Author Topic: Auto retry  (Read 6855 times)

antennaboy

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Auto retry
« on: March 25, 2013, 04:01:30 pm »
Dear Forum,

the Suntactics solar charger has a cool feature: Auto-Retry port

"...The Auto-Retry port is one of the reasons the sCharger-12 works so well. The Auto-Retry will activate within 5 minutes of first being placed in the sun. Once activated there are a few good things that start happening to further optimize charging. If a momentary shadow appears like a cloud or even a person walking in front of the panel, some USB devices will give up charging and show 7 a warning message. They will often not restart when the sun is again available. Charging from the Auto-Retry port takes care of interruptions by doing a charger reset automatically. As long as the sCharger-12 sees sun, the USB device will continue to charge. Any messages that may have been displayed on the device will eventually disappear when the Auto-Retry kicks in. Also, if the sun becomes brighter because cloud haze disappears, the Auto-Retry will cause some more sophisticated USB devices to kick into a bulk charging state. Some devices may make a signal sound when in auto mode, this is normal and is a nice indicator that your phone is still charging and not to forget about it...."

Any idea how it does that? what is inside that USB?

thanks,
antennaboy

Jan Axelson

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Re: Auto retry
« Reply #1 on: March 27, 2013, 11:03:03 am »
Perhaps because devices limit the charging current due to the requirement to stay at or above VCHG_SHT_DWN, but they don't monitor to see if they can increase the current when the voltage rises. And a reset takes care of that. 

Battery charging spec:

http://www.usb.org/developers/devclass_docs