12V DC to 110V AC Inverter on boat- Safety risk if wet or too hot in sun?

[Jordan22]

I'm looking at plugging in a splitter on the DC cigarette lighter outlet next to the captain's chair (see on Amazon here).

From there, Im then thinking of plugging in a DC to AC inverter (see on Amazon here) which would allow for more USB outlets and "regular" 110V AC plugs if/when needed.

I'm not an electrician (far from it) so wondering if there are any risks with doing this. If the inverter happened to get soaking wet while in use, could that cause a risk of someone getting shocked? Or, what if the inverter is in direct sunlight for a long time on a hot day while in use. Could that cause a risk of a fire? What about the risk of killing the boat battery by trying to draw too much power?

Appreciate any input or alternative methods to get additional outlets for power on the boat to charge phones, pumps and other devices when out for a long day on the boat.

[Nick55]

I get what you are trying to accomplish but I don’t think it’s really feasible.  Big boats often have inverter/charger systems to run outlets and appliances off batteries for a short time without running the generators, but the outlets are always in the cabin and on GFCI circuits as well.   That’s not really possible on a small boat and 120V can kill with low amperage.  I wouldn’t mix 120v and water myself.  Even marine inverters aren’t ignition protected so they can’t be installed where fumes are possibly present, including batteries.  I would rather build a relay circuit that is switched to control multiple USB charging outlets placed out of splash zones on the boat, and leave the 120V appliances at the shore. Also, I’d consider going with USB-C outlets instead of A or B sized.  Consider Rokk wireless chargers too if possible.  I’m putting one in my drivers cubby and one in my glovebox this winter.

[MLA]

16 hours ago, Jordan22 said:

which would allow for more USB

This, I dont understand. USB is DC and you can buy duel USB charge ports that will replace the old cig outlets. These can also be installed in other places around the boat. They run off 12DC and draw very little. 

As to the need for 110AC. I would suggest a marine grade and NOT wire it to the cig outlet circuit. It would be best wired to the battery - post or main BUS and the battery switch outlet B+ or main B+ BUS using proper circuit protection. 

[justgary]

Since you don't have a need for 120VAC, leave it off of your boat.  If you knew what you wanted to power, you would know how big your inverter should be.  An inverter will draw at least 10 times the current on the DC side than the AC side uses, so anything useful will want plenty of current.  For example, your 500 Watt blender for frozen daiquiris only wants a little over 4 Amps of 120VAC, but that translates to nearly 50 Amps on the 12VDC side (including losses).

The issues you mentioned are real (namely possible electrocution), so unless you have a real need and know how to do it properly, leave the inverter off of the boat.