Does anyone know of a USB power bank, capacity not particullary important, that has Solar charging and will not turn off when the current drawn (by the device its powering) drops to the 10uA region ?
I would like to use one to power a ESP32 based board I have been working on, the intention is that the board will be put into deep sleep for hours or days at a time, clearly a USB powerbank that turns itself off will not work.
Consider the Adafruit LiPo solar charger and any suitable LiPo battery. It has worked well for me. Sparkfun has a similar offering.
Both are for single cells, so you would need a boost regulator for 5V.
Powerbanks have a boost converter that steps up battery voltage to a constant 5volt.
That boost converter will use way more than 10uA when you keep it alive.
Maybe a LiFePOâ‚„ battery could be used directly (no experience).
Leo..
Its a complete packaged Solar USB powerbank I was looking for, not separate boards, or indeed batteries.
I am aware that the boost converter in a powerbank will likley have a much higher standby current than 10uA. How much power is drained by the powerbank overnight, or in dim daylight conditions, is something that only testing can determine.
However the main issue, that I am sure the forum is aware of, is that most of these powerbanks turn themselves off when they think they are not being used, hence the question.
They turn themselves off BECAUSE of the idle drain of the boost converter.
A typical small 5volt boost converter has ~1mA idle current.
Leo..
Wawa:
They turn themselves off BECAUSE of the idle drain of the boost converter.
A typical small 5volt boost converter has ~1mA idle current.
Leo..
Yes, but I have seen comment that there are some (non-solar) that can be forced on.
Another consideration is that you will possibly need this unit to be able to charge its battery while at the same time powering the project. Not many usb power banks can do this, I have a few and none can charge and discharge at the same time and they all power off under low load current.