connectors.

https://www.andersonpower.com/us/en/...urcesPage.html

They come in a number of different sizes, have silver plated copper contacts, and are self wiping when you put them together.

Figure out what connector size and wire size you want. Then Google them to find a number of different vendors that sell them. They're really not expensive, and are a far superior design. A light spray of the contacts with Corrosion X or similar product would be advisable.

Ted

[jclays]

Originally Posted by Comodave

He was talking about 12 volts not 120. So at12 volts, 350 watts is 29.1 amps.

The load on the inverter is 120v ac.
12v powers the inverter to convert 12v to 120 v. What do you fuse for? The Ac load or the Dc supply?

[C lectric]

Originally Posted by jclays

10a fuse should be fine. 350 watts is only 2.92 amps correct? The inverter is maxing out at 350 watts divided by 120v = 2.92 amps

NO, the inverter is using 12VDC to run itself and then produce 120V AC. What you have calculated is the output amps at 120VAC, NOT the input at 12VDC

That means the inverter will draw 350 W / 12V= 29.2A at 12 Volts. Actually to run itself at full tilt it will need about 10% -15% more power so in fact it will pull about 33.54 A DC.

Be very carefull about understanding how you do the conversions or you will have trouble.

I agree with OC Diver about the Anderson plugs but also the suggestion of using a trolling motor plug/receptacle at about 40A. ampacity. I am another that didn't think of these untill I started poking about the Marinco site.

[jclays]

The inverter is itself fused with a 40 amp fuse. Do I need to fuse the positive wire (12v) from the battery?

CORRECTION… inverter is a 300 Watt inverter.

[C lectric]

I would definitely do that. If you leave the battery wire to the inverter unprotected then any chafe or damage could result in a short circuit.
In fact the battery is the far more dangerous power supply.

[Comodave]

Originally Posted by jclays

The inverter is itself fused with a 40 amp fuse. Do I need to fuse the positive wire (12v) from the battery?

CORRECTION… inverter is a 300 Watt inverter.

Absolutely. What C Lecteic said. Most boat electrical fires are DC related.

[Bacchus]

Originally Posted by jclays

The inverter is itself fused with a 40 amp fuse. Do I need to fuse the positive wire (12v) from the battery?

CORRECTION… inverter is a 300 Watt inverter.

Absolutely. Fuses should be placed close to the source to protect wiring. Fusevat equip protects the equipment but can allow a short in supply wiring that's can cause a fire. Best to review & try to follow ABYC wiring reqmts for DIY projects.... generally much safer and frequently an insignificant cost premium.

[TowLou]

If a high amp 12v pull maybe convert to anderson connectors for a good dedicated power source?

[jclays]

Installed the cigarette lighter outlet in my cockpit.
Used 8ga wire(have a bunch) for the 6ft run. Fused 20a resettable inline breaker. Should be fine for my purposes.

[J0k3r]

Just my $.02, I would look at using something other than a cigarette lighter socket. Anderson make mountable sockets for their powerpole connectors in various sizes.

eg. https://powerwerx.com/panelpole-pane...e-black-single

That website has a lot of other options and is not the only source.

[TowLou]

What is the fuse size?

[gilbertpark]

Why not make life simple - find a 12v charger for your computer. I have one for my MacBook that works really well. Forget the inverter. Yes you will need a socket of some sort - I use a "cigarette lighter" socket fused to 10A. Gilbert

[High Wire]

To plug in your 300 watt inverter, first the 300 watts is the 120 VAC output of the inverter steady state. 300W divided by a guestimated 80% efficiency gives you about 375 watts of input DC needed to run the thing. Divide that by 12.0 volts is 31.25 amps DC. That's the MINIMUM I would size the DC wiring for if this is a permanent install. I would round up to 40A DC for the wiring. You can always size the fuse smaller. You have to take into account the entire round trip wire distance of the circuit. You said 15 ft from the source battery? The positive 15 ft and negative 15 ft would be 30 ft number for the ABYC table. 30 Ft at 40 amps at the 3 percent voltage drop (electronics) would be #4 gauge wire!!! An acceptable alternative for your laptop might be to use # 6 gauge and fuse it for 25 Amps DC, or #8 wire fused for 15 Amps DC. 15 Amps DC should be plenty for your laptop as long as no one plugs in a vacuum cleaner or blender. If they do then the fuse blows preventing turning the wires into a glowing bulb filament.

All of this sizing is explained the the back pages of the Blue Sea Systems Marine catalog.
And no way would I used a cigarette lighter plug/socket. They get hot pulling 10 amps.

[koliver]

Originally Posted by gilbertpark

Why not make life simple - find a 12v charger for your computer. I have one for my MacBook that works really well. Forget the inverter. Yes you will need a socket of some sort - I use a "cigarette lighter" socket fused to 10A. Gilbert

I have used a small inverter plugged into a cig lighter socket as the power supplier to my laptop for 20 years or more without issue. The incverter is quite small, probably smaller than the one the OP is planning to use, and has an on board fuse prominently displayed on its front.

I once decided to bypass the inverter by wiring a DC plug to my laptop directly, but an unforseen polarity difference caused it to burn up the wires attaching the GPS to the computer at one of the USB ports. Once the smoke has been let out of any electronic part, it is no longer functional, so once I had paid to replace the burned up USB to serial connector I was down a ways on that experiment and abandoned it. I returned to using the small inverter and have stayed with that system.

[Capt Ray]

I have two of these 2+ years going great in the weather on our boat.

https://www.amazon.com/Scanstrut-Cha...dp/B071WXWS9C/

ROKK Charge - Scanstrut - Amazon

Weatherproof even with "stuff" plugged into it.

IMHO: This company really needs to look at their marketing efforts because it does NOT come up when google searching or even searching on Amazon for this tpe of thing. But, once I found it and bought it, it is working well for us. Recommended.



12vdc to this device, two USB out in a weather proof enclosure.

Fuse with 3 amp and go one wire size larger (e.g. 14 AWG) than shown below.

[Jeff F]

Originally Posted by jclays

Good morning

I will be installing a 12v cigarette lighter style outlet in the cockpit area of my Mainship 350. I will mostly use it to plug in a 350 watt portable inverter. I can run my laptop when on the hook and also run my Christmas lighting when underway.

Should I fuse the positive leg to the battery?

How should I calculate the fuse size?

Thanks

Jim.

Why not add a 110v outlet instead? You have a house inverter, right?

[backinblue]

I think 30A would melt most cigarette lighter outlets. I use something similar to this for my laptop. Note that it has a USB outlet as well so I can plug in my phone at the same time.

https://www.amazon.com/Outtag-Univer...xpY2s9dHJ1ZQ==

[MVDarlin]

IMHO it is best to locate inverter as close to battery as possible. DC current does not perform well over long distance. An alternate option is to locate a battery next to the point of use inverter to handle demand surge. Connect to your DC systrm with a dc to dc charger.

Recomnend you go with bigger inverter snd conect it to your entire AC system so you can run all appliances. Blue Sea sells an AC source switch with 4 positions. Off, Shore, Gen , Inverter.