USB Sockets

[Strop]

Hi,

Looking at USB sockets like this:

http://www.ebay.com.au/itm/Waterproof-12V-Dual-USB-Car-Power-Adapter-Charger-Plug-Socket-Outlet-Motorcycles-/231301868739?pt=AU_Car_Parts_Accessories&hash=item35daaa6cc3

Just trying to figure out what power they are pulling and trying to understand the power concepts.

They output 5v at 1 Amp or 5v at 2.1 Amps. Therefore if both sockets are being used I am assuming that it is drawing current at 3.1 Amps. - but is that at 12v or 5v. Also if I put 2 PC these on the same circuit and they are all being used at the same time is that then 6.2 Amps being the maximum it can pull.

Could someone explain the 5v 12v thing to me please.

Laurie

[Strop]

So if Power = Volts x Current

5v x 3.1 Amps = 15.5 Watts
5v x 6.2 Amps = 31 Watts
So does

12v x 1.25 Amps = 15 Watts
12v x 2.5 Amps = 30 Watts

Mean roughly the same thing in terms of battery use. So 5 amp fuse and wire that will take 10 amps.

The next questions I have are

Do these kind of power outlets USE power when nothing is plugged into them - therefore needing a switch to turn them on/off?

Also if using them to charge your ipad/phone/camera battery overnight does the current stop flowing, or reduce it's flow when the device is fully charged?

Thanks

Laurie

[Dale M.]

Yes the use a tiny bit of electricity when nothing is plugged in to them, they are always on and always regulating....

Dale

[noseoil]

One thing I've read is that the blue LED light (at least on the ones I have) is always on and lit when power is attached. Still need to test this, but I'm going to mount mine in boxes with a switch for each one, just due to the annoyance factor of the light at night. If they're switched off, no light or current drain is possible. Seems like the best way to do things to me. Doing two in the headboard & one in the galley.

[Verna]

Good for night lights, but annoying if they are directly in your line of sight. I try to put something in front of them at night to "disperse" the light.

[Jdhiker]

One thing I've read is that the blue LED light (at least on the ones I have) is always on and lit when power is attached. Still need to test this, but I'm going to mount mine in boxes with a switch for each one, just due to the annoyance factor of the light at night. If they're switched off, no light or current drain is possible. Seems like the best way to do things to me. Doing two in the headboard & one in the galley.

Switching them off is a great idea. In the teardrop when boondocking, conserving battery is key!

[tony.latham]

I think I've got the same (or very similar) double USB socket in my teardrop galley. Realizing it would always be pulling juice, I wired a toggle switch next to it.


I put a GT Watt Meter ($20 on eBay) in my teardrop, it's a great tool to measure electrical usage. (that's not what's in the photo) It measures amp draw down to the hundredth of an amp. It read's zero amperage usage when the USB switch is activated (and the port's LED light is on). When I plug my iPhone into it –according to my meter– it draws 3 or 4 amps (I don't recall exactly how many).

In the ongoing teardrop build in my shop, I'll put a similar double USB port in the cabin but I will not bother to connect a toggle switch to it. If the LED bother's the occupants, they can cover it with a tiny bit of electrical tape. They'll be a master switch in the battery compartment.

When my teardrop is in a non-use state for short periods, I can turn off the master switch. For longer periods, the solar panels will be set out to maintain the battery.

I think those little LEDs pull such a small amount of power that the battery will discharge at about the same rate with or without it.

Tony - boondocker and proud of it!

[MtnDon]

I think those little LEDs pull such a small amount of power that the battery will discharge at about the same rate with or without it.

I am quite sure that any std flooded lead acid battery will self discharge at a rate higher than any of those LED indicator lamps. There is nothing that can be done about the self discharge.

[noseoil]

Don said "There is nothing that can be done about the self discharge." I would add, except for a small solar panel! It doesn't take much to charge up a battery if the sun's out and it just needs to be maintained.

[Dale M.]

I think I've got the same (or very similar) double USB socket in my teardrop galley. Realizing it would always be pulling juice, I wired a toggle switch next to it.


I put a GT Watt Meter ($20 on eBay) in my teardrop, it's a great tool to measure electrical usage. (that's not what's in the photo) It measures amp draw down to the hundredth of an amp. It read's zero amperage usage when the USB switch is activated (and the port's LED light is on). When I plug my iPhone into it –according to my meter– it draws 3 or 4 amps (I don't recall exactly how many).

In the ongoing teardrop build in my shop, I'll put a similar double USB port in the cabin but I will not bother to connect a toggle switch to it. If the LED bother's the occupants, they can cover it with a tiny bit of electrical tape. They'll be a master switch in the battery compartment.

When my teardrop is in a non-use state for short periods, I can turn off the master switch. For longer periods, the solar panels will be set out to maintain the battery.

I think those little LEDs pull such a small amount of power that the battery will discharge at about the same rate with or without it.

Tony - boondocker and proud of it!

Um you have sort off a conundrum here, you use the term watt meter and yet you state the current draw is in amps....

A watt meter measures POWER consumed in "watts"....

A amp meter measure electrical current flow in "amps"...

Excuse me, but if WATT meter is not showing a wattage useage and lamp (LED) is on, watt meter is not accurate or not sensitive enough to measure the amount of electricity being consumed .... A inline ma (mil-amp) meter will show a current draw, ohms law and general physics dictates that for something to be active (LED illuminated) electrical power has to be consumed.... If meter is reading "0" and LED is illuminated, them meter is not accurate enough to measure the range of the small scale current draw of device with LED in it.....

Dale

[tony.latham]

I think I've got the same (or very similar) double USB socket in my teardrop galley. Realizing it would always be pulling juice, I wired a toggle switch next to it.


I put a GT Watt Meter ($20 on eBay) in my teardrop, it's a great tool to measure electrical usage. (that's not what's in the photo) It measures amp draw down to the hundredth of an amp. It read's zero amperage usage when the USB switch is activated (and the port's LED light is on). When I plug my iPhone into it –according to my meter– it draws 3 or 4 amps (I don't recall exactly how many).

In the ongoing teardrop build in my shop, I'll put a similar double USB port in the cabin but I will not bother to connect a toggle switch to it. If the LED bother's the occupants, they can cover it with a tiny bit of electrical tape. They'll be a master switch in the battery compartment.

When my teardrop is in a non-use state for short periods, I can turn off the master switch. For longer periods, the solar panels will be set out to maintain the battery.

I think those little LEDs pull such a small amount of power that the battery will discharge at about the same rate with or without it.

Tony - boondocker and proud of it!

Um you have sort off a conundrum here, you use the term watt meter and yet you state the current draw is in amps....

A watt meter measures POWER consumed in "watts"....

A amp meter measure electrical current flow in "amps"...

Excuse me, but if WATT meter is not showing a wattage useage and lamp (LED) is on, watt meter is not accurate or not sensitive enough to measure the amount of electricity being consumed .... A inline ma (mil-amp) meter will show a current draw, ohms law and general physics dictates that for something to be active (LED illuminated) electrical power has to be consumed.... If meter is reading "0" and LED is illuminated, them meter is not accurate enough to measure the range of the small scale current draw of device with LED in it.....

Dale

Dale:

No conundrum. The company calls it "G.T.POWER LCD Rc Watt Meter and Power Analyzer"


It measures volts, watts, amps, amp hours, and watt hours. Is it a watt meter? No, I get that, but that's what the manufacturer calls it and you can see in my post I capitalized it since it's a proper noun.

Do LEDs use electricity? Yeah, the do (i get that too) but my G.T. "Watt Meter" can't detect the little amount of amperage that's being consumed. That is the point.

It is watt it is.

Tony

p.s. if you're curious as to how the device bench tests, take a look here: https://www.youtube.com/watch?v=Lxv9Rozs774

[Strop]

I was thinking it would use power. Interesting that it does not show up on the meter.

It kind of leads into my next question also. I suppose that a meter, be it a volt meter or amp meter - or even a combined meter, must also use up your battery.

So if you have a USB power plug with a switch should you put a switch on your volt/amp meter so it doesn't drain your battery.

Just planning how many switches I will have to buy.

Does a deep cycle battery gel or whatever also discharge at the same rate as a lead acid battery?

Thanks

Laurie

[Dale M.]

Good thought and if you want to stop the leaching of power (micro drains) everything that has a potential to drain battery even while "not in use" should have a cut off switch (maybe master disconnect for long periods of non use) .... Every item by its self may not be much, but as a whole system the drain is cumulative if you have several devices....

Ultimate test would be to put a temporary digital ammeter in line (at battery) and measure what the current draw is when everything is connected but "not in use"...

Dale

[tony.latham]

Meters use power too (of course), but again it's a very tiny amount. It's so small that it won't have an effect on your available energy.

I think all electrical systems need a master switch.

As far as the natural discharge of different batteries, I don't know. I do believe all RV batteries need to be on some type of maintainer when not in use for more than a couple of weeks.

[absolutsnwbrdr]

Just trying to figure out what power they are pulling and trying to understand the power concepts.

They output 5v at 1 Amp or 5v at 2.1 Amps. Therefore if both sockets are being used I am assuming that it is drawing current at 3.1 Amps. - but is that at 12v or 5v. Also if I put 2 PC these on the same circuit and they are all being used at the same time is that then 6.2 Amps being the maximum it can pull.

As others have stated, when nothing is plugged in the internal circuitry that drops the 12V down to 5V will have very minimal parasitic draw - not enough to worry about. Now as far as having things plugged in, the power drawn depends on the device that is plugged in to it.

The rating (5V @ 1A and 5V @ 2.1A) is the MAXIMUM current draw (per outlet).

Many, if not all, modern smart phones require the more robust 2.1A rated outlets to get a charge. Some will still charge when plugged into the 1A outlets, but it will be incredibly slow, and may actually only maintain the charge, rather than storing more energy. An iPhone will mock you if you plug it into a 1A outlet and won't charge at all. Other devices vary.