Alternative 5V chargers (currency?)

[appelflap]

Hi, I'm really a noob when it comes to electronics. For all I know, when a cable fits it should work

I have a couple of microUSB chargers laying around. They all have an output of 5 Volt but they output a currency that differs from the standard charger (1A).
What is the "golden rule" wrt currency? Are chargers with a currency that is less than 1A save?

 

[ozkaya]

current is not pushed, it is pulled by your device as necessary. voltage is pushed, so correct voltage,5V in this case, is very important. As for the current, if the charger can't supply enough current with that voltage it will get hot and cause problems. i.e., you should have a current greater or equal to your original charger and same voltage. this applies to ALL of your electronics.

 

[appelflap]

current is not pushed, it is pulled by your device as necessary. voltage is pushed, so correct voltage,5V in this case, is very important. As for the current, if the charger can't supply enough current with that voltage it will get hot and cause problems. i.e., you should have a current greater or equal to your original charger and same voltage. this applies to ALL of your electronics.

Thank you very much for this explanation. What do you think, a 5v charger with a current of 850mA will that cause big problems when I use it just accidentally to charge my device.

 

[ozkaya]

Thank you very much for this explanation. What do you think, a 5v charger with a current of 850mA will that cause big problems when I use it just accidentally to charge my device.

It probably wouldn't be a lot of problems, if you really have to do it, charge it when the screen is turned off, so that you will need less current.

 

[kilrah]

You can charge without risk with any USB charger. Unless the charger "signals" that it can supply more than 500mA by having the 2 USB data pins shorted, the HD2 won't pull more than 500mA, which is the minimum a USB charger must be able to supply.

 

[afropolak]

"Golden rule" - If You have 5V its safe for Your phone, current level is determining the time that You need to charge battery.

Kilrah sad that HD2 'pull' no more than 500 mA - ok, if this is true ( i believe it is , he always make some test for it ) original charger needs about 2h, with 250 mA charger it will take more than twice of that time - 4h ( it's not fully linear )

@Kilrah - did You test what's power ( current taken ) consumption during charging ? it's really only 500 mA ? if so, than why HTC use 1A charger ? usually safety rules are about 15 - 30% more than max current needed.
0.5 A + 30% = 0.65A , so why 1A ?

 

[regi7]

The minimum current what HD2 accepts is 500mA because this is the USB standart.
If the supply could deliver more than 500mA the HD2 will take it up to 1000mA. The maximum current which the HD2 can use is 1A (1000mA).
So if your charger can deliver 5V and 2000mA the HD2 will limit the current to 1000mA. So you can use a charger, when the voltage is 5V and the current at least 500mA.
The push pull principe in the post before is correct, because the charger is a voltage source and not a current source.

 

[PlayStation]

I am already enjoying the benefits of proposed standardisation of phone chargers to micro usb pin. Since I upgraded with HD2 from Nokia N97 I am using the nokia wall chargers as well as well as car charger. I didnt have to buy new charging accessories for this mighty HD2.

By the way would the Nokia data cables (micro usb) be able to sync data when used with HD2. Havent tried yet.....

 

[kilrah]

@Kilrah - did You test what's power ( current taken ) consumption during charging ? it's really only 500 mA ? if so, than why HTC use 1A charger ?

As said, IF the 2 USB data pins are NOT shorted (that's how it is by default on <500mA/3rd party chargers, or on a PC), the HD2 will limit the current it pulls to ~450mA.

IF they are shorted (on chargers that support higher current like the supplied one) the HD2 will pull more. With the supplied charger it's about 850mA, with a 3rd party "800mA" Chinese charger that didn't have the pins shorted but was modded to have it done, it pulls about 650mA.

By the way would the Nokia data cables (micro usb) be able to sync data when used with HD2. Havent tried yet.....

Micro USB is a standard, so every micro USB cable should be the same. If not, you've got a botched knockoff.

 

[cheahcl]

so how do you short the cable assuming I get a car charger without a USB to micro USB cable and sourced my own cable from a parts bin that was probably for computer usage?

 

[pa49]

so how do you short the cable assuming I get a car charger without a USB to micro USB cable and sourced my own cable from a parts bin that was probably for computer usage?

I don't think that would be a good move!
You would have to be certain of the regulation circuitry of the charger and it's ability to cope with the attendant initial draw of the battery when plugged in.
This will depend on the state of drain of the battery and the various functions in operation at the time on the phone.
At the moment of plugging in is when the draw will be highest and when any protection circuitry will be essential.
A well topped up battery will "draw" less than a depleted one and will continue charging on as little as 350mAh (again depending on what is running on the phone).
A very depleted battery may well not even start the charging process at such a level. That's why the HD2 comes with a 1000mAh wall charger!
The levels quoted for PC/Laptop USB power are nominal off load levels and will vary depending on any othe devices plugged in on the same bus supply.
So, with a PC that has a few attached USB devices, you may well NOT see 500mAh and as has been reported before, you can get battery depletion back into the USB port as other devices draw from the phone!
Always best to keep the battery topped up to prevent "charging strain" on the cells. This will maximise the capacity available when you need it for those longer periods of time.