Voltaic Systems V50 Always On External Battery Pack with Dual USB Ports - 12,800mAh

This is one of the view power banks that works as a UPS. You can plug and remove power to the side port without causing a raspberry pi it’s powering to reboot.Others claim this, but they all (nitecore, zendure, etc) have a blip. That’s probably because actual pass through requires a circuit path change. What you want are separate charge and power circuits like this unit has.It will charge at up to 10 watts. A new Pi will peak at 12, but average lower. So just enough on the pi4 I tested with.

If you are looking for an “always on” portable power source this is it. Other reviews touch on its purpose in solar or other scenarios. I purchased because I was looking for a portable power supply that didn’t require me to press “on” and merely drawing power by connecting a device would enable charging. This device does that. However, since it will always send a trickle of power if you don’t pair this battery with a solar panel or other continuous charge source it will discharge over the course of a week. This isn’t a design flaw. But if you are just trying to charge a phone it’s probably not the best power bank. That said, this tech is truly impressive. Pass thru charging. The ability to continuously trickle charge. The use of lithium ion instead of lithium polymer. This is engineered for a very specific purpose and I don’t think any other company is solving this. This takes IoT to new levels.

The always on feature is wonderful for charging things that don't take much current, like my FitBit watch. All the other power banks shut off at low charge rates. But the capacity is a bit small: would not fully charge my iPad, for example.If you need the always on feature for low charge rate devices, then this would be great, but for larger items, get something else.

I have a motion detector light in the hallway and since there is a lot of traffic I have to charge about every day. Regular power banks turn off when the light goes off and doesn’t turn on until you press the button to turn on as you know. With this it is constantly charging and I haven’t had to charge the battery for over a week so far and very little charge is depleted in the power bank. It is expensive so make sure you need this type of power bank. There appears no competition so that’s why it is expensive. All my other power banks are useless in this application. I intend to buy another one for sure.

I own a V20 and a V50. These packs are fantastic for my radio-related applications because they are 1) always on and 2) have overcharge protection.I use them to power unattended low power radio beacons (WSPR if you are interested). First, the "always on" feature is very important because the low power draw of the (0.2 watt) transmitters isn't enough to keep other Li-Ion battery banks operating (they turn themselves off). Second, the overcharge protection is great because I can semi-permanently hook the V20 / V50 up to a 20 watt solar panel (with a 5v buck transformer with USB output). One of my beacons has been operating (off-grid, of course) for 6 months now without any human intervention.For my sort of application - low power devices that are solar charged - the V20 / V50 saves me having to purchase a charge controller and lifepo battery. Using the V20/V50 is both cheaper and less bulky (and easier to fit and wire up in a weatherproof box).

We needed a power pack for the lights in our tent. It had to be always on even when the lights weren't working. This power bank works great. Is compact, hold enough charge for more than we need. Very simple to use, just plug in your device and its on! Easy to charge, great quality. Very happy with it.

I do stage video productions, and need my GoPro cameras to stay on for over 3 hours.. sometimes an entire day is needed. Usually there is A/C power nearby, but sometimes I'm mounting one in a suspended screen or middle of the room where there simply is no easy power access.Mistakingly I used a more typical external battery pack for one gig and lost half the show's footage as a result. As others have explained, typical battery packs shut off automatically when they sense your device is fully charged. Now imagine you're shooting a show -- and the GoPro fully charges.. and your battery pack shuts off as a result.. then the GoPro battery dies. Done.. no footage.. WAH!This battery pack works as advertised -- on = on. So if you're powering a device with it, that device will keep being powered (like being plugged into a wall receptacle. 5 Stars because it works exactly as expected, and holds a long charge.I agree with other reviewers -- it'd be nice to have a better indicator showing that the *always on* mode is indeed active.3/15/19 UPDATE -- love the battery still .. just purchased a second!

Lasted one year....very little use. Wont charge beyond 25%. Used less than 5 times, always kept in controlled environment.