The need to charge medical devices is just a fact of life for those of us living with diabetes; there's no way around it.
Our glucose meters, insulin pumps, CGMs (continuous glucose monitors) and even phone apps are constantly in use, and these days ever more D-Devices are moving away from traditional batteries to the kind that use a USB connector or plug-in adapter to recharge.
But what if you're not in a spot where you have access to a wall charger or computer-integrated USB port? There may be an answer in solar-charging straight from the sun. No kidding!
With rechargeable portable devices becoming more common in healthcare, there's also been a wave of new solar charging options coming out. One example is Intel's "smart bowl" concept that you could toss your smartphone, car keys and potentially even D-devices into and it would charge them. How cool would that be?!
Curious about just how easy it might be to use a solar charger to juice up common D-Devices, fellow PWD Terry Keelan in California went out and bought one of these retail chargers to give it a whirl. And stretching his talents beyond cartoon illustration to the writing world, Terry offered to share his observations with us here:
Scenario 1: You've been camping for three days and your Dexcom screeches at you that its battery is low. You are miles away from an electric outlet.
Scenario 2: The power has been out for three hours and the power company says that it may be out for another 24. Your t:slim insulin pump buzzes and the screen reports that its battery has just 10% charge left.
Scenario 3: It's the zombie apocalypse...
These are the things that keep me awake at night now that my diabetes gadgets -- a t:slim pump and Dexcom CGM -- use rechargeable instead of replaceable batteries.
I also have a rechargeable meter, the Verio IQ, but I don't use it for the simple reason that it doesn't have replaceable batteries. The fact is that replaceable vs. rechargeable batteries were not part of the equation when I chose my pump or CGM. I go back and forth on the relative convenience and practicality of replaceable vs. rechargeable, but rechargeable is the path I've taken. That means I need to look into recharging options in the event I'm off the grid, whether by choice or by accident.
After some online research at outdoorgearlab.com and about half an hour staring at the solar chargers at REI, I bought a Bushnell PowerSync Solarwrap Mini. Two reasons for this choice: its compact size and its $60 price that's less than most chargers that start closer to $100.
This PowerSync is a cylindrical battery case about the size of two C batteries and a flexible solar panel 18 inches long and 4 inches wide. The panel wraps around the battery when not in use and is kept in place with a velcro strip and a pair of connected end caps.
At one end is an input port through which you can charge the battery by attaching it to a computer with the included USB cable. Also at this end is a single LED light which glows red when the battery is charging and green when the battery is fully charged. At the other end of the cylinder is the output port, a USB outlet to which you connect whatever device you want to recharge, as long as it uses a USB cable.
After arriving home with my new toy I took a quick glance at the manual, unrolled the solar panel and came to a sad realization: it was nighttime. The manual said I could charge the battery in 4 hours by connecting it to my computer but what is the purpose of buying a solar charger if you're not going to charge it by the sun? I cursed the darkness and waited for daylight.
At sunrise I hung the PowerSync from our lemon tree in the backyard where it would get full sun all day and went about the business of draining power from my rechargeable devices. In other words, I did nothing. At the end of 10 hours the green light was ON, indicating a full charge. My t:slim was down to 35%, my Verio was at 0% and my Dexcom was somewhere on top of my bureau.
First thing was to charge the t:slim by attaching it via USB cable to the output end of the PowerSync. The t:slim chirped as it always does when plugged in and the charging indicator appeared. A good sign.
One advantage of recharging from a battery, I discovered, is mobility. Recharging requires one to be tethered to a wall outlet or a computer, in the case of a pump. In the case of the Dexcom, there's about a 20-foot range of movement. That's all fine if you recharge at night while sleeping, but if you recharge during the day, you're stuck near your power source for the duration. Not so with the PowerSync solar recharger. I put both in my pocket and moved around wherever I wanted.
Within 45 minutes the pump was fully charged. I couldn't tell how much charge was left in the PowerSync battery, but the manual told me that a fully charged battery can recharge one cell phone (or 2 MP3 players OR 2.5 digital cameras OR 1.5 digital gaming devices). I figured there must be more juice in it since it had only recharged .65 insulin pumps. So I attached the Verio meter. I could have attached my Dexcom, but I just didn't think of it. The Verio was fully recharged within an hour. Which brings me back to that red/green light.
Nonetheless, I had an answer to the primary question: can you recharge an insulin pump/blood glucose meter/CGM from a solar charger? The answer is "yes."
But. What if it actually WERE the zombie apocalypse or, more likely, I had neglected to fully charge the PowerSync before leaving on my camping trip? Could I use the solar panel to recharge the battery AND another device? Or could I recharge a device directly from the solar panel?
Sadly, no. At least not with the PowerSync. I connected my fully discharged Dexcom to the battery, unrolled the solar panel and left both in the sun. (I covered the Dexcom with a towel.) Two hours later the Dexcom was still uncharged. This meant that, contrary to my hopes, solar energy did not enter INTO the panels, go THROUGH the battery and CHARGE my Dexcom. I don't even know if the PowerSync battery was actually getting a charge, come to think of it.
There are, or course, other solar chargers on the market which cost more money and offer more options. Some can recharge multiple devices at once. Some have cigarette lighter adapters so they can recharge in a vehicle. Some have standard electrical outputs, bigger batteries, expansion batteries, or expansion solar panels. But they all work on the same basic premise. They take power from the sun, convert it into electricity and store it in a battery. The battery in turn recharges your essential electrical devices.
The PowerSync is a workable option if you enjoy a moderate amount of outdoor activity or occasionally spend more than a day or two away from electrical outlets. It's also a fair backup system for emergencies. It's lightweight and compact. It recharges one device quickly and you might get by with two in a pinch. But the 10-hour recharge period would require some patience if you have multiple devices -- you'll have to prioritize. The fact that you can't tell how much charge is left is an annoying drawback, but it's not like you're paying top dollar; it's one of the least expensive chargers on the market. So going forward, it's going to be an essential tool in my emergency preparedness -- as long as I remember to recharge it.
Thanks Terry, for this great insight on "alternative energy" in the D-world!