iCare Blog

There are several ways to use smartphones during multiday outdoor or Scouting events with your smartphone and have it fully charged and available every day.

Recharging a phone overnight in the tent offers the most convenience.

I present some ways you can have access to your phone in the daytime and recharge it in your tent at night. It incorporates the use of a USB recharger.

It’s a battery that supplies a built-in USB port with the 5 volts of power needed to allow a smartphone to plug in and recharge.

For example the iPhone 5 has a 3.8V, 5.45 Wh battery that should offer 1440 mAH of capacity.  You will need much more than 1440 mAH to recharge that battery however.

Why is a higher capacity recharge battery needed?  Recharging using batteries solely is not a one to one transfer of energy.  All batteries give off heat during recharging.  This means a recharger must be able to supply more than the rated capacity of the battery undergoing a recharge.  A rating double your smartphones battery rating acts as recharge insurance to insure a full recharge.  It also helps to insure against the gradual capacity reduction that develops over time with rechargeable batteries.

I present a series of blog articles on recharging options.  I’ll start with the simplest and continue to renewable but more expensive solutions.

Gadget Recharging When You Have No 110V access

Smartphones and other gadgets offer convenient ways to capture images and video while out in the wild.  They often require overnight recharging that would use a 110 V line.  When these are not available we need another solution.

USB Port recharging

If your gadget can recharge through the use of a USB connector, you have options.  The symbol above is the USB symbol.  The connector that plugs into the power source looks like this.

USB rechargers

There are many USB rechargers that allow you to recharge your gadget.  The problem is that most of them require a 110V to recharge themselves.  An outdoor activity longer than one night requires a different solution.

Tekkeon MP1580 TEKCHARGE

The feature that allows this gadget to work is it uses replaceable AA batteries.  You should be able to buy these at the trading post.  For traditional weekend adventures, you can also use Nickel Metal Hydride (NiMH) rechargeable AA batteries.  To recharge them, just plug the Tekkeon into a traditional 110V to USB converter like what comes with your gadgets.  The MP1580 supplies a neat adapter cable that converts to different sizes of USB A, B mini and micro sizes.

The Minty Boost – A Build it Yourself Option

Building a recharger offers a neat and simple solution that can be more customized.  It offers an educational value for adult or youth in electronics building that wont be too intimidating. It also doubles the efficiency due to it’s circuit design.

In Boy Scouting this project can also complete up to 70 percent of the Electronics merit badge.

In Venturing, this may be considered useful towards the Arts & Hobbies bronze award & Outdoor bronze award (emergency preparedness).

The first component functions similar to how the Tekkeon Tekcharge mentioned elsewhere in my Jamboree power series but you get the fun of building it yourself.  Adafruit supplies all the parts that you solder onto a circuit board.  This design will fit into an Altoids tin that you supply or you can order one for $2.00.

Soldering takes about a half hour.  An AA battery holder comes with the kit.  You can substitute D or C cells for more recharges.  My tests reveal that a 9 day event like a Jamboree reduces the AA cell count of 48 down to 13 D Cells for complete recharges nightly with no power access at all.

You can substitute D cells for more capacity.  Do not place more than 3 together.  The circuit is designed only to handle an input voltage of 5 volts or less.  Each battery cell supplies 1.5 volts.

The recharger circuit produces some heat that can get hot which is expected.

Batteries recharging other batteries is inefficient.  There will be some energy loss due to resistance – up to one half of the energy will be lost to heat.

Costs

Minty Boost               $19.50
Altoids tin                   $2.00 (or free)
D cell holder               under $2.00 (AA cell holder supplied in Minty Boost kit)

You can get D-Cell holders from your local or online Radio Shack.  Jameco is another popular electronic component supplier.

2D battery holder   http://www.radioshack.com/product/index.jsp?productId=2062241

Jameco 2D battery holder  http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_216390_-1

Results

In testing, 2 AA batteries brought an iPhone 5 that was 95% discharged to about 75% recharge state.  This compares to 4 AA batteries using the Tekkeon MP150 Tekcharge.  It appears the Minty boost is twice more efficient.

D-Cell output with the Minty Boost

Testing underway – results to be edited here soon.

AA cells are rated to about 2850 mAH while a single D cell can output up to 15000 mAH.

On the surface it would appear that a single D cell could replace up to 5.26 AA cells – lets round that down to 5.

In testing however the D cell did not seem to offer this great a capacity.  An explanation here might involve the observation by Duracell that:

• The AA format offers the greatest energy density.
• Hi loads decrease efficiency with more energy lost to heat and resistance.

Source (http://media.duracell.com/media/en-US/pdf/gtcl/Technical_Bulletins/Alkaline Technical Bulletin.pdf)

This compounds my previous observation that batteries recharging other batteries is an inefficient process.

Advantages

• AA cells can be bought nearly everywhere worldwide.
• This solution requires no electricity access.
• Recharging successful independent of weather conditions.
• Works for general travel power needs as well.

Disadvantages

• A 9 day event like a National Scout Jamboree would require 48 AA cells.

If this seems wasteful, I would have to agree.  Not exactly conservation-minded is it?

Scouting embraces sustainability as we strive to be conservation minded.

This solution ends up being more expensive if you go to two of these multiday events due to the cost of disposable batteries.

I explore in another post a more sustainable solution using solar power and rechargeable options in my Part 2: Renewable and Sustainable Solar Ideas.

In part 1 of this series, I describe ideas on recharging USB rechargeable gadgets using a USB power port.  Section 1 deals with disposable batteries.

This section explores solar rechargeable options.

The workflow for this option involves setting out a solar panel to collect energy during the daytime storing the energy in a rechargeable batteries.  At night, you recharge your gadget using the power stored inside the solar-recharged battery.

This series offers build it yourself solutions to offer educational guidance about electronics projects.  For this section the complexity of the project increases compared to part 1’s Minty Boost project.  It’s still obtainable however for the do-it-yourself solution.  However it appears to cost a little more than a commercial product now available.

Commercial solar station option

Goal Zero Guide 10 Plus Adventure Kit (MRSP $159.95) (street price $105.00 +)

This may offer a workable solar solution.  Reviews show acceptable performance but I have not personally tested this device.  Get the Plus unit as it has more capacity than the standard unit for just a little extra cost.

The solar cells hook up to a 4 AA cell battery pack that seems to offer similar functions as the Tekkeon MP1580 Tekcharge.

The iPhone 5 has a 3.8V, 5.45 WH battery that should offer 1440 mAH of capacity. I recommend a rechargeable solar storage battery capacity twice that rated for your smartphone.   The Guide Plus seems to have that capacity.

However, since it uses 4 AA’s I worry that it may not be able to recharge a fully depleted smartphone if its battery unit behaves similar to the Tekkeon.

Recharging using batteries solely is not a one to one transfer of energy.  All batteries give off heat during recharging.  This means a recharger must be able to supply more than the rated capacity of the battery undergoing a recharge.  A rating double your smartphones battery rating acts as recharge insurance to insure a full recharge.  It also helps to insure against the gradual capacity reduction that develops over time with rechargeable batteries.

Jamboree Solar Minty Boost

This is a great build-it-yourself project that gives you a backpackable solar power solution for your smartphone or USB rechargeable gadget.

This project is a collection of two projects available from Adafruit.com.

Part one

First build the minty boost project.  Part one of my series covers this project.  It provides USB port power via disposable or rechargeable AA batteries.

From there…

Adafruit.com supplies solar components that can convert the energy of the sun into battery power.

The USB / DC / Solar Lithium Ion / Polymer charger is easy to assemble.

The circuit board is nearly complete with just a capacitor left to solder.  A solar cable connection and another cable connects the circuit board to a battery or your Minty Boost.

You can solder the capacitor so it’s straight up. I folded my over to keep a flatter profile in storage.

The circuit board has connectors that allow the attachment of (clockwise from top center): micro USB slot, solar panel, Load (leading to your minty boost) and a battery.

Three LED’s give information.  A red LED on the top left indicates if the solar panel has current incoming.  An amber LED between the two bottom connectors, closer to the battery outlet indicates charging status while a green LED adjacent to the Load for the Minty Boost indicates when charging is complete.

The battery I chose was a Lithium polymer 3.7V 6600 mAH – the largest.  Larger is better as well when it comes to solar panels.  The largest panel outputs 3.4 watts at 6 Volts.

Take your Minty Boost project and solder in the power connecter supplied in the solar kit to the Minty Boost power supply leads.

You will still be able to use your minty boost with disposable AA batteries.  I would not recommend attaching it to the circuit board as I haven’t tested to see if the circuit might drain the batteries in some way.

The usual configuration would be set up to store the collected solar energy in the Lithium polymer cell.  At night it recharges via the attached Minty Boost.  This allows you to use your smartphone during the day and recharge at night.  I should note that if the gadget can be attached directly during the daytime it would be more efficient to charge into the minty boost directly.  You lose the flexibility of using the smartphone so we store those converted photons into a battery.

The minty boost and a rechargeable separate battery can be attached simultaneously as shown in the illustration below.

The circuit sends priority current to the load (the minty boost).  When done the circuit then automatically switches to send the excess into the lithium polymer battery.  It’s smart and well designed this way.

Costs for the kits

Minty Boost Kit                                                                                                      $19.50
USB / DC / Solar   Lithium Ion /Polymer recharger                              $24.95
Medium 6 V 3.4 W solar panel                                                                         $25.00
Lithium Ion Polymer battery pack 3.7V / 6600 maH                            $39.50
                                                                                                                                      $123.45

Note that the recharger circuit produces some heat that can get hot which is expected.

Advantages versus the Goal Zero solar product.

Jamboree Solar Minty Boost may have advantages of:

• Better solar panels
• Lithium polymer battery versus NiMH storage
• A project useable for Scouting Advancement
  • Boy Scouting – Electronics merit badge
  • Venturing – Arts & Hobbies bronze award & Outdoor bronze award

Other Advantages

• The cost of disposables eventually outweighs the cost of either the Goal Zero of the Jamboree Solar Minty Boost after about 20 days of use.
• These offer a lightweight energy source for backpacking

Disadvantages

• Bright sunny days are required else little to no power is generated.  Packing disposable batteries as an emergency source of power may be needed.
• Make sure to pack the Lithium ion battery in carry-on luggage if flying due to FAA rules.

In part 3 of this series I explore a larger scale solar energy station idea that has much more capacity but will cost 3 to 4 times more.

I also explore a solution unique to the BSA’s National Scout Jamboree where recharging stations are present during daytime hours.

In part 2 of this series, I describe ideas on solar recharging USB rechargeable gadgets on a small scale, most economical basis.

If you are willing to invest $350 to $600 or more, you can upsize your solar power plant.  Larger panels offer more power.  Newer solar cell technologies offer more efficient energy production.

Solar Power Station

I used this design at the 2005 National Scout Jamboree.

A Brunton SolarRoll 14 ($300+) connects to a circuit overcharge protection / solar controller ($35).  The controller prevents overcharging of the battery when complete.  This panel can produce a maximum of 12V @ 14 watts over 10 hours (14 / 12) x 10 = 11.67 AH  It’s shown draped on the edge of a dining fly in this image.

I have an AGM gel-cell battery ($25) to store it’s output.  I chose the battery based on what I need for replacements with an uninterruptable power supply protecting my computers at home.  A typical gel cell has a capacity of 7.2 AH, 12V or more.

Size matters, the bigger the solar panel the more power you can generate.  The size comes at a greater $ cost, sometimes significantly $$$ greater.

Storage battery

If you use uninterruptable power supplies (UPS) at home I recommend you buy a battery that will also serve as a UPS replacement.  This allows you to eventually put the battery into service and keep one spare ready and in use as needed for your solar project.

Consider AGM gel cells if practical (source).  AGM stands for absorptive glass mat and are also known as valve-regulated lead-acid battery (VLRA), sealed battery or gel cells.  Regular addition of water is not needed.

Costs

Brunton Solar Roll 14                       $250
Recharge voltage controller          $  20
AGM Gel cell battery                         $  20

Commonly Available Technologies

Amorphous thin film is the usual technology used in panels that can be rolled up.  The efficiency of these panels is around 10.1 to 12.5 %.

CIGS (Copper Indium Gallium deSelenide) is another thin film technology with an increase efficiency to a range of 11 to 14% and are roughly double the cost of amorphous thin film.

Monocrystalline solar cells are in common use as well and come in panels with efficiencies ranging from 10.5 to 25% with most cells in between 18 to 24%

By using a 12V battery, you can use car charger style electronics to recharge your gadget.

Advantages

• Higher power production abilities
• Should be able to recharge multiple gadgets on sunny days.

Disadvantages

• Much higher investment costs
• AGM cells are heavy – too heavy for backpacking.  Lithium cell batteries may offer lightweight options but themselves add costs for large capacities.

Amateur Radio operators are frequent users of solar as well as other portable power sources. Images courtesy of Oscar Staudt (WB5GCX).

Multiple panels can be set up to collect more power.

Deep cycle batteries are designed to offer power over an extended period of time and can manage nearly full discharges and accept full recharges.  Standard automobile batteries on the other hand are designed to offer massive amounts of current / power in short discharges – necessary to start car engines but not ideal for extended use low current draws.  If you have ever experienced a dead battery while listening to the car radio during a weekend car cleanup, you’ve experienced the weakness that car batteries show when under a low current load over an extended period of time.

In part 4 of this series I explore a solution unique to the BSA’s National Scout Jamboree where recharging stations are present during daytime hours.

Recharge stations have appeared at National and World Jamborees.  Most smaller scout encampments may not offer this service.  Access to a electricity port in a restroom, cabin or building can serve this role too.

Most youth and adult participants will likely use a smartphone to take pictures and video during the jamboree. Jamboree planners assume this as well and have incorporated recharge stations located at each of the base camps.  Recharge stations are set up because these large events may host many tens of thousands of participants.

Recharging however takes several hours and you would like to use the device during the daytime.  Recharging a phone overnight in the tent offers the most convenience.

Here’s a way you can have access to your phone in the daytime and recharge it in your tent at night. It incorporates the use of a rechargeable USB recharger.

It’s a rechargeable battery that supplies a built-in USB port with the 5 volts of power needed to allow a smartphone to plug in and recharge.  The recharger battery itself requires a 110 V line to recharge later.

The workflow of the use of the battery is shown below.  After an overnight recharge cycle in your tent, drop off the USB rechargeable recharger battery to a recharge station located inside each base camp headquarters.  Bring it’s 110V adapter to plug it in.  Have fun and use your phone to take pictures and video.  Pick up the recharged USB charger battery and it’s adapter on your way back to your campsite.

I would recommend a capacity twice that rated for your smartphone.

For example the iPhone 5 has a 3.8V, 5.45 Wh battery that should offer 1440 mAH of capacity.  A 2880 mAH or more USB Rechargeable battery rating should have enough capacity to fully recharge a fully depleted phone battery.

Why is a higher capacity recharge battery needed.  Recharging using batteries solely is not a one to one transfer of energy.  All batteries give off heat during recharging.  This means a recharger must be able to supply more than the rated capacity of the battery undergoing a recharge.  A rating double your smartphones battery rating acts as recharge insurance to insure a full recharge.  It also helps to insure against the gradual capacity reduction that develops over time with rechargeable batteries.

A quick review of retail pricing shows many USB rechargeable chargers exist with 2500 mAH or greater capacities between $28 to $50.

Some manufacturers sell batteries designed to supplement notebook batteries for extended run times.  If these products offer USB ports then you have a large capacity multi-function battery.  One example is the HyperJuice product for Macbooks.

Advantages

• The cheapest solution that keeps your smartphone going while you get to use it during the day.
• Efficient use for general travel as well.

Disadvantages

• Present only at large encampments unless you have special access to a single 110V outlet somewhere.

UPDATE (April 2013)

Monoprice.com has introduced an external battery that is the  best value I’ve tested  among USB rechargeable rechargers.  It has a huge capacity at 9000 mAh for only $29.19.  Its called the External Battery Pack and Charger for  iPad®, iPhone®, iPod®, and other USB Mobile Devices (9000mAh).  In my tests, I was able to achieve the equivalent of 4 complete zero to 100% recharges on one battery charge.  It comes with a special cable with a USB type A to round earphone type plug to recharge it’s battery.  Connect it to a powered 5V USB port and expect a full night to 12 hours to recharge.

There are probably many more ideas that work just as well if not better than some of the ones presented in this series.  I invite you to explore your creativity in making a system that works for you.

About ready to fall apart, our first sign will be restored and mounted on our new office as additional signage.

One of the benefits of starting a practice is the opportunity to design your own sign.  We did just that in 1992.

Twenty years pass and now the sign shows it’s age.  In addition to weathering the sign was just too small for drive-by traffic to notice.  The fonts were too small, the color faded and the wood framing was falling apart.

Consider that a future potential patient probably has blurred vision, there was no way this sign could deliver it’s message. A new sign was needed.

I used 3D modeling software SketchUp originally developed by Google to create a 3D mockup of our vision for a new sign.  This tool allows one to visualize and easily change parameters and explore it’s shape, size and color from different perspectives.  In the design I worked to incorporate concepts involving the geometry of the golden rectangle and incorporated its ratio of 1:1.618 in the layout and dimensions of  many of its design elements.  This helped to create an aesthetic balance pleasing to the eye.

The design can be described as a monument sign –  a black slab onto which our lettering and graphics shine from 1/2″ acrylic graphics pushed through aluminum panels that make up the sides of the slab.  Monument signs are often built on the ground with a brickwork foundation supporting and surrounding it.  We wanted ours elevated to help it stand out.  We envisioned a grid like tower that was offset to visually pull the attention of the viewer towards it.

While creative in concept, this made for a more challenging engineering fabrication compared to most signs that use a simple pole mount placed in the center. I approached several sign makers in our area.  Metro Sign rose to the challenge.  Researching some of their work revealed they create custom signage without cornering their customers into a cookie cutter template.  The company president, Jess, appreciated the look of our design and focused his company’s talents to engineering a structure to make this concept a reality.

I took a look inside the sign when during it’s installation.  The inside was well thought out – engineered and fabricated with welded steel square tubing for strength against Oklahoma’s weather.  The tower welded with square tubing supports the sign with a gridwork of bracing leading down into a cemented base underground.

Inside an LED array of lights sit adjacent to each graphic element.  LED lighting is gaining ground as the reliable choice given its 20,000 hour life rating and incredible efficiency.  Power costs are estimated to be one-fourth or less when compared to traditional halogen or fluorescent lighting in a typical sign.

In the image below, I was amazed how our signmaker matched the sign design to our 3D mockup.

Practice management experts say that investing in one’s sign offers the quickest return on investment when compared to other forms of media exposure such as yellow pages, newspapers or billboards.

Our name is visible from a much further distance – an important asset for an optometrist.  Coupled with an easy to remember phone number a new patient has all they need to set up their appointment.

Sometimes one needs to lift up the footrest to allow best access to your exam chair for the disabled or elderly.  At the end of the exam some folks forget they are on a platform and risk a fall off the footrest as they get up.  So I’ll lift up the footrest for them to exit.

The trouble begins with the heel of their foot catching the back side of the footrest.  Theres a little ledge under the pivot bar that the heel can push.  The platform pivots forward so that if crash lands behind them in with a loud metallic clunk after the first step away.

I invented a fix that prevents this unwanted surprise.  The chairs we use are the Topcon OC-20T.

A Magnetic Solution

After experimentation I found that N40 magnets from a business called “MagnetMan” on Amazon creates the perfect blend of attraction without requiring too much force to disengage.  These are strong neodynium magnets and you will need to take caution with this size or larger.  Skin caught in between two magnets can cause a blood blister or a bruise due to the strong magnetic forces attracting to each other.

The footrest on my chair is attached by a wingnut.  The back side has slots to allow the upholstery seam to attach.

Slip a magnet into the wooden slot and continuing through the padding to reach the backside of the upholstery.

You can use another magnet to guide it to where it’s best.

After positioning the 2 chair magnets behind the upholstery, determining where to place the magnets for the footrest is easy.  They will self center.  Keeping the placement high like shown may offer the best leverage  for keeping the footrest in place when raised.

The footrest is made of aluminum so the magnets won’t stay by themselves when when the footrest is lowered.  A dab of double-sided sticky foam tape holds them in placed when deployed.

Their may still be some instances of “kerbangs” but my solution should prevent most of them now.