12v USB outlet - Fiberglass RV


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-26-2017, 11:11 AM   #1
Member
 
Name: Jeroen
Trailer: Scamp
North Carolina
Posts: 74
12v USB outlet

I'm rebuilding a Scamp and I'm currently designing the electrical system. Does anyone know if the cheapo 12v USB outlet draw power when no USB device is connected to it? If so, how much? I plan on installing at least 6 to 8 USB ports, and I need to know if I need to put them behind a switch to prevent them from draining my battery.

12V Dual USB Car Cigarette Lighter Socket 12V Charger Power Adapter Outlet N3J1 | eBay
__________________

__________________
jeroen is offline   Reply With Quote
Old 09-26-2017, 11:18 AM   #2
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 6,243
Registry
Manuals.....

Manuals and specification sheets are your friend. Get the one(s) for those things you are planning on installing, read and understand them.
__________________

__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 09-26-2017, 11:22 AM   #3
Member
 
Name: Jeroen
Trailer: Scamp
North Carolina
Posts: 74
I doubt a 4 dollar USB outlet will come with a manual or a spec...
__________________
jeroen is offline   Reply With Quote
Old 09-26-2017, 11:27 AM   #4
Junior Member
 
Name: Philippe
Trailer: Boler Voyageur 1977
Quebec
Posts: 19
Quote:
Originally Posted by jeroen View Post
I'm rebuilding a Scamp and I'm currently designing the electrical system. Does anyone know if the cheapo 12v USB outlet draw power when no USB device is connected to it? If so, how much? I plan on installing at least 6 to 8 USB ports, and I need to know if I need to put them behind a switch to prevent them from draining my battery.

12V Dual USB Car Cigarette Lighter Socket 12V Charger Power Adapter Outlet N3J1 | eBay
I've installed a simple 12V socket in which I connect whatever I need, being a drill charger, dvd player or USB charger. If I want to make sure I it's not draining power, I simply have to pull it a 1/4 inch.

I don't like built in USB chargers as they are usually low end and quite slow, especially compared to a quick charger. Also, I only have to buy one for the car and bring it in the trailer when needed. It's also future proof, if a new technology comes.
__________________
wire is offline   Reply With Quote
Old 09-26-2017, 11:54 AM   #5
Member
 
Name: Alexander
Trailer: 1979 Boler B1300
New Hampshire
Posts: 59
First of all, I wouldn't buy that particular USB outlet. It is definitely one of the cheap ones. You need to look for one that puts out a minimum total of 4.2 amps and will put the entire output to one outlet if only one thing is connected. This will allow your devices to rapid charge versus slow charging. Don't worry about blowing up something that only draws 1 amp. The outlet will supply whatever the device pulls and not any more.

The only way I can think of to find out if there is a draw without something plugged in would be to either do an internet search or get one and measure to see if there is a draw.

Regardless of whether you get a dedicated USB outlet or use a cigarette USB adapter, be sure the minimum amperage for a 2 port is 4.2 amps and it can supply all 4.2 amps to one outlet. The minimum amperage for a single should be 2.1 amps.
__________________
Alex Adams is offline   Reply With Quote
Old 09-26-2017, 11:57 AM   #6
Senior Member
 
Name: K C
Trailer: 1980 18' Sunrader Motorhome and 1971 Trailswest Campster
Washington
Posts: 1,256
You can wire a small toggle switch into the circuit and install it right next to the USB outlet. That way you can cut the power to the USB when it is not being used. The little toggle switch is a low cost, hardware store or auto parts store electrical item. You can drill a small hole for the switch next to the hole for the USB charger outlet.

Of course there are some commercially produced, switched panels that have a 12v socket as well as USB connections. But these are not inexpensive. I am showing the photos below so that you understand the best way to make sure there is no power drain from such a device is to have a switch in combination with it so that you can turn off the power to the 12v socket such as a USB charger. For my own needs I have purchased a switch and sockets but I will be cutting my own custom panel plate to install them into so I can create my own charging station for my electronics. DIY brings my cost down to a total of about $20.00 for good quality components.


__________________
k corbin is offline   Reply With Quote
Old 09-26-2017, 12:13 PM   #7
Senior Member
 
Raspy's Avatar
 
Name: John
Trailer: Oliver Elite 2
Northern Nevada
Posts: 526
Aren't USB ports a standard 5 volts?

Might be best to install a cigarette lighter style socket and plug in a USB adapter. I know those sockets are big and old school, but there are a lot of things that use that format.

I use a 100 watt inverter in mine, for instance.
__________________
I only exaggerate enough to compensate for being taken with a grain of salt.
Raspy is offline   Reply With Quote
Old 09-26-2017, 12:23 PM   #8
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 3,987
The USB outlets are 12 volt to 5 volt DC to DC converters. They will use some power with nothing connected. When in use they dissapate more power than they provide and can get quite hot. I prefer using a 12 volt "lighter" socket and an external USB charger that can be unplugged when not in use. Easy to replace if it fails and it's in the open, not behind a wall. I installed something similar to this.

https://www.amazon.com/BANDC-Waterpr...12+volt+outlet
__________________
Raz is offline   Reply With Quote
Old 09-26-2017, 12:58 PM   #9
Senior Member
 
Byron Kinnaman's Avatar
 
Name: Byron
Trailer: 2006 Scamp 13' towed with a 2005 Dodge Dakota 4.7l Magnum W/full tow package (over kill)
Oregon
Posts: 6,243
Registry
Quote:
Originally Posted by jeroen View Post
I doubt a 4 dollar USB outlet will come with a manual or a spec...
What's the brand and model number?
I would almost be willing to bet I could find one.
__________________
Byron & Anne enjoying the everyday Saturday thing.
Byron Kinnaman is offline   Reply With Quote
Old 09-26-2017, 05:52 PM   #10
Senior Member
 
Name: Gordon
Trailer: Scamp (16 Std Layout 4) with '15 Toyota Sienna LE Tug
North Carolina
Posts: 1,788
Quote:
Originally Posted by jeroen View Post
I'm rebuilding a Scamp and I'm currently designing the electrical system. Does anyone know if the cheapo 12v USB outlet draw power when no USB device is connected to it?
Yes they will. Not a lot but every little bit hurts when boondocking. The one I installed draws 15-18 mA even with no load.

But the real problem I found was the radio interference (RFI) caused by the cheap device. It obliterates my FM radio reception. (I also had a LED bulb that blocked a single TV channel).

For both those reasons I put it on a switch and leave the switch off when the charger is not needed. If I had it to do over again I would use 12 VDC (cigarette lighter) outlets only, and use a plug in a lighter type USB charger when needed. That way I would have had an extra 12 VDC outlet drawing no power at all when not in use, and a USB charger that I could use in the camper or in the car. In fact I have one that is combo 12 VDC or 120 VAC, with dual USB charging ports... very handy. I have found the USB chargers that plug into cigarette lighter supplies do not create as much RFI. YMMV.

And it true, these cheap devices (usually form China) rarely come with a spec sheet and if they do, I would not trust it anyway.
__________________
gordon2 is offline   Reply With Quote
Old 09-26-2017, 08:57 PM   #11
Senior Member
 
Carl V's Avatar
 
Name: Carl
Trailer: 1981 Trillium 5500
Quebec
Posts: 475
Registry
Well the two USB outlets I installed in my trailer draw so little that my amp meter cannot read it (reads down to milliamps). Tried my digital multimeter, same thing, doesn't read anything.
So in my trailer they don't have a switch, they are powered all the time, and their draw when not is use is close to nil.
They recharge our devices nicely. Each have a 1A and a 2.1A port.
Motorcycle 1A / 2.1A Dual-USB Charger Adapter for Cellphones - Black - Free Shipping - DealExtreme
__________________
Carl V is offline   Reply With Quote
Old 09-27-2017, 03:39 AM   #12
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 3,987
Quote:
Originally Posted by gordon2 View Post
.

But the real problem I found was the radio interference (RFI) caused by the cheap device. It obliterates my FM radio reception. (I also had a LED bulb that blocked a single TV channel).

For both those reasons I put it on a switch and leave the switch off when the charger is not needed. If I had it to do over again I would use 12 VDC (cigarette lighter) outlets only, and use a plug in a lighter type USB charger when needed. That way I would have had an extra 12 VDC outlet drawing no power at all when not in use, and a USB charger that I could use in the camper or in the car. In fact I have one that is combo 12 VDC or 120 VAC, with dual USB charging ports... very handy. I have found the USB chargers that plug into cigarette lighter supplies do not create as much RFI. YMMV.

And it true, these cheap devices (usually form China) rarely come with a spec sheet and if they do, I would not trust it anyway.

Despite all the FCC compliance notices most consumer electronics is not well shielded leaving it quite susceptible to RFI (radio frequency interference). All these chargers are switching circuits that produce harmonics. Whether they interfere has more to do with the switching frequency than the cost. Different chargers produce different harmonics so some create problems while others do not. I suspect on your FM radio the noise enters through one of the IF stages though if the radio is plugged into the 12 supply, the noise could enter there. Try running on batteries to see. A bypass capacitor could cure the problem.

We enjoy listening to sports on the radio. Trying to listen to AM is a real challenge because of the much lower frequencies involved. Battery operation and radio placement both help.

The ARRL handbook used to have a pretty good section on RFI.
__________________
Raz is offline   Reply With Quote
Old 09-27-2017, 07:49 AM   #13
Raz
Senior Member
 
Raz's Avatar
 
Name: Raz
Trailer: Trillium 2010
Vermont
Posts: 3,987
When I measured the two plug in chargers I have, my measurements agree with Gordons. One was about 8 mA, the second about 12mA.
__________________
Raz is offline   Reply With Quote
Old 09-27-2017, 07:56 AM   #14
Senior Member
 
Name: Joe
Trailer: 1999 Casita 17' SD
Ohio
Posts: 512
I took the easy and future proof way and installed 4 additional 12 volt lighter outlets.

One IMPORTANT thing about 12vdc to USB adapters is it configured to "FAST CHARGE" the device. Doing research why my phone was "slow charging" I found out the difference.
A USB plug has 4 pins with the outer two being plus and minus.
In order to FAST CHARGE the adapter needs to have the middle two pins, normally for transmit and receive, shorted together. The device needing to be charged if it's capable of fast charging knows to fast charge. Devices that can't fast charge just ignore the two T&R pins.
So when looking for adapters you need to make sure it says fast charge or smart capable and they are not necessary more expensive.

I bought these and can verify they will fast charge capable devices.
Priced at TWO for $4.49 available in different colors shipped from California.
2Pcs Universal USB Car Charger Power Adapter Adapter for Smart Mobile Cell Phone | eBay

Joe
PS you don't get a data sheet or instructions either.
__________________

__________________
Joe Romas is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Cigarette Lighter Socket with USB for 12v battery wysiwyg Electrical | Charging, Systems, Solar and Generators 8 08-22-2017 05:21 PM
Run 12V TV/monitor off of 12V outlet or via inverter? Rod Scher Problem Solving | Owners Helping Owners 22 11-19-2016 01:11 PM
Does adding multi-outlet to 12v outlet diminish output? Kudzu Asheville Electrical | Charging, Systems, Solar and Generators 8 05-08-2014 05:05 AM
Installing 12v outlet in 2013 Scamp Dsironi Electrical | Charging, Systems, Solar and Generators 10 05-02-2014 02:32 PM
On adding inside outlet for plugging in USB Infogypsy Modifications, Alterations and Updates 41 03-20-2014 10:17 AM

» Upcoming Events
No events scheduled in
the next 465 days.
» Virginia Campgrounds

Reviews provided by


Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -6. The time now is 12:09 AM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.