12V Charger

[Snoking]

I bought a Ravpower dual port charger. One port is marked one amp and the other two amps. Is it OK to charge one of our Motor X via the two amp port. Will the phone charge logic just use what it wants? How many amps do modern PC USB ports supply? Chris

 

[FoxKat]

PC Ports supply several different levels of current depending on what version of USB they are...

From .5 to .9 Amps for general devices (hubs, printers, external hard drives, etc.), and up to 5 Amps for dedicated Charging ports (Non-PC USB ports).

Your phone SHOULD have a Current Limiter designed to protect the battery from being charged too rapidly which actually shortens the battery's lifespan. Still, I would refrain from using the high-power port for charging a phone directly. Power adapters are very inexpensive, even the good ones from Original Equipment Manufacturers, but to replace a phone that was damaged by excessive charging current could be very costly.

 

[Snoking]

Maybe I will just use the two amp port for my Tom Tom! Thanks Chris

 

[FoxKat]

Maybe I will just use the two amp port for my Tom Tom! Thanks Chris

Sounds like a good plan! Good luck! :biggrin:

 

[MotoXGirl]

I bought a Rayovac dual port charger. One port is marked one amp and the other two amps. Is it OK to charge one of our Motor X via the two amp port. Will the phone charge logic just use what it wants? How many amps do modern PC USB ports supply? Chris

I use my 2 amp s4 charger on my x all the time. Works just fine.

Sent from my XT1060 using Tapatalk

 

[Snoking]

Thanks. A love high powered girls! Ha! Ha! Chris

 

[MotoXGirl]

Thanks. A love high powered girls! Ha! Ha! Chris

Lol Thx it seems to charge faster too.

Sent from my XT1060 using Tapatalk

 

[tbolted]

The phone will draw what it needs, from .1 to 2 amps, no matter what the charger will supply.

 

[FoxKat]

I use my 2 amp s4 charger on my x all the time. Works just fine.

ent from my XT1060 using Tapatalk

Lol Thx it seems to charge faster too.

Sent from my XT1060 using Tapatalk

The phone will draw what it needs, from .1 to 2 amps, no matter what the charger will supply.

This is true (that the phone will draw up to what the charger will supply and yet no more than the phone will allow), but it's just good practice not to supply more power than needed. Things DO fail, and if the current limiter fails, the results could be very unpleasant. The phone won't draw 2 amps under any circumstances, it's designed not to - again to protect the battery from being charged too quickly and shortening the battery's lifespan. That's the purpose of the current limiter in the charging circuit. It's maximum charging rate is closer to between 900 mA (.9 Amps), and 1,100 mA (1.1 Amp). Even a so-called "rapid charger" will not exceed 1.1 Amp for these phones.

I am standing firm by my recommendation. You can do what you want but I guarantee that if the manufacturer were asked they would tell you NOT to use the 2 amp port under ANY circumstances and if you read the Warranty information you will find that it would VOID your WARRANTY.

People on this forum and elsewhere know me as a very reliable source of information regarding power and charging. I wouldn't tell you to avoid doing something if there wasn't good reason to.

To give you an analogy...your CAR has a 12 Volt battery and charging circuit that is capable of supplying quite a few HUNDRED Amps of current at a moment's notice. It's enough to melt a 1/4" thick piece of solid copper wire virtually instantly and send hot sparks flying in all directions if shorted across those terminals. However, there are FUSES in line between that system and the power port (also known as the "Cigarette Lighter Adapter Plug"), so that in the off-chance a device plugged into that port should somehow pull more than perhaps 20 Amps, that fuse blows to protect you, the device, the car, the battery, etc... Same goes for virtually ALL circuits in the car. The average car of today may have more than several dozen separate fuses of varying capacities from just a couple Amps to 20, 30, even more. If there weren't good reason to put "current limiters" (i.e. fuses), in those circuits, then there wouldn't be a "fuse box" and all wires would be directly connected straight to the battery and alternator.

 

[tbolted]

Look at it this way: the average 40" flat screen TV draws between 1.5 and 3 amps per hour, while most home wiring for outlets is on a 20 amp circuit. There is a maximum of 20 amps available, that doesn't mean that any device plugged into that circuit is going to get 20a, it simply gets what it needs in order to work up to a max of 20a. You're certainly not going to void your TV's warranty by plugging it into a 20a circuit.

The amp rating (amps per hour, aph) on a car charger is primarily determined by the wire gauge. A 2.0a charger is capable of supplying up to 2a of current. Same as in your house: the wall outlets are 12 gauge wire that can supply up to 20a, the light fixtures are typically 14 gauge wire rated at 15a. Using a 2a charger simply means that the phone can draw how ever much it requires, up to a maximum of 2 amps.

 

[FoxKat]

Look at it this way: the average 40" flat screen TV draws between 1.5 and 3 amps per hour, while most home wiring for outlets is on a 20 amp circuit. There is a maximum of 20 amps available, that doesn't mean that any device plugged into that circuit is going to get 20a, it simply gets what it needs in order to work up to a max of 20a. You're certainly not going to void your TV's warranty by plugging it into a 20a circuit.

The amp rating (amps per hour, aph) on a car charger is primarily determined by the wire gauge. A 2.0a charger is capable of supplying up to 2a of current. Same as in your house: the wall outlets are 12 gauge wire that can supply up to 20a, the light fixtures are typically 14 gauge wire rated at 15a. Using a 2a charger simply means that the phone can draw how ever much it requires, up to a maximum of 2 amps.

I'm not here to argue...I am giving good advice for the general population to follow. Unfortunately not everyone is well versed in Electrical Code or for that matter is intuitive enough to make the right decisions all the time and not burn their houses down. It's simply good practice on these devices to stick with the Specified Current output that the Manufacturer has indicated.

If I were to use your analogy, YES, the outlets in most home wiring circuits can supply up to either 15 Amps (standard socket - two vertical bars, one slightly wider than the other, and 14 gauge wire), or 20 Amps (high power socket - different plug configuration where one actually has a cross "tail" - see below and 12 gauge wire), not to mention higher power for things such as Electric Dryers, Air Conditioners, etc. However virtually ALL devices you will plug into those sockets (including that flat screen TV you're referring to) - except for things like straight loads such as light bulbs or those high-power devices, will have a fuse, circuit breaker or other current limiter between the wall outlet and the device for the very same reasons I've mentioned earlier.

View attachment 68403

If there were no reason to "LIMIT" the amount of current available in each circuit or at each socket, then ALL sockets would be 200 Amp capable and you wouldn't need a circuit breaker box on your home.

If I took 4 gauge wire and ran from a 200 Amp breaker and tied it to a 15 amp outlet (something an electrician would NEVER do), I wouldn't even consider the remote possibility of putting my 40" flat screen into that outlet's plug. Would the TV work...YES. Would it pull more than the outlet is rated for??? NO...not as long as everything is working perfectly, but is there a possibility of a failure of some kind in the device that could cause it to short internally or externally (i.e. pinched cord), and possibly have access to even more current than the outlet itself is rated for...well, YES. So again, I stand firm by my suggestions.

Proceed at your own risk.

 

[Snoking]

Guess I will jump back in here a bit. I race RC trucks and fly RC airplanes. Both use lipo batteriers. Voltage has to be raised above the batteries current level to get charge current to flow just like your car battery. Our RC chargers have current level settings among others.

So the question is as FoxKat states. Does one trust the phones charge circuit to limit current to an acceptable level of 1 amp when 2 amps are available. A switcher style supply/charger would be able regulate it easily. I will study this more with Motorola.

Found this quote:
"What's interesting however is that the Moto X can charge up to the maximum BC1.2 rate of 1.5A. If you use that kind of charger, it charges impressively fast, around 2.3 hours."

Chris

 

[Dalvik_Cache]

Ive charged my phone in ways you cant imagine...

 

[Snoking]

OK, here is a good wright up on USB charging.
How USB charging works, or how to avoid blowing up your smartphone | ExtremeTech

Chris

 

[Snoking]

Then there is this in the pipeline! Holly cr$%@#~!
Say hello to the hideous new USB 3.0 cable your new smartphone or tablet will come with

Chris