On 26 Dec, 20:12, "Dave Liquorice"
wrote:

USB (nominal 5v up to 500mA) is slowly creeping in as a defacto standard
on many things but frequently without the smarts that really should be
there for proper negotiation to get 500mA.

There's a (tiny) chipset for that.

I recently saw heated gloves with USB power connectors. Seems that off-
road cyclists are taking to these things as a simple power connector
for a few watts of lighting or heating.