Ingenious way to charge smart phones, tablets, etc in the coach!

supermanotorious · Nov 8, 2016

Well I found it incredibly brilliant anyway. And I only recently realized it. Realized it of course, after designing and installing advanced level inverter projects, and even using a small inverter from Harbor Freight to charge phones overnight.

Replace your radio (or install one), with an after market one, that has front facing USB. This only runs off 12V so you do not need to power an inverter to power the transformer that charges your device around 5V or so.

I've yet to try a USB "power strip" to see if it will charge several devices at once but when I do I will share my findings.

Dragginourbedaround · Nov 8, 2016

I just plug mine into a 12 volt socket. They make USB adapters that will charge more than one device,

Gary RV_Wizard · Nov 8, 2016

Same here. In fact most all of our 12v outlets have USB adapters semi-permanently residing there.

StephenM · Nov 8, 2016

This is a very clever idea for dry camping.

I have a 2005 coach without an inverter and my 12volt sockets are hooked up to my chassis battery. This will allow me to charge my usb battery packs when dry camping as the Stereo is connected to the 12v system.

This will do me until I can fit a 12v usb receptacle near my breaker box

BobNSam · Nov 8, 2016

Gary RV Roamer said:
Same here. In fact most all of our 12v outlets have USB adapters semi-permanently residing there.

Grumble, grumble. ..too much tech, added two 12VDC outlets to support gps, dash cam, brake buddy added a multiple outlet 12VDC adapter for additional chargers...will it never end!??

SeilerBird · Nov 8, 2016

bobsharon said:
Grumble, grumble. ..too much tech, added two 12VDC outlets to support gps, dash cam, brake buddy added a multiple outlet 12VDC adapter for additional chargers...will it never end!??

Not if you want to keep on RVing. Batteries and battery chargers are a way of life for RVers.

Stephen S. · Nov 8, 2016

Yee-gods! When I had my niece with me on a trip I had a 3 outlet extension on one of the 2 power outlets in the dash, with 2 double USB plugs. My Garmin pugged into the second dash outlet.

We were juggling 2 tablets, 2 phones, an iPod, and a Nook reader.

I'm still surprised we didn't blow a fuse.

StephenM · Nov 8, 2016

On my coach the 12 volt sockets connected to the coach battery still work when the engine is off.

Would having something plugged in kill the coach battery?

BobNSam · Nov 8, 2016

StephenM said:
On my coach the 12 volt sockets connected to the coach battery still work when the engine is off.

Would having something plugged in kill the coach battery?

Eventually. The chargers would be an additional parasitic draw on your chassis battery.

Stephen S. · Nov 8, 2016

StephenM said:
On my coach the 12 volt sockets connected to the coach battery still work when the engine is off.

Would having something plugged in kill the coach battery?

If you leave it plugged in for a week+ and don't start the motor, maybe. Just compare the size of the chassis battery to the one in your phone or pad.

StephenM · Nov 9, 2016

That's what I thought.

I always make sure any chassis 12 volt items are plugged out. The ones I got to watch are the reversing camera and the GPS as they are on a 12 volt socket. The Camera screen only comes on when my lights are on but the unit may still be drawing power.

Gary RV_Wizard · Nov 9, 2016

I have a 2005 coach without an inverter and my 12volt sockets are hooked up to my chassis battery. This will allow me to charge my usb battery packs when dry camping as the Stereo is connected to the 12v system.

Seems to me it is a lot easier - and cheaper - to install a 12v outlet with a direct battery connection (house or chassis, take your pick) than to swap radios.

As for parasitic draw from chargers, it's the same amount of amps whether it goes through a radio or a utility outlet, right?And once the item is charged, or disconnected from the charger, the amp draw is infinitesimal. Not zero, but tiny. In one test a total of six (6) idling chargers totaled a mere 0.3 watts. That's only 0.025 amps for six chargers! That's also just 7 watts in a 24 hour period, or about 0.6 AH from your battery.

This article gives some idea of what the parasitic (aka "vampire") power draw is for these chargers:
http://www.howtogeek.com/231886/tested-should-you-unplug-chargers-when-youre-not-using-them/

supermanotorious · Nov 9, 2016

I'm sure there is a small parasitic draw from a radio too, but a 12V socket is going to play your favorite CD, get you local weather and traffic, or tell you what time it is. I guess it's true, if you have no radio, installing one from scratch would be more difficult than a 12V outlet.

Gary RV_Wizard · Nov 9, 2016

Not talking about "from scratch". If you already have a radio that shows the time and plays CDs, why swap it out just get a 12v powered USB port? Modern vehicle radios typically have lots of connections, e.g. at least two power wires (main and standby) and 4 or more speaker connections. Speaker wires may or may not be compatible either.

StephenM · Nov 9, 2016

I swapped my stereo out already so I could use
Bluetooth and 3.5mm jack. Having a USB port in a bonus.

John From Detroit · Nov 9, 2016

To answer someone's question. Will using plug in 12 volt to USB chargers drain the RV's batteries. Well, yes, possibly, and slowly, Explanation follows.

My chassis battery is 73 amp hours, House original 220 now over 500. Amp hours

The plug in chargers I have are 1/2 to 2.25 Amps (I've seen up to 5 amps).

Of course the bigger the charger the faster the charge, My phone takes about 1.5 to 2 amps at max draw (yes it draws that much) when using as a GPS.

So eventually they will run down the batteries.

Of the 12 volt outlets
The original dash outlet in my RV is a CHASSIS device
The 2nd one near the passagner foot is a HOUSE device (Connected to house battery)
Outlets I've added all over the place are HOUSE both indoors and out.

In some RV's (mine included) the HOUSE converter, if connected to shore/generator power, charges both HOUSE and Chassis batteries.

and of course the Alternator when I'm driving does as well.

supermanotorious · Nov 9, 2016

well, if the coach has any type of harness for the radio, as vehicles do, then Metra likely has an adapter for an aftermarket radio, then you can connect the radio wiring to the harness at your kitchen table, and its plug and play in the RV

Old Radios · Nov 9, 2016

I would not use a radio with a USB outlet as my charger. Newer radios draw some power even when they are off. Better off using a 12 volt outlet with a USB adapter and pulling the adapter when not being used.

I have a newer radio connected to the house batteries but put it on a switch to shut off all power to it when it's not being used and also installed a couple of 12 volt outlets with a switch to turn them off when not in use. I use those to charge USB devices.

Ingenious way to charge smart phones, tablets, etc in the coach!

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