PROJECT-A-PALOOZA!!! -- USB Outlets with Timer

R

Ray

New member
Well, we all need plenty of USB power outlets for our "stuff" right?

[Warning: This one's pretty "geeky" - sorry!]

So I found the Marinco USB outlets. They are pretty nice. I put three of them in the boat. One aft at the back corner of the entry table:

800p_plugaft.sized.jpg

One forward at the co-pilot seat:

800p_plugatdash.sized.jpg

And one at the helm (photo later).

The problem with these was that they draw (IIRC) about 25mA or so when power is supplied to them - even when nothing is plugged in. I looked around and didn't find (easily) anything much better.

I was convinced I would inadvertently leave the power on to them and they would suck my battery dry.

There must be a better way........

I wanted simple button to press and have the ports turn on for, say an hour or two and then turn off automatically. I use a TON of AC Timer Plugs at home. I love these things! I wanted the same thing for a 12V source.

There are electronics to do this, but I didn't see anything cheap and readily available that worked exactly the way I needed. Then there are things called timed relays, but none of them did EXACTLY what I wanted. There were delayed on, delayed off, one-shot off, timed start, etc. But nothing fit easily the scenario above.

What I ended up with was a dual-element relay where one was timed and could be connected to the other. If I hooked them up right (after burning through LOTS of scratch pad drawings), I could get the functionality I wanted.

There were some issues with available coil voltages and the wide range of the boat's "12V" that could be exposed that I just kind of cheated with a bunch of diodes.

The beauty of this is that when it is off, it is truly off (just the way I like my boat stuff!). ZERO power consumption until the button is pressed.

Here is the schematic of what I rigged up:

800p_USBRelayTimer.jpg

And here is everything but the push button switch mounted behind the helm.

800p_relaycircuitmount.jpg

This is the helm plug outlet with the one-shot push button mounted right above it.

plugandbutton.jpg

After a year of use, I can say that it is working flawlessly. It was a good install/upgrade.

If you haven't shut your computer off in disgust after sending my PM's that I am nuts or what an idiot I am, and are somehow still interested in this insanity, here are the nitty-gritty details about the major parts used:

Relay
Part Number: Magnecraft / Schneider Electric - TDRSRXB-12V
Data Sheet
Purchase Option

Diodes
Part Number: Vishay 1N5820-E3/5
Data Sheet
Purchase Option

Push Button
Part Number: CW Industries – GPB527A202BB
Data Sheet
Purchase Option
 
Hi Ray,

No disgust here. You always do a class job with your upgrades. Just a word of caution, though: it is early in the winter season - you have PLENTY of time for more of these nice fixes... don't get 'em all done too soon. What will you do with yourself??

Happy Holidays,
Jim
 
Thanks, Jim, you are too kind!
Good advice - I will think hard about that. ;) ;)

All the best to you and yours,
Ray
 
Great idea. This is a good idea to supply tablet battery charging power when you're using your tablet for navigation.

I assume your schematic doesn't show the 5Vdc USB output though they must be fed directly from the 12Vdc output. We use a Verizon/LG phone and once in a while we grab the wrong "black box" charger and get the message "wrong charger" direct from LG. Have you checked that those Marinco chargers are compatible? It's a good installation and I'll have to use one of those to keep the phone and tablet charged.

My next question is where I can get a small 12Vdc to 12Vdc converter? I have an ethernet connection on board and the only ethernet hub I can get is one that runs off 110Vac and gives out a regulated 12 Vdc. I'd like to cut out the inverter and use a DC-DC converter to stabilize the voltage.

Boris
 
Borris:
http://www.powerstream.com/dc-2171.htm Has a 12.5 to 24 volt DC converter. for about $22.

If that doesn't do it and you want to get rid of a few bucks Pro Mariner makes the ProMar series to DC to DC converters….

One of the other companies made a similar converter for the electronics--but that just used a small Gel Cell battery, and 12 volt charger which was regulated.

Another way is a small AGM or motor cycle battery-- This is what I have done, and then charged it when not using it for critical application.
 
Well done Ray. I always check out the "Project-A-Palooza" when ever one appears. Your work is excellent. Keep them coming.
I have a Blue Sea USB charger outlet and it also comes with the parasitic draw that has me reserved about installing it. I think this will solve the problem, if only I can figure out what you did.
Could you install a simple switch before the USB charger and remember to switch it off after you unplug your phone or camera? I think this would be a less complicated approach, but perhaps not a Project-A-Palooza worthy write up. 8)

Grazer
 
I assume your schematic doesn't show the 5Vdc USB output though they must be fed directly from the 12Vdc output. We use a Verizon/LG phone and once in a while we grab the wrong "black box" charger and get the message "wrong charger" direct from LG. Have you checked that those Marinco chargers are compatible? It's a good installation and I'll have to use one of those to keep the phone and tablet charged.

My next question is where I can get a small 12Vdc to 12Vdc converter? I have an ethernet connection on board and the only ethernet hub I can get is one that runs off 110Vac and gives out a regulated 12 Vdc. I'd like to cut out the inverter and use a DC-DC converter to stabilize the voltage.
Click to expand...

Boris,

Yes, the schematic only shows the 12V output that is then routed to all of the USB converter plug modules.

The problem with the DC-DC converter is that it is a pretty sophisticated "buck-boost" circuit. You are asking it to provide clean 12V when the input voltage is well above 12V, but then also upconvert when the voltage is below 12V. They exist, but they are not cheap. There are some inexpensive ones from China on ebay and amazon, but I wouldn't trust any expensive electronics on them. Maybe a better (easier) solution is to look for a very small inverter and live with the inefficiency of the setup, knowing you didn't spend a lot of time setting it up. There are black boxes available, but they may be complex and costly to do right. You could also do the extra battery thing as thataway suggests.

Could you install a simple switch before the USB charger and remember to switch it off after you unplug your phone or camera?
Click to expand...

Absolutely, Grazer! That would be the straightforward, non-geeky-engineer way that most sane folks would do it. You could put the switch right next to the outlet as a reminder.
 
I had read in the past that the USB outlets tend to draw power even when not in use, so I've stuck with all cigar lighters and then have USB "plugs" that I can put in them when I want them. These can be left in or taken out. I have a couple of "singles," a double, and then a "four plug." Most of them provide the 2 amps that certain devices require (sometimes on one socket but not the other, if it's a double).

I went with this method because I still have a number of things that do use the cigar lighter (namely my laptop and dry cell battery charger), and I like that I can choose them to be either cigar lighter or USB, and/or remove the USB adapters and "lose" the constant draw (haven't tested but at this point presume the plug in USB adapters also draw power - they often have a light so how could they not).

But it's nowhere near as geekily cool as Ray's solution :D Ray: I always enjoy reading about your projects (no matter how technical - in fact that makes them extra cool), and often get really good ideas from them. Thanks for posting :thup
 
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