USB power bank as RPI supply/UPS

[ghervasze]

Hi. From what I understand, battery power is the "cleanest" of all means to power up a RPI. I know there are tutorials on how to use a powerbank as a RPI UPS involving the Ethernet port power drop. But this solution only (battery) powers it during a blackout.

How about this: Take one (fully charged) decent USB powerbank (maybe with a charge remainder display) and plug it to the RPI power port. Take one programmable power socket and plug the power bank charge port into that. Now figure out a program for the socket to power on and charge the powerbank before it gets depleated. Say once a week, the socket will stay on for one (or two) hour at night. This is based on the size of the powerbank and on how often the RPI is used. Of course one can't predict accurately for how long or how often the box is going to be used but I don't think charging the powerbank more often than needed will damage it that bad. Besides, I think a good powerbank has some kind of management of its own to avoid overcharging.

So do you think this would work? It's a really simple solution and your RPI would be both powered up from a quality source and be protected.

[silvrr]

Your solution will work just fine. Don't get to caught up in how often a battery is charged, the issues with charging frequently and not fully power cycling a battery are not really a concern any more.

You stated that battery power is the cleanest. Some things to think about are that the battery power my be relatively clean but that power is going into a number of circuits before reaching your Pi. Depending on the power bank design this could be better or worse than wall power.

I think that I remember seeing that the Apple iPad charger has pretty good performance on noise and ripple. IIRC there are a few other readily available chargers with good performance.

If you do go with the battery option make sure you get one with a decent amperage on the output. I used one I had for awhile and it would freeze the pi now and then when the power draw got to high. Most chargers rated for a tablet or 1-2 amps should be good.

[ghervasze]

Hey, silvrr. Thanks for the input. Sounds good, then (pun intended). I am going for this solution because it would implicitly double as a UPS, power in my area being rather unstable (frequent brownouts). I thought just the same - that power cycling/over charging is not anymore an issue. So I'm going for this. I am getting a solid, high current powerbank so a larger draw will not be an issue. See you around.