Some USB chargers won't charge nearly depleated battery

[KeepItSimpleStupid]

I have a vintage antique cell phone which desperately needs replacing.

Some chargers won't charge it at all. They are usually a high current port.
Others won't charge it when the battery is depleted.
Unfortunately, they are the car chargers.
I think the 120/12V charger works fine.
A hub port works fine.
It's a mini USB port.

Any ideas?

 

[Ian Rogers]

We had this on an Iphone 4s I was told to place the phone in my grill for a few minutes until it was warm.... To my surprise it started charging..
The heat on the battery gave enough charge to get usb going..

 

[Ian Rogers]

vintage antique cell phone

I have just re read that.... How old!! Antique.... Jesus what does that make me..

 

[KeepItSimpleStupid]

June 2010: https://en.wikipedia.org/wiki/Motorola_Backflip

I was told to place the phone in my grill for a few minutes until it was warm....

I had to bake the Formatter PCB in the oven for my HP P2015dn laser printer.

 

[rjenkinsgb]

A hub port works fine.
It's a mini USB port.

"Mini USB" devices have a five pin connector, four for standard USB power and signals and a 5th pin for a resistor to ground(?) which allows the device to identify its matching cable.

A lot of rechargeable devices that use Mini USB just will not work with any random cable, you have to find one with that resistor in the correct range that the device expects, for it to work normally.


The cable itself is also critical for any device expecting high current; many cheap USB cables use very thin wires and have high resistance, which means devices detect undervoltage as soon as they start to draw any significant current.

Try the shortest, thickest cable you can find - ones sold for use with portable hard drives are usually OK, they are intended for relatively high loads. But, it may still have a mismatch on the programming resistor.

Micro USB cables also have the cable detect resistor facility, but they seem a lot less critical between devices.

This article covers the same Mini USB power problem with a Garmin GPS:

How to: Decoding mini and micro-USB cables' identity resistor with a Garmin GPS | POI Factory

www.poi-factory.com

 

[shortbus=]

Others won't charge it when the battery is depleted.

You wouldn't like modern "smart" car battery chargers then. They have feed back from the battery that won't let them output any voltage unless there is a certain voltage already in the battery. I'd be willing to bet it is similar in the cell charger.