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 > Adding 12V outlet questions (did I do it right)

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KeithF40

Long Island, NY

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Posted: 05/11/21 12:48am Link  |  Quote  |  Print  |  Notify Moderator

My TT doesn't have a 12V outlet so I decided to add one. I have two 12V deep cycle batteries connected in parallel.

I decided to wire the DC outlet off of one of the LED lights. Everything is getting power. The DC outlet I purchased is below.

https://www.amazon.com/gp/product/B01B79F8CW/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Question I have is can I set up a pure sine inverter with this outlet? Also if so how large of an inverter can I do (how much can I have plugged into the inverter) without blowing anything.

Also if I add another 12V outlet to the front of the camper, the one I just installed is in the back of the camper, is there any benefit to wiring off a light vs water pump vs battery?

Thanks for all your help.

curt12914

Bombay NY (5 miles from Quebec, 15 from Ontario)

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Posted: 05/11/21 04:26am Link  |  Quote  |  Print  |  Notify Moderator

You probably won't be able to run a very big inverter because your wire/fuse on a light circuit won't be big enough. An inverter should have it's own fused circuit, with wiring and fuse specifically sized to the size of your inverter.


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wa8yxm

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Posted: 05/11/21 04:56am Link  |  Quote  |  Print  |  Notify Moderator

Can you set up a pure sine wave inverter off this outlet?
How big. 100 watts or less.. likely yes but not sure
More than that it gets very iffy
300 watts.. would not bet on it likely no
500 watts. Forget it

WHY LED lights are very low current. you will very likely blow the fuse plus the wires can not deliver that much current without voltage loss

Running current = roughly load wattage/10 Starting current can be inverter load rating (IE 300 watts)/5 or more. Just long enough to poppa fuse.

Recommend connecting inverter to batteries direct with the proper ga wire (10ga or bigger for 300 watts or smaller 1000 watts or bigger start thinking 00 ga welding cable or bigger)

Put inverter in compartment NEXT to batteries (not same air space)
Use 120 volt cord to deliver power to load.


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BurbMan

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Posted: 05/11/21 07:07am Link  |  Quote  |  Print  |  Notify Moderator

Short answer is yes...that 12v outlet that you linked to comes with 18 gauge wire, really only enough for cell phone charging and other small current draws. Wiring it into the light fixture is fine for that usage.

Basic electricity: volts x amps = watts. So that 100w inverter that will provide enough power for a flat screen TV and DVD player, or a laptop charger, is delivering 0.83 amps at 120v, but on the other side it is consuming 8.3 amps at 12v.

What you did is fine for what it is, but it's not correct for any kind of inverter, even a small one. The best way to work this is backwards....start with what you want to power with an inverter. Look at the labels on the equipment and add up the total watts, this sill tell you how big of an inverter you need. Use the formula above to figure out how much 12v power that size inverter will draw, that will tell you what wire size and fuse you'll need.


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mgirardo

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Posted: 05/11/21 07:40am Link  |  Quote  |  Print  |  Notify Moderator

I installed a very similar 12v outlet on our Jayco Class C. The only difference being, the one I purchased had a 12v meter in it. I pulled power from the LED lights over the sofa, which we rarely used. The lights were protected by a 10 amp fuse. The 12v outlet pulled less than 5 amps and we had no problems. We used ours a lot to charge phones and tablets.

You won't be able to run an inverter larger than maybe 150 watts. If you want to run an inverter, run it directly to the battery. Get a larger one than you think you will need as you will probably want a bigger one eventually.

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BB_TX

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Posted: 05/11/21 08:22am Link  |  Quote  |  Print  |  Notify Moderator

12 vdc times 10 amps equals 120 watts.
120 vac times 1 amp equals 120 watts.
So in the perfect world you could run a 120 watt inverter.
BUT. There are power losses involved in the inverter meaning you would only be able to run something less than 120 watts out of the inverter without popping the fuse. So you can count on maybe getting 3/4 amp or so of 120 vac out of the inverter.

mr_andyj

Georgia

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Posted: 05/11/21 09:22am Link  |  Quote  |  Print  |  Notify Moderator

Best is to run the inv off the battery with the right size wire, and short wire runs.
Any inverter will work off the thin-lighting DC-wiring as long as you are not requiring much power from it. a 1,000 watt inverter will run a 10 watt thing and not blow the fuse, but ask for the full 1,000 watts and it will blow the fuse, or if no fuse, the wire will melt or catch on fire behind the wall.
Do not install a higher rated fuse if you are blowing fuses. Fuses make wiring dummy-proof in that your fuse will blow before you over-heat the wires.
Inverters will work best if the wire connected to the battery is able to carry easily all the Dc power that the inverter needs. Running power over a lesser/thinn wire will starve the inverter, heat the wire and cause loss of capacity. I am not sure that the inverter will be damaged, but I do know your Air Cond unit can be damaged from using too thin of wire over time (as an example of damage from low amps...).

markchengr

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Posted: 05/11/21 11:46am Link  |  Quote  |  Print  |  Notify Moderator

My experience was that due to the small wire size, the inverter shut itself down on low voltage from line loss. I remedied that by running larger wire directly from the battery to the inverter fused approporiately.

KeithF40

Long Island, NY

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Posted: 05/12/21 06:56pm Link  |  Quote  |  Print  |  Notify Moderator

Thank you so much for all the responses. Will definitely go about using higher gauge wires and going straight to the battery. Any recommendations on products and/or any guides to help me. Can probably figure out on own but if any of you have any references that would be great.

One response said:
Put inverter in compartment NEXT to batteries (not same air space). Both batteries are on the tongue so where would I put the inverter (maybe under master bed which is also the pass through storage area)?

mr_andyj

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Posted: 05/13/21 09:52am Link  |  Quote  |  Print  |  Notify Moderator

5 or 6 feet of wire running to inv is short enough. You do not have to go crazy. 10 feet of big wire would work too, but keep it short if you can.
There should be a big wire running to your fuse box area (or circuit breaker). Connect there instead of to the battery if the feed wire is big wire. Battery terminal connections tend to corrode on the battery, so best practice is to connect one wire to battery, run that to a location to connect everything else. Batteries off-gas and that gas is corrosive and will make a mess, corrode, turn green and cause loss of contact. This is why other guy says to install in different compartment.

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