AT&T came up with a USB charger that would have “zero” vampire draw in 2010.
I think it had a solid-state relay before the rectifier/transformer and a capacitor after, and when the capacitor was full, it’d open the relay.
Plug USB device into charger, capacitor discharges, relay closes, device charges.
Unplug USB device, capacitor reaches charge threshold, relay opens until USB device is plugged in or the measurement circuit discharges the capacitor beyond the trigger threshold.
I may still have one of them laying around somewhere.
v2.0 designed, sleep over it and see if any errors accured
updates:
Power bank stuff removed
+ TP5100 2A charge chip installed
added on battery side a solder pad to switch between 0.75 and 1.5A
added + and chrg and full pads for Charge light indication
+ AMCs can now individually added or removed by pads on the battery side 3 AMCs per channel fixed up to 7 can be unlocked by bridging the solder pads with solder blob
May I request that 0.75A charging be the default, to minimise the chance of crashing a small solar panel?
I’m sorry to see the powerbank function go, but I’m still planning to buy at least one of these. I’ll decide what to do next once I’ve been able to play with the first one
for first version Powerbank got removed installing a simple charge board, then the preassembled charge boards were too big to reflow them onto the driver,
so it went on it as parts at least so we can control the quality of the used parts
default will be 0.75A
from the space also 0.5A, 1A and 1.5A would fit with 2 solder areas and 3 shunts, but I think 2 are well enough
It may for the manufacturer, but as for me it’s costing me money to help get it developed, but i don’t care about making money in this case, i just want to develop & bring a good lantern to the market where such a needed good quality & well designed light has been unavailable up until now.
I guess this depends on where you are in the world. Here in the US, Mini-USB is nearly impossible to find anymore. Micro is widespread, and USB-C is quickly taking over. Within a few years C will have taken hold and micro will start to become harder to find.