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Old 07-05-2016, 13:31   #16
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Re: USB jacks phantom loads

Blueseas has a new USB outlet(1045) that only has a 1mA parasitic draw and can handle powering 4.8 amps of devices, compared to their earlier 2.1amp version that has a 15mA parasitic draw.

https://www.bluesea.com/products/104...r_Socket_Mount

I have the older Blueseas USB 2.1a, and it can maintain 5.09v under a 1 amp load of my Android phone. My other USB outlets, they type which plug into a 12v powerport/ciggy receptacle cannot maintain 5+ volts under this 1 amp load, and phone recharging slows noticeably.

I'm not concerned about the 15mA parasitic draw, but I do sometimes pull its fuse when away for an extended period. the 12v plugs, I have those on switches, but rarely bother to switch them off or pull them from the sockets far enough to depower them.

I use the Blueseas 1018 outlet with an Anker brand 12 inch microUSB cable, and it is way faster recharging than the 5v USB source and cable provided by Samsung with my phone.

I'd definitely get the 1045 model today if I had need of a new USB source, even though I do not currently need its 4.8 amps of output on any device.
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Old 07-05-2016, 13:52   #17
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Re: USB jacks phantom loads

The amount of drain will vary. Two "identical" USN adapters, one using a low voltage drop regulator, the other using a cheaper part with a high voltage drop, will consume very different amounts of power.


USB adapters used to be standard at supplying 1 amp, and consume perhaps twice as much power from the 12v side. Then they went up to 2 and 2.1 amps to satisfay tablets and iPhones, and now often one 2.1 amp and the other 1 amp from a single adapter.


But anyone buying USB adapters these days should be looking for the new ones, 3A per socket, since the new phones and tablets will make use of that. And the new "USB C" devices will be able to use even more.
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Old 07-05-2016, 13:56   #18
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Re: USB jacks phantom loads

Something Sternwake just wrote is worth emphasizing: the cables you use can make a big difference in charge rates. Both Anker and Tronsmart make some high quality cables with 20AWG wire for the power conductors, and do not reduce charge rates even up to 6ft lengths. Most 6ft USB cables are so resistive as to dramatically slow charging, and many shorter ones are also pretty bad. It doesn't do much good to have a 2.4A socket if the cable isn't up to the job. (USB C cables are required to be able to handle high currents, but many of the early shipments have been defective, so buyer beware - Amazon has pulled many of them from their store).

The Blue Seas item he mentioned has typical 2 X 2.4A intelligent sockets, which should do great for most devices but not for the latest charging protocols. Then again, beyond phones and tablets there isn't much need for those protocols. YMMV

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Old 07-05-2016, 15:45   #19
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Re: USB jacks phantom loads

This is easy, and highly flexible..

there are plenty of dual output USB cig plugs that are flush.. plus you get the flexibility of using a host of other adapters in the cig plug..

Quote:
Originally Posted by sully75 View Post
Thanks! My other alternative would be to install cigarette lighter outlets and put USB converters in them as needed. That would be a no-draw solution, yeah?
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Old 12-05-2016, 10:30   #20
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Re: USB jacks phantom loads

So if i put in cigarette outlets (let's say 3) is there a good reason not to wire them into my cabin light circuit? It would mean running a lot less wire.


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Old 12-05-2016, 10:37   #21
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Re: USB jacks phantom loads

You can wire them in, sure. The drawback is that "stuff" in each plug could easily be 10A loads, and a couple of those could exceed your wire (fuse) capacity and leave you in the dark. But if the loads work out and you've got the capacity for it, and preferably your cabin lights are on split circuits (port/starboard) anyway...no reason not to.


There are even some small LED rechargeable flashlights that plug in, just like a cig lighter, to remain charged in the sockets. Obviously if they are left on "charge" they are a battery drain, but that can also be a way to keep small lights stashed around in convenient places.
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Old 12-05-2016, 11:04   #22
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Re: USB jacks phantom loads

So I'm rewriting everything. The lights will all be on one fuse. But I'm wiring pretty heavy I think (14g) for all led interior lights. And the runs are pretty short (10') max. So can I fuse for 10amps for the combined circuit?


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Old 12-05-2016, 11:14   #23
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Re: USB jacks phantom loads

Twenty feet (round trip) of 14 AWG, offhand sounds safe for a 10A fuse. You just need to make sure that will keep all the lights and outlets well fed. A double iPhone/Droid/Galaxy/tablet charger could pull 4-5 amps all by itself when both plugs were charging newer gadgets.
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Old 12-05-2016, 11:25   #24
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Re: USB jacks phantom loads

Thanks. Maybe I should use 12g wire?
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Old 12-05-2016, 11:57   #25
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Re: USB jacks phantom loads

14awg would have a 40 amp ampacity, 12awg would raise that to 60 amps. In a short run like yours, I don't think voltage drop either way would be an issue. The 14 would seem to do, as long as the ampacity is enough for you.
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Old 12-05-2016, 13:27   #26
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Re: USB jacks phantom loads

Quote:
Originally Posted by sully75 View Post
So if i put in cigarette outlets (let's say 3) is there a good reason not to wire them into my cabin light circuit? It would mean running a lot less wire.


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The "good reason" is that the outlets are capable od supplying 10 amps or more and someone might plug in a couple of devices that draw a lot of power. This could overload your lighting circuit and trip the breaker. Now you will be looking for the breaker in the dark.

Best practice is to have lighting and power on separate circuits.

While we are on the subject, "cigarette outlets" make really crappy power outlets. It's hard to get a good contact on the center pin because it's just a contact pushing on another contact and they are trying to push each other apart.

We're stuck with them because they are a "standard" but where possible it's best to go with something more reliable. Installing a cigarette outlet and then plugging in a USB adapter seems a bit silly.
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Old 12-05-2016, 13:29   #27
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Re: USB jacks phantom loads

Quote:
Originally Posted by hellosailor View Post
14awg would have a 40 amp ampacity, 12awg would raise that to 60 amps. In a short run like yours, I don't think voltage drop either way would be an issue. The 14 would seem to do, as long as the ampacity is enough for you.
Nope.

14 gauge wire should have 15 amp overcurrent protection. 12 gauge wire should have 20 amp overcurrent protection.
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Old 12-05-2016, 13:33   #28
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Re: USB jacks phantom loads

Quote:
Originally Posted by sully75 View Post
So I'm rewriting everything. The lights will all be on one fuse. But I'm wiring pretty heavy I think (14g) for all led interior lights. And the runs are pretty short (10') max. So can I fuse for 10amps for the combined circuit?


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If your LED fixtures have pigtail wires attached, you should really consider the wire gauge of the pigtails for overcurrent protection regardless of the size of the wire feeding the lights. You should use the smallest capacity breaker that will handle the current of the lights.

Doing this, of course, means not putting power outlets on the same circuit(s).
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Old 12-05-2016, 13:47   #29
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Re: USB jacks phantom loads

my 12 v lights for cabin and my 12 v outlets a on separate breakers. is a good idea so you donot keep blowing breakers and darkness makes changing stuff out a tad difficult.
and in daylight the cusswords are softer sounding and do not awaken your neighbors.....
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Old 12-05-2016, 14:36   #30
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Re: USB jacks phantom loads

Quote:
14 gauge wire should have 15 amp overcurrent protection. 12 gauge wire should have 20 amp overcurrent protection.
But Rwidman is correct about the small wires that usually come with the lights. And frequently not tinned. You want to keep those as short as possible.
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