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TekNinja81

Adding a 2nd 12V/other electronics?

7 posts in this topic

Hey folks,

I'm thinking about adding a 12V socket in the rear of my 2010 Smart, which could be used for powering items such as a rear dash-cam, or small cooler, air pump/compressor etc. This would need to be on a switched circuit so as to not accidentally drain the battery somehow if I leave something plugged into it. (I actually noted a circular cutout in the right-hand rear lights' access panel that looked like it might be reserved for a 12V socket -- is this what I think it is?)

I'm also considering wiring up some additional interior lighting, either under-dash and/or in the rear as well, which would need to be on a permanent/live circuit and would use its own toggle switch.

Back about 15 years ago I did something similar with an old Nissan Pathfinder of mine, but I basically just tapped into its existing 12V/lighter line and ran the wires directly from that. I suppose I could do the same here for the secondary socket, but I'd rather do a "clean" job of this project if possible and not be hacking apart any existing circuits or panelling etc.

For those of you who have tinkered with the 451's electrical system, how/where would be the best/safest method of doing this?

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On the side of the SAM, there are several empty fuse locations (8 total I think?). Half of them are always live, half are switched power. Off the top of my head, I can't remember which are which, but you could either test it yourself, or I'm sure someone here will chime in to say which are which. Stick one leg of the fuse into the SAM spot, put a space connector on the other leg, and then do the rest of your wiring! There are also fuse holders that make the whole thing a lot nicer, but aren't strictly necessary to tap into the switched/constant power locations.

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On the side of the SAM, there are several empty fuse locations (8 total I think?). Half of them are always live, half are switched power. Off the top of my head, I can't remember which are which, but you could either test it yourself, or I'm sure someone here will chime in to say which are which. Stick one leg of the fuse into the SAM spot, put a space connector on the other leg, and then do the rest of your wiring! There are also fuse holders that make the whole thing a lot nicer, but aren't strictly necessary to tap into the switched/constant power locations.

Oh nice! That definitely would simplify the process. I'll have a look later today, but do you recall whether these will be regular-sized fuses, or the "mini" sized ones? And, a 5A fuse should be more than sufficient for my 12V socket add-on given the items I may use in it?

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I believe they are regular sized fuse sockets. I would recommend looking to see what size fuse is on the existing 12V socket and using the same as that.

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Good call. I think I remember seeing a warning on the 12V plug saying not to exceed 5A as well, but I'll check.

BTW, one thing just occurred: Where should I be grounding my wiring to, given that the 12V positive will be to the fuse lead? Sorry, I'm a bit rusty on the car mods, lol! I think I recall seeing a ground point somewhere around the engine cover, or possibly in the access panel for the rear lights, should be safe to share to that if so right?

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Yep, just find a good ground point in the back area of the car somewhere, be it the one near the lights, or one down by the engine cover.

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If I ever install an accessory outlet in anything, I would use both a switched and unswitched feed, wire it up with a relay and button switch so you can latch the relay on to power the outlet with the key off if desired. Wire it right and it will be on with the car, safely powered off when the car is off unless you have deliberately pressed the button after turning off the car, to power it until the car is next shut off. It can be done, and would be useful. I rewired mine to be constant on so I can leave a device charging. The thought of a forgotten drain is worrisome but mine is a daily driver as a rule, so far so good. Managed to remember for vacations.

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