Tablet charging has been a top priority here at Voltaic. With the release of our V60 battery and updates to V11 and V39 batteries, it’s time to bring you up to speed on the compatibility with the expanded range of tablets on the market.

This resource will serve to update our previous Tablet Charging Guide post, enabling you to quickly find your device and determine which of Voltaic’s solar charging systems will work with your device.

Here’s an updated look at tablet PCs and eReaders and which of Voltaic’s battery packs can charge them:

**older models of the V11 have 500mA outputs and will not charge the iPad or Nook devices

There are a few devices on here that require 12V, 15V, and 19V power supplies. These are voltages that our V11 and V39 batteries cannot provide, but despair not!  We’re very close to unveiling a system that will allow the charging of these devices.

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In addition to the panel, you’ll also need our Female 3.5×1.1 MiniUSB adapter to connect from the panel to the GoPro.

The advantage of this approach is that it is cheap and you don’t have to worry about waterproofing anything as the panels are waterproof and nearly indestructible. The downside is that you don’t have a battery reservoir so this solution only works in direct sunlight. If you have one of our solar chargers like the Fuse 4W, you can charge from the battery or direct from panels at your option.

Techy note: the Hero does have a blocking diode so a shaded panel won’t pull charge back from the Hero.

Here’s the video of the car cruising through our offices.

If you want to make your own solar-powered lego car, you’ll need:
-Lego parts, including gears to transfer power from the motor to the wheels
-Lego motor
-2 Watt solar panel

Here’s a few close-ups of the car:

We did a quick mod of the car to put in a female 3.5×1.1mm jack so that we could easily plug and unplug the panel from the motor. You can use our “USB Out Cable 3.5×1.1” if you want to avoid cutting the plug on our panel.

Go Legos! Wanna race?

Go here to see all of Voltaic’s rugged small solar panels.

We tested the Domke 414 ($57 from B&H) which fits firmly inside the Array and safely carries two DSLRs, multiple lenses and more. And there is still room for your MacBook in the back pocket. Overall, we liked how secure our gear felt inside this package. It is a robust and well-padded insert.

The Compact III from Cameroo ($23 on Amazon) is smaller, but fits well inside our backpacks. If you had less camera gear and wanted to store non-camera gear in your backpack, this could be the way to go.

Overall, we’re seeing lots of people pairing their Array or Fuse 10W purchase with a camera cradle, enabling them to charge their laptop and DSLR. Follow the link to learn more about solar camera charging.

“After over 2,000 miles of bumpy road, dirt, rain, mud, dust, sand, ocean water, sweat, and food spills, I have to say I’m very impressed.”

Here’s a guide to building a USB powered LED lamp compatible with Voltaic Systems products. This is a quick and easy way to convert the solar energy we’ve stored in our Voltaic Systems batteries into light. We’ve used ours when building some cables in low light conditions, but it could also be useful on a camping trip.

Note: As with all our DIY projects, try this project at your own risk. Voltaic Systems makes no guarantees against damage to the Voltaic battery or your LEDs. Use caution in your wiring.

Instructions: Solar Lamp

Parts List:
• 3x White LEDs
• 3x 8 ohm resistors **
• Electrical Wire ( we recommend 22AWG stranded)
• Craft Wire (we recommend 18 AWG)
• Shrink Tube
• USB male plug
• USB Battery Pack

Tools:
• Soldering Iron
• Pliers
• Wire Cutters
• Wire Stripper
• Heat Gun

There are two pins on each LED, one is the positive (+) pin or anode, and the other is the negative (-) pin or cathode.

Attach the resistors to the anode pins of the LEDs. Then cover the resistors and LED pins in shrink tube to prevent short circuits in the future.

Twist together and solder the resistor pins so that the common connection is in the middle of the three LEDs. Trim back excess pin material.

Solder a red wire (for positive connection) to the bundle of resistor pins and cover this connection with shrink tube.

Solder wires to the cathode pins of the LEDs. Then twist and solder the other end of these wires together. Solder a white wire (for a negative connection) to the bundle of LED cathode wires. Cover this joint with shrink tube as well.

Cut a length of craft wire.

Wrap one end of the craft wire around the LED assembly. Use shrink tube to keep the electrical wires fixed to the craft wire. Wrap the electrical wire around the craft wire.

We used a USB connector from one of our output wires. The red wire is connected to pin #1 of the USB plug, and the white wire is connected to pin #4. Connect the wires from the LEDs to the wires on the USB plug. Cover the connection in shrink tube. Wrap the craft wire around the USB plug and twist to lock into place. You may consider using an epoxy or other adhesive to make this connection if wrapping and twisting isn’t enough.

Finally, turn on the battery and connect the light!

Performance
For a small 3-LED lamp, it outputs quite a bit of light. The quality leaves a little to be desired (it is a very cool 7500K) and the output is too focused to be a general use lamp. It works really as a reading light and as a focused work light for detail work. The LED Lamp is designed to use 500mA at 5V or 2.5W. The V11 capacity is 11Wh, so you can expect this LED Lamp to run for about 3.5 hours before the V11 needs to be recharged.

** Calculating the Resistor Size
To calculate the resistor size we determined that we wanted to draw no more than 500mA from the V11. Because the LEDs are wired in parallel the total share of 500mA for each is about 167mA (500mA / 3). For our lamp design, each LED is its own circuit consisting of a 5V power supply, an LED and a resistor. Our power supply is limited to 5V and the LEDs require 3.7V to begin conducting fully, which leaves a 1.3V drop across the resistor (according to Kirchoff’s Voltage Law). Because the resistor is the element which limits the current flow in the system, we must calculate its minimum size given the voltage drop across it and the current restriction we set above. Using Ohm’s Law (V=IR), we can solve for Resistance (R) using Voltage (V) =1.3V and Current (I) =.167A. We get about 7.8 ohms (R=1.3V/.167A). The closest standard resistor value we had in our lab was 8 ohms, which is what we recommend for your project.

Increasing the resistance will make your lamp less bright. It is not recommended to reduce the resistance below 8 ohms. This may cause damage to the LEDs or any USB supply you connect your lamp to.

Once you have assembled the LED lamp cluster, try inserting different resistor values between the USB connector and the red wire leading to the LEDs. Using a switch, it is possible to choose between full brightness and a dimmer output.

The Kindle Fire, Amazon’s answer to the Barnes and Noble Nook Color, is a compact 7” color tablet device that occupies a middle ground between full fledged tablet PC and eReader. There are loads of product reviews out there, but chances are, if you’re reading this post, you have one thing on your mind: Can I charge it from solar?

The short answer is: YES!

Voltaic Systems full line of solar batteries will charge the Kindle Fire using the supplied cable (USB to Micro USB) with no problem. Here’s a breakdown of the kind of performance you can expect from the different battery systems:

V11 USB Battery
The battery size in the Kindle is about 16.3 Wh so while the V11 won’t top up your Kindle Fire, it will bring it up to just over 60%. The current V11 models have a max output of about 2.5Wh so expect the boost from 0% to 60% to take about 4.5 hours. We are developing a new version of the V11 that will offer faster charge rates.

V39 USB Battery
With the increased battery size of the V39, you expect to get over 2 full charges of the Kindle Fire from a fully charged V39. The Kindle Fire should be charged from the 2000mA high power USB port for the best results. Expect charge times of about 3 hours for a full 0% to 100% charge cycle; the Kindle Fire draws 1.4A at 5V for a total of 7W.

V60 Universal Laptop Battery
Fully charged, this high capacity laptop battery will hold 3.5 full charges of the Kindle Fire. Expect charge times from the USB port in the V60 of about 3 hours for a full 0% to 100% charge cycle.

Direct From Solar Charging
Kindle Fire is a fickle device when it comes to charging, however it’s not as picky as the iPad2: it is possible to charge the Kindle Fire direct from solar. The caveat here is that you can only “trickle charge” at a slower rate than if you were connected to the V11, V39, V60 or the power supply provided with the Kindle Fire. Our testing showed that the Kindle Fire would take roughly 14 hours to charge directly from our 4W system (Amp, Fuse 4W, Switch, Converter, OffGrid). At 5V, only 250mA (1.25W) was utilized by the Kindle Fire. So, though it really is best to charge the Kindle Fire from one of our batteries, in a pinch you can trickle charge it directly from solar from our 4W, 8W (Spark), 10W (Fuse 10W, Array) systems set to 6V.