<-- An update to my own post 
- I came across this site describing exactly what I was looking for: Ravpower the ultimate UPS
I purchased the RAVPower 16,750mAh model from Amazon. It has 2 USB ports as shown. What I can say is that the 2.4A output does suffer from momentary power loss upon loss of commercial power. HOWEVER, the 2.1A output DOES NOT .... it stays ON and thus is an ideal "UPS" for the Pi (and other USB powered devices).
As Mark, G7LTT / NI2O pointed out previously, of course to be absolutely solid, you'd have to have your entire network on a UPS, etc. However, that's not my intention here. I just want to prevent the Pi from getting confused during power blips / minimize the chances of SD card corruption, etc., since this system is going to a remote location down in FL :).
Oh BTW - another tip - came across this power bar (a really inexpensive alternative to the IP-9255/9258 series):
Individual control of the AC outlets ... but the USB devices are ganged together, meaning that they are up or down - but the good thing is that you can cycle them (even if it does mean all at once). Of course, you can use a 120V / USB charger and plug it into an AC outlet for individual control too.
Cheers!
Ramesh, VA3UV
27919 / 29109
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On 2017-07-10 11:38 AM, Ramesh Dhami wrote:
Hi Folks:
Wonder if anyone has a lead on a USB Battery Bank that supports pass-through charging and does NOT interrupt the output voltage when there is loss of commercial power?
I'd like to use a battery bank on my remote node down in FL (renowned for electrical storms!), so keeping the Pi up during brown-outs and loss of commercial power is a big plus.
In case folks are interested - here is a link to a good article providing a review of various products:
http://www.theoutpost.org/6-techy/raspberry-pi-usb-power-bank-ups-pass-through/
Unfortunately, the leading contender, the product from RS Electronics (brings back memories of my "jollies" as an Apprentice heading up to Alum Rock in Birmingham
Anyone have a lead on such a product?
Thanks!