USB chargers

[skeptic36]

There seems to be conflicting opinions all over the interwebs, about whether or not charging an iPhone with a 2.5 amp USB port will damage the battery. So I thought I would play it safe and get a dual outlet, one for the phone and one for the iPad. I have also read that a lot of the cheapies don't put out there rated amperage.

 

Problem is when I look at brands, that I know of, that should be quality, they only offer the 2.5 amp port.

 

Does anybody know of a quality panel mount one with the 2.5 amp and the 1 amp outlets in it. Or can you reassure me that plugging into the bigger one won't damage the phone battery.

 

Thanks

 

Regards Bill

 

 

[aj_richo]

I've used the Apple AC charger for iPad on the iPhone an vice versa... no problems with battery damage, apart from the age of the iPhone 4 I own. (depletes in a day)

 

The AC charger is capable of producing higher amps, so I can't see the difference in plugging in a DC USB charger capable of 2.5A.

 

I think where the issue would be is the quality of the USB DC output. I have read some are not good at filtering any noise on the input. In a car probably wouldn't be an issue.

 

I am about to try a Jaycar unit in my Sonex - http://www.jaycar.com.au/productView.asp?ID=MP3616

 

Hopefully it can handle the noisy Jabiru electrical system...

 

 

[sfGnome]

There seems to be conflicting opinions all over the interwebs

As the wise man said, "Opinions are like arseholes - everybody has one. However, unlike arseholes, you should get yours out every once in a while and give them a thorough examination under a strong light".

Simplistically, you can always supply a lower-drawing load from a higher-capacity supply. This is because the high capacity is merely a measure of how much current it can supply before the voltage starts to droop. If a supply is rated at 2.5A, that doesn't mean that it forces 2.5A into the load; merely that it can supply it if the load wants. In the case of your phone, it doesn't want to draw more than 1A, so that's all the supply will give it.

 

Now, before the smart folk leap in with a 'yes-but', yes, it is possible with a really (really!) poorly designed power supply that under-loading it will cause it to go unstable, but even with the poorest of poor, the load has to be in the order of under 10% of rated (ie in this case, under 250mA) before it would start playing up. If you're using such a supply, your phone is going to die from the high transients that the crappy supply lets straight through when your motor starts or stops, so instability is the least of your problems.

 

What to do? Start by purchasing a charger from Apple (they're actually made by Belkin) and make sure that you don't buy one on super special from a dubious source. Then, if you really want to be sure, unplug the phone/iPad while you start and stop the motor. If you're lucky, your 12V outlet will be switched on your avionics switch, and you always turn it off when starting or stopping the motor (don't you? ).

 

 

[Geoff13]

As the wise man said, "Opinions are like arseholes - everybody has one. However, unlike arseholes, you should get yours out every once in a while and give them a thorough examination under a strong light". Simplistically, you can always supply a lower-drawing load from a higher-capacity supply. This is because the high capacity is merely a measure of how much current it can supply before the voltage starts to droop. If a supply is rated at 2.5A, that doesn't mean that it forces 2.5A into the load; merely that it can supply it if the load wants. In the case of your phone, it doesn't want to draw more than 1A, so that's all the supply will give it.

 

Now, before the smart folk leap in with a 'yes-but', yes, it is possible with a really (really!) poorly designed power supply that under-loading it will cause it to go unstable, but even with the poorest of poor, the load has to be in the order of under 10% of rated (ie in this case, under 250mA) before it would start playing up. If you're using such a supply, your phone is going to die from the high transients that the crappy supply lets straight through when your motor starts or stops, so instability is the least of your problems.

 

What to do? Start by purchasing a charger from Apple (they're actually made by Belkin) and make sure that you don't buy one on super special from a dubious source. Then, if you really want to be sure, unplug the phone/iPad while you start and stop the motor. If you're lucky, your 12V outlet will be switched on your avionics switch, and you always turn it off when starting or stopping the motor (don't you? ).

Now there is a man who knows his shit. A battery in general will draw what it needs not what is available.

 

 

[pmccarthy]

The chargers that came with my iPhone, iPad and iPad mini are all rated differently if you read the fine print on the data plate on the back. There must be a reason for this, as it would be cheaper to mass produce the same unit for all. They all look identical.

 

 

[Kyle Communications]

The reason is inside the USB connection on pins 2 and 3 I think it is there are different resistor values. These resistor values denote what should be connected as they provide different charge rates. This is why a charger supplied for a iPhone is actually different to the charger supplied for a iPad. It limits the current output depending on the model.

 

http://www.epanorama.net/newepa/2010/08/18/apple-charger-secrets/

 

 

[dazza 38]

I have a Iphone and a Mini Ipad. I leave one charger at home and charge both and the other charger I leave at camp in my Donga (FIFO) and charge both.

 

 

[rankamateur]

I have a Iphone and a Mini Ipad. I leave one charger at home and charge both and the other charger I leave at camp in my Donga (FIFO) and charge both.

Well one is probably charging slowly at home and the other getting half baked at work or visa versa. Have you checked to see if one gets hotter than normal as it is charging.

 

My Samsung phone charges much quicker on it's wall charger than it does on the computer USB tethering.

 

 

[dazza 38]

The phone is two years old and the Ipad 8 months old. Both seem to charge fine.

 

 

[facthunter]

I've done a lot of work with small lead acid batteries and chargers. The small batteries strictly specify a charge rate limit and if you hook them up to an oversize charger it will heat them up and distort the plates and/or discharge electrolite. The limiting voltage is the same and a charged battery won't suffer if connected. I can't agree the charge rate will be adjusted automatically to the needs of the battery. The only way I can use a big charger is to incorporate a resistance in the circuit. If I'm stuck I use a filament bulb of appropriate wattage. IF you have 6 volts as the rated voltage you need about 7.1 volts. If you want 2 amps limit fit a 12 watt bulb. It goes dull when charged. Nev

 

 

[SDQDI]

The phone is two years old and the Ipad 8 months old. Both seem to charge fine.

I do basically the same dazza, if I want a quick charge I will put my iPhone on the 10w iPad charger and bobs your uncle. But the difference between iPad and iPhone chargers is 5watts. Are they the same amps? Using the cheap dual USB units in the tractors to charge iphone and iPad and I have trouble with one of the outlets not wanting to charge, I just can't remember if it was the 1 amp or the 2.5, seems some internal circuitry on the iPad and iPhone must sense the different amps??

 

 

[rankamateur]

The cheap dual USB Cig lighter plug ones usually have one 1.1 amp and one 2 amp outlet. The one I bought from Clearprop is only 500mAmp at the USB and three Cig points, don't think it is going to make it into the plane at all.

 

 

[Kyle Communications]

This may answer your question SDQDI

 

http://www.popularmechanics.com/technology/how-to/tips/can-you-use-the-same-power-adapter-for-iphone-and-ipad-10283982

 

 

[pmccarthy]

My Kindke device will not charge from the iPhone charger but will charge from the iPad charger. They look identical.

 

 

[sfGnome]

There's an important difference between normal battery chargers (be they lead acid or NiCad or whatever) and iPhone/Pad chargers. In the former case, the charger is driving a constant current (up to a certain voltage limit) directly into the battery. In that case, the charger is, indeed, in charge. However, in the case of the phone and pad (and many other small electronic devices), the "charger" that we have been discussing is actually just a constant voltage power supply. The part that is controlling the battery charging is built into the phone, because lithium batteries are too dangerous to leave to the great unwashed to connect any old charger to... :)