A question about USB chargers.

Avoriaz

Hi, I have an old Motorola RAZR3 phone and a newish Pure One mi DAB radio.

Each has a mains charger with a small USB plug on the end of a cable.

The Motorola charger outputs 5.0 volts and is rated up to 550 mA. The battery is 3.7 volts Li-Ion 680 mAh.

The Pure charger outputs 5.0 volts and is rated up to 800 mA. The battery is 3.7 volts Li-Ion 2,200 mAh.

According to Pure's specs, the radio uses 1.54 watts when active. I can’t find a figure for the phone, but presumably it is a less as it is not decoding DAB or powering more than a tiny speaker. Or maybe not, I don't know.

The Motorola charger will recharge both devices, although I have only connected it to the Pure radio for a few seconds in case it tries to draw too much power and damages the charger. The radio was switched off so the power draw would have been to recharge the battery only.

The Pure charger will recharge the Pure radio but it won't recharge the Motorola phone. When I connect it, the phone keyboards lights up, so it is “seeing” it, but the battery charging symbol and words don’t appear. The phone battery is not fully charged as it recharges from the phone charger.

I’m going on holiday and taking the phone, the Pure radio and a few other USB powered devices. I’d like to just take one charger with me rather than have to bring two or more chargers.

1) Any suggestions why the Pure charger will not recharge the Motorola phone battery?

2) If I use the 550 rated Motorola to charge the Pure radio, might that overload the charger and damage it or worse?

The Pure Charger is marked Pin 1 + Pin 5 – which I assume are the standard small USB power pins.

The Motorola charger isn’t marked with which Pin is which.

Thanks

almillar

USB devices generally take what they want, to prevent overloading. They can be fussy about chargers, and will only take full power (and charge faster) from their own charger. Not much you can do about these 2 specific devices, but no worries about overloading a device.

Splott

The important thing with some phones such as Blackberry isn't the USB charger but the cable itself. I have a cig lighter USB charge socket. If I try to charge my sons Blackberry with the Samsung USB cable it won't play but it will with the Blackberry one even though they're both plugging in the same cig lighter to usb adapter.

If the Motorola charger does both, take that.

Lifeforms

If each has their own lead, then I'd suggest buying a universal typed usb charger and work with that, with their own leads (with several usb items). But obviously before you go, make sure it'll charge each one. My preferred is a slightly bulky charger here. But out of a couple it's the only one I've found to charge by my ipad 2/ipad mini, as well as the regular phones, and my small mp3 player on top. 2 sockets, and a surge protected plug so you could potentially charge 3 in one go. Works ok with a travel adaptor as well.

If the Motorola does both, as said above, you could just take that one.

DavidFx

Some devices use the voltage superimposed on the USB data lines on the USB charger to determine the current available.
These are USB charging ports as defined in the USB Battery Charging Specification of 2007.
If the charger doesn't support this and the device requires it then it will not charge. Sometimes shorting the data lines together can fool the device being charged.
see wikipedia - universal serial bus and scroll down to Charging ports and accessory charging adapters

john1

Something to be aware of
Depending where you are holidaying the DAB side may not work as UK version of One Mi only supports DAB not DAB+/DMB-Radio which some other countries use.


FM should be OK though.


Apparently Pure will not pay the extra licence fees for DAB+/DBM-Radio software for UK purchased radios as we only use DAB.




see http://www.pure.com/product/one-mi-vl-61410/#Specifications

Avoriaz

Thanks for all the replies. Very helpful. :beer:

DavidFx wrote: »

Some devices use the voltage superimposed on the USB data lines on the USB charger to determine the current available.
These are USB charging ports as defined in the USB Battery Charging Specification of 2007.
If the charger doesn't support this and the device requires it then it will not charge. Sometimes shorting the data lines together can fool the device being charged.
see wikipedia - universal serial bus and scroll down toCharging ports and accessory charging adapters

That would explain my situation.

I'll read that Wiki article.

Thanks.

Lifeforms

john1 wrote: »

Something to be aware of
Depending where you are holidaying the DAB side may not work as UK version of One Mi only supports DAB not DAB+/DMB-Radio which some other countries use.

Good point, my mum had to have her DAB radio "adjusted" to work over in France, but it worked brilliantly, and she was happy enough for French radio. idk what was done, or how.