Broke my charger, can I use a spare

[groomt]

And I believe he is correct. There is no inherent risk with using a .5A adapter with a mod that can handle 1A charging as long as it is a decent adapter. The mod will not "pull" more than the adapter will put out.
Most modern mods only come with a usb cable, hardly any come with the wall adapter anymore.

 

[bwh79]

There is no inherent risk with using a .5A adapter with a mod that can handle 1A charging as long as it is a decent adapter.

And therein lies the rub. How can you -- or rather, how could an inexperienced user, someone likely to be coming on here asking for advice -- how could that person tell if their adapter is what you'd consider "decent" or not? Why would you suggest to them that they should use an under-powered adapter that may or may not be safe, when they can know they're safe by using one rated at or above the device's input requirements?

 

[groomt]

A crappy adapter is a problem regardless of what the stated output is. I realize you are saying that using one with some "headroom" would be slightly safer, but unless you are going to start recommending specific adapters just saying get one with higher output than the charging capability of your mod is also inherently dangerous.

 

[NU_FTW]

A crappy adapter is a problem regardless of what the stated output is. I realize you are saying that using one with some "headroom" would be slightly safer, but unless you are going to start recommending specific adapters just saying get one with higher output than the charging capability of your mod is also inherently dangerous.

no its the other way around.

for instance my wife has a 6mo old dual usb outlet on her side of the bed, she damaged the micro USB tip to where it was shorting out got the thing super hot just like a coil, couldn't touch either the adapter or micro USB tip too hot. It's a power supply not limiter. Just like your house wires are rated for ~20amps but that doesn't mean a 5amo box fan will be PUSHED 20amps no it (the load) draws what it needs

 

[groomt]

It is absolutely a limiter. The adapter is limited to what its specs says it outputs. It takes in power, converts it, and outputs whatever amperage it is designed for. If that is .5A output then that is what it will output, regardless of what your mod can handle for input. If it is a 2A output that is what it outputs. Plugging a mod with a 1A input into an adapter that only outputs .5A will not cause the adapter to put out more then it is designed for, unless it is faulty.

 

[Joergl100]

How should that work? Not at all! I=U/R...got it?

 

[NU_FTW]

It is absolutely a limiter. The adapter is limited to what its specs says it outputs. It takes in power, converts it, and outputs whatever amperage it is designed for. If that is .5A output then that is what it will output, regardless of what your mod can handle for input. If it is a 2A output that is what it outputs. Plugging a mod with a 1A input into an adapter that only outputs .5A will not cause the adapter to put out more then it is designed for, unless it is faulty.

yea and a 20amp battery denies any attempt to surpass the RATING

 

[groomt]

You are comparing apples to oranges. Last I checked, batteries have no circuitry to control that. Why do you think they list output on the adapter?

 

[NU_FTW]

You are comparing apples to oranges. Last I checked, batteries have no circuitry to control that. Why do you think they list output on the adapter?

DC adapters do not supply a constant current, they supply what is requested, The LOAD determines the current. I am not saying it is impossible for an adapter to do as you claim but these things have very basic circuitry and are not nearly as smart/advanced as you think they are.

 

[Joergl100]

Excactly. Like that:

 

[groomt]

The way I understand it is the adapter is built to output up to a certain amount, .5A, 1A, etc . (You are correct that they don't put out a constant voltage, I was wrong there.) But, depending on the device (load) attached to it, it will deliver whatever the device can handle up to the maximum that the adapter is designed for. Using a .5A adapter on a mod that can charge at 1A will not feed 1A to the mod, it is limited to .5A by design. As mentioned earlier it may heat up the adapter since it is running at full capacity, and I will agree it is not recommended, but the adapter should not feed more load then it is designed for unless it is faulty.
The main problem that I see is that many mods do not include an adapter anymore and do not state what the mods charging capability is.

 

[NU_FTW]

The way I understand it is the adapter is built to output up to a certain amount, .5A, 1A, etc . (You are correct that they don't put out a constant voltage, I was wrong there.) But, depending on the device (load) attached to it, it will deliver whatever the device can handle up to the maximum that the adapter is designed for. Using a .5A adapter on a mod that can charge at 1A will not feed 1A to the mod, it is limited to .5A by design. As mentioned earlier it may heat up the adapter since it is running at full capacity, and I will agree it is not recommended, but the adapter should not feed more load then it is designed for unless it is faulty.
The main problem that I see is that many mods do not include an adapter anymore and do not state what the mods charging capability is.

unfortunately that's not how it works, it's just a rating of what it is designed for and it will "try" but struggle because of design, it can/will over heat and pose potential problems. the load dictates current, it draws current. The adapter simply is a source. Now some might be underrated for what max amp threshold is so might not get problems. Having had new adapters overheating because a short in a cord I can say with certainty more current can be drawn than what the adapter was designed and rated for.

now expensive phones can likely detect the struggle to draw current and alters the amount to a predesignated low amp charging mode.

 

[groomt]

So explain to me this from this article in the power curve section where he is driving the adapters to "..its shutdown point due to excessive load, and rapidly drops to no output in the lower left corner to avoid damage.". Isn't he saying the adapters shut down output when pushed past their designed output limit? So wouldn't this imply that they do limit current? Just trying to understand this.
A dozen USB chargers in the lab: Apple is very good, but not quite the best

 

[NU_FTW]

So explain to me this from this article in the power curve section where he is driving the adapters to "..its shutdown point due to excessive load, and rapidly drops to no output in the lower left corner to avoid damage.". Isn't he saying the adapters shut down output when pushed past their designed output limit? So wouldn't this imply that they do limit current? Just trying to understand this.
A dozen USB chargers in the lab: Apple is very good, but not quite the best

I think i see what you are getting at the ones with a clear shutdown are the name brand cell chargers and nod random simple usb adapters. The more expensive cell adapters have a soft fuse in them but many many many cheap new usb adapters don't spend for it and you cannot just look at the adapter to tell

 

[bwh79]

So explain to me this from this article in the power curve section where he is driving the adapters to "..its shutdown point due to excessive load, and rapidly drops to no output in the lower left corner to avoid damage.". Isn't he saying the adapters shut down output when pushed past their designed output limit? So wouldn't this imply that they do limit current? Just trying to understand this.
A dozen USB chargers in the lab: Apple is very good, but not quite the best

"[14] The chargers use a design called constant-voltage, constant-current (CVCC), since they provide a constant voltage (and increasing current) up to the maximum load and then a constant current (and decreasing voltage) if the load continues to increase."

So, this is interesting, and it certainly puts a new spin on things. So the adapter doesn't necessarily need to "communicate" with the device to control the current by asking the device to draw less power, it just measures the current passing through and if it gets too high, the adapter drops its own output voltage, to compensate? See, I was not aware of that, and sort of thought they would just blindly output 5v until they either burned up or burned out. That does seem to support the idea that it doesn't really matter too much what the output rating is, from a safety standpoint.

I guess the question then is, what happens on the device end when it receives a lower voltage than what's expected? Are there any problems there, besides a reduced rate of charging?

 

[NU_FTW]

"[14] The chargers use a design called constant-voltage, constant-current (CVCC), since they provide a constant voltage (and increasing current) up to the maximum load and then a constant current (and decreasing voltage) if the load continues to increase."

So, this is interesting, and it certainly puts a new spin on things. So the adapter doesn't necessarily need to "communicate" with the device to control the current by asking the device to draw less power, it just measures the current passing through and if it gets too high, the adapter drops its own output voltage, to compensate? That does seem to support the idea that it doesn't really matter too much what the output rating is, from a safety standpoint.

I guess the question then is, what happens on the device end when it receives a lower voltage than what's expected? Are there any problems there, besides a reduced rate of charging?

with a mod I have no clue, I do not like the idea of usb charging the battery built in or replaceable. Phones can detect things out of whack. Some phones won't charge or will charge with less current if it cannot detect the manufacturer supplied charger via the usb data lines.

End of the day its far more safe to over provision available current as its the device that draws current.

cell phones are not mods either.

 

[bwh79]

[double post, sorry]

 

[groomt]

Yeah, the more I read, the deeper in the rabbit hole I go.
I wonder if this is why so many internal battery mods don't list the charging capability?
I appreciate the courteous discussion on this.

 

[NU_FTW]

Yeah, the more I read, the deeper in the rabbit hole I go.
I wonder if this is why so many internal battery mods don't list the charging capability?
I appreciate the courteous discussion on this.

I try to error on the side of caution. I have a 60watt usb adapter but no device that can utilize all the available power

 

[Joergl100]

Things are mixed here...the wall wart is NOT the charger...it is only the power supply! The charger is inside of the mod!

CV-CC is wrong (and weird!!!). It is CC...and then CV until the termination current is reached! Otherwise it would kill the battery...maybe not immediately, but soon for sure!