Most helpful critical review
18 of 21 people found the following review helpful
One defective, one unimpressive
on April 20, 2013
We got a free one as part of supporting a local radio station. In this case we got what we paid for. It worked once, charging an iPhone from 95% to 100%. Since then it goes dead within seconds of plugging in a phone, and letting it bake in the sun for a day just causes it to report it's fully charged - to go dead again seconds after anything is plugged in.
A nice idea, and it would have been useful on mission trips to Haiti where power is frequently hard to come by. But the implementation is a disaster.
We got a replacement unit, and this one didn't die the first day we used it. So I tried some experiments.
First, I charged it in the sun for a half day, and it showed some blue on the indicator bar. so I plugged in my iPhone. The iPhone battery began to drop, fairly quickly. Frustrated, I disconnected the iPhone and plugged the juicebar into my laptop, to charge it that way. After a few hours the bar went solid blue, and I plugged the iPhone back again.
Now the iPhone began to charge.
Apparently, the juicebar compares its internal battery to whatever it's plugged into, and decides whether it should charge itself up, or charge the other device, based on that. In other words if its internal battery is low and you plug it into a mostly-charged iPhone, it's going to assume you want it to drain the iPhone to charge its own battery. Consequence: forget using the juicebar to "top off" a mostly charged iPhone. You'll drain power instead.
Looking at the specs, this is a 2000 mAh battery and a 100 mAh solar cell (some apparently are rated at 80mAh). Even in a perfect world, it would take 20 hours of noonday sun to charge up the juicebar. 20 hours of bright sunlight being hard to come by in a day, this means that if you want a purely solar solution, you probably need to let the juicebar sit in the sun for 4 days, and maybe longer, to get it full. Then you can use it to charge a few devices, but once the juicebar starts to get low, it may start draining power instead.
I suspect the device would be fine in an Arizona summer. I live in Massachusetts. I doubt the juicebar is going to provide a complete charging solution. I kill an iPhone battery in a typical day of use.
Yes, you can fill the juicebar from your laptop. That goes quickly. But it's not efficient to charge a juicebar to charge an device; it wastes less power to just charge the device directly. The only way the juicebar is a win is if it charges from free sunlight, and see above.
I'm hoping this will be a better solution on trips to Haiti, which has plenty of bright sun and (where I go) unreliable power. In Massachusetts, my combination of heavy phone use and cloudy days means I'll continue to be tethered to charging from laptops, some amount of the time. And given how cheap it is to charge an iPhone, it would take a LOOONG time for this device to pay for itself on solar power.
Amusing idea, but in terms of ideal implementation, this is no titanium spork. Improvements: add a switch that tells the juicebar whether to charge, or be charged, from the USB port. Put a better battery indicator on it. Make it larger so a bigger solar cell can be added, or give it a fold out solar cell.